安卓13媒体投影截图为黑色

Question

我在媒体投影和截屏方面有一个错误，但只有在安卓13上，有时会出现黑色，但并不总是如此。我试着设置一个延迟(最多5秒(，看看是否是安卓系统造成的，但它仍然会发生，任何帮助都将不胜感激。我确实搜索了这个网站，但没有出现安卓13的问题。

WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
windowManager.getDefaultDisplay().getRealSize(size);
final int width = size.x, height = size.y;
final ImageReader imageReader = ImageReader.newInstance(width, height, PixelFormat.RGBA_8888, 1);
imageReader.setOnImageAvailableListener(reader -> {
//-> Stop our media projection just in case it is running
mediaProjection.stop();
Image image = reader.acquireLatestImage();
if (image != null){
Image.Plane[] planes = image.getPlanes();
ByteBuffer buffer = planes[0].getBuffer();
int pixelStride = planes[0].getPixelStride(), rowStride = planes[0].getRowStride(), rowPadding = rowStride - pixelStride * width;
bitmap = Bitmap.createBitmap(width + rowPadding / pixelStride, height, Bitmap.Config.ARGB_8888);
bitmap.copyPixelsFromBuffer(buffer); 
String fileName = "Screenshot_" + System.currentTimeMillis() + ".jpg";
String destinationPath = this.getExternalFilesDir(null) + "/screenshots/" + fileName;
File imageFile = new File(destinationPath);
FileOutputStream outputStream = new FileOutputStream(imageFile);
int quality = 100;
bitmap.compress(Bitmap.CompressFormat.JPEG, quality, outputStream);
outputStream.flush();
outputStream.close();
String mediaPath = Environment.DIRECTORY_PICTURES + File.separator + "Screenshots/myapp" + File.separator;
ContentValues values = new ContentValues();
values.put(MediaStore.Images.Media.DATE_TAKEN, System.currentTimeMillis());
values.put(MediaStore.Images.Media.IS_PENDING, 0);
values.put(MediaStore.Images.Media.RELATIVE_PATH, mediaPath);
values.put(MediaStore.Images.Media.MIME_TYPE, "image/jpeg");
values.put(MediaStore.Images.Media.SIZE, imageFile.length());
values.put(MediaStore.Images.Media.DISPLAY_NAME, fileName);
Uri path = this.getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values);
OutputStream imageOutStream = this.getContentResolver().openOutputStream(path);
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, imageOutStream);
if (imageOutStream != null) {
imageOutStream.flush();
imageOutStream.close();
}
if (image != null) { image.close(); }
mediaProjection.stop();
if (reader != null){ reader.close(); }
}
}, null);

Answer 1

在我的测试和观察中，在Android 13 上使用带有媒体投影的ImageReader时存在两个问题

首先，setOnImageAvailableListener的回调结果有时会返回空像素的缓冲区。因此，我们可以等待下一个图像，直到我们得到非空位图

imageReader.setOnImageAvailableListener({ imageReader ->
val image = imageReader.acquireLatestImage()
// ... get buffer here
val bitmap = Bitmap.createBitmap(screenWidth + rowPadding / pixelStride, screenHeight, Bitmap.Config.ARGB_8888)
bitmap.copyPixelsFromBuffer(buffer)
// IMPORTANT!
val isEmptyBitmap = bitmap.isEmptyBitmap()
if (isEmptyBitmap) {
// don't stop the listener and let the imageReader continue to run so that we can get next round of image buffer
} else {
// save bitmap to file
}
}, Handler(Looper.getMainLooper()))

isEmptyBitmap((只是Bitmap:的扩展

fun Bitmap.isEmptyBitmap(): Boolean {
val emptyBitmap = Bitmap.createBitmap(width, height, config)
return this.sameAs(emptyBitmap)
}

第二个问题是，OnImageAvailableListener有时甚至不回调！在这种情况下，我设置了一个超时来等待结果，当超时时，从同一个MediaProjection实例重新创建VirtualDisplay对象，它就可以工作了。

我正在使用kotlin协程，所以代码片段可能看起来像：

retry(10) {
val imageVirtualDisplay = createVirtualDisplay(...)
try {
withTimeout(100) {
// awaitImageAvailable will suspend here to get the non-empty bitmap
val bitmap = imageReader.awaitImageAvailable(screenWidth, screenHeight)
// save bitmap to file
}
} finally {
Timber.d("screenshot imageVirtualDisplay release")
imageVirtualDisplay?.release()
}
}

awaitImageAvailable:的实现

suspend fun ImageReader.awaitImageAvailable(screenWidth: Int, screenHeight: Int): Bitmap =
suspendCancellableCoroutine { cont ->
setOnImageAvailableListener({ imageReader ->
val image = imageReader.acquireLatestImage() ?: throw Error("get screen image result failed")
val planes = image.planes
val buffer = planes[0].buffer
val pixelStride = planes[0].pixelStride
val rowStride = planes[0].rowStride
val rowPadding: Int = rowStride - pixelStride * screenWidth
var bitmap =
Bitmap.createBitmap(screenWidth + rowPadding / pixelStride, screenHeight, Bitmap.Config.ARGB_8888)
bitmap.copyPixelsFromBuffer(buffer)
bitmap = Bitmap.createBitmap(bitmap, 0, 0, screenWidth, screenHeight)
image.close()
if (!bitmap.isEmptyBitmap()) {
Timber.d("image not empty")
setOnImageAvailableListener(null, null)
cont.resume(bitmap)
} else {
Timber.w("image empty")
}
}, Handler(Looper.getMainLooper()))
cont.invokeOnCancellation { setOnImageAvailableListener(null, null) }
}