目前，我的应用程序登录会提示用户输入用户名和密码，然后提交按钮将信息发送到服务和我的服务器：
private ServiceConnection mConnection = new ServiceConnection() {
public void onServiceConnected(ComponentName className, IBinder service) {
imService = ((MessagingService.IMBinder) service).getService();
if (imService.isUserAuthenticated() == true) {
Intent i = new Intent(LoggingIn.this, MainActivity.class);
startActivity(i);
LoggingIn.this.finish();
}
}
public void onServiceDisconnected(ComponentName className) {
imService = null;
Toast.makeText(LoggingIn.this, R.string.local_service_stopped,
Toast.LENGTH_SHORT).show();
}
};
/*
* Start and bind the imService
*/
startService(new Intent(LoggingIn.this, MessagingService.class));
usernameText = (EditText) findViewById(R.id.username);
passwordText = (EditText) findViewById(R.id.password);
loginButton.setOnClickListener(new OnClickListener() {
public void onClick(View arg0) {
if (imService == null) {
Toast.makeText(getApplicationContext(),
R.string.not_connected_to_service,
Toast.LENGTH_LONG).show();
// showDialog(NOT_CONNECTED_TO_SERVICE);
return;
} else if (imService.isNetworkConnected() == false) {
Toast.makeText(getApplicationContext(),
R.string.not_connected_to_network,
Toast.LENGTH_LONG).show();
// showDialog(NOT_CONNECTED_TO_NETWORK);
} else if (usernameText.length() > 0
&& passwordText.length() > 0) {
Thread loginThread = new Thread() {
private Handler handler = new Handler();
@Override
public void run() {
String result = null;
try {
result = imService.authenticateUser(
usernameText.getText().toString().trim(),
passwordText.getText().toString().trim());
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
if (result == null
|| result.equals(AUTHENTICATION_FAILED)) {
/*
* Authenticatin failed, inform the user
*/
handler.post(new Runnable() {
public void run() {
Toast.makeText(
getApplicationContext(),
R.string.make_sure_username_and_password_correct,
Toast.LENGTH_LONG).show();
// showDialog(MAKE_SURE_USERNAME_AND_PASSWORD_CORRECT);
}
});
} else {
/*
* if result not equal to authentication failed,
* result is equal to friend and group list of
* the user 0: is for friends, 1: is for groups
*/
handler.post(new Runnable() {
public void run() {
// If log in successful, then save
// username and password to shared
// preferences:
SaveSharedPreference.setUserName(
getApplicationContext(),
usernameText.getText()
.toString());
SaveSharedPreference.setPassword(
getApplicationContext(),
passwordText.getText()
.toString());
Intent i = new Intent(LoggingIn.this,
MainActivity.class);
startActivity(i);
LoggingIn.this.finish();
}
});
}
}
};
loginThread.start();
} else {
/*
* Username or Password is not filled, alert the user
*/
Toast.makeText(getApplicationContext(),
R.string.fill_both_username_and_password,
Toast.LENGTH_LONG).show();
// showDialog(FILL_BOTH_USERNAME_AND_PASSWORD);
}
}
});
哪种方法效果很好。我希望实现的是用户自动登录，因为他们已经登录，因此用户名和密码存储在共享首选项中。
因此，当他们再次访问该应用时，应该自动将其登录为：
private ServiceConnection mConnection = new ServiceConnection() {
public void onServiceConnected(ComponentName className, IBinder service) {
imService = ((MessagingService.IMBinder) service).getService();
if (imService.isUserAuthenticated() == true) {
Intent i = new Intent(LoggingIn.this, MainActivity.class);
startActivity(i);
LoggingIn.this.finish();
}
}
public void onServiceDisconnected(ComponentName className) {
imService = null;
Toast.makeText(LoggingIn.this, R.string.local_service_stopped,
Toast.LENGTH_SHORT).show();
}
};
startService(new Intent(LoggingIn.this, MessagingService.class));
final String userName = SaveSharedPreference.getUserName(getApplicationContext());
final String password = SaveSharedPreference.getPassword(getApplicationContext());
Thread loginThread = new Thread() {
private Handler handler = new Handler();
@Override
public void run() {
String result = null;
try {
result = imService.authenticateUser(
userName.trim(),
password.trim());
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
if (result == null
|| result.equals(AUTHENTICATION_FAILED)) {
/*
* Authenticatin failed, inform the user
*/
handler.post(new Runnable() {
public void run() {
Toast.makeText(
getApplicationContext(),
R.string.make_sure_username_and_password_correct,
Toast.LENGTH_LONG).show();
// showDialog(MAKE_SURE_USERNAME_AND_PASSWORD_CORRECT);
}
});
} else {
handler.post(new Runnable() {
public void run() {
Intent i = new Intent(LoggingIn.this,
MainActivity.class);
startActivity(i);
LoggingIn.this.finish();
}
});
}
}
};
loginThread.start();
用户信息已成功存储在共享首选项中，但在执行此代码块时，它始终在线返回NullPointerException：
result = imService.authenticateUser(
userName.trim(),
password.trim());
在try {} catch块中。
我试图在应用程序中放置一个计时器，也许该服务没有时间启动，但即使在20秒以上仍然无效。
如何获得自动登录功能而不返回？
更新注意： private Manager imService;是一个接口：
public interface Manager {
public boolean isNetworkConnected();
public boolean isUserAuthenticated();
}