Question

我在服务中的onstartcommand中声明了值。然后我无法将它们传递给run方法中的displayedText。任何解决方法？

也许是为了优化时间任务？
声明全局无法完成，因为不允许使用公共修饰符。此外，如果我重新定义displayedText，它将不会传递来自displayedText = intent.getStringExtra的任何值（＆＃34; PassToService＆＃34;）;

MyService.java

public class MyService extends Service {
public static final long INTERVAL=3000;//variable to execute services every 5 second
private Handler mHandler=new Handler(); // run on another Thread to avoid crash
private Timer mTimer=null; // timer handling

@Nullable
@Override
public IBinder onBind(Intent intent) {
    throw new UnsupportedOperationException("unsupported Operation");
}
@Override
public void onCreate() {

}

private String displayingText;

public int onStartCommand (Intent intent, int flags, int startId) {
    String displayingText = intent.getStringExtra("PassToService");
    Toast.makeText(this, displayingText, Toast.LENGTH_SHORT).show();

    mTimer=new Timer(); // recreate new timer
    mTimer.scheduleAtFixedRate(new TimeDisplayTimerTask(),0,INTERVAL);

    //return super.onStartCommand(intent, flags, startId);
    return START_STICKY;
}


@Override
public void onTaskRemoved(Intent rootIntent) {
    stopSelf();///its will stop service
    super.onTaskRemoved(rootIntent);
}
@Override
public void onDestroy() {
    Toast.makeText(this, "In Destroy", Toast.LENGTH_SHORT).show();//display toast when method called
    mTimer.cancel();//cancel the timer
    super.onDestroy();

}

//inner class of TimeDisplayTimerTask
private class TimeDisplayTimerTask extends TimerTask {
    @Override
    public void run() {

        // run on another thread
        mHandler.post(new Runnable() {
            @Override
            public void run() {
                // display toast at every 10 second
                final Toast Notify = Toast.makeText(getApplicationContext(), displayingText, Toast.LENGTH_SHORT);
                Notify.setGravity(Gravity.CENTER, 0, 0);
                Notify.show();

                Handler cancelToast = new Handler();
                cancelToast.postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        Notify.cancel();
                    }
                }, 1000);

            }
        });
    }
}

Answer 1

全局声明你的字符串

而非此行：

String displayingText = intent.getStringExtra("PassToService");

用作：

public String displayText;
displayingText = intent.getStringExtra("PassToService");

Answer 2

您的问题是您没有在TimeDisplayTimerTask课程中声明，您应该使用displayingText作为全局变量。

尝试使用

String displayingText;

private class TimeDisplayTimerTask extends TimerTask {
    @Override
    public void run() {

        // run on another thread
        mHandler.post(new Runnable() {
            @Override
            public void run() {
                // display toast at every 10 second
                final Toast Notify = Toast.makeText(getApplicationContext(), displayingText, Toast.LENGTH_SHORT);
                Notify.setGravity(Gravity.CENTER, 0, 0);
                Notify.show();

                Handler cancelToast = new Handler();
                cancelToast.postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        Notify.cancel();
                    }
                }, 1000);

            }
        });
    }
}

并在代码中获得价值。

public int onStartCommand (Intent intent, int flags, int startId) {
    displayingText = intent.getStringExtra("PassToService");
    Toast.makeText(this, displayingText, Toast.LENGTH_SHORT).show();
    // edited here ,change the return value 
    return super.onStartCommand(intent, flags, startId);
}

修改

在getStringExtra
之后使用计时器
private String displayingText; public int onStartCommand (Intent intent, int flags, int startId) { displayingText = intent.getStringExtra("PassToService"); //SharedPreferences prefs = getSharedPreferences("MyPrefs",MODE_PRIVATE); //String displayingText = prefs.getString("data",""); Toast.makeText(this, displayingText, Toast.LENGTH_SHORT).show(); // cancel if service is already existed mTimer=new Timer(); // recreate new timer mTimer.scheduleAtFixedRate(new TimeDisplayTimerTask(),0,INTERVAL);// schedule task //Intent intent = getIntent(); //String displayingText = intent.getStringExtra("PassToService"); return START_STICKY; } //inner class of TimeDisplayTimerTask private class TimeDisplayTimerTask extends TimerTask { @Override public void run() { // run on another thread mHandler.post(new Runnable() { @Override public void run() { // display toast at every 10 second final Toast Notify = Toast.makeText(getApplicationContext(), displayingText, Toast.LENGTH_SHORT); Notify.setGravity(Gravity.CENTER, 0, 0); Notify.show(); Handler cancelToast = new Handler(); cancelToast.postDelayed(new Runnable() { @Override public void run() { Notify.cancel(); } }, 1000); } }); } }

修改

你可以测试我的代码。并为你改变一些东西。

public class MyService extends Service { public static final String TAG = "MyService"; private Timer timer = new Timer(); private static final int UPDATE = 1; private Handler mHandler = new Handler() { @Override public void handleMessage(Message msg) { switch (msg.what) { case UPDATE: Log.d(TAG, "onStartCommand() executed"); break; } } }; @Override public void onCreate() { super.onCreate(); Log.d(TAG, "onCreate() executed"); } @Override public int onStartCommand(Intent intent, int flags, int startId) { timer.schedule(new TimerTask() { @Override public void run() { Message message = new Message(); message.what = UPDATE; mHandler.sendMessage(message); } }, 1000, 5000); return super.onStartCommand(intent, flags, startId); } @Override public void onDestroy() { super.onDestroy(); Log.d(TAG, "onDestroy() executed"); timer.cancel(); timer = null; }

Answer 3

试试这个：

String displayText;

public int onStartCommand (Intent intent, int flags, int startId) {
displayingText = intent.getStringExtra("PassToService");
Toast.makeText(this, displayingText, Toast.LENGTH_SHORT).show();
return START_STICKY;
}

private class TimeDisplayTimerTask extends TimerTask {
@Override
public void run() {

    // run on another thread
    mHandler.post(new Runnable() {
        @Override
        public void run() {
            // display toast at every 10 second
            final Toast Notify = Toast.makeText(getApplicationContext(), displayingText, Toast.LENGTH_SHORT);
            Notify.setGravity(Gravity.CENTER, 0, 0);
            Notify.show();

            Handler cancelToast = new Handler();
            cancelToast.postDelayed(new Runnable() {
                @Override
                public void run() {
                    Notify.cancel();
                }
            }, 1000);

        }
    });
}
}

Answer 4

谢谢大家的帮助。我真的很感激他们。我找到了解决传球的方法。而不是试图按照KeLiuyue为我做的那样继续返回价值。（长时间的讨论）我刚刚调整了一下。

包含一个新变量。

private String serviceText;

定义新变量的服务价值。

public int onStartCommand (Intent intent, int flags, int startId) {
    String displayingText = intent.getStringExtra("PassToService");
    Toast.makeText(this, displayingText, Toast.LENGTH_SHORT).show();
    serviceText = displayingText;

如果有任何建议，请告诉我。

未传递给类的值 - 无法解析符号

4 个答案: