Android Thread 修改 EditText

问题描述

我在线程启动的另一个函数中修改 EditText 时遇到问题:

I am having a problem with modifying EditText in another function started by the thread:

Thread thRead = new Thread( new Runnable(){
    public void run(){
       EditText _txtArea = (EditText) findViewById(R.id.txtArea);
       startReading(_txtArea);
    }
 });

我的功能如下:

public void startReading(EditText _txtArea){
         _txtArea.setText("Changed");
}

它总是在尝试修改编辑文本时强制关闭.有人知道为什么吗?

It always force closes while trying to modify the edittext. Does someone know why?

推荐答案

不应从非 UI 线程修改 UI 视图.唯一可以接触 UI 视图的线程是main"或UI"线程，即调用 onCreate()、onStop() 和其他类似组件生命周期函数的线程.

UI views should not be modified from non-UI thread. The only thread that can touch UI views is the "main" or "UI" thread, the one that calls onCreate(), onStop() and other similar component lifecycle function.

因此，每当您的应用程序尝试从非 UI 线程修改 UI 视图时，Android 都会提前抛出异常以警告您这是不允许的.那是因为 UI 不是线程安全的，而这样的预警实际上是一个很棒的功能.

So, whenever your application tries to modify UI Views from non-UI thread, Android throws an early exception to warn you that this is not allowed. That's because UI is not thread-safe, and such an early warning is actually a great feature.

更新:

您可以使用 Activity.runOnUiThread() 来更新 UI.或者使用 AsyncTask.但是由于在您的情况下您需要不断地从蓝牙读取数据，因此不应使用 AsyncTask.

You can use Activity.runOnUiThread() to update UI. Or use AsyncTask. But since in your case you need to continuously read data from Bluetooth, AsyncTask should not be used.

这是 runOnUiThread() 的示例:

runOnUiThread(new Runnable() {            
    @Override
    public void run() {
        //this will run on UI thread, so its safe to modify UI views.
         _txtArea.setText("Changed");
    }
});

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