Question

我正在尝试在服务内部注册FileObserver，以监视新照片何时保存到“ / DCIM / Camera /”。到目前为止，我已经尝试了所有可以在网上找到的内容。我认为它应该已经可以工作了……

我确实请求清单中的权限：

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <service android:name=".FileWatcherService"
             android:enabled="true"
             android:exported="false"/>
    <!-- Declaring broadcast receiver for BOOT_COMPLETED event. -->
    <receiver android:name=".StartupReceiver" android:enabled="true" android:exported="false">
        <intent-filter>
            <action android:name="android.intent.action.BOOT_COMPLETED"/>
        </intent-filter>
    </receiver>

我的观察者：

public class FileWatcherService extends Service {

static String PATH = Environment.getExternalStorageDirectory().getAbsolutePath() + "/DCIM/Camera/";
private static String TAG = "FileWatcher";

public static FileObserver fileObserver = new FileObserver(PATH, CREATE) {
    @Override
    public void onEvent(int i, @Nullable String s) {
        Log.d(TAG, "eventttttt"); //never triggered
    }
};

@Nullable
@Override
public IBinder onBind(Intent intent) {
    return null;
}

@Override
public void onDestroy() {
    Log.d(TAG, "onDestroy: service destroyed");
}

@Override
public void onCreate() {
    super.onCreate();
    Log.d(TAG, "onCreate: service created");
}

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

    int res = super.onStartCommand(intent, flags, startId);

    fileObserver.startWatching();

    Log.d(TAG,"Service started!");
    return Service.START_STICKY;
}

public static void start(Context ctx) {
    Intent i = new Intent(ctx, FileWatcherService.class);
    ctx.startService(i);
}
}

主要活动：

public class MainActivity extends AppCompatActivity {

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if(grantResults[0]== PackageManager.PERMISSION_GRANTED){
        Log.v(".","Permission: "+permissions[0]+ "was "+grantResults[0]);

        FileWatcherService.start(getApplicationContext());
    }
}


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

    ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
}
}

我想念什么？服务开始就很好。

感谢您的帮助。

Answer 1

要在本地确认更改，请转到“设置”->“应用程序信息”->“您的应用程序”->“权限”，然后启用“存储”权限。完全关闭您的应用程序（也从任务中删除），然后检查您的代码是否有效。

实际上似乎缺少的是请求用户访问外部存储。

参考：https://developer.android.com/training/permissions/requesting

Android FileObserver不会触发onEvent

1 个答案: