在 Android 10 及更早的版本中,可以通过以下代码启动屏幕录制:
MediaProjectionManager mediaProjectionManager = (MediaProjectionManager) getSystemService(Context.MEDIA_PROJECTION_SERVICE); Intent captureIntent = mediaProjectionManager.createScreenCaptureIntent(); startActivityForResult(captureIntent, REQUEST_CODE_SCREENCAST);
但在 Android 11 中,由于安全原因,必须添加 "android.permission.CAPTURE_VIDEO_OUTPUT" 权限,如下所示:
然后,在启动屏幕录制时需要检查该权限是否已授予,如下所示:
MediaProjectionManager mediaProjectionManager = (MediaProjectionManager) getSystemService(Context.MEDIA_PROJECTION_SERVICE); Intent captureIntent = mediaProjectionManager.createScreenCaptureIntent(); if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAPTURE_VIDEO_OUTPUT) == PackageManager.PERMISSION_GRANTED) { startActivityForResult(captureIntent, REQUEST_CODE_SCREENCAST); } else { ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAPTURE_VIDEO_OUTPUT}, REQUEST_CODE_PERMISSION); }
如果权限未被授予,则需要先请求它,如下所示:
@Override public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { if (requestCode == REQUEST_CODE_PERMISSION) { if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { Toast.makeText(this, "Permission granted", Toast.LENGTH_SHORT).show(); startActivityForResult(captureIntent, REQUEST_CODE_SCREENCAST); } else { Toast.makeText(this, "Permission denied", Toast.LENGTH_SHORT).show(); } return; } super.onRequestPermissionsResult(requestCode, permissions, grantResults); }
在开始屏幕录制后,如果只出现缩略图并无法播放视频,则需要查询 MediaCodecInfo 和 MediaCodecList 是否支持此编解码器。例如,以下代码将查询是否支持 H.264 编码器:
MediaCodecInfo[] codecInfos = new MediaCodecList(MediaCodecList.REGULAR_CODECS).getCodecInfos(); for (MediaCodecInfo codecInfo : codecInfos) { if (codecInfo.isEncoder()) { String[] types = codecInfo.getSupportedTypes(); for (String type : types) { if (type.equalsIgnoreCase(MediaFormat.MIMETYPE_VIDEO_AVC)) { Log.d(TAG, "H.264 encoder found: " + codecInfo.getName()); } } } }
如果无法找到支持的编解码器,则需要使用支持的编解码器或