0

我正在开发需要登录的 android 应用程序。我想检查用户何时按下 PostIdea 活动按钮，然后检查用户是否登录，如果没有，则重定向到登录页面，否则继续执行任务。

在这里，我为此使用 SharedPreferences。现在，当我按下登录按钮时，将用户名和密码添加到 SharedPreferences 中，当按下 PostIdea Activity 时，我得到了用户名和密码。

但我的问题是，当我重新启动应用程序并在没有登录的情况下进入 PostIdea 活动时，它会记住 SharedPreferences 数据的最后一次登录（用户名/密码）。如何从 SharedPreferences 中删除该数据，以便我的应用程序正常工作。让我知道我在哪里做错了，或者我的问题还有其他解决方案。

谢谢。

登录活动类

public class LoginActivity extends CheerfoolznativeActivity {

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_login);
    setHeader("Login");

    editUser = (EditText) findViewById(R.id.login_useredit);
    editPass = (EditText) findViewById(R.id.login_passedit);
    txterror = (TextView) findViewById(R.id.login_error);
    textlogin = (TextView) findViewById(R.id.login_postidea_textView);
    btngotoregister = (Button) findViewById(R.id.login_btnLinkToRegisterScreen);
    btnlogin = (Button) findViewById(R.id.login_button);
    pgb = (ProgressBar) findViewById(R.id.login_progressBar);

    btnlogin.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

            new Login().execute();

        }
    });

}

public class Login extends AsyncTask<Void, Void, Void> {

    int i = 0;
    String uName ;
    String Password;

    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub
        super.onPreExecute();

        uName = editUser.getText().toString().trim();
        Password = editPass.getText().toString().trim();

        if (uName.equals("") | Password.equals("")) {
            Toast.makeText(getApplicationContext(), "Enter the Data",
                    Toast.LENGTH_SHORT).show();

            if (editUser.length() == 0) {
                editUser.setError("Enter Username");
            }
            if (editPass.length() == 0) {
                editPass.setError("Enter Password");
            }
        } else {

            pgb.setVisibility(View.VISIBLE);
        }

    }

    @Override
    protected Void doInBackground(Void... params) {
        // TODO Auto-generated method stub


            String loginURL = "http://www.cheerfoolz.com/rest/user/login";

            strResponse = util.makeWebCall(loginURL, uName, Password);

        return null;
    }

    @Override
    public void onPostExecute(Void result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);

    txterror.setText("");

            try {
                if (strResponse.substring(KEY_SUCCESS) != null) {
                    txterror.setText("");

                    // SharedPreferences Logic
                    SharedPreferences userDetails =getSharedPreferences("userdetails", MODE_PRIVATE);
                    Editor edit = userDetails.edit();
                    edit.clear();
                    edit.putString("username", uName);
                    edit.putString("password", Password);
                    edit.commit();


                    new FetchUserProfileTask().execute();

                } else {
                    txterror.setText("Username and Password Not valid !!!");
                }
            } catch (Exception e) {
                // TODO: handle exception
            }

    }

}

public class FetchUserProfileTask extends AsyncTask<Void, Void, Void> {

    int i = 0;

    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub
        super.onPreExecute();


    }

    @Override
    protected Void doInBackground(Void... params) {

        //logic for the featch user profile data

    return null;
    }

    @Override
    public void onPostExecute(Void result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);

         pgb.setVisibility(View.GONE);
        displayProfile();

    }
}

public void displayProfile() {

    Intent in1 = new Intent(LoginActivity.this, post_myprofile.class);
    in1.putExtra("loginObject", bean);
    startActivity(in1);
}

}

Post_idea_Activity.class

public class Post_idea_Activity extends CheerfoolznativeActivity {

TextView txtwelcome;
String Uname="";
String pass = ""; 
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);


    SharedPreferences userDetails = getSharedPreferences("userdetails", MODE_PRIVATE);
    System.out.println("value of the userdertails ==========>"+ userDetails);
    //String Uname="";
    //String pass= ""; 

    Uname = userDetails.getString("username", "");
    pass = userDetails.getString("password", "");

    Toast.makeText(getApplicationContext(),"username : "+Uname +" \n password :"+pass, Toast.LENGTH_SHORT).show();

    if (Uname.equals(null)) 
    {
        Intent in1 = new Intent(this, LoginActivity.class);
        in1.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        startActivity(in1);

    }
    else {

        setContentView(R.layout.post_idea);
        setHeader("Post idea");

        txtwelcome =(TextView)findViewById(R.id.post_welcome_text);
             }


       }

   //  coding for the layout
}
4

3 回答 3

2

清除初始屏幕中的共享首选项 在初始屏幕中使用以下代码，这意味着您的应用程序的第一个活动

SharedPreferences userDetails =getSharedPreferences("userdetails", MODE_PRIVATE);
                    Editor edit = userDetails.edit();
                    edit.clear();
                    edit.putString("username", "");
                    edit.putString("password", "");
                    edit.commit();
于 2012-06-07T09:50:21.420 回答
1

在您的应用启动时清除您的共享偏好。

SharedPreferences userDetails =getSharedPreferences("userdetails", MODE_PRIVATE);
Editor edit = userDetails.edit();
edit.clear();
edit.commit();

您可以在应用程序的应用程序类中编写它。

于 2012-06-07T09:56:25.290 回答
1 
    Write in login page.....
    //variables
    String PREFS_USER_ID = "USER_ID";
    String  PREF_NAME = "Pref";
    String  USER_ID;
    //write in where u want to store data....
    setPreferences(PREF_NAME, PREFS_USER_ID, USER_ID);
    // methods
    private void setPreferences(String preferenceName, String key, String value)
    {
            SharedPreferences settings = getSharedPreferences(preferenceName, 0);
            SharedPreferences.Editor editor = settings.edit();
            editor.putString(key, value);
            editor.commit();
    }
    private String getSharedPreferences(String preferenceName, String key)
    {
            // Restore preferences
            SharedPreferences settings = getSharedPreferences(preferenceName, 0);
            String value = settings.getString(key, null);
            return value;
    }
    in the other activity u get user name and password.........
    String userid=getSharedPreferences(PREF_NAME, PREFS_USER_ID);
    //method
    private String getSharedPreferences(String preferenceName, String key)
    {
        // Restore preferences
            SharedPreferences settings = getSharedPreferences(preferenceName, 0);
            String value = settings.getString(key, null);
            return value;
    }
// for delete  or remove the data from sharepreferences
SharedPreferences wmbPreference = PreferenceManager.getDefaultSharedPreferences(this);
    SharedPreferences.Editor editor = wmbPreference.edit();
    editor.clear();
    editor.commit();
于 2012-06-07T10:01:33.147 回答