Android：以编程方式截取通知栏的屏幕截图

Question

我使用无障碍服务来扩展接收通知时的通知栏。我正在尝试在通知抽屉中截取通知的屏幕截图。

从辅助功能服务的文档中，可以仅从 Android P 截取设备的屏幕截图。

由于我的应用不在前台，是否还有其他可能截取通知抽屉的屏幕截图。它在后台运行

Answer 1

是的，你可以做到这一点，虽然这很棘手。诀窍是利用媒体投影管理器与与您的服务在同一包中的活动相结合。然后，您可以利用 MediaProjectionManager 捕获图像的能力以及共享存储来抓取屏幕截图。

在创建 AccessibilityService 时执行以下操作：

@Override
public void onCreate() {

    //Launch image capture intent for Color Contrast.
    final Intent imageCaptureIntent = new Intent(this, ImageCaptureActivity.class);
    imageCaptureIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    imageCaptureIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

    startActivity(imageCaptureIntent);
}

那么您的 ImageCaptureActivity 将只是一个标准活动，但不会有任何 UI。它只会管理与媒体投影管理器的交互。就我而言，它最终成为一个像素清晰的点。这实际上很难设置。我将复制我的 ImageCaptureActivity。这可能不会完全适合你，但是当我深入研究这个时，我发现这个过程的记录非常糟糕。我没有修改这个，但也许它会帮助你。

public class ImageCaptureActivity extends AppCompatActivity {

    private static final int REQUEST_MEDIA_PROJECTION = 1;

    private MediaProjectionManager mProjectionManager;

    private String mFileName;

    private MediaProjection mMediaProjection = null;

    private VirtualDisplay mVirtualDisplay;

    private ImageReader mImageReader;

    private static final int MAX_IMAGE_BUFFER = 10;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_image_capture);

        mFileName = getFilesDir() + RuleColorContrast.IMAGE_CAPTURE_FILE_NAME;

        OrientationChangedListener mOrientationChangedListener = new OrientationChangedListener(this);
        mOrientationChangedListener.enable();

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            mProjectionManager = (MediaProjectionManager)getSystemService(MEDIA_PROJECTION_SERVICE);
            startActivityForResult(mProjectionManager.createScreenCaptureIntent(), REQUEST_MEDIA_PROJECTION);
        }
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public void onActivityResult(int requestCode, int resultCode, Intent resultData) {
        if (requestCode == REQUEST_MEDIA_PROJECTION) {
            String message;

            if (resultCode != Activity.RESULT_OK) {
                message = "Media Projection Declined";
                mMediaProjection = null;
            } else {
                message = "Media Projection Accepted";
                mMediaProjection = mProjectionManager.getMediaProjection(resultCode, resultData);
                attachImageCaptureOverlay();
            }

            Toast toast = Toast.makeText(this, message, Toast.LENGTH_SHORT);
            toast.show();

            finish();

        }
    }

    private class OrientationChangedListener extends OrientationEventListener {

        int mLastOrientation = -1;

        OrientationChangedListener(Context context) {
            super(context);
        }

        @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
        @Override
        public void onOrientationChanged(int orientation) {

            final int screenOrientation = getWindowManager().getDefaultDisplay().getRotation();

            if (mVirtualDisplay == null) return;

            if (mLastOrientation == screenOrientation) return;

            mLastOrientation = screenOrientation;

            detachImageCaptureOverlay();
            attachImageCaptureOverlay();
        }
    }

    private final ImageReader.OnImageAvailableListener mOnImageAvailableListener = new ImageReader.OnImageAvailableListener() {

        @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
        @Override
        public void onImageAvailable(ImageReader reader) {

            Image image = reader.acquireLatestImage();

            if (image == null || image.getPlanes().length <= 0) return;

            final Image.Plane plane = image.getPlanes()[0];

            final int rowPadding = plane.getRowStride() - plane.getPixelStride() * image.getWidth();
            final int bitmapWidth = image.getWidth() + rowPadding / plane.getPixelStride();

            final Bitmap tempBitmap = Bitmap.createBitmap(bitmapWidth, image.getHeight(), Bitmap.Config.ARGB_8888);
            tempBitmap.copyPixelsFromBuffer(plane.getBuffer());

            Rect cropRect = image.getCropRect();
            final Bitmap bitmap = Bitmap.createBitmap(tempBitmap, cropRect.left, cropRect.top, cropRect.width(), cropRect.height());

            //Do something with the bitmap

            image.close();
        }
    };

    @RequiresApi(Build.VERSION_CODES.LOLLIPOP)
    private void attachImageCaptureOverlay() {

        if (mMediaProjection == null) return;

        final DisplayMetrics metrics = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getRealMetrics(metrics);

        mImageReader = ImageReader.newInstance(metrics.widthPixels, metrics.heightPixels, PixelFormat.RGBA_8888, MAX_IMAGE_BUFFER);

        mVirtualDisplay = mMediaProjection.createVirtualDisplay("ScreenCaptureTest",
                metrics.widthPixels, metrics.heightPixels, metrics.densityDpi,
                DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,
                mImageReader.getSurface(), null, null);

        mImageReader.setOnImageAvailableListener(mOnImageAvailableListener, null);
    }

    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
    private void detachImageCaptureOverlay() {
        mVirtualDisplay.release();
        mImageReader.close();
    }
}

注意：这种方法可以追溯到 Android 5.0。