我正在为Androdid创建聊天应用。错误是当我运行signUp活动时，我得到java.lang.nullpointerExecption错误，我无法解决此错误。这是我的SighnUp活动
错误：`
处理：com.example.hazziq.slidechat，PID：2106 java.lang.NullPointerException：尝试调用接口方法'java.lang.String com.exmaple.hazziq.slidechat.interfacer.Manager.signUpUser（java.lang.String，java.lang.String，java.lang.String）'在null对象引用上 在com.example.hazziq.slidechat.SigningUp $ 2 $ 1.run（SigningUp.java:107）
错误行：
result = imService.signUpUser(usernameText.getText().toString(),
passwordText.getText().toString(),
eMailText.getText().toString());
android.app.AlertDialog;
import android.app.Dialog;
import android.content.ComponentName;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import com.example.example.hazziq.slidechat.serve.MessagingService;
import com.exmaple.hazziq.slidechat.interfacer.Manager;
public class SigningUp extends Activity {
private static final int FILL_ALL_FIELDS = 0;
protected static final int TYPE_SAME_PASSWORD_IN_PASSWORD_FIELDS = 1;
private static final int SIGN_UP_FAILED = 9;
private static final int SIGN_UP_USERNAME_CRASHED = 3;
private static final int SIGN_UP_SUCCESSFULL = 4;
protected static final int USERNAME_AND_PASSWORD_LENGTH_SHORT = 5;
//private static final String SERVER_RES_SIGN_UP_FAILED = "0";
private static final String SERVER_RES_RES_SIGN_UP_SUCCESFULL = "1";
private static final String SERVER_RES_SIGN_UP_USERNAME_CRASHED = "2";
private EditText usernameText;
private EditText passwordText;
private EditText eMailText;
private EditText passwordAgainText;
private Manager imService;
private Handler handler = new Handler();
private ServiceConnection mConnection = new ServiceConnection() {
public void onServiceConnected(ComponentName className, IBinder service) {
// This is called when the connection with the service has been
// established, giving us the service object we can use to
// interact with the service. Because we have bound to a explicit
// service that we know is running in our own process, we can
// cast its IBinder to a concrete class and directly access it.
imService = ((MessagingService.IMBinder)service).getService();
}
public void onServiceDisconnected(ComponentName className) {
// This is called when the connection with the service has been
// unexpectedly disconnected -- that is, its process crashed.
// Because it is running in our same process, we should never
// see this happen.
imService = null;
Toast.makeText(SigningUp.this, R.string.local_service_stopped,
Toast.LENGTH_SHORT).show();
}
};
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_signing_up);
setTitle("Sign up");
Button signUpButton = (Button) findViewById(R.id.signUp);
Button cancelButton = (Button) findViewById(R.id.cancel_signUp);
usernameText = (EditText) findViewById(R.id.userName);
passwordText = (EditText) findViewById(R.id.password);
passwordAgainText = (EditText) findViewById(R.id.passwordAgain);
eMailText = (EditText) findViewById(R.id.email);
signUpButton.setOnClickListener(new OnClickListener(){
public void onClick(View arg)
{
if (usernameText.length() > 0&&
passwordText.length() > 0 &&
passwordAgainText.length() > 0 &&
eMailText.length() > 0
)
{
//TODO check email address is valid
if (passwordText.getText().toString().equals(passwordAgainText.getText().toString())){
if (usernameText.length() >= 5 && passwordText.length() >= 5) {
Thread thread = new Thread(){
String result = new String();
@Override
public void run() {
result = imService.signUpUser(usernameText.getText().toString(),
passwordText.getText().toString(),
eMailText.getText().toString());
handler.post(new Runnable(){
public void run() {
if (result!= null && equals(SERVER_RES_RES_SIGN_UP_SUCCESFULL)) {
Toast.makeText(getApplicationContext(),R.string.signup_successfull, Toast.LENGTH_LONG).show();
}
else if (result.equals(SERVER_RES_SIGN_UP_USERNAME_CRASHED)){
Toast.makeText(getApplicationContext(),R.string.signup_username_crashed, Toast.LENGTH_LONG).show();
;
}
else //if (result.equals(SERVER_RES_SIGN_UP_FAILED))
{
Toast.makeText(getApplicationContext(),R.string.signup_failed, Toast.LENGTH_LONG).show();
//showDialog(SIGN_UP_FAILED);
}
}
});
}
};
thread.start();
}
else{
Toast.makeText(getApplicationContext(),R.string.username_and_password_length_short, Toast.LENGTH_LONG).show();
//showDialog(USERNAME_AND_PASSWORD_LENGTH_SHORT);
}
}
else {
Toast.makeText(getApplicationContext(),R.string.signup_type_same_password_in_password_fields, Toast.LENGTH_LONG).show();
//showDialog(TYPE_SAME_PASSWORD_IN_PASSWORD_FIELDS);
}
}
else {
Toast.makeText(getApplicationContext(),R.string.signup_fill_all_fields, Toast.LENGTH_LONG).show();
//showDialog(FILL_ALL_FIELDS);
}
}
});
cancelButton.setOnClickListener(new OnClickListener(){
public void onClick(View arg0)
{
finish();
}
});
}
protected Dialog onCreateDialog(int id)
{
switch (id)
{
case TYPE_SAME_PASSWORD_IN_PASSWORD_FIELDS:
return new AlertDialog.Builder(SigningUp.this)
.setMessage(R.string.signup_type_same_password_in_password_fields)
.setPositiveButton(R.string.OK, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
/* User clicked OK so do some stuff */
}
})
.create();
case FILL_ALL_FIELDS:
return new AlertDialog.Builder(SigningUp.this)
.setMessage(R.string.signup_fill_all_fields)
.setPositiveButton(R.string.OK, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
/* User clicked OK so do some stuff */
}
})
.create();
case SIGN_UP_FAILED:
return new AlertDialog.Builder(SigningUp.this)
.setMessage(R.string.signup_failed)
.setPositiveButton(R.string.OK, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
/* User clicked OK so do some stuff */
}
})
.create();
case SIGN_UP_USERNAME_CRASHED:
return new AlertDialog.Builder(SigningUp.this)
.setMessage(R.string.signup_username_crashed)
.setPositiveButton(R.string.OK, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
/* User clicked OK so do some stuff */
}
})
.create();
case SIGN_UP_SUCCESSFULL:
return new AlertDialog.Builder(SigningUp.this)
.setMessage(R.string.signup_successfull)
.setPositiveButton(R.string.OK, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
finish();
}
})
.create();
case USERNAME_AND_PASSWORD_LENGTH_SHORT:
return new AlertDialog.Builder(SigningUp.this)
.setMessage(R.string.username_and_password_length_short)
.setPositiveButton(R.string.OK, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
/* User clicked OK so do some stuff */
}
})
.create();
default:
return null;
}
}
@Override
protected void onResume() {
bindService(new Intent(SigningUp.this, MessagingService.class), mConnection , Context.BIND_AUTO_CREATE);
super.onResume();
}
@Override
protected void onPause()
{
unbindService(mConnection);
super.onPause();
}
}
请帮助我长期坚持这个错误..
答案 0 :(得分：2)
您必须检查EditText是否为空。像这样：
if(usernameText != null && passwordText != null && eMailText != null) {
if(!TextUtils.isEmpty(usernameText.getText()) && !TextUtils.isEmpty(passwordText.getText()) &&
!TextUtils.isEmpty(eMailText.getText()) {
result = imService.signUpUser(usernameText.getText().toString(),
passwordText.getText().toString(),
eMailText.getText().toString());
} else {
// ask user to fill all required fields
}
}