每个人都好！
我是android编程新手，我在logcat中遇到错误，控制台没有错误。我试着一遍又一遍地搜索，但似乎我是唯一一个面临这些错误的人。
BTW这个代码不是我的，我在教程中发现它特别是＆＃34; Sinch Group Chat＆＃34;如果你在google上搜索一下这个很受欢迎。除了它是谷歌我在Eclipse上适应它，我相信他们为Android Studio制作了这个教程。
09-24 13:47:52.195: E/AndroidRuntime(1467): FATAL EXCEPTION: main
09-24 13:47:52.195: E/AndroidRuntime(1467): Process: com.groupchat, PID: 1467
09-24 13:47:52.195: E/AndroidRuntime(1467): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.groupchat/com.groupchat.LogIn}: java.lang.NullPointerException
09-24 13:47:52.195: E/AndroidRuntime(1467): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)
09-24 13:47:52.195: E/AndroidRuntime(1467): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
09-24 13:47:52.195: E/AndroidRuntime(1467): at android.app.ActivityThread.access$800(ActivityThread.java:135)
09-24 13:47:52.195: E/AndroidRuntime(1467): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
09-24 13:47:52.195: E/AndroidRuntime(1467): at android.os.Handler.dispatchMessage(Handler.java:102)
09-24 13:47:52.195: E/AndroidRuntime(1467): at android.os.Looper.loop(Looper.java:136)
09-24 13:47:52.195: E/AndroidRuntime(1467): at android.app.ActivityThread.main(ActivityThread.java:5001)
09-24 13:47:52.195: E/AndroidRuntime(1467): at java.lang.reflect.Method.invokeNative(Native Method)
09-24 13:47:52.195: E/AndroidRuntime(1467): at java.lang.reflect.Method.invoke(Method.java:515)
09-24 13:47:52.195: E/AndroidRuntime(1467): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
09-24 13:47:52.195: E/AndroidRuntime(1467): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
09-24 13:47:52.195: E/AndroidRuntime(1467): at dalvik.system.NativeStart.main(Native Method)
09-24 13:47:52.195: E/AndroidRuntime(1467): Caused by: java.lang.NullPointerException
09-24 13:47:52.195: E/AndroidRuntime(1467): at com.parse.Parse.getParseDir(Parse.java:313)
09-24 13:47:52.195: E/AndroidRuntime(1467): at com.parse.ParseCorePlugins.getCurrentUserController(ParseCorePlugins.java:124)
09-24 13:47:52.195: E/AndroidRuntime(1467): at com.parse.ParseUser.getCurrentUserController(ParseUser.java:56)
09-24 13:47:52.195: E/AndroidRuntime(1467): at com.parse.ParseUser.getCurrentUser(ParseUser.java:892)
09-24 13:47:52.195: E/AndroidRuntime(1467): at com.parse.ParseUser.getCurrentUser(ParseUser.java:879)
09-24 13:47:52.195: E/AndroidRuntime(1467): at com.groupchat.LogIn.onCreate(LogIn.java:35)
09-24 13:47:52.195: E/AndroidRuntime(1467): at android.app.Activity.performCreate(Activity.java:5231)
09-24 13:47:52.195: E/AndroidRuntime(1467): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
09-24 13:47:52.195: E/AndroidRuntime(1467): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)
09-24 13:47:52.195: E/AndroidRuntime(1467): ... 11 more
这是我的Login.java
package com.groupchat;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import com.parse.LogInCallback;
import com.parse.ParseException;
import com.parse.ParseUser;
import com.parse.SignUpCallback;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class LogIn extends Activity {
private Button signUpButton;
private Button loginButton;
private EditText usernameField;
private EditText passwordField;
private String username;
private String password;
private Intent intent;
private Intent serviceIntent;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
intent = new Intent(getApplicationContext(), ListUsersActivity.class);
serviceIntent = new Intent(getApplicationContext(), MessageService.class);
ParseUser currentUser = ParseUser.getCurrentUser();
if (currentUser != null) {
startActivity(intent);
startService(serviceIntent);
}
setContentView(R.layout.activity_log_in);
loginButton = (Button) findViewById(R.id.loginButton);
signUpButton = (Button) findViewById(R.id.signupButton);
usernameField = (EditText) findViewById(R.id.loginUsername);
passwordField = (EditText) findViewById(R.id.loginPassword);
loginButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
username = usernameField.getText().toString();
password = passwordField.getText().toString();
ParseUser.logInInBackground(username, password, new LogInCallback() {
public void done(ParseUser user, com.parse.ParseException e) {
if (user != null) {
startActivity(intent);
startService(serviceIntent);
} else {
Toast.makeText(getApplicationContext(),
"Wrong username/password combo",
Toast.LENGTH_LONG).show();
}
}
});
}
});
signUpButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
username = usernameField.getText().toString();
password = passwordField.getText().toString();
ParseUser user = new ParseUser();
user.setUsername(username);
user.setPassword(password);
user.signUpInBackground(new SignUpCallback() {
public void done(com.parse.ParseException e) {
if (e == null) {
startActivity(intent);
startService(serviceIntent);
} else {
Toast.makeText(getApplicationContext(),
"There was an error signing up."
, Toast.LENGTH_LONG).show();
}
}
});
}
});
}
@Override
public void onDestroy() {
stopService(new Intent(this, MessageService.class));
super.onDestroy();
}
}
控制台上没有错误。
谢谢！
答案 0 :(得分：0)
你的例外被抛出：
ParseUser currentUser = ParseUser.getCurrentUser();
getCurrentUser()类的方法ParseUser正在尝试完成所有这些（从下到上阅读）：
at com.parse.Parse.getParseDir(Parse.java:313) <---- THIS THROWS NPE
at com.parse.ParseCorePlugins.getCurrentUserController(ParseCorePlugins.java:124)
at com.parse.ParseUser.getCurrentUserController(ParseUser.java:56)
at com.parse.ParseUser.getCurrentUser(ParseUser.java:892)
at com.parse.ParseUser.getCurrentUser(ParseUser.java:879)
这似乎表明您的ParseUser类在之前需要其他信息它可以解析用户，或者它需要一个它没有的权限。
在任何情况下，如果无法访问ParseUser类'源代码，就无法分辨。