android.view.WindowManager$BadTokenException: Unable to add window异常

android.view.WindowManager$BadTokenException: Unable to add window -- token android.os.BinderProxy@40514f68 is not valid; is your activity running?

因为使用了AsyncTask 异步线程在线程完成以后的onPostExecute方法里面弹出窗口。

这个时候如果用户在onPostExecute调用之间按了返回按钮,activity已经onDestory了，

那么就会报出android.view.WindowManager$BadTokenException: Unable to add window -- token android.os.BinderProxy@4479b390 is not valid; is your activity running?

解决方法一在弹出窗口之前用Activity的isFinishing判断一下Activity是否还存在

protected void onPostExecute(Object result) {

    if (!isFinishing()) {

        showDialog(MY_DIALOG_ID);

    }

}

解决方法二在show的时候捕获一下异常

以下是测试验证

运行这个小程序 默数4的时候按返回 如果不加异常捕获或者判断isFinish的话会崩溃。

public class DialogTestActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
new Task().execute();

}

private class Task extends AsyncTask<Void, Void, Void> {

@Override
protected Void doInBackground(Void... params) {
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
return null;
}

@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
//if (!isFinishing()) {
//try {
createAlertDialog().show();
//} catch (Exception e) {
//}
//}
}

}

private AlertDialog createAlertDialog() {
return new AlertDialog.Builder(DialogTestActivity.this).setTitle("fadfasdf")
.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {

}
}).setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {

}
}).create();
}

}