Android打开camera实现录屏

要在 Android 上实现录屏，您可以使用 MediaProjection API。下面是一个简单的示例代码：

首先，在 AndroidManifest.xml 文件中添加以下权限：

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

然后，在您的 Activity 中，您可以按照以下步骤进行操作：

1. 请求录屏权限：

private static final int REQUEST_CODE = 1;
private MediaProjectionManager mediaProjectionManager;

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

    mediaProjectionManager = (MediaProjectionManager) getSystemService(Context.MEDIA_PROJECTION_SERVICE);
    startActivityForResult(mediaProjectionManager.createScreenCaptureIntent(), REQUEST_CODE);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == REQUEST_CODE && resultCode == RESULT_OK) {
        MediaProjection mediaProjection = mediaProjectionManager.getMediaProjection(resultCode, data);
        startRecording(mediaProjection);
    }
}

2. 开始录屏：

private MediaRecorder mediaRecorder;
private VirtualDisplay virtualDisplay;

private void startRecording(MediaProjection mediaProjection) {
    mediaRecorder = new MediaRecorder();
    mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    mediaRecorder.setVideoSource(MediaRecorder.VideoSource.SURFACE);
    mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
    mediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
    mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
    mediaRecorder.setVideoEncodingBitRate(512 * 1000);
    mediaRecorder.setVideoFrameRate(30);

    // 保存录屏文件
    File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES), "screen.mp4");
    mediaRecorder.setOutputFile(file.getAbsolutePath());

    try {
        mediaRecorder.prepare();
        Surface surface = mediaRecorder.getSurface();
        virtualDisplay = mediaProjection.createVirtualDisplay("ScreenRecording",
                getResources().getDisplayMetrics().widthPixels,
                getResources().getDisplayMetrics().heightPixels,
                getResources().getDisplayMetrics().densityDpi,
                DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,
                surface, null, null);
        mediaRecorder.start();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

3. 停止录屏：

private void stopRecording() {
    if (mediaRecorder != null) {
        mediaRecorder.stop();
        mediaRecorder.reset();
        mediaRecorder.release();
        mediaRecorder = null;
    }

    if (virtualDisplay != null) {
        virtualDisplay.release();
        virtualDisplay = null;
    }
}

请注意，这只是一个简单的示例代码，您可能需要根据您的需求进行适当的修改和完善。此外，录屏期间可能会有一些性能和兼容性方面的问题，您可能需要进行一些额外的处理。