[移动开发]Android 截屏实现、屏幕截图、MediaProjection、ImageReader

1. 第一步：调起系统捕获屏幕的Intent

MainActivity:

public void goCaptureIntent() {
    //第一步.调起系统捕获屏幕的Intent
    mMediaProjectionManager = (MediaProjectionManager) getSystemService(MEDIA_PROJECTION_SERVICE);
    Intent captureIntent = mMediaProjectionManager.createScreenCaptureIntent();
    startActivityForResult(captureIntent, SCREEN_SHOT_CODE);
}

2. 第二步：通过startForegroundService来获取mediaProjection

注：sdk 28以及以下可以直接在Activity中获取，29以及以上在Activity中获取会报错

MainActivity:

@RequiresApi(api = Build.VERSION_CODES.O)
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if(requestCode==SCREEN_SHOT_CODE && resultCode == RESULT_OK){
        //第二步通过startForegroundService来获取mediaProjection
        Intent service = new Intent(this, ScreenShootService.class);
        service.putExtra("code", resultCode);
        service.putExtra("data", data);
        service.putExtra("width", getScreenWidth(this));
        service.putExtra("height", getScreenHeight(this));
        startForegroundService(service);
    }
}

3.?第三步：获取mediaProjection

注：AndroidManifest.xml中注册的service要加上以下属性

<service android:name=".ScreenShootService"
     android:enabled="true"
     android:foregroundServiceType="mediaProjection">

</service>

?第三步的代码：

ScreenShootService：

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
        int resultCode = intent.getIntExtra("code", -1);
        Intent data = intent.getParcelableExtra("data");
        width = intent.getIntExtra("width",1080);
        height = intent.getIntExtra("height",1920);
        notification();
        //第三步：获取mediaProjection
        MediaProjectionManager mMediaProjectionManager = (MediaProjectionManager) getSystemService(MEDIA_PROJECTION_SERVICE);
        MediaProjection mediaProjection = mMediaProjectionManager.getMediaProjection(resultCode, data);
        if (mediaProjection == null) {
            Log.e(TAG, "media projection is null");
        }
        Bitmap bitmap = screenShot(mediaProjection);
        EventBus.getDefault().post(bitmap);
        return super.onStartCommand(intent, flags, startId);
}

?4.?第四步：通过mediaProjection截图获取Image

ScreenShootService：

//第四步；通过mediaProjection截图获取Image
public Bitmap screenShot(MediaProjection mediaProjection){
        Objects.requireNonNull(mediaProjection);
        @SuppressLint("WrongConstant")
        ImageReader imageReader = ImageReader.newInstance(width, height, PixelFormat.RGBA_8888, 60);
        VirtualDisplay virtualDisplay = mediaProjection.createVirtualDisplay("screen", width, height, 1, DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,imageReader.getSurface(), null, null);
        //取现在最新的图片
        SystemClock.sleep(1000);
        //取最新的图片
        Image image = imageReader.acquireLatestImage();
//        Image image = imageReader.acquireNextImage();
        //释放 virtualDisplay,不释放会报错
        virtualDisplay.release();
        return image2Bitmap(image);
}

5. 第五步：将Image转为Bitmap

ScreenShootService：

//第五步:将Image转为Bitmap
public static Bitmap image2Bitmap(Image image) {
        if (image == null) {
            System.out.println("image 为空");
            return null;
        }
        int width = image.getWidth();
        int height = image.getHeight();

        final Image.Plane[] planes = image.getPlanes();
        final ByteBuffer buffer = planes[0].getBuffer();
        int pixelStride = planes[0].getPixelStride();
        int rowStride = planes[0].getRowStride();
        int rowPadding = rowStride - pixelStride * width;

        Bitmap bitmap = Bitmap.createBitmap(width+ rowPadding / pixelStride , height, Bitmap.Config.ARGB_8888);
        bitmap.copyPixelsFromBuffer(buffer);
        //截取图片
//        Bitmap cutBitmap = Bitmap.createBitmap(bitmap,0,0,width/2,height/2);

        //压缩图片
//        Matrix matrix = new Matrix();
//        matrix.setScale(0.5F, 0.5F);
//        System.out.println(bitmap.isMutable());
//        bitmap = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, false);

        image.close();
        return bitmap;
}

6.?第六步：展示截图结果

这里是通过EventBust从Service传到了Activity

MainActivity：

//接收service返回的bitmap图片数据
@Subscribe(threadMode = ThreadMode.MAIN)//在ui线程执行
public void onMoonEvent(Bitmap bitmap){
   //第六步：展示截图结果
   imgShowImage.setBackground(new BitmapDrawable(bitmap));
}

异常处理1.?E/BufferQueueProducer: [ImageReader-2340x1080f1m1-24598-0](id:601600000001,api:1,p:1080,c:24598) dequeueBuffer: BufferQueue has been abandoned

分析：异常：BufferQueue已经被丢弃了，还在使用

说明有在可能是截图中使用到的某个对象被GC了，BufferQueue的对象大概有三个ImageReader 、VirtualDisplay 和 Image，Image在截图万之后已经close掉了，然后尝试截图后分别对ImageReader和VirtualDisplay进行释放，ImageReader释放问题依然存在，VirtualDisplay释放解决了该问题。

VirtualDisplay virtualDisplay = mediaProjection.createVirtualDisplay("screen", width, height, 1, DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,imageReader.getSurface(), null, null);
...

使用完Image之后...
...

virtualDisplay.release();

?异常处理2：Media projections require a foreground service of type ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PROJECTION

sdk版本产生的适配问题

两种解决方案：

方案一：将sdk降低到28或者以下

?方案二：即需要使用 startForegroundService

也就是上面demo中使用到的方法

Activity：

public void goCaptureIntent() {
        //第一步.调起系统捕获屏幕的Intent
        mMediaProjectionManager = (MediaProjectionManager) getSystemService(MEDIA_PROJECTION_SERVICE);
        Intent captureIntent = mMediaProjectionManager.createScreenCaptureIntent();
        startActivityForResult(captureIntent, SCREEN_SHOT_CODE);
}

@RequiresApi(api = Build.VERSION_CODES.O)
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if(requestCode==SCREEN_SHOT_CODE && resultCode == RESULT_OK){
        //第二步通过startForegroundService来获取mediaProjection
        Intent service = new Intent(this, ScreenShootService.class);
        service.putExtra("code", resultCode);
        service.putExtra("data", data);
        service.putExtra("width", getScreenWidth(this));
        service.putExtra("height", getScreenHeight(this));
        startForegroundService(service);
    }
}

Service：

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    int resultCode = intent.getIntExtra("code", -1);
    Intent data = intent.getParcelableExtra("data");
    width = intent.getIntExtra("width",1080);
    height = intent.getIntExtra("height",1920);
    notification();
    //第二步：创建mediaProjection
    MediaProjectionManager mMediaProjectionManager = (MediaProjectionManager) getSystemService(MEDIA_PROJECTION_SERVICE);
    MediaProjection mediaProjection = mMediaProjectionManager.getMediaProjection(resultCode, data);
    if (mediaProjection == null) {
        Log.e(TAG, "media projection is null");
    }
    Bitmap bitmap = screenShot(mediaProjection);
    EventBus.getDefault().post(bitmap);
    return super.onStartCommand(intent, flags, startId);
}

AndroidManifest.xml：


<service android:name=".ScreenShootService"
    android:enabled="true"
    android:foregroundServiceType="mediaProjection">

?最终效果图：

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