Java 如果我在设备中更改墙纸，如何跟踪事件

我正在创建一个应用程序，其中我正在设置一个具有墙纸洗牌效果的图像库。若应用程序在后台，则洗牌效果有效。 但问题是，当我将我的壁纸从我的设备更改为设置在主屏幕上时（不是从应用程序，而是选择设备的形式壁纸），该壁纸将设置在我的主屏幕上，并且洗牌效果仍将继续（因为我认为服务正在运行）。有人能告诉我是什么问题以及如何解决这个问题吗。这是我的服务课：

public class WallpaperService extends Service {
ArrayList<String> arrayList = new ArrayList<>();
int counter = 0;
Bitmap bmImg = null;
int seconds;
public WallpaperService() {
}

@Override
public IBinder onBind(Intent intent) {
    // TODO: Return the communication channel to the service.
    throw new UnsupportedOperationException("Not yet implemented");
}

@Override
public int onStartCommand(Intent intent, int flag, int startId) {
    super.onStartCommand(intent, flag, startId);
    arrayList = intent.getStringArrayListExtra("image_url");
    seconds = intent.getIntExtra("seconds", 5000 * 60);
    Toast.makeText(this, "Hello", Toast.LENGTH_SHORT).show();
    SaveWallpaperAsync async = new SaveWallpaperAsync();
    async.execute();
           return START_STICKY;
}

@Override
public void onCreate() {
    super.onCreate();
}

@Override
public void onTaskRemoved(Intent rootIntent){
    Intent restartServiceTask = new Intent(getApplicationContext(),this.getClass());
    restartServiceTask.setPackage(getPackageName());
    PendingIntent restartPendingIntent =PendingIntent.getService(getApplicationContext(), 1,restartServiceTask, PendingIntent.FLAG_ONE_SHOT);
    AlarmManager myAlarmService = (AlarmManager) getApplicationContext().getSystemService(Context.ALARM_SERVICE);
    myAlarmService.set(
            AlarmManager.ELAPSED_REALTIME,
            SystemClock.elapsedRealtime() + 1000,
            restartPendingIntent);
}

public class SaveWallpaperAsync extends AsyncTask<String, Integer, Void> {
    URL ImageUrl;
    Bitmap bmImg = null;

    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub
        super.onPreExecute();
        Toast.makeText(WallpaperService.this, "downloading", Toast.LENGTH_SHORT).show();
    }

    @Override
    protected Void doInBackground(String... args) {
        // TODO Auto-generated method stub

        InputStream is = null;

        for (int i = 0; i < arrayList.size(); i++) {
            try {
                ImageUrl = new URL(arrayList.get(i));
                HttpURLConnection conn = (HttpURLConnection) ImageUrl.openConnection();
                conn.setDoInput(true);
                conn.connect();
                is = conn.getInputStream();

                BitmapFactory.Options options = new BitmapFactory.Options();
                options.inPreferredConfig = Bitmap.Config.RGB_565;
                bmImg = BitmapFactory.decodeStream(is, null, options);
                saveImageToInternalStorage(bmImg, i);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        // TODO Auto-generated method stub
        Toast.makeText(WallpaperService.this, "Downloaded", Toast.LENGTH_SHORT).show();
        createNotificationIcon();
    }
}

protected String saveImageToInternalStorage(Bitmap bitmap, int index) {

    File filepath = Environment.getExternalStorageDirectory();
    File dir = new File(filepath.getAbsolutePath()
            + "/Dark Wallpapers/");
    if (!dir.exists()){
        dir.mkdirs();
    }
    File file = new File(dir, "UniqueFileName" + index + ".jpg");

    try {
        OutputStream stream = null;
        stream = new FileOutputStream(file);
        bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);
        stream.flush();
        stream.close();

    } catch (IOException e) {
        e.printStackTrace();
    }

    Uri savedImageURI = Uri.parse(file.getAbsolutePath());
    return savedImageURI.toString();
}

private Bitmap loadImageFromStorage(int counter) {
    Bitmap b = null;
    try {
        File file = new File(Environment.getExternalStorageDirectory().getAbsolutePath()+"/Dark Wallpapers/", "UniqueFileName" + counter + ".jpg");
        b = BitmapFactory.decodeStream(new FileInputStream(file));
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }
    return b;
}

public void createNotificationIcon() {
    final WallpaperManager wallpaperManager = WallpaperManager.getInstance(this);
    Timer t = new Timer();
    t.scheduleAtFixedRate(new TimerTask() {
                              @Override
                              public void run() {
                                  counter += 1;
                                  if (counter < arrayList.size()) {
                                      try {
                                          wallpaperManager.setBitmap(loadImageFromStorage(counter));
                                          wallpaperManager.suggestDesiredDimensions(1080, 1920);
                                      } catch (IOException e) {
                                          e.printStackTrace();
                                      }
                                  } else if (counter == arrayList.size()) {
                                      counter = 0;
                                      try {
                                          wallpaperManager.setBitmap(loadImageFromStorage(counter));
                                          wallpaperManager.suggestDesiredDimensions(1080, 1920);
                                      } catch (IOException e) {
                                          e.printStackTrace();
                                      }
                                  }

                              }

                          },
            0,
            seconds);

}}

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如果我理解的很好，你想得到一个“事件”（或只是想知道…）当家庭壁纸改变。是这样吗？ 如果检测到用户希望从那时起设置固定墙纸，您可能希望停止服务

没有任何事件可以这样做，但有一个解决方案：记住你从应用程序中自动更改的壁纸（可能记住/xxxxx/files文件夹中文件的路径+文件名），然后在尝试设置新壁纸之前检查当前壁纸，使用以下方法：

wallpermanager=wallpermanager.getInstance（this）；
Drawable wallparDrawable=wallparkmanager.getDrawable（）

通过这种方式，如果当前壁纸与您上次记忆的文件名相同，则99%的可能性是用户没有自行设置固定的壁纸。（剩下的1%可能是用户手动设置与上次自动设置的墙纸相同的墙纸，但这种情况非常罕见）

Intent intent = new Intent(CategoryActivity.this, WallpaperService.class);
intent.putExtra("image_url", img_urls);
            intent.putExtra("seconds", 60);
            intent.setAction(Constants.ACTION.STARTFOREGROUND_ACTION);
            startService(intent);