Question

I would like to store class object in android sharedpreference. I did some basic search on that and I got some answers like make it serializable object and store it but my need is so simple. I would like to store some user info like name, address, age and boolean value is active. I made one user class for that.

public class User {
    private String  name;
    private String address;
    private int     age;
    private boolean isActive;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public boolean isActive() {
        return isActive;
    }

    public void setActive(boolean isActive) {
        this.isActive = isActive;
    }
}

Thanks.

Answer 1

1. Download gson-1.7.1.jar from this link: GsonLibJar

2. Add this library to your android project and configure build path.

3. Add the following class to your package.

   package com.abhan.objectinpreference;
   
   import java.lang.reflect.Type;
   import android.content.Context;
   import android.content.SharedPreferences;
   import com.google.gson.Gson;
   import com.google.gson.reflect.TypeToken;
   
   public class ComplexPreferences {
       private static ComplexPreferences       complexPreferences;
       private final Context                   context;
       private final SharedPreferences         preferences;
       private final SharedPreferences.Editor  editor;
       private static Gson                     GSON            = new Gson();
       Type                                    typeOfObject    = new TypeToken<Object>(){}
                                                                   .getType();
   
   private ComplexPreferences(Context context, String namePreferences, int mode) {
       this.context = context;
       if (namePreferences == null || namePreferences.equals("")) {
           namePreferences = "abhan";
       }
       preferences = context.getSharedPreferences(namePreferences, mode);
       editor = preferences.edit();
   }
   
   public static ComplexPreferences getComplexPreferences(Context context,
           String namePreferences, int mode) {
       if (complexPreferences == null) {
           complexPreferences = new ComplexPreferences(context,
                   namePreferences, mode);
       }
       return complexPreferences;
   }
   
   public void putObject(String key, Object object) {
       if (object == null) {
           throw new IllegalArgumentException("Object is null");
       }
       if (key.equals("") || key == null) {
           throw new IllegalArgumentException("Key is empty or null");
       }
       editor.putString(key, GSON.toJson(object));
   }
   
   public void commit() {
       editor.commit();
   }
   
   public <T> T getObject(String key, Class<T> a) {
       String gson = preferences.getString(key, null);
       if (gson == null) {
           return null;
       }
       else {
           try {
               return GSON.fromJson(gson, a);
           }
           catch (Exception e) {
               throw new IllegalArgumentException("Object stored with key "
                       + key + " is instance of other class");
           }
       }
   } }
   

4. Create one more class by extending Application class like this

   package com.abhan.objectinpreference;
   
   import android.app.Application;
   
   public class ObjectPreference extends Application {
       private static final String TAG = "ObjectPreference";
       private ComplexPreferences complexPrefenreces = null;
   
   @Override
   public void onCreate() {
       super.onCreate();
       complexPrefenreces = ComplexPreferences.getComplexPreferences(getBaseContext(), "abhan", MODE_PRIVATE);
       android.util.Log.i(TAG, "Preference Created.");
   }
   
   public ComplexPreferences getComplexPreference() {
       if(complexPrefenreces != null) {
           return complexPrefenreces;
       }
       return null;
   } }
   

5. Add that application class in your manifest’s application tag like this.

   <application android:name=".ObjectPreference"
       android:allowBackup="false"
       android:icon="@drawable/ic_launcher"
       android:label="@string/app_name"
       android:theme="@style/AppTheme" > 
   ....your activities and the rest goes here
   </application>
   

6. In Your Main Activity where you wanted to store value in Shared Preference do something like this.

   package com.abhan.objectinpreference;
   
   import android.app.Activity;
   import android.content.Intent;
   import android.os.Bundle;
   import android.view.View;
   
   public class MainActivity extends Activity {
       private final String TAG = "MainActivity";
       private ObjectPreference objectPreference;
   
       @Override
       protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_main);
   
       objectPreference = (ObjectPreference) this.getApplication();
   
       User user = new User();
       user.setName("abhan");
       user.setAddress("Mumbai");
       user.setAge(25);
       user.setActive(true);
   
       User user1 = new User();
       user1.setName("Harry");
       user.setAddress("London");
       user1.setAge(21);
       user1.setActive(false);
   
       ComplexPreferences complexPrefenreces = objectPreference.getComplexPreference();
       if(complexPrefenreces != null) {
           complexPrefenreces.putObject("user", user);
           complexPrefenreces.putObject("user1", user1);
           complexPrefenreces.commit();
       } else {
           android.util.Log.e(TAG, "Preference is null");
       }
   }
   
   }
   

7. In another activity where you wanted to get the value from Preference do something like this.

   package com.abhan.objectinpreference;
   
   import android.app.Activity;
   import android.os.Bundle;
   
   public class SecondActivity extends Activity {
       private final String TAG = "SecondActivity";
       private ObjectPreference objectPreference;
   
       @Override
       protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_second);
   
       objectPreference = (ObjectPreference) this.getApplication();
       ComplexPreferences complexPreferences = objectPreference.getComplexPreference();
   
       android.util.Log.i(TAG, "User");
       User user = complexPreferences.getObject("user", User.class);
       android.util.Log.i(TAG, "Name " + user.getName());
       android.util.Log.i(TAG, "Address " + user.getAddress());
       android.util.Log.i(TAG, "Age " + user.getAge());
       android.util.Log.i(TAG, "isActive " + user.isActive());
       android.util.Log.i(TAG, "User1");
       User user1 = complexPreferences.getObject("user", User.class);
       android.util.Log.i(TAG, "Name " + user1.getName());
       android.util.Log.i(TAG, "Address " + user1.getAddress());
       android.util.Log.i(TAG, "Age " + user1.getAge());
       android.util.Log.i(TAG, "isActive " + user1.isActive());
   }  }
   

Hope this can help you. In this answer I used your class for the reference ‘User’ so you can better understand. However we can not relay on this method if you opted to store very large objects in preference as we all know that we have limited memory size for each app in data directory so that if you are sure you have only limited data to store in shared preference you can use this alternative.

Any suggestions on this implement are most welcome.