android - 如何只获取一次 MediaProjectionManager 屏幕捕获权限而不是每次都使用？

Question

public class MainActivity extends AppCompatActivity {

private static final String TAG = "MainActivity";
private static final int REQUEST_CODE = 1234;
private int mScreenDensity;
private MediaProjectionManager mProjectionManager;
private static final int DISPLAY_WIDTH = 720;
private static final int DISPLAY_HEIGHT = 1280;
private MediaProjection mMediaProjection;
private VirtualDisplay mVirtualDisplay;
private ToggleButton mToggleButton;
private MediaRecorder mMediaRecorder;
private static final SparseIntArray ORIENTATIONS = new SparseIntArray();
private static final int REQUEST_PERMISSIONS = 10;

static {
    ORIENTATIONS.append(Surface.ROTATION_0, 90);
    ORIENTATIONS.append(Surface.ROTATION_90, 0);
    ORIENTATIONS.append(Surface.ROTATION_180, 270);
    ORIENTATIONS.append(Surface.ROTATION_270, 180);
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    DisplayMetrics metrics = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(metrics);
    mScreenDensity = metrics.densityDpi;


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

    mToggleButton = (ToggleButton) findViewById(R.id.toggle);
    mToggleButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (ContextCompat.checkSelfPermission(MainActivity.this,
                    Manifest.permission.WRITE_EXTERNAL_STORAGE) + ContextCompat
                    .checkSelfPermission(MainActivity.this,
                            Manifest.permission.RECORD_AUDIO)
                    != PackageManager.PERMISSION_GRANTED) {
                if (ActivityCompat.shouldShowRequestPermissionRationale
                        (MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) ||
                        ActivityCompat.shouldShowRequestPermissionRationale
                                (MainActivity.this, Manifest.permission.RECORD_AUDIO)) {
                    mToggleButton.setChecked(false);
                    Snackbar.make(findViewById(android.R.id.content), R.string.label_permissions,
                            Snackbar.LENGTH_INDEFINITE).setAction("ENABLE",
                            new View.OnClickListener() {
                                @Override
                                public void onClick(View v) {
                                    ActivityCompat.requestPermissions(MainActivity.this,
                                            new String[]{Manifest.permission
                                                    .WRITE_EXTERNAL_STORAGE, Manifest.permission.RECORD_AUDIO},
                                            REQUEST_PERMISSIONS);
                                }
                            }).show();
                } else {
                    ActivityCompat.requestPermissions(MainActivity.this,
                            new String[]{Manifest.permission
                                    .WRITE_EXTERNAL_STORAGE, Manifest.permission.RECORD_AUDIO},
                            REQUEST_PERMISSIONS);
                }
            } else {
                onToggleScreenShare(v);
            }
        }
    });
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {

    Log.d(TAG, " requestCode " + requestCode + " resultCode " + requestCode);

    if (REQUEST_CODE == requestCode) {
        if (resultCode == RESULT_OK) {
            mMediaProjection = mProjectionManager.getMediaProjection(resultCode, data);
            startRecording(); // defined below
        } else {
            Log.d(TAG, "Persmission denied");
        }
    }
}

private static final String VIDEO_MIME_TYPE = "video/avc";
private static final int VIDEO_WIDTH = 720;
private static final int VIDEO_HEIGHT = 1280;
// …
private boolean mMuxerStarted = false;
private Surface mInputSurface;
private MediaMuxer mMuxer;
private MediaCodec mVideoEncoder;
private MediaCodec.BufferInfo mVideoBufferInfo;
private int mTrackIndex = -1;

private final Handler mDrainHandler = new Handler(Looper.getMainLooper());
private Runnable mDrainEncoderRunnable = new Runnable() {
    @Override
    public void run() {
        drainEncoder();
    }
};

private void startRecording() {

    DisplayManager dm = (DisplayManager) getSystemService(Context.DISPLAY_SERVICE);
    Display defaultDisplay = dm.getDisplay(Display.DEFAULT_DISPLAY);
    if (defaultDisplay == null) {
        throw new RuntimeException("No display found.");
    }
    prepareVideoEncoder();

    try {
        mMuxer = new MediaMuxer(Environment.getExternalStoragePublicDirectory(Environment
                .DIRECTORY_DOWNLOADS) + "/video.mp4", MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
    } catch (IOException ioe) {
        throw new RuntimeException("MediaMuxer creation failed", ioe);
    }

    // Get the display size and density.
    DisplayMetrics metrics = getResources().getDisplayMetrics();
    int screenWidth = metrics.widthPixels;
    int screenHeight = metrics.heightPixels;
    int screenDensity = metrics.densityDpi;

    // Start the video input.
    mMediaProjection.createVirtualDisplay("Recording Display", screenWidth,
            screenHeight, screenDensity, 0 /* flags */, mInputSurface,
            null /* callback */, null /* handler */);

    // Start the encoders
    drainEncoder();
}

private void prepareVideoEncoder() {

    mVideoBufferInfo = new MediaCodec.BufferInfo();
    MediaFormat format = MediaFormat.createVideoFormat(VIDEO_MIME_TYPE, VIDEO_WIDTH, VIDEO_HEIGHT);
    int frameRate = 15; // 30 fps

    // Set some required properties. The media codec may fail if these aren't defined.
    format.setInteger(MediaFormat.KEY_COLOR_FORMAT, MediaCodecInfo.CodecCapabilities.COLOR_FormatSurface);
    //format.setInteger(MediaFormat.KEY_SAMPLE_RATE, 8000);
    format.setInteger(MediaFormat.KEY_BIT_RATE, 6000000); // 6Mbps
    format.setInteger(MediaFormat.KEY_FRAME_RATE, frameRate);
    //format.setInteger(MediaFormat.KEY_CAPTURE_RATE, frameRate);
    // format.setInteger(MediaFormat.KEY_REPEAT_PREVIOUS_FRAME_AFTER, 1000000 / frameRate);
    //format.setInteger(MediaFormat.KEY_CHANNEL_COUNT, 1);
    format.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, 10); // 1 seconds between I-frames

    // Create a MediaCodec encoder and configure it. Get a Surface we can use for recording into.
    try {
        mVideoEncoder = MediaCodec.createEncoderByType(VIDEO_MIME_TYPE);
        mVideoEncoder.configure(format, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
        mInputSurface = mVideoEncoder.createInputSurface();
        mVideoEncoder.start();
    } catch (IOException e) {
        releaseEncoders();
    }
}

private void releaseEncoders() {


    mDrainHandler.removeCallbacks(mDrainEncoderRunnable);
    if (mMuxer != null) {
        if (mMuxerStarted) {
            mMuxer.stop();
        }
        mMuxer.release();
        mMuxer = null;
        mMuxerStarted = false;
    }
    if (mVideoEncoder != null) {
        mVideoEncoder.stop();
        mVideoEncoder.release();
        mVideoEncoder = null;
    }
    if (mInputSurface != null) {
        mInputSurface.release();
        mInputSurface = null;
    }
    if (mMediaProjection != null) {
        mMediaProjection.stop();
        mMediaProjection = null;
    }
    mVideoBufferInfo = null;
    //mDrainEncoderRunnable = null;
    mTrackIndex = -1;
}

private boolean drainEncoder() {
    mDrainHandler.removeCallbacks(mDrainEncoderRunnable);
    while (true) {
        int bufferIndex = mVideoEncoder.dequeueOutputBuffer(mVideoBufferInfo, 0);

        if (bufferIndex == MediaCodec.INFO_TRY_AGAIN_LATER) {
            // nothing available yet
            break;
        } else if (bufferIndex == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
            // should happen before receiving buffers, and should only happen once
            if (mTrackIndex >= 0) {
                throw new RuntimeException("format changed twice");
            }
            mTrackIndex = mMuxer.addTrack(mVideoEncoder.getOutputFormat());
            if (!mMuxerStarted && mTrackIndex >= 0) {
                mMuxer.start();
                mMuxerStarted = true;
            }
        } else if (bufferIndex < 0) {
            // not sure what's going on, ignore it
        } else {
            ByteBuffer encodedData = mVideoEncoder.getOutputBuffer(bufferIndex);
            if (encodedData == null) {
                throw new RuntimeException("couldn't fetch buffer at index " + bufferIndex);
            }

            if ((mVideoBufferInfo.flags & MediaCodec.BUFFER_FLAG_CODEC_CONFIG) != 0) {
                mVideoBufferInfo.size = 0;
            }

            if (mVideoBufferInfo.size != 0) {
                if (mMuxerStarted) {
                    encodedData.position(mVideoBufferInfo.offset);
                    encodedData.limit(mVideoBufferInfo.offset + mVideoBufferInfo.size);
                    mMuxer.writeSampleData(mTrackIndex, encodedData, mVideoBufferInfo);
                } else {
                    // muxer not started
                }
            }

            mVideoEncoder.releaseOutputBuffer(bufferIndex, false);

            if ((mVideoBufferInfo.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
                break;
            }
        }
        Log.d(TAG, "Recording");
    }

    mDrainHandler.postDelayed(mDrainEncoderRunnable, 10);

    return false;
}


public void onToggleScreenShare(View view) {
    if (((ToggleButton) view).isChecked()) {
        if (mMediaProjection == null) {
            startActivityForResult(mProjectionManager.createScreenCaptureIntent(), REQUEST_CODE);
        } else {
            startRecording();
        }
    } else {
        releaseEncoders();
    }
}

startActivityForResult(mProjectionManager.createScreenCaptureIntent(), REQUEST_CODE);

这行代码请求捕获屏幕的权限。每次我的代码调用它时，它都会显示一个对话框以获得许可。但是如果我点击“不再显示”，它不会请求权限，而是在后台授予权限。我怎样才能只获得一次许可并在不选择不再显示的情况下授予所有时间？完整代码在这里给出

Answer 1

public void onToggleScreenShare(View view) {
if (((ToggleButton) view).isChecked()) {
    if (mMediaProjection == null) {
        startActivityForResult(mProjectionManager.createScreenCaptureIntent(), REQUEST_CODE);
    } else {
        startRecording();
    }
} else {
    releaseEncoders();
}
}

在这个Method上的startActivityForResult()方法提示截屏权限。如果授予权限或拒绝它代码传输调用 onActivityResultMethod()

    @Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {

Log.d(TAG, " requestCode " + requestCode + " resultCode " + requestCode);

if (REQUEST_CODE == requestCode) {
    if (resultCode == RESULT_OK) {
        mMediaProjection = mProjectionManager.getMediaProjection(resultCode, data);
        startRecording(); // defined below
    } else {
        Log.d(TAG, "Persmission denied");
    }
}
}

在这个方法中我们得到了 Intent 数据和 resultCode。为了进一步使用 MediaProjectionManager 而无需请求持续许可，我们必须保存 Intent 的引用和 resultCode 的值，并通过这行代码使用 mediaProjectionManager

mMediaProjection = mProjectionManager.getMediaProjection(saveResult, savedIntent);

所以它不会再次请求权限，因为权限已经被授予