asynctask中的对话框错误
当我尝试显示异步任务的工作对话框时，出现以下错误： java.lang.reflect.InitationTargetException java.lang.NullPointerException
活动和异步任务的代码是：
public class MainActivity extends Activity {
private ControlLogin ctlLogin;
private ProgressDialog dialog;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
ctlLogin = (ControlLogin)findViewById(R.id.controlLogin);
ctlLogin.setOnLoginListener(new OnLoginListener()
{
@Override
public void onLogin(String email, String password, Boolean saveAccount){
ProgressDialog dialog = new ProgressDialog(getApplicationContext());
dialog.setMessage("Signing...");
dialog.setIndeterminate(true);
dialog.setCancelable(false);
new Login().execute(email, password);
}
});
}
public class Login extends AsyncTask<String, Float, CloudApp> {
protected void onPreExecute(){
dialog.show();
}
@Override
protected CloudApp doInBackground(String... arg0) {
CloudApp api = new CloudAppImpl(arg0[0], arg0[1]);
return api;
}
protected void onPostExecute(CloudApp api){
dialog.dismiss();
try {
CloudAppAccount acc = api.getAccountDetails();
Toast toast = Toast.makeText(getBaseContext(), "test: " + acc.getEmail(), Toast.LENGTH_LONG);
toast.show();
} catch (CloudAppException e) {
e.printStackTrace();
}
}
}
}
有帮助吗？？？谢谢！！
When I try to show a working dialog for an asynctask i get the following errors:
java.lang.reflect.InvocationTargetException
java.lang.NullPointerException
The code of the activity and asynctask is:
public class MainActivity extends Activity {
private ControlLogin ctlLogin;
private ProgressDialog dialog;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
ctlLogin = (ControlLogin)findViewById(R.id.controlLogin);
ctlLogin.setOnLoginListener(new OnLoginListener()
{
@Override
public void onLogin(String email, String password, Boolean saveAccount){
ProgressDialog dialog = new ProgressDialog(getApplicationContext());
dialog.setMessage("Signing...");
dialog.setIndeterminate(true);
dialog.setCancelable(false);
new Login().execute(email, password);
}
});
}
public class Login extends AsyncTask<String, Float, CloudApp> {
protected void onPreExecute(){
dialog.show();
}
@Override
protected CloudApp doInBackground(String... arg0) {
CloudApp api = new CloudAppImpl(arg0[0], arg0[1]);
return api;
}
protected void onPostExecute(CloudApp api){
dialog.dismiss();
try {
CloudAppAccount acc = api.getAccountDetails();
Toast toast = Toast.makeText(getBaseContext(), "test: " + acc.getEmail(), Toast.LENGTH_LONG);
toast.show();
} catch (CloudAppException e) {
e.printStackTrace();
}
}
}
}
Any help??? Thanks!!
如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱，如果其他用户或者作者回复了您的评论，将不能在第一时间通知您！
发布评论
评论（2）
您可以通过在
onLogin(...)方法中定义局部变量dialog来隐藏代码中的成员dialog。因此，dialog永远不会初始化为任何内容，这就是您在Login类中获得 NPE 的原因。You are hiding your member
dialogin your code by defining a local variabledialogin youronLogin(...)method. Because of this,dialogis never initialized to anything and that is why you get an NPE in yourLoginclass.当您关闭对话框时，您确定对话框存在吗？我认为在 onLogin 中，您重新创建了一个与活动字段变量同名的新对话框变量。
你可以谨慎行事：
Are you sure your dialog exist when you dismiss it? I think in the onLogin you recreate a new dialog variable with the same name as your activity field variable.
You might play safe: