Android 获取屏幕指定坐标的颜色

用到的API

• MediaProjectionManager
• MediaProjection
• VirtualDisplay
• ImageReader

原理：利用Android系统提供的投影功能把屏幕投影到ImageReader中，通过ImageReader获取到Bitmap，调用Bitmap的getPixel(x, y)方法获取到指定坐标的颜色。

代码

创建虚拟显示器

    private static final int REQUEST_MEDIA_PROJECTION = 1;
    private MediaProjectionManager mMediaProjectionManager;
    private MediaProjection mMediaProjection;
    private VirtualDisplay mVirtualDisplay;   
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mMediaProjectionManager = (MediaProjectionManager) getSystemService(Context.MEDIA_PROJECTION_SERVICE);

        assert mMediaProjectionManager != null;
        startActivityForResult(
                mMediaProjectionManager.createScreenCaptureIntent(),
                REQUEST_MEDIA_PROJECTION);
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == REQUEST_MEDIA_PROJECTION) {
            if (resultCode != Activity.RESULT_OK) {
                Log.i(TAG, "User cancelled");
                Toast.makeText(this, "User cancelled!", Toast.LENGTH_SHORT).show();
                return;
            }

            Log.i(TAG, "Starting screen capture");

            mMediaProjection = mMediaProjectionManager.getMediaProjection(resultCode, data);
            setUpVirtualDisplay();
        }
    }

    private void setUpVirtualDisplay() {
        DisplayMetrics dm = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getRealMetrics(dm);
        ImageReader imageReader = ImageReader.newInstance(dm.widthPixels, dm.heightPixels, PixelFormat.RGBA_8888, 1);
        mMediaProjection.createVirtualDisplay("ScreenCapture",
            dm.widthPixels, dm.heightPixels, dm.densityDpi,
            DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,
            imageReader.getSurface(), null, null);
        GBData.reader = imageReader;
    }

获取指定坐标的颜色

public class GBData {
    private static final String TAG = "GBData";
    static ImageReader reader;
    private static Bitmap bitmap;

    public static int getColor(int x, int y) {
        if (reader == null) {
            Log.w(TAG, "getColor: reader is null");
            return -1;
        }

        Image image = reader.acquireLatestImage();

        if (image == null) {
            if (bitmap == null) {
                Log.w(TAG, "getColor: image is null");
                return -1;
            }
            return bitmap.getPixel(x, y);
        }
        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;
        if (bitmap == null) {
            bitmap = Bitmap.createBitmap(width + rowPadding / pixelStride, height, Bitmap.Config.ARGB_8888);
        }
        bitmap.copyPixelsFromBuffer(buffer);
        image.close();

        return bitmap.getPixel(x, y);
    }
}

在代码中使用

int color = GBData.getColor(x,y)

参考

• https://github.com/googlesamples/android-ScreenCapture/#readme
• https://developer.android.com/reference/android/media/ImageReader.html#getSurface()
• https://www.jianshu.com/p/d7eb518195fd