Android拍照或从相册中取照片

此文章只为记录本人在开发中遇到的坑以及学到的知识，里面可能还是存在问题，如果有问题希望大家能指出来，谢谢！

1.拍照

拍照需要适配7.0和7.0以下的手机，然后还需要申请相机和SD卡的读写权限。这次没有用到裁剪的功能，所以该文章中没有裁剪代码。

7.0及以上的手机需要用到provider。

第一步 在application中定义provider

<provider
    android:name="android.support.v4.content.FileProvider"//固定值
    android:authorities="com.weconex.maanshancitizencard.fileprovider"//包名加上.fileprovider
   android:exported="false"//是否支持其他应用调用当前组件，要求为false
    android:grantUriPermissions="true">
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"//固定值
        android:resource="@xml/filepaths" />//在res目录下创建一个xml文件夹，创建xml文件，名字可以自定义
</provider>

第二步 xml文件定义

<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <!--相机相册裁剪-->
    <root-path name="camera_no_sdcard" path=""/>//这里我是放在SD卡的根目录下，所以这里用root-path
</paths>

第三步 调用代码

1.初始化对象

mCameraFile = new File(Environment.getExternalStorageDirectory(), "cameraFile");//照相机的File对象
mGalleryFile = new File(Environment.getExternalStorageDirectory(), "imageGallery");//相册的File对象

2.调用相机

Intent intentFromCapture = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {//7.0及以上
    Uri uriForFile = FileProvider.getUriForFile(context, "com.weconex.maanshancitizencard.fileprovider", file);
    intentFromCapture.putExtra(MediaStore.EXTRA_OUTPUT, uriForFile);
    intentFromCapture.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
    intentFromCapture.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
} else {
    intentFromCapture.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file));
}
fragment.startActivityForResult(intentFromCapture, code);

3.处理拍照后的回调

通过mCameraFile.getPath()方法可以得到拍照后得到的图片地址。这里需要对图片进行压缩处理，否则会报异常。

2.从相册中获取图片

1.调用相册

这里需要对7.0及以上、7.0以下4.4及以上和4.4以下进行适配。

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {//如果大于等于7.0使用FileProvider
    Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
    intent.addCategory(Intent.CATEGORY_OPENABLE);
    intent.setType("image/*");
    Uri uriForFile = FileProvider.getUriForFile(context, "com.weconex.maanshancitizencard.fileprovider", mGalleryFile);
    intent.putExtra(MediaStore.EXTRA_OUTPUT, uriForFile);
    intent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
    intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
    fragment.startActivityForResult(intent, code7);
} else if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT){//7.0以下，4.4以上
    Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
    intent.addCategory(Intent.CATEGORY_OPENABLE);
    intent.setType("image/*");
    fragment.startActivityForResult(intent, code);
}else{//4.4以下
    Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
    intent.addCategory(Intent.CATEGORY_OPENABLE);
    intent.setType("image/*");
    fragment.startActivityForResult(intent, code);
}

2.处理相册的回调

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT){//4.4以上
    return ImageUtils.zoomImage(getPath(context,data.getData()));//这里要解决分水岭问题，在getPath()方法中实现了
}else{//4.4以下
    Uri selectedImage = data.getData(); //获取系统返回的照片的Uri
    String[] filePathColumn = { MediaStore.Images.Media.DATA };
    Cursor cursor =context.getContentResolver().query(selectedImage,
            filePathColumn, null, null, null);//从系统表中查询指定Uri对应的照片
    cursor.moveToFirst();
    int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
    String picturePath = cursor.getString(columnIndex);  //获取照片路径
    cursor.close();
    return ImageUtils.zoomImage(picturePath);
}

4.4及以上的手机获取的图片面临这分水岭问题，可以通过以下代码来解决

@TargetApi(Build.VERSION_CODES.KITKAT)
private String getPath(final Context context, final Uri uri) {

    final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;

    // DocumentProvider
    if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
        // ExternalStorageProvider
        if (isExternalStorageDocument(uri)) {
            final String docId = DocumentsContract.getDocumentId(uri);
            final String[] split = docId.split(":");
            final String type = split[0];

            if ("primary".equalsIgnoreCase(type)) {
                return Environment.getExternalStorageDirectory() + "/" + split[1];
            }

        }
        // DownloadsProvider
        else if (isDownloadsDocument(uri)) {

            final String id = DocumentsContract.getDocumentId(uri);
            final Uri contentUri = ContentUris.withAppendedId(
                    Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));

            return getDataColumn(context, contentUri, null, null);
        }
        // MediaProvider
        else if (isMediaDocument(uri)) {
            final String docId = DocumentsContract.getDocumentId(uri);
            final String[] split = docId.split(":");
            final String type = split[0];

            Uri contentUri = null;
            if ("image".equals(type)) {
                contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
            } else if ("video".equals(type)) {
                contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
            } else if ("audio".equals(type)) {
                contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
            }

            final String selection = "_id=?";
            final String[] selectionArgs = new String[] {
                    split[1]
            };

            return getDataColumn(context, contentUri, selection, selectionArgs);
        }
    }
    // MediaStore (and general)
    else if ("content".equalsIgnoreCase(uri.getScheme())) {

        // Return the remote address
        if (isGooglePhotosUri(uri))
            return uri.getLastPathSegment();

        return getDataColumn(context, uri, null, null);
    }
    // File
    else if ("file".equalsIgnoreCase(uri.getScheme())) {
        return uri.getPath();
    }

    return null;
}

/**
 * Get the value of the data column for this Uri. This is useful for
 * MediaStore Uris, and other file-based ContentProviders.
 *
 * @param context The context.
 * @param uri The Uri to query.
 * @param selection (Optional) Filter used in the query.
 * @param selectionArgs (Optional) Selection arguments used in the query.
 * @return The value of the _data column, which is typically a file path.
 */
private String getDataColumn(Context context, Uri uri, String selection,
                                   String[] selectionArgs) {

    Cursor cursor = null;
    final String column = "_data";
    final String[] projection = {
            column
    };

    try {
        cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs,
                null);
        if (cursor != null && cursor.moveToFirst()) {
            final int index = cursor.getColumnIndexOrThrow(column);
            return cursor.getString(index);
        }
    } finally {
        if (cursor != null)
            cursor.close();
    }
    return null;
}


/**
 * @param uri The Uri to check.
 * @return Whether the Uri authority is ExternalStorageProvider.
 */
private boolean isExternalStorageDocument(Uri uri) {
    return "com.android.externalstorage.documents".equals(uri.getAuthority());
}

/**
 * @param uri The Uri to check.
 * @return Whether the Uri authority is DownloadsProvider.
 */
private boolean isDownloadsDocument(Uri uri) {
    return "com.android.providers.downloads.documents".equals(uri.getAuthority());
}

/**
 * @param uri The Uri to check.
 * @return Whether the Uri authority is MediaProvider.
 */
private boolean isMediaDocument(Uri uri) {
    return "com.android.providers.media.documents".equals(uri.getAuthority());
}

/**
 * @param uri The Uri to check.
 * @return Whether the Uri authority is Google Photos.
 */
private boolean isGooglePhotosUri(Uri uri) {
    return "com.google.android.apps.photos.content".equals(uri.getAuthority());
}

完成。