安卓相机和相册的调用

相机：

1.创建file对象，用来存储拍照后的照片

File file=new file（getExternalCacheDir()【获取缓存相关路径，可以跳过存储权限】,"照片名.jpg"）;

2.判断file是否存在

3.把file对象转为uri对象

判断安卓版本（7.0前后）

if(Build.VERSION.SDK_INT>=24)

{Uri uri=FileProvider.getUriForFile(context，内容提供器的authority，file)；}

else{Uri uri=Uri.fromFile(file);}

4.intent跳转并设置图片缓存路径

Intentintent=new Intent(action值)；

intent.putExtra(MEdiaStore.ExTRA_OUTPUT,uri);

startActivityForResult(intent,requqestCode);

5.重写onActivityResult方法

@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    switch (requestCode) {
        case 1:
            if (resultCode == RESULT_OK) {
                try {
                    Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(pictureuri));
                    zhanshi.setImageBitmap(bitmap);
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                }
            }
            break;
        default:
            break;
    }
}

6.在AndroidManifest.xml设置内容提供器

<provider
    android:authorities="com.example.servicebestpractice.take_photo"
    android:name="androidx.core.content.FileProvider"
    android:exported="false"
    android:grantUriPermissions="true">
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/file_paths"/>//xml共享路径文件

</provider>

7.创建xml包和file_path.xml文件

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.servicebestpractice">
    <external-path
        name="my_images"
        path=""/>
</paths>

完整项目代码：

MainActivity：

public class MainActivity extends AppCompatActivity implements View.OnClickListener{
private Button take_photo;
private Uri pictureuri;
private ImageView zhanshi;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        take_photo=(Button)findViewById(R.id.take_photoes);
      
        zhanshi=(ImageView)findViewById(R.id.zhanshi);
        take_photo.setOnClickListener(this);
        picture.setOnClickListener(this);
    }
    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.take_photoes:
                File file=new File(getExternalCacheDir(),"new_picture.jpg");
                if(file.exists()){
                    file.delete();
                }
                try {
                    file.createNewFile();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (Build.VERSION.SDK_INT<24){
                    pictureuri=Uri.fromFile(file);
                }else {
                    pictureuri= FileProvider.getUriForFile(MainActivity.this,"com.example.servicebestpractice.take_photo",file);
                }
                Intent intent=new Intent("android.media.action.IMAGE_CAPTURE");
                intent.putExtra(MediaStore.EXTRA_OUTPUT,pictureuri);
                startActivityForResult(intent,1);
                break;
            default:
        }

    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch (requestCode) {
            case 1:
                if (resultCode == RESULT_OK) {
                    try {
                        Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(pictureuri));
                        zhanshi.setImageBitmap(bitmap);
                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    }
                }
                break;
            default:
                break;
        }
    }
}

相册：

1.申请sd卡读取权限

2intent跳转并设置类型

3.判断版本号

4.对不同版本号的不同处理方式

public class MainActivity2 extends AppCompatActivity {
    /*声明组件*/
    private Button getimage1;
    private ImageView display;
    Bitmap bitmap;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        getimage1=(Button)findViewById(R.id.getpicture);
        display=(ImageView)findViewById(R.id.zhanshixiangce);
        getimage1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(ContextCompat.checkSelfPermission(MainActivity2.this, Manifest.permission.WRITE_EXTERNAL_STORAGE)!= PackageManager.PERMISSION_GRANTED){
                    ActivityCompat.requestPermissions(MainActivity2.this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},1);
                }else {
                    openAlbum();
                }
            }
        });
    }

    //打开相机
    private void openAlbum(){
        Intent intent=new Intent("android.intent.action.GET_CONTENT");
        intent.setType("image/*");
        startActivityForResult(intent,2);
    }
    //获取相机权限
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode){
            case 1:
                if(grantResults.length>0&&grantResults[0]==PackageManager.PERMISSION_GRANTED){
                    openAlbum();
                }else {
                    Toast.makeText(MainActivity2.this,"授予权限失败",Toast.LENGTH_LONG).show();
                }break;
            default:
                break;
        }
    }
    @Override
    public void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode,resultCode,data);
        switch (requestCode) {
            case 2:
                if(Build.VERSION.SDK_INT>=19){
                    handleImageOnKitKat(data);
                }else {
                    handleImageBeforeKitKat(data);
                }
                break;
            default:
                break;
        }
    }


    //安卓4.4以下版本
    @TargetApi(19)
    private void handleImageOnKitKat(Intent data){
        String imagePath =null;
        Uri uri=data.getData();
        if(DocumentsContract.isDocumentUri(MainActivity2.this,uri)){
            String docId =DocumentsContract.getDocumentId(uri);
            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);
            }else if("com.android.providers.downloads.documents".equals(uri.getAuthority())){
                Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"),Long.valueOf(docId));
                imagePath =uri.getPath();
            }else if ("file".equalsIgnoreCase(uri.getScheme())){
                imagePath =uri.getPath();
            }

        }
        displayImage(imagePath);
    }
    //回传照片到activity
    private void handleImageBeforeKitKat(Intent data){
        Uri uri =data.getData();
        String imagePath =getImagePath(uri,null);
        displayImage(imagePath);
    }
    private String getImagePath(Uri uri,String selection){
        String path =null;
        Cursor cursor=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;
    }
    private void displayImage(String imagePath){
        if (imagePath!=null){
            bitmap = BitmapFactory.decodeFile(imagePath);
            display.setImageBitmap(bitmap);
        }else {
            Toast.makeText(MainActivity2.this,"获取照片失败",Toast.LENGTH_LONG).show();
        }
    }
}