在更新文本视图时在服务中使用倒数计时器和运行

Question

如标题所示，我在我的应用程序中使用了倒数计时器，我希望用户能够在后台有倒数计时器运行的同时退出应用程序并相应地更新文本视图。我假设需要一项服务，但我不知道如何在我的应用程序中为倒数计时器实施服务。下面提供的代码块将说明我在评论中遇到的问题。

更新

public class CountDownService extends Service {

    TextView timeTextView;
    int data;


    public  String hms;
    public CountDownAct countDownAct;
    public CountDownTime countDownTimer;

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

    }

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


    }

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

      data = intent.getIntExtra("the", 0);
        countDownTimer = new CountDownTime(data,1000 );
        countDownTimer.start();


        return START_STICKY; 


    }

    @Override
    public boolean stopService(Intent name) {

        Log.i("CountDownService", "Stop Service");
        return super.stopService(name);

    }

    @Override
    public void onDestroy() {

        countDownTimer.cancel();

    }

    public class CountDownTime extends CountDownTimer {


        /**
         * @param millisInFuture    The number of millis in the future from the call
         *                          to {@link #start()} until the countdown is done and {@link #onFinish()}
         *                          is called.
         * @param countDownInterval The interval along the way to receive
         *                          {@link #onTick(long)} callbacks.
         */
        public CountDownTime(long millisInFuture, long countDownInterval) {
            super(millisInFuture, countDownInterval);
        }

        @Override
        public void onTick(long millisUntilFinished) {



            long millis = millisUntilFinished;

            // this is the format which reads the time data from the user and makes it readable
            hms = String.format("%02d:%02d:%02d", TimeUnit.MILLISECONDS.toHours(millis),
                    TimeUnit.MILLISECONDS.toMinutes(millis) - TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(millis)),
                    TimeUnit.MILLISECONDS.toSeconds(millis) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millis)));


            //the textview is updated with each tick that goes by and contains the current time that is left
            // I want this text to be updated even if the user exits the app. The textview has to be updated with the current time left until finishing

//            countDownAct.timeTextView.setText(hms);
            CountDownAct.timeTextView.setText(hms);
            Log.i("CountDownService", hms);

        }

        @Override
        public void onFinish() {
            Intent goBack = new Intent(getApplicationContext(), alarmtimefinished.class);
            goBack.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            goBack.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
            startActivity(goBack);

        }




    }

}

分类目录

07-24 18:27:41.629  19054-19054/com.personalproject.peter.timerapp E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.NullPointerException
            at com.personalproject.peter.timerapp.CountDownService$CountDownTime.onTick(CountDownService.java:79)
            at android.os.CountDownTimer.handleMessage(CountDownTimer.java:124)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:4867)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:511)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1007)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:774)
            at dalvik.system.NativeStart.main(Native Method)

Answer 1

我最近一直在使用服务，它非常简单，只需制作一个扩展服务的 class，检查一下：http://developer.android.com/guide/components/services.html

将您的代码放在 onStartCommand 方法中

你为什么不在服务中创建一个定时器的对象class

如果您希望您的服务重复执行某些操作，请使用：

Handler mHandler;
private void doSomething() {


    scheduleNext(10*1000); // time in m seconds 
    //your code here



}

private void scheduleNext(int time) {
    mHandler.postDelayed(new Runnable() {
        public void run() {

            doSomething();

        }
    },time);

希望对您有所帮助

在更新文本视图时在服务中使用倒数计时器和运行

Using Countdown timer and running it in a service while updating a textview

android

service

countdowntimer

更新

分类目录

在更新文本视图时在服务中使用倒数计时器和 运行

Using Countdown timer and running it in a service while updating a textview

android

service

countdowntimer

更新

分类目录

在更新文本视图时在服务中使用倒数计时器和运行