我想做的是制作一个可以在屏幕关闭时录制视频或音频的应用程序。我们要么开始录制，然后关闭屏幕，要么录音机应该通过语音或任何其他外部命令触发。无论哪种情况，应用程序都应继续录制。

请提供您可以使用的代码。

最佳答案

大多数时候，当需要离线完成某些事情时，它是在 service 中完成的。

(www.slideshare.net)

假设您从文档中不知道服务是什么:

A Service is an application component representing either an application's desire to perform a longer-running operation while not interacting with the user or to supply functionality for other applications to use. Each service class must have a corresponding declaration in its package's AndroidManifest.xml. Services can be started with Context.startService() and Context.bindService().

所以基本上，它只是在后台运行的东西，包括屏幕关闭时。现在，您所要做的就是将录制代码放入服务中。您可能会遇到服务被系统杀死的问题，正如 android 文档所指定的那样:

Note this means that most of the time your service is running, it may be killed by the system if it is under heavy memory pressure. If this happens, the system will later try to restart the service. An important consequence of this is that if you implement onStartCommand() to schedule work to be done asynchronously or in another thread, then you may want to use START_FLAG_REDELIVERY to have the system re-deliver an Intent for you so that it does not get lost if your service is killed while processing it.

在这种情况下，您需要添加某些代码以将服务保持在前台并确保它不会被杀死:

startForeground();//keeps service from getting destroyed.

这可能提供的唯一问题是服务处于 Activity 状态时的持续通知。

你也可以使用 startSticky():

@Override
public int onStartCommand(Intent intent, int flags, int startId) {

       // We want this service to continue running until it is explicitly
       // stopped, so return sticky.
       return START_STICKY;
}

现在，假设您已完成录制。您可以使用:

stopSelf();

停止服务，或者:

Context.stopService();

不过，这个通知并不是什么大问题，因为服务运行时屏幕很可能是关闭的。您还可以自定义通知，让用户知道后台发生了什么会更好。

这是一些示例录制代码:

public class VideoCapture extends Activity implements OnClickListener, SurfaceHolder.Callback {
    MediaRecorder recorder;
    SurfaceHolder holder;
    boolean recording = false;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

        recorder = new MediaRecorder();
        initRecorder();
        setContentView(R.layout.main);

        SurfaceView cameraView = (SurfaceView) findViewById(R.id.CameraView);
        holder = cameraView.getHolder();
        holder.addCallback(this);
        holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

        cameraView.setClickable(true);
        cameraView.setOnClickListener(this);
    }

    private void initRecorder() {
        recorder.setAudioSource(MediaRecorder.AudioSource.DEFAULT);
        recorder.setVideoSource(MediaRecorder.VideoSource.DEFAULT);

        CamcorderProfile cpHigh = CamcorderProfile
                .get(CamcorderProfile.QUALITY_HIGH);
        recorder.setProfile(cpHigh);
        recorder.setOutputFile("/sdcard/videocapture_example.mp4");
        recorder.setMaxDuration(50000); // 50 seconds
        recorder.setMaxFileSize(5000000); // Approximately 5 megabytes
    }

    private void prepareRecorder() {
        recorder.setPreviewDisplay(holder.getSurface());

        try {
            recorder.prepare();
        } catch (IllegalStateException e) {
            e.printStackTrace();
            finish();
        } catch (IOException e) {
            e.printStackTrace();
            finish();
        }
    }

    public void onClick(View v) {
        if (recording) {
            recorder.stop();
            recording = false;

            // Let's initRecorder so we can record again
            initRecorder();
            prepareRecorder();
        } else {
            recording = true;
            recorder.start();
        }
    }

    public void surfaceCreated(SurfaceHolder holder) {
        prepareRecorder();
    }

    public void surfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        if (recording) {
            recorder.stop();
            recording = false;
        }
        recorder.release();
        finish();
    }
}

( How can I capture a video recording on Android? )

再次，正如我之前解释的那样，将该代码放入一个长时间运行的前台服务中。

如果您需要更多帮助，请随时提出。

~鲁基尔

关于java - 屏幕关闭时的Android应用程序视频录制，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/26397382/