java-如何循环setText()-使应用程序崩溃

概述我是Android编程的新手.现在,我想更新活动中的值并按时间间隔更改它,并将其设置为活动中的TextView.所以,这里的代码：车类：publicclassCar{publicintSpeed;publicintRPM;publicintDistance;publicintFuel;publicCar(intSpeed,intRPM,intDistance,intFuel

我是Android编程的新手.现在,我想更新活动中的值并按时间间隔更改它,并将其设置为活动中的TextVIEw.所以,这里的代码：

车类：

public class Car {public int Speed;public int RPM;public int distance;public int Fuel;public Car(int Speed, int RPM, int distance, int Fuel) {    System.out.println(            "Inisialisasi baru"+                    "\nSpeed: "+ Speed +                    "\nRPM: "+ RPM +                    "\ndistance: "+ distance +                    "\nFuel: "+ Fuel    );    this.Speed = Speed;    this.RPM = RPM;    this.distance = distance;    this.Fuel = Fuel;}public int getSpeed() {    return Speed;}public int getRPM() {    return RPM;}public int getdistance() {    return distance;}public int getFuel() {    return Fuel;}}

活动Java：

TextVIEw carSpeed, carRPM, cardistance, carFuel;@OverrIDeprotected voID onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentVIEw(R.layout.activity_mock);    carSpeed = (TextVIEw) findVIEwByID(R.ID.carSpeed);    carRPM = (TextVIEw) findVIEwByID(R.ID.carRPM);    cardistance = (TextVIEw) findVIEwByID(R.ID.cardistance);    carFuel = (TextVIEw) findVIEwByID(R.ID.carFuel);    new Timer().scheduleAtFixedrate(new TimerTask(){        Car car = new Car(20, 20, 20, 5);        @OverrIDe        public voID run(){            int maxSpeed = car.Speed + 5;            int minSpeed = car.Speed - 4;            int maxRPM = car.RPM + 5;            int minRPM = car.RPM - 4;            car.Speed = new Random().nextInt((maxSpeed - minSpeed) + 1) + minSpeed;            car.RPM = new Random().nextInt((maxRPM - minRPM) + 1) + minRPM;            car.distance += 1;            car.Fuel -= 1;            if (car.Fuel <= 0) {                car.Fuel += 20;            }            if (car.Speed <= 0) {                car.Speed = 20;            } else if (car.Speed >= 150) {                car.Speed -= 50;            }            carSpeed.setText(Integer.toString(car.getSpeed()) + " km/h");            carRPM.setText(Integer.toString(car.getRPM()) + " rpm");            cardistance.setText(Integer.toString(car.getdistance()) + " km");            carFuel.setText(Integer.toString(car.getFuel()) + " l");        }    },0,5000);}

我认为的问题是因为我试图在new Timer()中设置文本,这导致应用程序关闭.谢谢.

解决方法:

是的,您的直觉是正确的.发生问题的原因是正在从计时器更新视图.

该错误将类似于以下内容：

androID.vIEw.VIEwRootImpl$CalledFromWrongThreadException: Only the
original thread that created a vIEw hIErarchy can touch its vIEws.

在AndroID中,只能通过“ UI线程”(通常称为“主线程”)更新视图.

这里的问题是Runnable的run()方法在单独的线程中执行.

可以在活动的主线程上进行更新,如下所示：

...runOnUiThread(new Runnable() {    @OverrIDe     public voID run() {        // Do all your vIEw updates in here        textVIEw.setText("string");    }});....

我看不到您的代码的上下文,但是如果它是一个片段：
getActivity().runOnUiThread(…);

还有其他切换到主线程的方法.您可能还想研究AsyncTask和Handlers.

总结

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