Android 如何在正在运行的线程中显示警报对话框？
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How to show alert dialog in a running thread?
提问by user1602798
I'm developing an Android Game.In this game, There are tracks on which trains run. This is running thread. I want to show an alert dialog when there is a collision between. when I'm applying alert dialog showing error can't create handler inside thread that has not called looper.prepare().
我正在开发一个 Android 游戏。在这个游戏中，有火车运行的轨道。这是运行线程。我想在两者之间发生碰撞时显示一个警报对话框。当我应用显示错误的警报对话框时，无法在未调用的线程内创建处理程序looper.prepare()。
回答by Ankitkumar Makwana
This will help you:
这将帮助您：
runOnUiThread(new Runnable() {
@Override
public void run() {
// Your dialog code.
}
});
回答by Daud Arfin
You must need to create AlertDialoginside UI thread else it will never work. If you are in different thread use MessageHandleror can use runOnUiThread(using runnable) to create your dialog inside.
您必须需要AlertDialog在 UI 线程内创建，否则它将永远无法工作。如果你在不同的线程中使用MessageHandler或者可以使用runOnUiThread（使用 runnable）在你的对话框里面创建。
回答by prakash
You can use Handlers to do this work.
您可以使用处理程序来完成这项工作。
Handler mHandler = new Handler(Looper.getMainLooper());
mHandler.post(new Runnable() {
@Override
public void run() {
// Your UI updates here
}
});
回答by jeet
You can create an handler in Activity Class, and can invoke sendMessage to that handler object. Write code to display alert in handleMessage method of Handler, for Example:
您可以在 Activity 类中创建一个处理程序，并且可以调用该处理程序对象的 sendMessage。编写代码在Handler的handleMessage方法中显示alert，例如：
Activity Class
活动课
Handler mHandler = new Handler()
{
public void handleMessage(Message msg)
{
//Display Alert
}
};
//Thread
Thread thread= new Thread()
{
public void run()
{
//Logic
MHandler.sendEmptyMessage(0);
}
}
回答by Sankar
You have to show your dialog on UI thread like below
您必须在 UI 线程上显示您的对话框，如下所示
runOnUiThread(new Runnable() {
@Override
public void run() {
// Your dialog code.
}
});
回答by Виталий Фадеев
You can try this, with check App is visible
你可以试试这个，检查应用程序是可见的
Activity currentActivity = MainClassApp.getCurrentActivity();
boolean isAppVisible = currentActivity != null;
if (isAppVisible) {
currentActivity.runOnUiThread(() ->
// Your Dialog Code
}
