未保存共享首选项

Question

我已经尝试了其他关于共享偏好的答案中给出的所有可能的解决方案，但仍然无法解决，因此提出了这个问题。

我一直在使用这些文件

Config.java

public class Config {
    //URL to our login.php file
    public static final String LOGIN_URL = "http://192.168.211.1/Remedcu/login.php";

    public static final String KEY_NAME = "Name";
    public static final String KEY_EMAIL = "Email";
    public static final String KEY_PASSWORD = "Password";

    //If server response is equal to this that means login is successful
    public static final String LOGIN_SUCCESS = "success";

    //Keys for Sharedpreferences
    //This would be the name of our shared preferences
    public static final String SHARED_PREF_NAME = "iamhere";

    //This would be used to store the email of current logged in user
    public static String EMAIL_SHARED_PREF = null;

    //We will use this to store the boolean in sharedpreference to track user is loggedin or not
    public static String LOGGEDIN_SHARED_PREF = "loggedin";
}

和 Login.java

public class Login extends AppCompatActivity {
private static final String TAG = "LoginActivity";
private Vibrator vib;
Animation animShake;
private EditText signupInputName, signupInputPassword;
private TextInputLayout signupInputLayoutName,
        signupInputLayoutPassword;
private Button btnSignUp;
ProgressDialog progress;
private static final String LOGIN_URL = "http://192.168.211.1/Remedcu/login.php";

public static final String KEY_NAME = "Username";
public static final String KEY_PASSWORD = "Password";
TextView textView;
private boolean loggedIn = false;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_login);

    signupInputLayoutName = (TextInputLayout) findViewById(R.id.signup_input_layout_name);
    signupInputLayoutPassword = (TextInputLayout) findViewById(R.id.signup_input_layout_password);
    textView = (TextView) findViewById(R.id.textView2);
    textView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(Login.this, Registration.class);
            startActivity(intent);

        }
    });

    signupInputName = (EditText) findViewById(R.id.signup_input_name);

    signupInputPassword = (EditText) findViewById(R.id.signup_input_password);

    btnSignUp = (Button) findViewById(R.id.btn_signup);

    animShake = AnimationUtils.loadAnimation(getApplicationContext(), R.anim.shakei);
    vib = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);

    btnSignUp.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            submitForm();
            //Intent intent=new Intent(Intent.ACTION_VIEW);
         }
    });
}

private void submitForm() {
    final   String      Name = signupInputName.getText().toString().trim();
    final   String    Password=signupInputPassword.getText().toString().trim();

    StringRequest stringRequest = new StringRequest(Request.Method.POST,LOGIN_URL,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    if(response.equalsIgnoreCase("Invalid credentials")) {
                    Toast.makeText(Login.this, response, Toast.LENGTH_SHORT).show();
                    }
                    //String LOGIN_SUCCESS = "success";
                    if(response.equalsIgnoreCase("success")){
                      final String Use ="Welcome "+Name;
                      Toast.makeText(getApplicationContext(),Use,Toast.LENGTH_SHORT).show();

                        //Creating a shared preference
                        SharedPreferences sharedPreferences = Login.this.getSharedPreferences(Config.SHARED_PREF_NAME, Context.MODE_PRIVATE);

                        //Creating editor to store values to shared preferences
                        SharedPreferences.Editor editor = sharedPreferences.edit();

                        //Adding values to editor
                        editor.putBoolean(Config.LOGGEDIN_SHARED_PREF, true);
                        editor.putString(Config.EMAIL_SHARED_PREF, Name);
                        //Saving values to editor
                        editor.apply();

                        Toast.makeText(getApplicationContext(), "The data is saved as "+Config.EMAIL_SHARED_PREF,Toast.LENGTH_SHORT).show();


                        Intent intent = new Intent(Login.this, MapsActivity.class);
                        startActivity(intent);
                    }//else{
                        //If the server response is not success
                        //Displaying an error message on toast
                    //    Toast.makeText(Login.this, "Invalid credentials", Toast.LENGTH_LONG).show();
                    //}
                    //  Intent intent = new Intent(Registration.this, MainActivity.class);
                    // startActivity(intent);
                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    Toast.makeText(Login.this,error.toString(),Toast.LENGTH_LONG).show();
                }
            }){
        @Override
        protected Map<String,String> getParams(){
            Map<String,String> params = new HashMap<String, String>();
            params.put(KEY_NAME,Name);
            params.put(KEY_PASSWORD,Password);
            return params;
        }

    };

    RequestQueue requestQueue = Volley.newRequestQueue(this);
    requestQueue.add(stringRequest);


    if (!checkName()) {
        signupInputName.setAnimation(animShake);
        signupInputName.startAnimation(animShake);
        vib.vibrate(120);
        return;
    }
    if (!checkPassword()) {
        signupInputPassword.setAnimation(animShake);
        signupInputPassword.startAnimation(animShake);
        vib.vibrate(120);
        return;
    }


    signupInputLayoutName.setErrorEnabled(false);
    signupInputLayoutPassword.setErrorEnabled(false);

    //   Toast.makeText(getApplicationContext(),
    //    "You are logged in !!", Toast.LENGTH_SHORT).show();
}

private boolean checkName() {
    if (signupInputName.getText().toString().trim().isEmpty()) {

        signupInputLayoutName.setErrorEnabled(true);
        signupInputLayoutName.setError(getString(R.string.err_msg_name));
        signupInputName.setError(getString(R.string.err_msg_required));
        return false;
    }
    signupInputLayoutName.setErrorEnabled(false);
    return true;
}


private boolean checkPassword() {
    if (signupInputPassword.getText().toString().trim().isEmpty()) {

        signupInputLayoutPassword.setError(getString(R.string.err_msg_password));
        requestFocus(signupInputPassword);
        return false;
    }
    signupInputLayoutPassword.setErrorEnabled(false);
    return true;
}

private static boolean isValidEmail(String email) {
    return !TextUtils.isEmpty(email) &&
            android.util.Patterns.EMAIL_ADDRESS.matcher(email).matches();
}

private void requestFocus(View view) {
    if (view.requestFocus()) {
        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);
    }
}

@Override
protected void onResume() {
    super.onResume();
    //In onresume fetching value from sharedpreference
    SharedPreferences sharedPreferences = getSharedPreferences(Config.SHARED_PREF_NAME, Context.MODE_PRIVATE);

    //Fetching the boolean value form sharedpreferences
    loggedIn = sharedPreferences.getBoolean(Config.LOGGEDIN_SHARED_PREF, false);

    //If we will get true
    if (loggedIn) {
        //We will start the Profile Activity
        Intent intent = new Intent(Login.this, MapsActivity.class);
        startActivity(intent);
    }
}}

在我将更改提交到编辑器后的 Login.java 中，我只想检查值是否已保存。

因此下面的代码在那里：

Toast.makeText(getApplicationContext(), "The data is saved as "+Config.EMAIL_SHARED_PREF,Toast.LENGTH_SHORT).show();

但是每当我运行程序，登录后，吐司总是“数据保存为空”

有什么办法吗？

Answer 1

需要从sharedPreferences中获取email，即keyEMAIL_SHARED_PREF的值：

String email = sharedPreferences.getString(Config.EMAIL_SHARED_PREF, "NOT FOUND");

'NOT FOUND' 是如果 EMAIL_SHARED_PREF 未使用 SharedPreferences 中的值初始化时将设置为电子邮件的值。接下来，您可以在吐司机中拨打email。

    Toast.makeText(getApplicationContext(), "The data is saved as "+ email,Toast.LENGTH_SHORT).show();

Answer 2

如果您想查看在密钥 Config.EMAIL_SHARED_PREF 下保存的内容，请改为运行以下代码：

 Toast.makeText(getApplicationContext(), "The data is saved as "+sharedPreferences.getString(Config.EMAIL_SHARED_PREF, ""),Toast.LENGTH_SHORT).show();

但是，请记住，除了 null 之外，您没有为 Config.EMAIL_SHARED_PREF 分配任何其他内容，因此您只需将其存储在 null 下。