android 录屏功能实现

在 Android 上实现录屏功能可以使用 MediaProjection API。以下是一个简单的实现步骤：

1.获取屏幕的分辨率和密度。

DisplayMetrics metrics = getResources().getDisplayMetrics();
int screenWidth = metrics.widthPixels;
int screenHeight = metrics.heightPixels;
int screenDensity = metrics.densityDpi;

2.请求访问媒体投影，以允许应用程序捕获屏幕内容。

MediaProjectionManager manager = (MediaProjectionManager) getSystemService(MEDIA_PROJECTION_SERVICE);
Intent permissionIntent = manager.createScreenCaptureIntent();
startActivityForResult(permissionIntent, PERMISSION_REQUEST_CODE);

3.在 onActivityResult() 方法中，获取 MediaProjection 对象。

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == PERMISSION_REQUEST_CODE) {
        if (resultCode == RESULT_OK) {
            MediaProjectionManager manager = (MediaProjectionManager) getSystemService(MEDIA_PROJECTION_SERVICE);
            MediaProjection mediaProjection = manager.getMediaProjection(resultCode, data);
            startRecording(mediaProjection);
        } else {
            // Permission denied
        }
    }
}

4.使用 MediaRecorder 开始录制屏幕。

private void startRecording(MediaProjection mediaProjection) {
    String fileName = "screen_record_" + System.currentTimeMillis() + ".mp4";
    File outputFile = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS), fileName);

    final int videoWidth = screenWidth;
    final int videoHeight = screenHeight;
    final int videoBitrate = 6000000;
    final int videoFrameRate = 30;

    MediaRecorder mediaRecorder = new MediaRecorder();
    mediaRecorder.setVideoSource(MediaRecorder.VideoSource.SURFACE);
    mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
    mediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
    mediaRecorder.setVideoSize(videoWidth, videoHeight);
    mediaRecorder.setVideoFrameRate(videoFrameRate);
    mediaRecorder.setVideoEncodingBitRate(videoBitrate);
    mediaRecorder.setOutputFile(outputFile.getAbsolutePath());

    try {
        mediaRecorder.prepare();
    } catch (IOException e) {
        e.printStackTrace();
    }

    Surface surface = mediaRecorder.getSurface();
    VirtualDisplay virtualDisplay = mediaProjection.createVirtualDisplay("ScreenCapture",
            videoWidth, videoHeight, screenDensity,
            DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,
            surface, null, null);

    mediaRecorder.start();

    // Stop recording and release resources
    mediaRecorder.stop();
    mediaRecorder.release();
    virtualDisplay.release();
    mediaProjection.stop();
}

5.在录制完成后，停止录制并释放资源。

请注意，需要在 AndroidManifest.xml 文件中添加 RECORD_AUDIO 和 WRITE_EXTERNAL_STORAGE 权限。

<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />