Android：将用户名保持在会话中，直到注销

Question

我很难弄清楚如何使用 SharedPreferences 将用户名存储在手机中并保持会话直到注销。我还需要知道它在会话中如何将用户名与用户在列表视图中单击的数据一起发送出去。以下是我正在使用的代码，并且想知道为了实现这一目标而放置的位置和代码。登录时它会进入菜单并停留在菜单上（避免返回按钮返回登录屏幕）每个菜单都有一个注销项，它将返回登录屏幕。

我之前看过的问题是this和this

Logcat 详细信息

05-26 10:42:19.146: WARN/KeyCharacterMap(26071): Using default keymap: /system/usr/keychars/qwerty.kcm.bin
05-26 10:42:23.926: DEBUG/AndroidRuntime(26071): Shutting down VM
05-26 10:42:23.926: WARN/dalvikvm(26071): threadid=3: thread exiting with uncaught exception (group=0x40013140)
05-26 10:42:23.926: ERROR/AndroidRuntime(26071): Uncaught handler: thread main exiting due to uncaught exception
05-26 10:42:23.936: ERROR/AndroidRuntime(26071): java.lang.NullPointerException
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at com.merrill2.Login$1.onClick(Login.java:42)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at android.view.View.performClick(View.java:2232)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at android.view.View.onTouchEvent(View.java:3905)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at android.widget.TextView.onTouchEvent(TextView.java:6414)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at android.view.View.dispatchTouchEvent(View.java:3421)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:906)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:906)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:906)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:906)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1707)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1197)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at android.app.Activity.dispatchTouchEvent(Activity.java:1993)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1691)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1533)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at android.os.Handler.dispatchMessage(Handler.java:99)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at android.os.Looper.loop(Looper.java:123)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at android.app.ActivityThread.main(ActivityThread.java:3992)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at java.lang.reflect.Method.invokeNative(Native Method)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at java.lang.reflect.Method.invoke(Method.java:521)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:782)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:540)
05-26 10:42:23.936: ERROR/AndroidRuntime(26071):     at dalvik.system.NativeStart.main(Native Method)
05-26 10:42:23.946: INFO/Process(899): Sending signal. PID: 26071 SIG: 3
05-26 10:42:23.956: INFO/dalvikvm(26071): threadid=7: reacting to signal 3
05-26 10:42:23.966: INFO/dalvikvm(26071): Wrote stack trace to '/data/anr/traces.txt'
05-26 10:42:25.646: DEBUG/dalvikvm(25722): GC freed 973 objects / 63040 bytes in 93ms
05-26 10:42:27.777: DEBUG/DispatchService(945): Handled message = TIMED_SERVICE_UNMASK
05-26 10:42:29.856: DEBUG/DispatchService(945): DISPATCH SERVICE getIdenPacketDataState: returning: 4
05-26 10:42:29.876: INFO/iDENWAPReceiver(953): Received a android.intent.action.ANY_DATA_STATE

登录.java

public class Login extends Activity {
    protected static final SharedPreferences settings = null;
    private EditText etUsername;
    private Button btnLogin;
    private Button btnCancel;
    private TextView lblResult;
    /** Called when the activity is first created. */
    //@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.login);

        etUsername = (EditText)findViewById(R.id.username);
        btnLogin = (Button)findViewById(R.id.login_button);
        btnCancel = (Button)findViewById(R.id.cancel_button);
        lblResult = (TextView)findViewById(R.id.result);

        btnLogin.setOnClickListener(new OnClickListener() {
            //@Override
            public void onClick(View v) {
            // Check Login
            String username = etUsername.getText().toString();

            SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
            SharedPreferences.Editor editor = settings.edit();
            editor.putString("username", username);

            if(username.equals("1111")){
                lblResult.setText("Login successful.");

                //startActivity(new Intent(this, Activity2.class));


                Intent i = new Intent(getApplicationContext(), Customer.class);
                startActivity(i);

如果我取出下面的行：

protected static final SharedPreferences settings = null;

我把这个：

btnLogin.setOnClickListener(new OnClickListener() {
            private SharedPreferences settings;

'settings' 给出错误，所以我不得不使用上面提到的那些行之一

Answer 1

添加用户只需：

import android.preference.PreferenceManager;
....
SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
SharedPreferences.Editor editor = settings.edit();
editor.putString("username", username);

然后在注销中删除它：

SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
SharedPreferences.Editor editor = settings.edit();
editor.remove("username");

这样可以确保用户只持续一个会话，直到它注销。当你打开你的应用程序时，你应该检查一下（以防万一），如果发生错误，看看是否已经在之前的会话中设置了用户名。

至于在 ListView 中传递数据，您必须手动完成。 SharedPreference 框架负责处理其他所有事情。

Answer 2

我认为这个例子应该很有帮助。

http://www.androidhive.info/2012/08/android-session-management-using-shared-preferences/

主类在这里：

public class SessionManager {
    // Shared Preferences
    SharedPreferences pref;

    // Editor for Shared preferences
    Editor editor;

    // Context
    Context _context;

    // Shared pref mode
    int PRIVATE_MODE = 0;

    // Sharedpref file name
    private static final String PREF_NAME = "AndroidHivePref";

    // All Shared Preferences Keys
    private static final String IS_LOGIN = "IsLoggedIn";

    // User name (make variable public to access from outside)
    public static final String KEY_NAME = "name";

    // Email address (make variable public to access from outside)
    public static final String KEY_EMAIL = "email";

    // Constructor
    public SessionManager(Context context){
        this._context = context;
        pref = _context.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
        editor = pref.edit();
    }

    /**
     * Create login session
     * */
    public void createLoginSession(String name, String email){
        // Storing login value as TRUE
        editor.putBoolean(IS_LOGIN, true);

        // Storing name in pref
        editor.putString(KEY_NAME, name);

        // Storing email in pref
        editor.putString(KEY_EMAIL, email);

        // commit changes
        editor.commit();
    }   

    /**
     * Check login method wil check user login status
     * If false it will redirect user to login page
     * Else won't do anything
     * */
    public void checkLogin(){
        // Check login status
        if(!this.isLoggedIn()){
            // user is not logged in redirect him to Login Activity
            Intent i = new Intent(_context, LoginActivity.class);
            // Closing all the Activities
            i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

            // Add new Flag to start new Activity
            i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

            // Staring Login Activity
            _context.startActivity(i);
        }

    }



    /**
     * Get stored session data
     * */
    public HashMap<String, String> getUserDetails(){
        HashMap<String, String> user = new HashMap<String, String>();
        // user name
        user.put(KEY_NAME, pref.getString(KEY_NAME, null));

        // user email id
        user.put(KEY_EMAIL, pref.getString(KEY_EMAIL, null));

        // return user
        return user;
    }

    /**
     * Clear session details
     * */
    public void logoutUser(){
        // Clearing all data from Shared Preferences
        editor.clear();
        editor.commit();

        // After logout redirect user to Loing Activity
        Intent i = new Intent(_context, LoginActivity.class);
        // Closing all the Activities
        i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

        // Add new Flag to start new Activity
        i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

        // Staring Login Activity
        _context.startActivity(i);
    }

    /**
     * Quick check for login
     * **/
    // Get Login State
    public boolean isLoggedIn(){
        return pref.getBoolean(IS_LOGIN, false);
    }
}

Answer 3

当用户登录成功后，将用户的username添加到您的应用程序的SharedPreference中。

SharedPreferences settings = getSharedPreferences("MyPrefsFile", 0);
SharedPreferences.Editor editor = settings.edit();
editor.putString("username", username);

每次用户打开应用时，检查是否设置了“userID”首选项。如果是，则他已登录。否则显示登录屏幕。当用户注销时，从共享首选项中删除“用户名”条目。

我还需要知道它在会话中如何将用户名与用户在列表视图中单击的数据一起发送出去

您将可以通过该共享首选项访问用户 ID，以便您可以在需要时使用它。 Android 框架不会为您执行此操作，但您可以轻松完成。

Answer 4

要存储在存储的首选项中，请使用此

 SharedPreferences.Editor editor = getSharedPreferences("DeviceToken",MODE_PRIVATE).edit();
                        editor.putString("DeviceToken","ABABABABABABABB12345");
editor.apply();

用于检索相同用途

    SharedPreferences prefs = getSharedPreferences("DeviceToken", 
 MODE_PRIVATE);
    String deviceToken = prefs.getString("DeviceToken", null);