Android “只有创建视图层次结构的原始线程才能触及它的视图。” for循环错误

Question

我试图每半秒运行一次 for 循环。循环每次调用时都会更改视图中的某些内容，但更改是由另一个类（即 Speedometer）进行的。

 Thread thread=new Thread(){
        @Override
        public void run() {
            float i;
            try {

                for ( i = 0; i <= 100; i++) {
                            Speedometer1.onSpeedChanged(Speedometer1.getCurrentSpeed(i) + 8);
                            Speedometer2.onSpeedChanged(Speedometer2.getCurrentSpeed(i) + 8);
                            Speedometer3.onSpeedChanged(Speedometer3.getCurrentSpeed(i) + 8);
                            Speedometer4.onSpeedChanged(Speedometer4.getCurrentSpeed(i) + 8);
                            Speedometer5.onSpeedChanged(Speedometer5.getCurrentSpeed(i) + 8);
                            Speedometer6.onSpeedChanged(Speedometer6.getCurrentSpeed(i) + 8);

                    sleep(500);
                }
            }
            catch (InterruptedException e)
            {e.printStackTrace();}
        }
    };thread.start();

原文由 Ariel 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

那是因为任何视图只能在主线程或 ui 线程中修改。尝试运行 onSpeedChanged() 使用 runOnUiThread() 。像这样：

     Thread thread=new Thread(){
    @Override
    public void run() {
        float i;
        try {

            for ( i = 0; i <= 100; i++) {
                runOnUiThread(new Runnable() {
                    public void run() {
                        Speedometer1.onSpeedChanged(Speedometer1.getCurrentSpeed(i) + 8);
                        Speedometer2.onSpeedChanged(Speedometer2.getCurrentSpeed(i) + 8);
                        Speedometer3.onSpeedChanged(Speedometer3.getCurrentSpeed(i) + 8);
                        Speedometer4.onSpeedChanged(Speedometer4.getCurrentSpeed(i) + 8);
                        Speedometer5.onSpeedChanged(Speedometer5.getCurrentSpeed(i) + 8);
                        Speedometer6.onSpeedChanged(Speedometer6.getCurrentSpeed(i) + 8)

                    }

                });

                sleep(500);
            }
        }
        catch (InterruptedException e)
        {e.printStackTrace();}
    }
};thread.start();

原文由 Miguel Benitez 发布，翻译遵循 CC BY-SA 3.0 许可协议

Answer 2

您应该更新 runOnUIThread 中的 UI 组件。示例代码是

runOnUiThread(new Runnable() {
     @Override
     public void run() {

       //stuff that updates ui

    }
});

原文由 Mujammil Ahamed 发布，翻译遵循 CC BY-SA 3.0 许可协议