Android 如何在AsyncTask中举杯，提示我使用Looper
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How to raise a toast in AsyncTask, I am prompted to used the Looper
提问by Pentium10
I have tasks completed by AsyncTask in background. At some point I need to issue a Toast that something is completed.
我有 AsyncTask 在后台完成的任务。在某些时候，我需要发出一个 Toast 来表示某事已完成。
I've tried and I failed because
Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
我试过了，但我失败了，因为
Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
How can I do that?
我怎样才能做到这一点？
回答by Alex Volovoy
onPostExecute - executes on UI thread
or
publishProgress(); in your doinbackground and
onPostExecute - 在 UI 线程上执行或
publishProgress()；在你的 doinbackground 和
protected void onProgressUpdate(Integer... progress) {
}
http://developer.android.com/reference/android/os/AsyncTask.html
http://developer.android.com/reference/android/os/AsyncTask.html
回答by Hyman K Fouani
you can Toast inside doInBackground
你可以在 doInBackground 中 Toast
add this code where you want to Toast appear
将此代码添加到您想要 Toast 出现的位置
runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(<your class name>.this, "Cool Ha?", Toast.LENGTH_SHORT).show();
}
});
回答by Alexander Oleynikov
You can also use runOnUiThreadmethod to manipulate your UI from background threads.
您还可以使用runOnUiThread方法从后台线程操作您的 UI。
回答by Korean
If you want to use Toast You should use this method : onProgressUpdate()
如果你想使用 Toast 你应该使用这个方法：onProgressUpdate()
protected Integer doInBackground(Void...Params) {
int check_point = 1;
publishProgress(check_point);
return check_point;
}
protected void onProgressUpdate(Integer integers) {
if(integers == 1) {
Toast.makeText(classname.this, "Text", 0).show();
}
回答by Brandon O'Rourke
If you want to display the Toast from the background thread you'll have to call runOnUiThread from doInBackground. I don't believe there's another way.
如果要从后台线程显示 Toast，则必须从 doInBackground 调用 runOnUiThread。我不相信还有其他方法。
Edit: I take that back. I think you can implement onProgressUpdate, which runs on the UI thread, to show the Toast and make calls to publishProgress from doInBackground.
编辑：我收回。我认为您可以实现在 UI 线程上运行的 onProgressUpdate 来显示 Toast 并从 doInBackground 调用 publishProgress。
回答by Nilay
If you want to display the Toast in doInBackground, you can use it in the OnPostExecute method of AsyncTask.
如果要在doInBackground中显示Toast，可以在AsyncTask的OnPostExecute方法中使用。
protected void onPostExecute(String file_url) {
Toast.makeText(getApplicationContext(),"Your Message", Toast.LENGTH_LONG).show();
pDialog.dismiss();//dismiss the progress dialouge
}
