java.lang.RuntimeException的：内螺纹尚未调用无法建立处理活套prepare（）; [英] java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare();

问题描述

我有一个Android应用程序正在运行的线程。我想敬酒消息有消息显示。

I have an Android app running a thread. I want a Toast message to show with a message.

当我这样做，我得到了以下异常：

When I do this, I get the below exception:

的logcat 跟踪：

FATAL EXCEPTION: Timer-0 
 java.lang.RuntimeException: Can't create handler inside thread that has not 
    called Looper.prepare()

 at android.os.Handler.<init>(Handler.java:121)
 at android.widget.Toast$TN.<init>(Toast.java:322)
 at android.widget.Toast.<init>(Toast.java:91)
 at android.widget.Toast.makeText(Toast.java:238) 

有没有变通的推动敬酒的消息从线程的用户界面？

Is there a work around for pushing Toast messages from threads to the User Interface?

推荐答案

我得到这个例外，因为我试图让从后台线程举杯弹出。
吐司需要一个活动推向用户界面和线程不必说。照片 所以，一个解决办法就是给线程一个链接到一个父活动，并举杯说。

I got this exception because I was trying to make a Toast popup from a background thread.
Toast needs an Activity to push to the user interface and threads don't have that.
So one workaround is to give the thread a link to a parent Activity and Toast to that.

将这个code在线程要发送一个吐司消息：

Put this code in the thread where you want to send a Toast message:

parent.runOnUiThread(new Runnable() {
  public void run() {
    Toast.makeText(parent.getBaseContext(), "Hello", Toast.LENGTH_LONG).show();
  }
});

请创建此线程后台线程链接到父活动。将这个变量在你的线程类：

Keep a link to the parent Activity in the background thread that created this thread. Put this variable in your thread class:

private static YourActivity parent;

在创建线程，通过父活动作为参数，通过这样的构造：

When you create the thread, pass the parent Activity as a parameter through the constructor like this:

public YourBackgroundThread(YourActivity parent){
    this.parent = parent;
}

现在的后台线程可以把吐司消息到屏幕。

Now the background thread can push Toast messages to the screen.

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