android檢查用戶是否已登錄

Question

我想檢查用戶是否已經登錄到應用程序，所以如果用戶沒有登錄，他將被定向到Login.class，如果用戶已經登錄，他將被定向到他的Profile.class。

我看到一個關於檢查用戶使用SplashActivity.class登錄的用戶的教程，但我試過了，並沒有爲我工作，我不知道也許我只是不知道它是如何工作的，因爲我是新的在編程

我的代碼：

登錄類

public class DocLogin extends Fragment { 

    ImageView ivIcon; 
    TextView tvItemName, tvRegister; 
    EditText user, pass; 
    Button btnLogin; 
    String username, password; 
    SQLController dbcon; 
    SharedPreferences sh_Pref; 
    Editor editor; 

    private static final String IS_LOGIN = "IsLoggedIn"; 
    int PRIVATE_MODE = 0; 


    public DocLogin() { 

    } 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
      Bundle savedInstanceState) { 

     View view = inflater.inflate(R.layout.doc_log_in, container, false); 

     dbcon = new SQLController(getActivity()); 
     dbcon.open(); 

     // Log in 
     user = (EditText) view.findViewById(R.id.etUser); 
     pass = (EditText) view.findViewById(R.id.etPassword); 
     btnLogin = (Button) view.findViewById(R.id.btnLogin); 

     // Sign up 
     tvRegister = (TextView) view.findViewById(R.id.tvRegDoc); 
     tvRegister.setMovementMethod(LinkMovementMethod.getInstance()); 
     tvRegister.setOnTouchListener(new OnTouchListener() { 

      @Override 
      public boolean onTouch(View v, MotionEvent event) { 
       // TODO Auto-generated method stub 
       FragmentManager fm = getFragmentManager(); 
       FragmentTransaction ft = fm.beginTransaction(); 
       ft.replace(R.id.content_frame, new DocReg()); 
       ft.commit(); 
       return false; 
      } 
     }); 

     // btnLogin onClickListener 
     btnLogin.setOnClickListener(new OnClickListener() { 

      @Override 
      public void onClick(View view) { 
       // TODO Auto-generated method stub 

       dbcon = new SQLController(getActivity()); 
       dbcon.open(); 

       username = user.getText().toString(); 
       password = pass.getText().toString(); 
       sharedPreferences(); 
       Toast.makeText(getActivity(), "Login Successful", 20).show(); 

       Log.v("LoginDetails", user.getText().toString() + "../.." 
         + pass.getText().toString()); 
       Cursor cur = dbcon.getuser_information(user.getText() 
         .toString(), pass.getText().toString()); 
       if (cur.getCount() != 0) { 
        FragmentManager fm = getFragmentManager(); 
        FragmentTransaction ft = fm.beginTransaction(); 
        ft.replace(R.id.content_frame, new DocProfile()); 
        ft.commit(); 
       } else { 
        AlertDialog alertDialog = new AlertDialog.Builder(
          getActivity()).create(); 
        alertDialog.setTitle("Login Error"); 
        alertDialog 
          .setMessage("Doctor Code and Password does not match"); 
        alertDialog.setButton("OK", 
          new DialogInterface.OnClickListener() { 

           @Override 
           public void onClick(DialogInterface dialog, 
             int which) { 
            // TODO Auto-generated method stub 
            // dismiss dialog 
           } 
          }); 
        alertDialog.show(); 
       } 

      } 
     }); 

     return view; 
    } 


    public void sharedPreferences() { 

     sh_Pref = getActivity().getSharedPreferences("Login Credentials", PRIVATE_MODE); 
     editor = sh_Pref.edit(); 
     editor.putBoolean(IS_LOGIN, true); 
     editor.putString("Username", username); 
     editor.putString("Password", password); 
     editor.commit(); 
    } 

} 

請指引我正確的方式來實現我的目標。

Answer 1

你需要在登錄表中添加alreadylogin字段在database.if用戶第一次登錄時，將alreadylogin字段設置爲true否則默認爲false。每次必須檢查alreadylogin字段。如果字段爲true，則必須重定向。

Answer 2

您的代碼顯示您的偏好設置。所以把以下內容放在你想檢查你是否登錄的地方。

SharedPreferences sh_Pref = getActivity().getSharedPreferences("Login Credentials", PRIVATE_MODE); 
boolean check = sh_Pref.getBoolean(IS_LOGIN, false); 
if(check){ 
    Intent intent = new Intent(this, Profile.class); 
    startActivity(intent); 
    finish(); 
} 

如果用戶已經在隨後已經登錄的用戶將被引導到Profile.class