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android - getUsername 返回 null,而 CurrentUser 不是

转载 作者:行者123 更新时间:2023-11-29 17:25:53 27 4
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因此,我正在尝试设置一个条件,如果用户未登录,它会将用户发送到登录屏幕,但如果用户已登录,则将用户名输出到日志并停留在当前屏幕上。问题是我从 getUsername 得到一个空指针异常是 null,但是我的 if (getCurrentUser == null) 条件没有捕获到该语句。我哪里错了?在此先感谢您的帮助。

/*
* Copyright (c) 2015-present, Parse, LLC.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
package com.parse.starter;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;

import com.parse.Parse;
import com.parse.ParseAnalytics;
import com.parse.ParseObject;
import com.parse.ParseUser;



public class MainActivity extends AppCompatActivity {
public static final String TAG = MainActivity.class.getSimpleName();

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ParseAnalytics.trackAppOpenedInBackground(getIntent());

ParseUser currentUser = ParseUser.getCurrentUser();
if (currentUser == null) {
Intent intent = new Intent(this, LoginActivity.class);
intent.addFlags(intent.FLAG_ACTIVITY_NEW_TASK);
intent.addFlags(intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(intent);
}

else {
Log.i(TAG, currentUser.getUsername());
}
}

public boolean onCreateOptionsMenu (Menu menu){
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}

public boolean onOptionsItemSelected (MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();

//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}

return super.onOptionsItemSelected(item);
}
}

这是我用来创建新用户的代码

mUsername = (EditText)findViewById(R.id.usernameField);
mPassword = (EditText)findViewById(R.id.passwordField);
mEmail = (EditText)findViewById(R.id.emailField);
mSignupButton = (Button)findViewById(R.id.signupButton);
mSignupButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String username = mUsername.getText().toString();
String password = mPassword.getText().toString();
String email = mEmail.getText().toString();

username = username.trim();
password = password.trim();
email = email.trim();

if (username.isEmpty() || password.isEmpty() || email.isEmpty()) {
AlertDialog.Builder builder = new AlertDialog.Builder(SignupActivity.this); //warn the user they left some necessary info out
builder.setMessage(R.string.signup_error_message)
.setTitle(R.string.signup_error_title)
.setPositiveButton(android.R.string.ok, null);

AlertDialog dialog = builder.create();
dialog.show();

}

else {
ParseUser newUser = new ParseUser();
newUser.setUsername(username);
newUser.setPassword(password);
newUser.setEmail(email);
newUser.signUpInBackground(new SignUpCallback() {
@Override
public void done(ParseException e) {
if (e == null) {
// Success!
Intent intent = new Intent(SignupActivity.this, MainActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);

startActivity(intent);

} else {
AlertDialog.Builder builder = new AlertDialog.Builder(SignupActivity.this); //warn the user they left some necessary info out
builder.setMessage(e.getMessage())
.setTitle(R.string.signup_error_title)
.setPositiveButton(android.R.string.ok, null);

AlertDialog dialog = builder.create();
dialog.show();
}
}
});


}
}
});

}
}

最佳答案

看来你正在使用 ParseUser.enableAutomaticUser(); ,从 onCreate 中删除这行代码

your_app extends Application{
}

使用 ParseUser.enableAutomaticUser();

匿名用户也可以在不需要网络请求的情况下自动为您创建,这样您就可以在应用程序启动时立即开始使用您的用户。当您在应用程序启动时启用自动匿名用户创建时,ParseUser.getCurrentUser() 永远不会是 null。首次保存用户或与用户相关的任何对象时,将在云中自动创建用户。到那时,用户的对象 ID 将为 null。启用自动用户创建可以轻松地将数据与用户相关联。例如,在您的 Application.onCreate() 方法中,您可以这样写:

https://parse.com/docs/android/guide#users-anonymous-users

关于android - getUsername 返回 null,而 CurrentUser 不是,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/34669996/

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