Android MVVM框架搭建（七）Permission、AlertDialog、拍照和相册选取

/**

• 版本升级迁移到5 在用户表中新增一个avatar字段

*/

static final Migration MIGRATION_4_5 = new Migration(4, 5) {

@Override

public void migrate(@NonNull @NotNull SupportSQLiteDatabase database) {

//User表中新增avatar字段

database.execSQL(“ALTER TABLE user ADD COLUMN avatar TEXT”);

}

};

这表示我在User表中增加一个avatar字段，然后我们添加迁移

再把数据库版本改成5。

这样，数据库的升级迁移就完成了。

二、数据操作

---

UserRepository中的代码也需要更新，在里面增加如下代码：

private static volatile UserRepository mInstance;

public static UserRepository getInstance() {

if (mInstance == null) {

synchronized (UserRepository.class) {

if (mInstance == null) {

mInstance = new UserRepository();

}

}

}

return mInstance;

}

这一篇文章中将会涉及到HomeActivity中的页面数据交互，因此，我们需要一个HomeViewModel，在viewmodels包下创建它，里面的代码如下：

public class HomeViewModel extends BaseViewModel {

public LiveData user;

public String defaultName = “初学者-Study”;

public String defaultIntroduction = “Android | Java”;

public void getUser() {

user = UserRepository.getInstance().getUser();

}

public void updateUser(User user) {

UserRepository.getInstance().updateUser(user);

failed = UserRepository.getInstance().failed;

getUser();

}

}

这里我放置了两个默认值，因为在注册的时候，昵称和简介是可以不用填写的，所以在显示的时候如果没有填就显示这个默认值，如果是Kotlin的话就直接使用缺省值就好了，这两个默认值会在xml中用到的。同时这个HomeViewModel里面有一个获取用户信息和修改用户信息的方法，当我们登录成功进入的HomeActivity时是获取，当修改用户信息的时候是更新，这很好理解。这一步说清楚之后下面就要做新的操作了。

二、自定义Dialog

---

下面要定义一个dialog，用于App中使用，在view包下新建一个dialog包，包下新建一个DialogViewHelper类，里面的代码如下：

① DialogViewHelper

public class DialogViewHelper {

private View mContentView;

private SparseArray<WeakReference> mViews;

public DialogViewHelper(Context context, int layoutResId) {

this();

mContentView = LayoutInflater.from(context).inflate(layoutResId, null);

}

public DialogViewHelper() {

mViews = new SparseArray<>();

}

public void setText(int viewId, CharSequence text) {

TextView tv = getView(viewId);

if (tv != null) {

tv.setText(text);

}

}

public T getView(int viewId) {

WeakReference weakReference = mViews.get(viewId);

View view = null;

if (weakReference != null) {

view = weakReference.get();

}

if (view == null) {

view = mContentView.findViewById(viewId);

if (view != null) {

mViews.put(viewId, new WeakReference<>(view));

}

}

return (T) view;

}

public void setOnClickListener(int viewId, View.OnClickListener onClickListener) {

View view = getView(viewId);

if (view != null) {

view.setOnClickListener(onClickListener);

}

}

public void setIcon(int viewId, int resId) {

ImageView iv = getView(viewId);

if (iv != null) {

iv.setImageResource(resId);

}

}

public void setContentView(View contentView) {

mContentView = contentView;

}

public View getContentView() {

return mContentView;

}

}

② AlertController

同样在dialog包下新建一个AlertController类，代码如下：

public class AlertController {

private AlertDialog mAlertDialog;

private Window mWindow;

private DialogViewHelper mViewHelper;

public AlertController(AlertDialog alertDialog, Window window) {

mAlertDialog = alertDialog;

mWindow = window;

}

public void setDialogViewHelper(DialogViewHelper dialogViewHelper) {

mViewHelper = dialogViewHelper;

}

public void setText(int viewId, CharSequence text) {

mViewHelper.setText(viewId, text);

}

public void setIcon(int viewId, int resId) {

mViewHelper.setIcon(viewId, resId);

}

public T getView(int viewId) {

return mViewHelper.getView(viewId);

}

public void setOnClickListener(int viewId, View.OnClickListener onClickListener) {

mViewHelper.setOnClickListener(viewId, onClickListener);

}

public AlertDialog getDialog() {

return mAlertDialog;

}

public Window getWindow() {

return mWindow;

}

//-------------------------------------------------------------------------------------------------

public static class AlertParams {

public Context mContext;

//对话框主题背景

public int mThemeResId;

public boolean mCancelable;

public DialogInterface.OnCancelListener mOnCancelListener;

public DialogInterface.OnDismissListener mOnDismissListener;

public DialogInterface.OnKeyListener mOnKeyListener;

//文本颜色

public SparseArray mTextColorArray = new SparseArray<>();

//存放文本的更改

public SparseArray mTextArray = new SparseArray<>();

//存放点击事件

public SparseArray<View.OnClickListener> mClickArray = new SparseArray<>();

//存放长按点击事件

public SparseArray<View.OnLongClickListener> mLondClickArray = new SparseArray<>();

//存放对话框图标

public SparseArray mIconArray = new SparseArray<>();

//存放对话框图片

public SparseArray mBitmapArray = new SparseArray<>();

//对话框布局资源id

public int mLayoutResId;

//对话框的view

public View mView;

//对话框宽度

public int mWidth;

//对话框高度

public int mHeight;

//对话框垂直外边距

public int mHeightMargin;

//对话框横向外边距

public int mWidthMargin;

//动画

public int mAnimation;

//对话框显示位置

public int mGravity = Gravity.CENTER;

public AlertParams(Context context, int themeResId) {

mContext = context;

mThemeResId = themeResId;

}

public void apply(AlertController alert) {

//设置对话框布局

DialogViewHelper dialogViewHelper = null;

if (mLayoutResId != 0) {

dialogViewHelper = new DialogViewHelper(mContext, mLayoutResId);

}

if (mView != null) {

dialogViewHelper = new DialogViewHelper();

dialogViewHelper.setContentView(mView);

}

if (dialogViewHelper == null) {

throw new IllegalArgumentException(“please set layout”);

}

//将对话框布局设置到对话框

alert.getDialog().setContentView(dialogViewHelper.getContentView());

//设置DialogViewHelper辅助类

alert.setDialogViewHelper(dialogViewHelper);

//设置文本

for (int i = 0; i < mTextArray.size(); i++) {

alert.setText(mTextArray.keyAt(i), mTextArray.valueAt(i));

}

//设置图标

for (int i = 0; i < mIconArray.size(); i++) {

alert.setIcon(mIconArray.keyAt(i), mIconArray.valueAt(i));

}

//设置点击

for (int i = 0; i < mClickArray.size(); i++) {

alert.setOnClickListener(mClickArray.keyAt(i), mClickArray.valueAt(i));

}

//配置自定义效果，底部弹出，宽高，动画，全屏

Window window = alert.getWindow();

window.setGravity(mGravity);//显示位置

if (mAnimation != 0) {

window.setWindowAnimations(mAnimation);//设置动画

}

//设置宽高

WindowManager.LayoutParams params = window.getAttributes();

params.width = mWidth;

params.height = mHeight;

params.verticalMargin = mHeightMargin;

params.horizontalMargin = mWidthMargin;

window.setAttributes(params);

}

}

}

下面自定义Dialog

③ AlertDialog

在dialog包下新建一个AlertDialog，里面的代码如下：

public class AlertDialog extends Dialog {

private AlertController mAlert;

public AlertDialog(@NonNull Context context, @StyleRes int themeResId) {

super(context, themeResId);

mAlert = new AlertController(this, getWindow());

}

public void setText(int viewId, CharSequence text) {

mAlert.setText(viewId, text);

}

public T getView(int viewId) {

return mAlert.getView(viewId);

}

public void setOnClickListener(int viewId, View.OnClickListener onClickListener) {

mAlert.setOnClickListener(viewId, onClickListener);

}

//----------------------------------------------------------------------------------------------

public static class Builder {

private final AlertController.AlertParams P;

public Builder(Context context) {

this(context, R.style.dialog);

}

public Builder(Context context, int themeResId) {

P = new AlertController.AlertParams(context, themeResId);

}

/**

• 设置对话框布局

• @param view

• @return

*/

public Builder setContentView(View view) {

P.mView = view;

P.mLayoutResId = 0;

return this;

}

/**

• @param layoutId

• @return

*/

public Builder setContentView(int layoutId) {

P.mView = null;

P.mLayoutResId = layoutId;

return this;

}

/**

• 设置文本

• @param viewId

• @param text

• @return

*/

public Builder setText(int viewId, CharSequence text) {

P.mTextArray.put(viewId, text);

return this;

}

/**

• 设置文本颜色

• @param viewId

• @param color

• @return

*/

public Builder setTextColor(int viewId, int color) {

P.mTextColorArray.put(viewId, color);

return this;

}

/**

• 设置图标

• @param iconId

• @return

*/

public Builder setIcon(int iconId, int resId) {

P.mIconArray.put(iconId, resId);

return this;

}

/**

• 设置图片

• @param viewId

• @return

*/

public Builder setBitmap(int viewId, Bitmap bitmap) {

P.mBitmapArray.put(viewId, bitmap);

return this;

}

/**

• 设置对话框宽度占满屏幕

• @return

*/

public Builder fullWidth() {

P.mWidth = ViewGroup.LayoutParams.MATCH_PARENT;

return this;

}

/**

• 对话框底部弹出

• @param isAnimation

• @return

*/

public Builder fromBottom(boolean isAnimation) {

if (isAnimation) {

P.mAnimation = R.style.dialog_from_bottom_anim;

}

P.mGravity = Gravity.BOTTOM;

return this;

}

/**

• 对话框右部弹出

• @param isAnimation

• @return

*/

public Builder fromRight(boolean isAnimation) {

if (isAnimation) {

P.mAnimation = R.style.dialog_scale_anim;

}

P.mGravity = Gravity.RIGHT;

return this;

}

/**

• 设置对话框宽高

• @param width

• @param heigth

• @return

*/

public Builder setWidthAndHeight(int width, int heigth) {

P.mWidth = width;

P.mHeight = heigth;

return this;

}

/**

• 设置对话框宽高

• @param width

• @param heigth

• @return

*/

public Builder setWidthAndHeightMargin(int width, int heigth, int heightMargin, int widthMargin) {

P.mWidth = width;

P.mHeight = heigth;

P.mHeightMargin = heightMargin;

P.mWidthMargin = widthMargin;

return this;

}

/**

• 添加默认动画

• @return

*/

public Builder addDefaultAnimation() {

P.mAnimation = R.style.dialog_scale_anim;

return this;

}

/**

• 设置动画

• @param styleAnimation

• @return

*/

public Builder setAnimation(int styleAnimation) {

P.mAnimation = styleAnimation;

return this;

}

/**

• 设置点击事件

• @param viewId

• @param onClickListener

• @return

*/

public Builder setOnClickListener(int viewId, View.OnClickListener onClickListener) {

P.mClickArray.put(viewId, onClickListener);

return this;

}

public Builder setOnLongClickListener(int viewId, View.OnLongClickListener onLongClickListener) {

P.mLondClickArray.put(viewId, onLongClickListener);

return this;

}

/**

• Sets whether the dialog is cancelable or not. Default is true.

• @return This Builder object to allow for chaining of calls to set methods

*/

public Builder setCancelable(boolean cancelable) {

P.mCancelable = cancelable;

return this;

}

public Builder setOnCancelListener(OnCancelListener onCancelListener) {

P.mOnCancelListener = onCancelListener;

return this;

}

public Builder setOnDismissListener(OnDismissListener onDismissListener) {

P.mOnDismissListener = onDismissListener;

return this;

}

public Builder setOnKeyListener(OnKeyListener onKeyListener) {

P.mOnKeyListener = onKeyListener;

return this;

}

public AlertDialog create() {

// Context has already been wrapped with the appropriate theme.

final AlertDialog dialog = new AlertDialog(P.mContext, P.mThemeResId);

P.apply(dialog.mAlert);

dialog.setCancelable(P.mCancelable);

if (P.mCancelable) {

dialog.setCanceledOnTouchOutside(true);

}

dialog.setOnCancelListener(P.mOnCancelListener);

dialog.setOnDismissListener(P.mOnDismissListener);

if (P.mOnKeyListener != null) {

dialog.setOnKeyListener(P.mOnKeyListener);

}

return dialog;

}

public AlertDialog show() {

final AlertDialog dialog = create();

dialog.show();

return dialog;

}

}

}

④ 样式

在设置弹窗的样式和弹窗出现的方式，在themes.xml下新增如下代码：

这里还用到动画样式文件，在res文件夹下新建一个anim文件夹，里面定义了7个xml文件，如下所示：

新建dialog_from_bottom_anim_in.xml，代码如下：

<?xml version="1.0" encoding="utf-8"?>

<translate

android:duration=“400”

android:fromXDelta=“0”

android:fromYDelta=“1000”

android:toXDelta=“0”

android:toYDelta=“0” />

dialog_from_bottom_anim_out.xml，代码如下：

<?xml version="1.0" encoding="utf-8"?>

<translate

android:duration=“400”

android:fromXDelta=“0”

android:fromYDelta=“0”

android:toXDelta=“0”

android:toYDelta=“1000” />

dialog_from_top_anim_in.xml，代码如下：

<?xml version="1.0" encoding="utf-8"?>

<translate

android:duration=“1000”

android:fromYDelta=“-100%”

android:toYDelta=“0” />

dialog_from_top_anim_out.xml，代码如下：

<?xml version="1.0" encoding="utf-8"?>

<translate

android:duration=“1000”

android:fromYDelta=“0”

android:toYDelta=“-100%” />

dialog_scale_anim_in.xml，代码如下：

<?xml version="1.0" encoding="utf-8"?>

<scale

android:duration=“135”

android:fromXScale=“0.8”

android:fromYScale=“0.8”

android:pivotX=“50%”

android:pivotY=“50%”

android:toXScale=“1.05”

android:toYScale=“1.05” />

<scale

android:duration=“105”

android:fromXScale=“1.05”

android:fromYScale=“1.05”

android:pivotX=“50%”

android:pivotY=“50%”

android:startOffset=“135”

android:toXScale=“0.95”

android:toYScale=“0.95” />

<scale

android:duration=“60”

android:fromXScale=“0.95”

android:fromYScale=“0.95”

android:pivotX=“50%”

android:pivotY=“50%”

android:startOffset=“240”

android:toXScale=“1.0”

android:toYScale=“1.0” />

<alpha

android:duration=“90”

android:fromAlpha=“0.0”

android:interpolator=“@android:anim/accelerate_interpolator”

android:toAlpha=“1.0” />

dialog_scale_anim_out.xml，代码如下：

<?xml version="1.0" encoding="utf-8"?>

<scale

android:duration=“150”

android:fromXScale=“1.0”

android:fromYScale=“1.0”

android:pivotX=“50%”

android:pivotY=“50%”

android:toXScale=“0.6”

android:toYScale=“0.6” />

<alpha

android:duration=“150”

android:fromAlpha=“1.0”

android:interpolator=“@android:anim/accelerate_interpolator”

android:toAlpha=“0.0” />

loading_animation.xml，代码如下：

<?xml version="1.0" encoding="utf-8"?>

<rotate

android:interpolator=“@android:anim/linear_interpolator”

android:pivotX=“50%”

android:pivotY=“50%”

android:fromDegrees=“0”

android:toDegrees=“+360”

android:duration=“1500”

android:startOffset=“-1”

android:repeatMode=“restart”

android:repeatCount=“-1”/>

这里还有一个shape_bg_white_radius_6.xml样式，在drawable中创建，里面的代码如下：

<?xml version="1.0" encoding="utf-8"?>

同样再创建一个shape_bg_white_radius_12.xml，代码如下：

<?xml version="1.0" encoding="utf-8"?>

还有一个shape_bg_white_radius_24.xml，代码如下：

<?xml version="1.0" encoding="utf-8"?>

⑤ 布局

在本文章将会创建三个弹窗布局，一个用于表示加载状态，一个用于表示修改用户信息，最后一个用于输入信息。

在layout下新建一个dialog_edit.xml，代码如下：

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout

android:layout_width=“300dp”

android:layout_height=“wrap_content”

android:background=“@drawable/shape_bg_white_radius_12”>

<TextView

android:id=“@+id/tv_title”

android:layout_width=“match_parent”

android:layout_height=“wrap_content”

android:gravity=“center”

android:padding=“12dp”

android:text=“标题”

android:textSize=“16sp” />

<androidx.appcompat.widget.AppCompatEditText

android:id=“@+id/et_content”

android:layout_width=“match_parent”

android:layout_height=“wrap_content”

android:layout_below=“@+id/tv_title”

android:layout_margin=“12dp”

android:maxLength=“18”

android:singleLine=“true”

android:textSize=“@dimen/sp_14” />

<View

android:id=“@+id/v_line”

android:layout_width=“match_parent”

android:layout_height=“1dp”

android:layout_below=“@+id/et_content”

android:background=“@color/line” />

<TextView

android:id=“@+id/tv_cancel”

android:layout_width=“150dp”

android:layout_height=“50dp”

android:textSize=“@dimen/sp_14”

android:layout_below=“@+id/v_line”

android:foreground=“?attr/selectableItemBackground”

android:gravity=“center”

android:text=“取消” />

<View

android:layout_width=“1dp”

android:layout_height=“50dp”

android:layout_below=“@+id/v_line”

android:layout_centerHorizontal=“true”

android:background=“@color/line” />

<TextView

android:id=“@+id/tv_sure”

android:layout_width=“150dp”

android:layout_height=“50dp”

android:textColor=“@color/purple_500”

android:layout_below=“@+id/v_line”

android:textSize=“@dimen/sp_14”

android:layout_toEndOf=“@+id/tv_cancel”

android:foreground=“?attr/selectableItemBackground”

android:gravity=“center”

android:text=“确定” />

在layout下新建一个dialog_loading.xml，代码如下：

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android=“http://schemas.android.com/apk/res/android”

android:id=“@+id/dialog_view”

android:orientation=“vertical”

android:layout_width=“120dp”

android:layout_height=“120dp”

android:gravity=“center”

android:padding=“10dp”>

<ImageView

android:id=“@+id/iv_loading”

android:layout_width=“40dp”

android:layout_height=“40dp”

android:src=“@mipmap/ic_loading” />

<TextView

android:id=“@+id/tv_loading_tx”

android:layout_width=“wrap_content”

android:layout_height=“wrap_content”

android:layout_marginTop=“10dp”

android:maxLines=“1”

android:text=“Loading…”

android:textColor=“@color/purple_500”

android:textSize=“14sp” />

这里有一个图标

放在mipmap下。

最后在layout下新建一个dialog_modify_user_info.xml，里面的代码如下：

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout

android:layout_width=“330dp”

android:layout_height=“wrap_content”

android:background=“@drawable/shape_bg_white_radius_24”

android:orientation=“vertical”>

<TextView

android:layout_width=“match_parent”

android:layout_height=“wrap_content”

android:gravity=“center”

android:padding=“12dp”

android:text=“修改用户信息”

android:textColor=“@color/purple_500”

android:textSize=“16sp” />

<View

android:layout_width=“match_parent”

android:layout_height=“1dp”

android:background=“@color/line” />

<TextView

android:id=“@+id/tv_modify_avatar”

android:layout_width=“match_parent”

android:layout_height=“wrap_content”

android:foreground=“?selectableItemBackground”

android:gravity=“center”

android:padding=“12dp”

android:text=“修改头像”

android:textColor=“@color/black”

android:textSize=“16sp” />

<LinearLayout

android:id=“@+id/lay_modify_avatar”

android:layout_width=“match_parent”

android:layout_height=“wrap_content”

android:orientation=“vertical”

android:visibility=“gone”>

<TextView

android:id=“@+id/tv_album_selection”

android:layout_width=“match_parent”

android:layout_height=“wrap_content”

android:background=“@color/line”

android:foreground=“?selectableItemBackground”

android:gravity=“center”

android:padding=“12dp”

android:text=“相册选择”

android:textColor=“@color/black”

android:textSize=“16sp” />

<TextView

android:id=“@+id/tv_camera_photo”

android:layout_width=“match_parent”

android:layout_height=“wrap_content”

android:background=“@color/line”

android:foreground=“?selectableItemBackground”

android:gravity=“center”

android:padding=“12dp”

android:text=“相机拍照”

android:textColor=“@color/black”

android:textSize=“16sp” />

<View

android:layout_width=“match_parent”

android:layout_height=“0.5dp”

android:background=“@color/line” />

<TextView

android:id=“@+id/tv_modify_nickname”

android:layout_width=“match_parent”

android:layout_height=“wrap_content”

android:foreground=“?selectableItemBackground”

android:gravity=“center”

android:padding=“12dp”

android:text=“修改昵称”

android:textColor=“@color/black”

android:textSize=“16sp” />

<View

android:layout_width=“match_parent”

android:layout_height=“0.5dp”

android:background=“@color/line” />

<TextView

android:id=“@+id/tv_modify_Introduction”

android:layout_width=“match_parent”

android:layout_height=“wrap_content”

android:foreground=“?selectableItemBackground”

android:gravity=“center”

android:padding=“12dp”

android:text=“修改简介”

android:textColor=“@color/black”

android:textSize=“16sp” />

<View

android:layout_width=“match_parent”

android:layout_height=“0.5dp”

android:background=“@color/line” />

<TextView

android:id=“@+id/tv_close”

android:layout_width=“match_parent”

android:layout_height=“wrap_content”

android:gravity=“center”

android:padding=“12dp”

android:text=“关闭”

android:textColor=“@color/purple_500”

android:textSize=“16sp” />

这里的准备工作就都做好了，后面会用到，先不着急，然后在BaseActivity中增加一个加载弹窗，

private LoadingDialog loadingDialog;

/**

• 显示加载弹窗

*/

protected void showLoading() {

loadingDialog = new LoadingDialog(this);

loadingDialog.show();

}

/**

• 显示加载弹窗

• @param isClose true 则点击其他区域弹窗关闭， false 不关闭。

*/

protected void showLoading(boolean isClose) {

loadingDialog = new LoadingDialog(this, isClose);

loadingDialog.show();

}

/**

• 隐藏加载弹窗

*/

protected void dismissLoading() {

if (loadingDialog != null) {

loadingDialog.dismiss();

}

}

这样在Activity中就可以直接使用，显示加载弹窗，隐藏加载弹窗。

三、权限请求

---

权限在Android上是一个麻烦但是又不得不做的事情，如果你要是还是Android6.0以下的手机就可以不用管这些，但是很可惜现在都是Android10，11了，因此我们还需要做兼容。

① 权限配置

因为要用到文件读写和相机，所以就需要在AndroidManifest.xml中增加如下代码：

<uses-permission

android:name=“android.permission.WRITE_EXTERNAL_STORAGE”

tools:ignore=“ScopedStorage” />

<uses-permission

android:name=“android.permission.MANAGE_EXTERNAL_STORAGE”

tools:ignore=“ScopedStorage” />

这还没有完的，在Android10.0上要访问文件，需要在application比前中添加

android:requestLegacyExternalStorage=“true”

如下图所示：

同事我们还需要兼容Android7.0，在xml文件夹下新建一个file_paths.xml，里面的代码如下：

<?xml version="1.0" encoding="utf-8"?>

<external-files-path

name=“images”

path=“Pictures” />

然后我们在AndroidManifest.xml中配置它，代码如下：

<provider

android:name=“androidx.core.content.FileProvider”

android:authorities=“${applicationId}.fileprovider”

android:exported=“false”

android:grantUriPermissions=“true”>

<meta-data

android:name=“android.support.FILE_PROVIDER_PATHS”

android:resource=“@xml/file_paths” />

添加位置如下：

② 权限工具类

我这里可以自己写一个工具类，当然也可以用第三方框架，在utils包下新建一个PermissionUtils类，里面的代码如下：

public class PermissionUtils {

private static PermissionUtils mInstance;

public static final String READ_EXTERNAL_STORAGE = Manifest.permission.READ_EXTERNAL_STORAGE;

public static final String WRITE_EXTERNAL_STORAGE = Manifest.permission.WRITE_EXTERNAL_STORAGE;

public static final String CAMERA = Manifest.permission.CAMERA;

public static final int REQUEST_STORAGE_CODE = 1001;

public static final int REQUEST_CAMERA_CODE = 1002;

public static final int REQUEST_MANAGE_EXTERNAL_STORAGE_CODE = 1000;

public static PermissionUtils getInstance() {

if (mInstance == null) {

synchronized (PermissionUtils.class) {

if (mInstance == null) {

mInstance = new PermissionUtils();

}

}

}

return mInstance;

}

/**

• 检查是有拥有某权限

• @param permission 权限名称

• @return true 有 false 没有

*/

public static boolean hasPermission(Activity activity, String permission) {

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {

return activity.checkSelfPermission(permission) == PackageManager.PERMISSION_GRANTED;

} else {

return true;

}

}

/**

• 通过权限名称获取请求码

• @param permissionName 权限名称

• @return requestCode 权限请求码

*/

private static int getPermissionRequestCode(String permissionName) {

int requestCode;

switch (permissionName) {

case READ_EXTERNAL_STORAGE:

case WRITE_EXTERNAL_STORAGE:

requestCode = REQUEST_STORAGE_CODE;

break;

case CAMERA:

requestCode = REQUEST_CAMERA_CODE;

break;

default:

requestCode = 1000;

break;

}

return requestCode;

}

/**

• 请求权限

• @param permission 权限名称

*/

public static void requestPermission(Activity activity, String permission) {

int requestCode = getPermissionRequestCode(permission);

//请求此权限

ActivityCompat.requestPermissions(activity, new String[]{permission}, requestCode);

}

}

然后因为权限请求是Activity有关系，那么我们可以在BaseActivity中再封装一层，

/**

• 打开相册请求码

*/

protected static final int SELECT_PHOTO_CODE = 2000;

/**

• 打开相机请求码

*/

protected static final int TAKE_PHOTO_CODE = 2001;

添加两个请求吗，因为打开相机和相册都需要跳转到系统的页面，还需要获取返回的数据，这里我就提前定义好，然后在onCreate中对PermissionUtils进行初始化。

在BaseActivity中添加如下代码：

/**

• 当前是否在Android11.0及以上

*/

protected boolean isAndroid11() {

return Build.VERSION.SDK_INT >= Build.VERSION_CODES.R;

}

/**

• 当前是否在Android10.0及以上

*/

protected boolean isAndroid10() {

return Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q;

}

/**

• 当前是否在Android7.0及以上

*/

protected boolean isAndroid7() {

return Build.VERSION.SDK_INT >= Build.VERSION_CODES.N;

}

/**

• 当前是否在Android6.0及以上

*/

protected boolean isAndroid6() {

return Build.VERSION.SDK_INT >= Build.VERSION_CODES.M;

}

protected boolean isStorageManager() {

return Environment.isExternalStorageManager();

}

protected boolean hasPermission(String permissionName) {

return PermissionUtils.hasPermission(this, permissionName);

}

protected void requestPermission(String permissionName) {

PermissionUtils.requestPermission(this, permissionName);

}

/**

• 请求外部存储管理 Android11版本时获取文件读写权限时调用

*/

protected void requestManageExternalStorage() {

Intent intent = new Intent(Settings.ACTION_MANAGE_APP_ALL_FILES_ACCESS_PERMISSION);

intent.setData(Uri.parse(“package:” + getPackageName()));

startActivityForResult(intent, PermissionUtils.REQUEST_MANAGE_EXTERNAL_STORAGE_CODE);

}

定义了一些需要用到的方法。下面进行DataBinding使用，弹窗中怎么获取DataBinding。

四、DataBinding

---

首先在activity_home.xml中添加 , 代码如下：

<variable

name=“homeViewModel”

type=“com.llw.mvvm.viewmodels.HomeViewModel” />

然后修改主页面的头像数据DataBinding，代码如下：

<com.llw.mvvm.view.CustomImageView

android:id=“@+id/iv_avatar”

localUrl=“@{homeViewModel.user.avatar}”

android:layout_width=“36dp”

android:layout_height=“36dp”

android:padding=“0.5dp”

android:scaleType=“centerCrop”

android:src=“@drawable/logo”

app:shapeAppearanceOverlay=“@style/circleImageStyle”

app:strokeColor=“@color/white”

app:strokeWidth=“1dp” />

这里的localUrl需要我们再去CustomImageView类中定义，在CustomImageView中添加如下代码：

private static final RequestOptions OPTIONS_LOCAL = new RequestOptions()

.placeholder(R.drawable.logo)//图片加载出来前，显示的图片

.fallback(R.drawable.logo) //url为空的时候,显示的图片

.error(R.mipmap.ic_loading_failed)//图片加载失败后，显示的图片

.diskCacheStrategy(DiskCacheStrategy.NONE)//不做磁盘缓存

.skipMemoryCache(true);

@BindingAdapter(value = {“localUrl”}, requireAll = false)

public static void setLocalUrl(ImageView imageView, String url) {

Glide.with(BaseApplication.getContext()).load(url).apply(OPTIONS_LOCAL).into(imageView);

}

然后就是在nav_header.xml中绑定DataBinding，里面的代码如下：

<?xml version="1.0" encoding="utf-8"?>

<layout xmlns:android=“http://schemas.android.com/apk/res/android”

xmlns:app=“http://schemas.android.com/apk/res-auto”>

<variable

name=“homeViewModel”

type=“com.llw.mvvm.viewmodels.HomeViewModel” />

<LinearLayout

android:layout_width=“match_parent”

android:layout_height=“wrap_content”

android:orientation=“vertical”>

<RelativeLayout

android:id=“@+id/lay_user_info”

android:layout_width=“match_parent”

android:layout_height=“120dp”

android:background=“@color/purple_500”>

<com.llw.mvvm.view.CustomImageView

android:id=“@+id/iv_avatar”

localUrl=“@{homeViewModel.user.avatar}”

android:layout_width=“80dp”

android:layout_height=“80dp”

android:layout_centerVertical=“true”

android:layout_marginStart=“24dp”

android:layout_marginEnd=“24dp”

android:padding=“1dp”

android:scaleType=“centerCrop”

android:src=“@drawable/logo”

app:shapeAppearanceOverlay=“@style/circleImageStyle”

app:strokeColor=“@color/white”

app:strokeWidth=“2dp” />

<TextView

android:id=“@+id/tv_name”

android:layout_width=“wrap_content”

android:layout_height=“wrap_content”

android:layout_alignTop=“@+id/iv_avatar”

android:layout_marginTop=“16dp”

android:layout_toEndOf=“@+id/iv_avatar”

android:text=“@{homeViewModel.user.nickname ?? homeViewModel.defaultName}”

android:textColor=“#FFF”

android:textSize=“16sp” />

<TextView

android:id=“@+id/tv_tip”

android:layout_width=“wrap_content”

android:layout_height=“wrap_content”

android:layout_below=“@+id/tv_name”

android:layout_marginTop=“8dp”

android:layout_toEndOf=“@+id/iv_avatar”

android:text=“@{homeViewModel.user.introduction ?? homeViewModel.defaultIntroduction}”

android:textColor=“#FFF”

android:textSize=“14sp” />

这里面的这一行代码需要说一下

homeViewModel.user.nickname ?? homeViewModel.defaultName

这一行代码就等同于

homeViewModel.user.nickname != null ? homeViewModel.user.nickname : homeViewModel.defaultName

这个defaultName是我前面设置的默认值，因为注册时可能不会填写昵称和简介。这里要让这个默认值起作用，在保存用户信息的使用。这里需要修改注册页面中的默认值，从之前的空字符串改成null，这样在xml中的判断值才会有作用，同时及时你的值为null，在xml中也不会报错，这是DataBinding做了处理，类似于Kotlin中的空安全。

这里的DataBinding主要实现两个功能，第一个是HomeActivity的标题栏头像能够根据用户修改图片变化而变化，没有修改则使用默认的头像，第二个就是NavigationView中的head_layout也是通过用户手动去修改昵称、简介、头像时发生变化。

五、工具类

---

很快就要进入主要内容了，在代码中我们经常会用到一些工具类，比如dp转px，时间处理、Bitmp处理，相机图片处理，鉴于在后面我将会用到这些工具类，现在就给贴出来。这里的工具类都放在utils包下面，新建SizeUtils类，代码如下：

public final class SizeUtils {

private SizeUtils() {

throw new UnsupportedOperationException(“u can’t instantiate me…”);

}

/**

• Value of dp to value of px.

• @param dpValue The value of dp.

• @return value of px

*/

public static int dp2px(Context context, final float dpValue) {

final float scale = context.getApplicationContext().getResources().getDisplayMetrics().density;

return (int) (dpValue * scale + 0.5f);

}

/**

• Value of px to value of dp.

• @param pxValue The value of px.

• @return value of dp

*/

public static int px2dp(Context context, final float pxValue) {

final float scale = context.getApplicationContext().getResources().getDisplayMetrics().density;

return (int) (pxValue / scale + 0.5f);

}

/**

• Value of sp to value of px.

• @param spValue The value of sp.

• @return value of px

*/

public static int sp2px(Context context, final float spValue) {

final float fontScale = context.getApplicationContext().getResources().getDisplayMetrics().scaledDensity;

return (int) (spValue * fontScale + 0.5f);

}

/**

• Value of px to value of sp.

• @param pxValue The value of px.

• @return value of sp

*/

public static int px2sp(Context context, final float pxValue) {

final float fontScale = context.getApplicationContext().getResources().getDisplayMetrics().scaledDensity;

return (int) (pxValue / fontScale + 0.5f);

}

/**

• Converts an unpacked complex data value holding a dimension to its final floating

• point value. The two parameters unit and value

• are as in {@link TypedValue#TYPE_DIMENSION}.

• @param value The value to apply the unit to.

• @param unit The unit to convert from.

• @return The complex floating point value multiplied by the appropriate

• metrics depending on its unit.

*/

public static float applyDimension(Context context, final float value, final int unit) {

DisplayMetrics metrics = context.getApplicationContext().getResources().getDisplayMetrics();

switch (unit) {

case TypedValue.COMPLEX_UNIT_PX:

return value;

case TypedValue.COMPLEX_UNIT_DIP:

return value * metrics.density;

case TypedValue.COMPLEX_UNIT_SP:

return value * metrics.scaledDensity;

case TypedValue.COMPLEX_UNIT_PT:

return value * metrics.xdpi * (1.0f / 72);

case TypedValue.COMPLEX_UNIT_IN:

return value * metrics.xdpi;

case TypedValue.COMPLEX_UNIT_MM:

return value * metrics.xdpi * (1.0f / 25.4f);

}

return 0;

}

/**

• Force get the size of view.

• e.g.

• SizeUtils.forceGetViewSize(view, new SizeUtils.onGetSizeListener() {

• Override
  

• public void onGetSize(final View view) {
  

•     view.getWidth();
  

• }
  

• });

• @param view The view.

• @param listener The get size listener.

*/

public static void forceGetViewSize(final View view, final onGetSizeListener listener) {

view.post(new Runnable() {

@Override

public void run() {

if (listener != null) {

listener.onGetSize(view);

}

}

});

}

/**

• Return the width of view.

• @param view The view.

• @return the width of view

*/

public static int getMeasuredWidth(final View view) {

return measureView(view)[0];

}

/**

• Return the height of view.

• @param view The view.

• @return the height of view

*/

public static int getMeasuredHeight(final View view) {

return measureView(view)[1];

}

/**

• Measure the view.

• @param view The view.

• @return arr[0]: view’s width, arr[1]: view’s height

*/

public static int[] measureView(final View view) {

ViewGroup.LayoutParams lp = view.getLayoutParams();

if (lp == null) {

lp = new ViewGroup.LayoutParams(

ViewGroup.LayoutParams.MATCH_PARENT,

ViewGroup.LayoutParams.WRAP_CONTENT

);

}

int widthSpec = ViewGroup.getChildMeasureSpec(0, 0, lp.width);

int lpHeight = lp.height;

int heightSpec;

if (lpHeight > 0) {

heightSpec = View.MeasureSpec.makeMeasureSpec(lpHeight, View.MeasureSpec.EXACTLY);

} else {

heightSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);

}

view.measure(widthSpec, heightSpec);

return new int[]{view.getMeasuredWidth(), view.getMeasuredHeight()};

}

public interface onGetSizeListener {

void onGetSize(View view);

}

}

EasyDate类，代码如下：

public final class EasyDate {

public static final String STANDARD_TIME = “yyyy-MM-dd HH:mm:ss”;

public static final String FULL_TIME = “yyyy-MM-dd HH:mm:ss.SSS”;

public static final String YEAR_MONTH_DAY = “yyyy-MM-dd”;

public static final String YEAR_MONTH_DAY_CN = “yyyy年MM月dd号”;

public static final String HOUR_MINUTE_SECOND = “HH:mm:ss”;

public static final String HOUR_MINUTE_SECOND_CN = “HH时mm分ss秒”;

public static final String YEAR = “yyyy”;

public static final String MONTH = “MM”;

public static final String DAY = “dd”;

public static final String HOUR = “HH”;

public static final String MINUTE = “mm”;

public static final String SECOND = “ss”;

public static final String MILLISECOND = “SSS”;

public static final String YESTERDAY = “昨天”;

public static final String TODAY = “今天”;

public static final String TOMORROW = “明天”;

public static final String SUNDAY = “星期日”;

public static final String MONDAY = “星期一”;

public static final String TUESDAY = “星期二”;

public static final String WEDNESDAY = “星期三”;

public static final String THURSDAY = “星期四”;

public static final String FRIDAY = “星期五”;

public static final String SATURDAY = “星期六”;

public static final String[] weekDays = {SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY};

/**

• 获取标准时间

• @return 例如 2021-07-01 10:35:53

*/

public static String getDateTime() {

return new SimpleDateFormat(STANDARD_TIME, Locale.CHINESE).format(new Date());

}

/**

• 获取完整时间

• @return 例如 2021-07-01 10:37:00.748

*/

public static String getFullDateTime() {

return new SimpleDateFormat(FULL_TIME, Locale.CHINESE).format(new Date());

}

/**

• 获取年月日(今天)

• @return 例如 2021-07-01

*/

public static String getTheYearMonthAndDay() {

return new SimpleDateFormat(YEAR_MONTH_DAY, Locale.CHINESE).format(new Date());

}

/**

• 获取年月日

• @return 例如 2021年07月01号

*/

public static String getTheYearMonthAndDayCn() {

return new SimpleDateFormat(YEAR_MONTH_DAY_CN, Locale.CHINESE).format(new Date());

}

/**

• 获取年月日

• @param delimiter 分隔符

• @return 例如 2021年07月01号

*/

public static String getTheYearMonthAndDayDelimiter(CharSequence delimiter) {

return new SimpleDateFormat(YEAR + delimiter + MONTH + delimiter + DAY, Locale.CHINESE).format(new Date());

}

/**

• 获取时分秒

• @return 例如 10:38:25

*/

public static String getHoursMinutesAndSeconds() {

return new SimpleDateFormat(HOUR_MINUTE_SECOND, Locale.CHINESE).format(new Date());

}

/**

• 获取时分秒

• @return 例如 10时38分50秒

*/

public static String getHoursMinutesAndSecondsCn() {

return new SimpleDateFormat(HOUR_MINUTE_SECOND_CN, Locale.CHINESE).format(new Date());

}

/**

• 获取时分秒

• @param delimiter 分隔符

• @return 例如 2021/07/01

*/

public static String getHoursMinutesAndSecondsDelimiter(CharSequence delimiter) {

return new SimpleDateFormat(HOUR + delimiter + MINUTE + delimiter + SECOND, Locale.CHINESE).format(new Date());

}

/**

• 获取年

• @return 例如 2021

*/

public static String getYear() {

return new SimpleDateFormat(YEAR, Locale.CHINESE).format(new Date());

}

/**

• 获取月

• @return 例如 07

*/

public static String getMonth() {

return new SimpleDateFormat(MONTH, Locale.CHINESE).format(new Date());

}

/**

• 获取天

• @return 例如 01

*/

public static String getDay() {

return new SimpleDateFormat(DAY, Locale.CHINESE).format(new Date());

}

/**

• 获取小时

• @return 例如 10

*/

public static String getHour() {

return new SimpleDateFormat(HOUR, Locale.CHINESE).format(new Date());

}

/**

• 获取分钟

• @return 例如 40

*/

public static String getMinute() {

return new SimpleDateFormat(MINUTE, Locale.CHINESE).format(new Date());

}

/**

• 获取秒

• @return 例如 58

*/

public static String getSecond() {

return new SimpleDateFormat(SECOND, Locale.CHINESE).format(new Date());

}

/**

• 获取毫秒

• @return 例如 666

*/

public static String getMilliSecond() {

return new SimpleDateFormat(MILLISECOND, Locale.CHINESE).format(new Date());

}

/**

• 获取时间戳

• @return 例如 1625107306051

*/

public static long getTimestamp() {

return System.currentTimeMillis();

}

/**

• 将时间转换为时间戳

• @param time 例如 2021-07-01 10:44:11

• @return 1625107451000

*/

public static long dateToStamp(String time) {

SimpleDateFormat simpleDateFormat = new SimpleDateFormat(STANDARD_TIME, Locale.CHINESE);

Date date = null;

try {

date = simpleDateFormat.parse(time);

} catch (ParseException e) {

e.printStackTrace();

}

return Objects.requireNonNull(date).getTime();

}

/**

• 将时间戳转换为时间

• @param timeMillis 例如 1625107637084

• @return 例如 2021-07-01 10:47:17

*/

public static String stampToDate(long timeMillis) {

return new SimpleDateFormat(STANDARD_TIME, Locale.CHINESE).format(new Date(timeMillis));

}

/**

• 获取今天是星期几

• @return 例如 星期四

*/

public static String getTodayOfWeek() {

Calendar cal = Calendar.getInstance();

cal.setTime(new Date());

int index = cal.get(Calendar.DAY_OF_WEEK) - 1;

if (index < 0) {

index = 0;

}

return weekDays[index];

}

/**

• 根据输入的日期时间计算是星期几

• @param dateTime 例如 2021-06-20

• @return 例如 星期日

*/

public static String getWeek(String dateTime) {

Calendar cal = Calendar.getInstance();

if (“”.equals(dateTime)) {

cal.setTime(new Date(System.currentTimeMillis()));

} else {

SimpleDateFormat sdf = new SimpleDateFormat(YEAR_MONTH_DAY, Locale.getDefault());

Date date;

try {

date = sdf.parse(dateTime);

} catch (ParseException e) {

date = null;

e.printStackTrace();

}

if (date != null) {

cal.setTime(new Date(date.getTime()));

}

}

return weekDays[cal.get(Calendar.DAY_OF_WEEK) - 1];

}

/**

• 获取输入日期的昨天

• @param date 例如 2021-07-01

• @return 例如 2021-06-30

*/

public static String getYesterday(Date date) {

Calendar calendar = new GregorianCalendar();

calendar.setTime(date);

calendar.add(Calendar.DATE, -1);

date = calendar.getTime();

return new SimpleDateFormat(YEAR_MONTH_DAY, Locale.getDefault()).format(date);

}

/**

• 获取输入日期的明天

• @param date 例如 2021-07-01

• @return 例如 2021-07-02

*/

public static String getTomorrow(Date date) {

Calendar calendar = new GregorianCalendar();

calendar.setTime(date);

calendar.add(Calendar.DATE, +1);

date = calendar.getTime();

return new SimpleDateFormat(YEAR_MONTH_DAY, Locale.getDefault()).format(date);

}

/**

• 根据年月日计算是星期几并与当前日期判断 非昨天、今天、明天 则以星期显示

• @param dateTime 例如 2021-07-03

• @return 例如 星期六

*/

public static String getDayInfo(String dateTime) {

String dayInfo;

String yesterday = getYesterday(new Date());

String today = getTheYearMonthAndDay();

String tomorrow = getTomorrow(new Date());

if (dateTime.equals(yesterday)) {

dayInfo = YESTERDAY;

} else if (dateTime.equals(today)) {

dayInfo = TODAY;

} else if (dateTime.equals(tomorrow)) {

dayInfo = TOMORROW;

} else {

dayInfo = getWeek(dateTime);

}

return dayInfo;

}

/**

• 获取本月天数

• @return 例如 31

*/

public static int getCurrentMonthDays() {

Calendar calendar = Calendar.getInstance();

//把日期设置为当月第一天

calendar.set(Calendar.DATE, 1);

//日期回滚一天，也就是最后一天

calendar.roll(Calendar.DATE, -1);

return calendar.get(Calendar.DATE);

}

/**

• 获得指定月的天数

• @param year 例如 2021

• @param month 例如 7

• @return 例如 31

*/

public static int getMonthDays(int year, int month) {

Calendar calendar = Calendar.getInstance();

calendar.set(Calendar.YEAR, year);

calendar.set(Calendar.MONTH, month - 1);

//把日期设置为当月第一天

calendar.set(Calendar.DATE, 1);

//日期回滚一天，也就是最后一天

calendar.roll(Calendar.DATE, -1);

return calendar.get(Calendar.DATE);

}

}

CameraUtils类，代码如下：

public class CameraUtils {

/**

• 相机Intent

• @param context

• @param outputImagePath

• @return

*/

public static Intent getTakePhotoIntent(Context context, File outputImagePath) {

// 激活相机

Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);

// 判断存储卡是否可以用，可用进行存储

if (hasSdcard()) {

if (Build.VERSION.SDK_INT < Build.VERSION_CODES.N) {

// 从文件中创建uri

Uri uri = Uri.fromFile(outputImagePath);

intent.putExtra(MediaStore.EXTRA_OUTPUT, uri);

} else {

//兼容android7.0 使用共享文件的形式

ContentValues contentValues = new ContentValues(1);

contentValues.put(MediaStore.Images.Media.DATA, outputImagePath.getAbsolutePath());

Uri uri = context.getApplicationContext().getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, contentValues);

intent.putExtra(MediaStore.EXTRA_OUTPUT, uri);

}

}

return intent;

}

/**

• 相册Intent

• @return

*/

public static Intent getSelectPhotoIntent() {

Intent intent = new Intent(“android.intent.action.GET_CONTENT”);

intent.setType(“image/*”);

return intent;

}

/**

• 判断sdcard是否被挂载

*/

public static boolean hasSdcard() {

return Environment.getExternalStorageState().equals(

Environment.MEDIA_MOUNTED);

}

/**

• 4.4及以上系统处理图片的方法

*/

@TargetApi(Build.VERSION_CODES.KITKAT)

public static String getImageOnKitKatPath(Intent data, Context context) {

String imagePath = null;

Uri uri = data.getData();

Log.d(“uri=intent.getData :”, “” + uri);

if (DocumentsContract.isDocumentUri(context, uri)) {

//数据表里指定的行

String docId = DocumentsContract.getDocumentId(uri);

Log.d(“getDocumentId(uri) :”, “” + docId);

Log.d(“uri.getAuthority() :”, “” + uri.getAuthority());

if (“com.android.providers.media.documents”.equals(uri.getAuthority())) {

String id = docId.split(“:”)[1];

String selection = MediaStore.Images.Media._ID + “=” + id;

imagePath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, selection, context);

} else if (“com.android.providers.downloads.documents”.equals(uri.getAuthority())) {

Uri contentUri = ContentUris.withAppendedId(Uri.parse(“content://downloads/public_downloads”), Long.valueOf(docId));

imagePath = getImagePath(contentUri, null, context);

}

} else if (“content”.equalsIgnoreCase(uri.getScheme())) {

imagePath = getImagePath(uri, null, context);

}

return imagePath;

}

/**

• 通过uri和selection来获取真实的图片路径,从相册获取图片时要用

*/

public static String getImagePath(Uri uri, String selection, Context context) {

String path = null;

Cursor cursor = context.getContentResolver().query(uri, null, selection, null, null);

if (cursor != null) {

if (cursor.moveToFirst()) {

path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));

}

cursor.close();

}

return path;

}

/**

• 更改图片显示角度

• @param filepath

• @param orc_bitmap

• @param iv

*/

public static void ImgUpdateDirection(String filepath, Bitmap orc_bitmap, ImageView iv) {

//图片旋转的角度

int digree = 0;

//根据图片的filepath获取到一个ExifInterface的对象

ExifInterface exif = null;

try {

exif = new ExifInterface(filepath);

if (exif != null) {

// 读取图片中相机方向信息

int ori = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_UNDEFINED);

// 计算旋转角度

switch (ori) {

case ExifInterface.ORIENTATION_ROTATE_90:

digree = 90;

break;

case ExifInterface.ORIENTATION_ROTATE_180:

digree = 180;

break;

case ExifInterface.ORIENTATION_ROTATE_270:

digree = 270;

break;

default:

digree = 0;

break;

}

}

//如果图片不为0

if (digree != 0) {

// 旋转图片

Matrix m = new Matrix();

m.postRotate(digree);

orc_bitmap = Bitmap.createBitmap(orc_bitmap, 0, 0, orc_bitmap.getWidth(),

orc_bitmap.getHeight(), m, true);

}

if (orc_bitmap != null) {

iv.setImageBitmap(orc_bitmap);

}

} catch (IOException e) {

e.printStackTrace();

exif = null;

}

}

/**

• 4.4以下系统处理图片的方法

*/

public static String getImageBeforeKitKatPath(Intent data, Context context) {

Uri uri = data.getData();

String imagePath = getImagePath(uri, null, context);

return imagePath;

}

/**

• 比例压缩

• @param image

• @return

*/

public static Bitmap compression(Bitmap image) {

ByteArrayOutputStream outputStream = new ByteArrayOutputStream();

image.compress(Bitmap.CompressFormat.JPEG, 100, outputStream);

//判断如果图片大于1M,进行压缩避免在生成图片（BitmapFactory.decodeStream）时溢出

if (outputStream.toByteArray().length / 1024 > 1024) {

//重置outputStream即清空outputStream

outputStream.reset();

//这里压缩50%，把压缩后的数据存放到baos中

image.compress(Bitmap.CompressFormat.JPEG, 50, outputStream);

}

ByteArrayInputStream inputStream = new ByteArrayInputStream(outputStream.toByteArray());

BitmapFactory.Options options = new BitmapFactory.Options();

//开始读入图片，此时把options.inJustDecodeBounds 设回true了

options.inJustDecodeBounds = true;

Bitmap bitmap = BitmapFactory.decodeStream(inputStream, null, options);

options.inJustDecodeBounds = false;

int outWidth = options.outWidth;

int outHeight = options.outHeight;

//现在主流手机比较多是800*480分辨率，所以高和宽我们设置为

float height = 800f;//这里设置高度为800f

float width = 480f;//这里设置宽度为480f

//缩放比。由于是固定比例缩放，只用高或者宽其中一个数据进行计算即可

int zoomRatio = 1;//be=1表示不缩放

if (outWidth > outHeight && outWidth > width) {//如果宽度大的话根据宽度固定大小缩放

zoomRatio = (int) (options.outWidth / width);

} else if (outWidth < outHeight && outHeight > height) {//如果高度高的话根据宽度固定大小缩放

zoomRatio = (int) (options.outHeight / height);

}

if (zoomRatio <= 0) {

zoomRatio = 1;

}

options.inSampleSize = zoomRatio;//设置缩放比例

options.inPreferredConfig = Bitmap.Config.RGB_565;//降低图片从ARGB888到RGB565

//重新读入图片，注意此时已经把options.inJustDecodeBounds 设回false了

inputStream = new ByteArrayInputStream(outputStream.toByteArray());

//压缩好比例大小后再进行质量压缩

bitmap = BitmapFactory.decodeStream(inputStream, null, options);

return bitmap;

}

}

BitmapUtils类，代码如下（本文中没有用到，因为我没有服务器，但是如果你需要上传到服务器的话，常规做法是将图片转成Base64，发送给服务器）：

public class BitmapUtils {

/**

• bitmap转为base64

• @param bitmap

• @return

*/