android - 为什么 BroadcastReceiver 不起作用？

Question

我有一项 Activity 和一项服务。在服务中，我有一个 BroadcastReceiver，我想在其中输出一条消息。当我启动上述服务时，为什么它不显示消息？

Activity :

public class MainActivity extends AppCompatActivity
{
private Button button_sel; //adaugat

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

    checkLicenta(); //adaugat

    // adaugat
    findViewById(R.id.button).setOnClickListener(new View.OnClickListener()
    {
        @Override
        public void onClick(View v)
        {
            Intent intent = new Intent(MainActivity.this, MainService.class);
            startService(intent);
            Toast.makeText(MainActivity.this, "Service, Running", Toast.LENGTH_SHORT).show();
        }
    }); //pana aici

    // adaugat
    findViewById(R.id.button2).setOnClickListener(new View.OnClickListener()
    {
        @Override
        public void onClick(View v)
        {
            Intent intent = new Intent(MainActivity.this, MainService.class);
            stopService(intent);
            Toast.makeText(MainActivity.this, "Service, Stopped", Toast.LENGTH_SHORT).show();
        }
    }); //pana aici
}

}

服务:

public class MainService extends Service
{
private static final String TAG = "HelloService";

private boolean isRunning  = false;

@Override
public void onCreate()
{
    registerReceiver(counter, new IntentFilter(Intent.ACTION_SCREEN_ON));
    Log.i(TAG, "Service, onCreate");
    Toast.makeText(MainService.this, "Service, Created", Toast.LENGTH_SHORT).show();
    isRunning = true;
}

private BroadcastReceiver counter = new BroadcastReceiver()
{
    @Override
    public void onReceive(Context context, Intent intent)
    {
        Toast.makeText(MainService.this, "LALALA", Toast.LENGTH_SHORT).show();
    }
};

@Override
public int onStartCommand(Intent intent, int flags, int startId)
{
    Log.i(TAG, "Service, onStartCommand");
    Toast.makeText(MainService.this, "Service, Started", Toast.LENGTH_SHORT).show();
    return super.onStartCommand(intent, flags, startId);
}

@Override
public void onDestroy()
{
    Log.i(TAG, "Service, onDestroy");
    Toast.makeText(MainService.this, "Service, Destroyed", Toast.LENGTH_SHORT).show();
    isRunning = false;
}

@Override
public IBinder onBind(Intent intent)
{
    Log.i(TAG, "Service, onBind");
    return null;
}
}

更新:由于 ACTION_SCREEN_ON，该消息实际上会在您打开屏幕时出现。

Answer 1

您的代码工作正常，您是否在 AndroidManifest 中声明了您的服务？

   <application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name=".MainActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
       <service
        android:name="com.example.test.MainService"
        android:exported="true" >
          <intent-filter>
            <action android:name="com.example.test.MainService" />

            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </service>
</application>