当尝试更新TextView时，SharedPreferences不工作

Question

更新:我已经添加了整个MainService和MainActivity，以防在其他地方出现问题。此外，我还添加了下面提供的解决方案，虽然它仍然不会更新TextView。

我试图改变一个TextView，我希望它是永久的，所以我使用的是SharedPreferences。遗憾的是，有些东西是错误的，因为TextView不更新。

MainService:

public class MainService extends Service {
public static final String BROADCAST_ACTION = "com.example.vladpintea.friendsbeforecents.displayevent";
private final Handler handler = new Handler();
int counterr = 0;
Intent intentt;
String usedTimer;
long interval;
//TimerTask that will cause the run() runnable to happen.
TimerTask myTask = new TimerTask() {
    public void run() {
        stopSelf();
    }
};
//Timer that will make the runnable run.
Timer myTimer = new Timer();
@Override
public void onCreate() {
    intentt = new Intent(BROADCAST_ACTION);
    registerReceiver(counter, new IntentFilter(Intent.ACTION_SCREEN_ON));
    Toast.makeText(MainService.this, "Service, Created", Toast.LENGTH_SHORT).show();
}
private BroadcastReceiver counter = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        Toast.makeText(MainService.this, "Whoops! You've Lost.", Toast.LENGTH_SHORT).show();
        Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_OFF_TIMEOUT, 30000);
    }
};
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    Toast.makeText(MainService.this, "Service, Started", Toast.LENGTH_SHORT).show();
    usedTimer = intent.getStringExtra("timer");
    try {
        interval = Long.parseLong(usedTimer);
    } catch (NumberFormatException ignored) {}
    myTimer.schedule(myTask, interval);
    handler.removeCallbacks(sendUpdatesToUI);
    handler.postDelayed(sendUpdatesToUI, 1000);
    return super.onStartCommand(intent, flags, startId);
}
private Runnable sendUpdatesToUI = new Runnable() {
    public void run() {
        handler.postDelayed(this, 1000);
    }
};
public void DisplayLoggingInfoPlus() {
    intentt.putExtra("counter", String.valueOf(++counterr));
    sendBroadcast(intentt);
}
@Override
public void onDestroy() {
    DisplayLoggingInfoPlus();
    PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
    PowerManager.WakeLock wakeLock = pm.newWakeLock(PowerManager.FULL_WAKE_LOCK
            | PowerManager.ACQUIRE_CAUSES_WAKEUP
            | PowerManager.ON_AFTER_RELEASE, "MyWakeLock");
    wakeLock.acquire();
    Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_OFF_TIMEOUT, 30000);
}
@Override
public IBinder onBind(Intent intent) {
    return null;
}

MainActivity:

public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    final Button startApp = (Button) findViewById(R.id.startApp);
    final EditText timer = (EditText) findViewById(R.id.insertTimer);
    assert startApp != null;
    startApp.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Toast.makeText(MainActivity.this, "Countdown, Started", Toast.LENGTH_SHORT).show();
            Intent intent = new Intent(MainActivity.this, MainService.class);
            assert timer != null;
            intent.putExtra("timer", timer.getText().toString());
            Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_OFF_TIMEOUT, 1000);
            registerReceiver(broadcastReceiver, new IntentFilter(MainService.BROADCAST_ACTION));
            startService(intent);
        }
    });
}
private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        updateUI(intent);
    }
};
private void updateUI(Intent intent) {
    String counter = intent.getStringExtra("counter");
    TextView txtCounter = (TextView) findViewById(R.id.txtCounter);
    assert txtCounter != null;
    SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
    SharedPreferences.Editor editor = preferences.edit();
    editor.putString(counter,txtCounter.getText().toString());
    editor.commit();
}

}

Answer 1

遗憾的是，有些事情是错误的，因为TextView不更新。

你需要通过调用setText()来更新TextView:

String counter = intent.getStringExtra("counter");
TextView txtCounter = (TextView) findViewById(R.id.txtCounter);
txtCounter.setText(counter);

Answer 2

在共享首选项中存储值:

SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("Counter",String.valueOf(txtCounter));
editor.apply();

从共享首选项中检索值:

SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
String Counter= preferences.getString("Counter", "");
if(!Counter.equalsIgnoreCase(""))
{
    Counter= Counter+ "  Counter";  /* Edit the value here*/
}

Answer 3

更改以下行

从

editor.putString(String.valueOf(txtCounter), counter);

editor.putString("counter",txtCounter.getText().toString());