大家好,
我有一个将一些数据发布到服务器的 AsyncTask。它通过调用我从 doInBackground 编写的静态方法来实现这一点。当我运行 AsyncTask 时,我发送调用 execute() 的活动的上下文,我将其发送到我的静态方法,因为如果在与服务器通信时出现问题,它需要它来制作 Toast。但是,当在静态方法中创建 Toast 时出现此错误:
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): FATAL EXCEPTION: AsyncTask #1
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): java.lang.RuntimeException: An error occured while executing doInBackground()
04-21 12:49:16.689: ERROR/AndroidRuntime(2123):at android.os.AsyncTask$3.done(AsyncTask.java:200)
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274)
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): at java.util.concurrent.FutureTask.setException(FutureTask.java:125)
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308)
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): at java.util.concurrent.FutureTask.run(FutureTask.java:138)
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): at java.lang.Thread.run(Thread.java:1019)
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): at android.os.Handler.<init>(Handler.java:121)
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): at android.widget.Toast.<init>(Toast.java:68)
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): at android.widget.Toast.makeText(Toast.java:23
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): at com.microogle.dev.util.ServerConnections.PostToLoginPage(ServerConnections.java:36)
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): at com.microogle.dev.Whiteboard.WhiteboardLogin$LoginTask.doInBackground(WhiteboardLogin.java:150)
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): at com.microogle.dev.Whiteboard.WhiteboardLogin$LoginTask.doInBackground(WhiteboardLogin.java:1)
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): at android.os.AsyncTask$2.call(AsyncTask.java:185)
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306)
04-21 12:49:16.689: ERROR/AndroidRuntime(2123): ... 4 more
随后是泄漏的窗口错误。我假设这是因为在静态方法中传递给 Toast 的上下文出错。AsyncTask 是:
private class LoginTask extends AsyncTask<Void, Void, Void> {
private WhiteboardLogin activity;
private Context callingContext;
private ProgressDialog dialog;
private String user, pass;
private boolean sendIntent = true, loginError = false, populateError = false;
public LoginTask(WhiteboardLogin activity, String user, String pass, Context callingContext){
this.activity = activity;
this.user = user.trim();
this.pass = pass.trim();
this.callingContext = callingContext;
}
@Override
protected Void doInBackground(Void... params) {
ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
nameValuePairs.add(new BasicNameValuePair("user",user));
nameValuePairs.add(new BasicNameValuePair("pass",pass));
sessionUser = user;
sessionPassword = pass;
//Posts the username and password to the login page and toasts an error if the login doesn't work
if(ServerConnections.PostToLoginPage(callingContext, nameValuePairs, activity.getString(R.string.loginPageURI)) == 1){
dialog.dismiss();
sendIntent = false;
loginError = true;
publishProgress();
return null;
}
else{
userDataList = populateUserDataList(callingContext, user,pass);
if(userDataList == null){
dialog.dismiss();
sendIntent = false;
populateError = true;
return null;
}
}
return null;
}