共享偏好，它们去哪儿了？

Question

我知道共享首选项是如何工作的，但我只是不知道在下面的代码中的何处插入代码以保存用户数据。我有一个登录后台任务，可以完成所有工作和注册。我希望应用程序打开到用户登录时的启动页面。无法从其他答案中弄清楚

登录.java

Button bttnLogin;
EditText loginEmail, loginPassword;
TextView regLink;
AlertDialog.Builder alert;


@Override
protected void onCreate(Bundle savedInstanceState)
{

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_login);

    loginEmail = (EditText) findViewById(R.id.email);
    loginPassword = (EditText) findViewById(R.id.password);

    regLink = (TextView) findViewById(R.id.regLink);
    regLink.setOnClickListener(new View.OnClickListener()
    {
        @Override
        public void onClick(View v)
        {
            startActivity(new Intent(Login.this, Register.class));

        }
    });


    bttnLogin = (Button) findViewById(R.id.bttnLogin);
    bttnLogin.setOnClickListener(new View.OnClickListener()
    {

        @Override
        public void onClick(View v)
        {
            if (loginEmail.getText().toString().equals("") || loginPassword.getText().toString().equals(""))
            {
                alert = new AlertDialog.Builder(Login.this);
                alert.setTitle("Login Failed");
                alert.setMessage("Try again");
                alert.setPositiveButton("OK", new DialogInterface.OnClickListener()
                {

                    @Override
                    public void onClick(DialogInterface dialog, int which)
                    {

                        dialog.dismiss();
                    }

                });

                AlertDialog alertDialog = alert.create();
                alertDialog.show();
            } else  //if user provides proper data
            {
                BackgroundTask backgroundTask = new BackgroundTask(Login.this);
                backgroundTask.execute("login", loginEmail.getText().toString(), loginPassword.getText().toString());
            }

        }


    });

Register.java

        private Button regButton;
        public EditText regName;
        public EditText regEmail;
        public EditText regPassword;
        public EditText conPassword;
        private AlertDialog.Builder alert;



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

    regName = (EditText) findViewById(R.id.name);
    regEmail = (EditText) findViewById(R.id.email);
    regPassword = (EditText) findViewById(R.id.password);
    conPassword = (EditText) findViewById(R.id.conPassword);
    regButton = (Button) findViewById(R.id.regButton);
    regButton.setOnClickListener(this);
}


@Override
public void onClick(View v)
{

    if (regName.getText().toString().equals("") || regEmail.getText().toString().equals("") ||  regPassword.getText().toString().equals("") || conPassword.getText().toString().equals(""))
    {
        alert = new AlertDialog.Builder(Register.this);
        alert.setTitle("Something not quite right");
        alert.setMessage("Please fill in all the fields");
        alert.setPositiveButton("OK", new DialogInterface.OnClickListener()
        {

            @Override
            public void onClick(DialogInterface dialog, int which)
            {

                dialog.dismiss();
            }

        });

        AlertDialog alertDialog = alert.create();
        alertDialog.show();

    } else if (!(regPassword.getText().toString().equals(conPassword.getText().toString())))
    {

        alert = new AlertDialog.Builder(Register.this);
        alert.setTitle("Passwords do not match");
        alert.setMessage("Try Again");
        alert.setPositiveButton("OK", new DialogInterface.OnClickListener()
        {

            @Override
            public void onClick(DialogInterface dialog, int which)
            {

                dialog.dismiss();

                conPassword.setText("");
                regPassword.setText("");
            }

        });

        AlertDialog alertDialog = alert.create();
        alertDialog.show();


    }
    else //if user provides proper data
    {
        BackgroundTask backgroundTask = new BackgroundTask(Register.this);
        backgroundTask.execute("register", regName.getText().toString(), regEmail.getText().toString()
                , regPassword.getText().toString(), conPassword.getText().toString());
    }

BackgroundTask.java

 public class BackgroundTask extends AsyncTask<String,Void,String>
{

private Context context;
private Activity activity;
private String reg_url = "http://blaah.com/register.php";
private String login_url = "http://blaah.com/login.php";
private AlertDialog.Builder builder;
private ProgressDialog progressDialog;


public BackgroundTask(Context context)
{

    this.context = context;
    activity = (Activity) context;
}

@Override
protected void onPreExecute()
{
    builder = new AlertDialog.Builder(activity);
    progressDialog = new ProgressDialog(context);
    progressDialog.setTitle("Please wait");
    progressDialog.setMessage("Connecting to Server...");
    progressDialog.setIndeterminate(true);
    progressDialog.setCancelable(false);
    progressDialog.show();
}

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

    String method = params[0];

    if (method.equals("register"))
    {

        try
        {
            URL url = new URL(reg_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setDoInput(true);
            OutputStream outputStream = httpURLConnection.getOutputStream();
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
            String name = params[1];
            String email = params[2];
            String username = params[3];
            String password = params[4];
            String data = URLEncoder.encode("name", "UTF-8") + "=" + URLEncoder.encode(name, "UTF-8") + "&" +
                    URLEncoder.encode("email", "UTF-8") + "=" + URLEncoder.encode(email, "UTF-8") + "&" +
                    URLEncoder.encode("password", "UTF-8") + "=" + URLEncoder.encode(password, "UTF-8");
            bufferedWriter.write(data);
            bufferedWriter.flush();
            bufferedWriter.close();
            outputStream.close();
            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
            StringBuilder stringBuilder = new StringBuilder();
            String line = "";
            while ((line = bufferedReader.readLine()) != null)
            {

                stringBuilder.append(line).append("\n");

            }


            httpURLConnection.disconnect();
            Thread.sleep(8000);
            return stringBuilder.toString().trim();

        } catch (MalformedURLException e)
        {
            e.printStackTrace();
        } catch (IOException e)
        {
            e.printStackTrace();
        } catch (InterruptedException e)
        {
            e.printStackTrace();
        }

    }
    else if (method.equals("login"))
    {
        try
        {
            URL url = new URL(login_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setDoInput(true);
            OutputStream outputStream = httpURLConnection.getOutputStream();
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));


            String username,password;

            username = params[1];
            password = params [2];
            String data = URLEncoder.encode("email", "UTF-8") + "=" + URLEncoder.encode(username, "UTF-8") + "&" +
                    URLEncoder.encode("password", "UTF-8") + "=" + URLEncoder.encode(password, "UTF-8");
            bufferedWriter.write(data);
            bufferedWriter.flush();
            bufferedWriter.close();
            outputStream.close();

            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
            StringBuilder stringBuilder = new StringBuilder();
            String line = "";
            while ((line = bufferedReader.readLine()) != null)
            {

                stringBuilder.append(line + "\n");

            }


            httpURLConnection.disconnect();
            Thread.sleep(5000);
            return stringBuilder.toString().trim();


        } catch (MalformedURLException e)
        {
            e.printStackTrace();
        } catch (ProtocolException e)
        {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e)
        {
            e.printStackTrace();
        } catch (IOException e)
        {
            e.printStackTrace();
        } catch (InterruptedException e)
        {
            e.printStackTrace();
        }
    }

    return null;
}

@Override
protected void onProgressUpdate(Void... values)
{
    super.onProgressUpdate(values);
}

@Override
protected void onPostExecute(String json)
{
   try
   {

       progressDialog.dismiss();


       Log.v("JSON", json);
       JSONObject jsonObject = new JSONObject(json);
       JSONArray jsonArray = jsonObject.getJSONArray("server_response");
       JSONObject jsonobject = jsonArray.getJSONObject(0);
       String code = jsonobject.getString("code");
       String message = jsonobject.getString("message");



       if(code.equals("reg_true"))
       {
           showDialog("Sucessful registration.Thank you.Enjoy_AS!", message, code);
       }

       else if (code.equals("reg_false"))
       {
           showDialog("User Already exists", message, code);
       }

       else if (code.equals("login_true"))
       {
           Toast.makeText(context, "You are logged in", Toast.LENGTH_LONG).show();
           Intent intent = new Intent(activity, SplashScreen.class);
           activity.startActivity(intent);


       } else if (code.equals("login_false"))
       {
           showDialog("Login Error", message, code);
       }


   } catch (JSONException e){
       e.printStackTrace();
   }


}

public void  showDialog(String title,String message,String code)
{

    builder.setTitle(title);
    if (code.equals("reg_true") || code.equals("reg_false"))
    {
        builder.setMessage(message);//message form server
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener()

        {
            @Override
            public void onClick(DialogInterface dialog, int which)
            {
                dialog.dismiss();
                activity.finish();

            }
        });


    }

    else if (code.equals("login_false"))
    {


        builder.setMessage(message);
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener()
        {
            @Override
            public void onClick(DialogInterface dialog, int which)
            {
                EditText loginEmail, loginPassword;
                loginEmail = (EditText) activity.findViewById(R.id.email);
                loginPassword = (EditText) activity.findViewById(R.id.password);
                loginEmail.setText("");
                loginPassword.setText("");
                dialog.dismiss();

            }


        });


    }
    AlertDialog alertDialog = builder.create();
    alertDialog.show();
}

}

我希望应用打开到的初始屏幕

 final String TAG = this.getClass().getName();
private static int SPLASH_TIME_OUT = 4000;
private TextView saying;

@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    //this.requestWindowFeature(Window.FEATURE_NO_TITLE);
    supportRequestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                         WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.activity_splash_screen);

    saying = (TextView) findViewById(R.id.saying);
    Typeface mainHead =  Typeface.createFromAsset(getAssets(), "fonts/emporo.TTF");
    saying.setTypeface(mainHead);
    //Set text custom font for subhead text


    new Handler().postDelayed(new Runnable()
    {


        @Override
        public void run()
        {
            // This method will be executed once the timer is over
            // Start your app main activity
            Intent i = new Intent(SplashScreen.this, HomeScreen.class);
            startActivity(i);

            // close this activity
            finish();
        }
    }, SPLASH_TIME_OUT);

}
}

Answer 1

这是我在每个 Android 应用程序中使用的 SharedPreferences

import android.content.Context;
import android.content.SharedPreferences;

/**
 * Created by Jimit Patel on 30/07/15.
 */
public class Prefs {

    private static final String TAG = Prefs.class.getSimpleName();

    private static final String MY_APP_PREFS = "my_app";

    /**
     * <p>Provides Shared Preference object</p>
     * @param context
     * @return
     */
    private static SharedPreferences getPrefs(Context context) {
        return context.getSharedPreferences(MY_APP_PREFS, Context.MODE_PRIVATE);
    }

    /**
     * <p>Saves a string value for a given key in Shared Preference</p>
     * @param context
     * @param key
     * @param value
     */
    public static void setString(Context context, String key, String value) {
        getPrefs(context).edit().putString(key, value).apply();
    }

    /**
     * <p>Saves integer value for a given key in Shared Preference</p>
     * @param context
     * @param key
     * @param value
     */
    public static void setInt(Context context, String key, int value) {
        getPrefs(context).edit().putInt(key, value).apply();
    }

    /**
     * <p>Saves float value for a given key in Shared Preference</p>
     * @param context
     * @param key
     * @param value
     */
    public static void setFloat(Context context, String key, float value) {
        getPrefs(context).edit().putFloat(key, value).apply();
    }

    /**
     * <p>Saves long value for a given key in Shared Preference</p>
     * @param context
     * @param key
     * @param value
     */
    public static void setLong(Context context, String key, long value) {
        getPrefs(context).edit().putLong(key, value).apply();
    }

    /**
     * <p>Saves boolean value for a given key in Shared Preference</p>
     * @param context
     * @param key
     * @param value
     */
    public static void setBoolean(Context context, String key, boolean value) {
        getPrefs(context).edit().putBoolean(key, value).apply();
    }

    /**
     * Provides string from the Shared Preferences
     * @param context
     * @param key
     * @param defaultValue
     * @return
     */
    public static String getString(Context context, String key, String defaultValue) {
        return getPrefs(context).getString(key, defaultValue);
    }

    /**
     * Provides int from Shared Preferences
     * @param context
     * @param key
     * @param defaultValue
     * @return
     */
    public static int getInt(Context context, String key, int defaultValue) {
        return getPrefs(context).getInt(key, defaultValue);
    }

    /**
     * Provides boolean from Shared Preferences
     * @param context
     * @param key
     * @param defaultValue
     * @return
     */
    public static boolean getBoolean(Context context, String key, boolean defaultValue) {
        return getPrefs(context).getBoolean(key, defaultValue);
    }

    /**
     * Provides float value from Shared Preferences
     * @param context
     * @param key
     * @param defaultValue
     * @return
     */
    public static float getFloat(Context context, String key, float defaultValue) {
        return getPrefs(context).getFloat(key, defaultValue);
    }

    /**
     * Provides long value from Shared Preferences
     * @param context
     * @param key
     * @param defaultValue
     * @return
     */
    public static long getLong(Context context, String key, long defaultValue) {
        return getPrefs(context).getLong(key, defaultValue);
    }

    public static void clearPrefs(Context context) {
        getPrefs(context).edit().clear().commit();
    }
}

要使用它，您可以使用其中的那些功能

Answer 2

从服务器收到登录成功后，执行以下代码

SharedPreferences sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);    
SharedPreferences.Editor editor = sharedpreferences.edit();
editor.putString("hasLoggedIn", true);
editor.commit();

而无论你想在哪里检查用户是否登录，都可以使用以下代码进行检查。

boolean hasLoggedIn = sharedpreferences.getBoolean("hasLoggedIn", false);

如果 hasLogged 布尔值为 true，则表示用户已登录。

Answer 3

您创建了共享首选方法并保存

您可以使用此代码 ...对您有帮助

savaLoginValue(mobileno, password, userTypeId, clientid);

private void savaLoginValue(String mobileno, String password) 
{
        SharedPreferences login = getSharedPreferences("Preferance", MODE_PRIVATE);
        SharedPreferences.Editor editor = login.edit();
        editor.putString("SPMobileno", mobileno);
        editor.putString("SPPass", password);
        editor.commit();
}

BackgoundTask.Class

public class BackgroundTask extends AsyncTask<String,Void,String>
{

private Context context;
private Activity activity;
private String reg_url = "http://blaah.com/register.php";
private String login_url = "http://blaah.com/login.php";
private AlertDialog.Builder builder;
private ProgressDialog progressDialog;


public BackgroundTask(Context context)
{

    this.context = context;
    activity = (Activity) context;
}

@Override
protected void onPreExecute()
{
    builder = new AlertDialog.Builder(activity);
    progressDialog = new ProgressDialog(context);
    progressDialog.setTitle("Please wait");
    progressDialog.setMessage("Connecting to Server...");
    progressDialog.setIndeterminate(true);
    progressDialog.setCancelable(false);
    progressDialog.show();
}

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

    String method = params[0];

    if (method.equals("register"))
    {

        try
        {
            URL url = new URL(reg_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setDoInput(true);
            OutputStream outputStream = httpURLConnection.getOutputStream();
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
            String name = params[1];
            String email = params[2];
            String username = params[3];
            String password = params[4];
            String data = URLEncoder.encode("name", "UTF-8") + "=" + URLEncoder.encode(name, "UTF-8") + "&" +
                    URLEncoder.encode("email", "UTF-8") + "=" + URLEncoder.encode(email, "UTF-8") + "&" +
                    URLEncoder.encode("password", "UTF-8") + "=" + URLEncoder.encode(password, "UTF-8");
            bufferedWriter.write(data);
            bufferedWriter.flush();
            bufferedWriter.close();
            outputStream.close();
            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
            StringBuilder stringBuilder = new StringBuilder();
            String line = "";
            while ((line = bufferedReader.readLine()) != null)
            {

                stringBuilder.append(line).append("\n");

            }


            httpURLConnection.disconnect();
            Thread.sleep(8000);
            return stringBuilder.toString().trim();

        } catch (MalformedURLException e)
        {
            e.printStackTrace();
        } catch (IOException e)
        {
            e.printStackTrace();
        } catch (InterruptedException e)
        {
            e.printStackTrace();
        }

    }
    else if (method.equals("login"))
    {
        try
        {
            URL url = new URL(login_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setDoInput(true);
            OutputStream outputStream = httpURLConnection.getOutputStream();
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));


            String username,password;

            username = params[1];
            password = params [2];
            String data = URLEncoder.encode("email", "UTF-8") + "=" + URLEncoder.encode(username, "UTF-8") + "&" +
                    URLEncoder.encode("password", "UTF-8") + "=" + URLEncoder.encode(password, "UTF-8");
            bufferedWriter.write(data);
            bufferedWriter.flush();
            bufferedWriter.close();
            outputStream.close();

            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
            StringBuilder stringBuilder = new StringBuilder();
            String line = "";
            while ((line = bufferedReader.readLine()) != null)
            {

                stringBuilder.append(line + "\n");

            }


            httpURLConnection.disconnect();
            Thread.sleep(5000);
            return stringBuilder.toString().trim();


        } catch (MalformedURLException e)
        {
            e.printStackTrace();
        } catch (ProtocolException e)
        {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e)
        {
            e.printStackTrace();
        } catch (IOException e)
        {
            e.printStackTrace();
        } catch (InterruptedException e)
        {
            e.printStackTrace();
        }
    }

    return null;
}

@Override
protected void onProgressUpdate(Void... values)
{
    super.onProgressUpdate(values);
}

@Override
protected void onPostExecute(String json)
{
   try
   {

       progressDialog.dismiss();


       Log.v("JSON", json);
       JSONObject jsonObject = new JSONObject(json);
       JSONArray jsonArray = jsonObject.getJSONArray("server_response");
       JSONObject jsonobject = jsonArray.getJSONObject(0);
       String code = jsonobject.getString("code");
       String message = jsonobject.getString("message");



       if(code.equals("reg_true"))
       {
           showDialog("Sucessful registration.Thank you.Enjoy_AS!", message, code);
       }

       else if (code.equals("reg_false"))
       {
           showDialog("User Already exists", message, code);
       }

       else if (code.equals("login_true"))
       {
         
         // Please You Can Take The Username & Password And Save It For Shared Preference Then Share Preference File Any where To Use It.. 
           Toast.makeText(context, "You are logged in", Toast.LENGTH_LONG).show();
           Intent intent = new Intent(activity, SplashScreen.class);
           activity.startActivity(intent);


       } else if (code.equals("login_false"))
       {
           showDialog("Login Error", message, code);
       }


   } catch (JSONException e){
       e.printStackTrace();
   }


}

public void  showDialog(String title,String message,String code)
{

    builder.setTitle(title);
    if (code.equals("reg_true") || code.equals("reg_false"))
    {
        builder.setMessage(message);//message form server
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener()

        {
            @Override
            public void onClick(DialogInterface dialog, int which)
            {
                dialog.dismiss();
                activity.finish();

            }
        });


    }

    else if (code.equals("login_false"))
    {


        builder.setMessage(message);
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener()
        {
            @Override
            public void onClick(DialogInterface dialog, int which)
            {
                EditText loginEmail, loginPassword;
                loginEmail = (EditText) activity.findViewById(R.id.email);
                loginPassword = (EditText) activity.findViewById(R.id.password);
                loginEmail.setText("");
                loginPassword.setText("");
                dialog.dismiss();

            }


        });


    }
    AlertDialog alertDialog = builder.create();
    alertDialog.show();
}

}

Answer 4

只需创建一个名为 SessionManagement.java 的类并粘贴以下代码

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import java.util.HashMap;

/**
* Created by naveen.tp on 21/4/2016.
*/
public class SessionManagement {

SharedPreferences sharedPreferences;
SharedPreferences.Editor editor;
Context context;

int PRIVATE_MODE = 0;

private static final String PREF_NAME = "YourPreferences";

private static final String IS_LOGIN = "isLogedIn";

//Constructor
public SessionManagement(Context context) {

    this.context = context;
    sharedPreferences = context.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
    editor = sharedPreferences.edit();
}


//Create Login Session
public void createLoginSession(boolean flag)
{
    editor.putBoolean(IS_LOGIN, flag);
    editor.commit();
}

//check for isLogin returns True/false
public boolean isLoggedIn()
{
    return sharedPreferences.getBoolean(IS_LOGIN, false);
}

}

在您的代码BackgroundTask.java onPostExcecute 方法中

已编辑

else if(code.equals("login_true"))
{
 SessionManagement session = new SessionManagement(context);
 session.createLoginSession(true);
 Toast.makeText(context, "You are logged in", Toast.LENGTH_LONG).show();
 Intent intent = new Intent(activity, SplashScreen.class);
 activity.startActivity(intent);
}

您也可以在下次启动画面中检查登录状态，只需调用

已编辑

SessionManagement session = new SessionManagement(this); 
boolean isLogin = session.isLoggedIn();
if(isLogin)
{
  //Already logged in
}
else
{
  //Not logged in
}

希望对你有所帮助！