CODEWITHSUNDEEP
javaandroidsettergettergetter-setter
Mac
Mac

Reputation: 1163

Android getter setter returns null data?

I have one class ApplicationDetails, with getter and setter methods.

public class ApplicationDetails {
    String supportURL;
    String companyURL;
    String copyRightText;

    // with getter and setter methods 

}

I am setting all data in my splash screen activity. 

ApplicationDetails appDetails = new ApplicationDetails();
String supportURL = getResources().getString(R.string.support_url);
appDetails.setSupportURL(supportURL);

For sample I just setting data from string file but in app its coming from different sources.

But when I tried to access data in different activity its returns null value. e.g.

public class AboutViewController extends Activity {

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

        ApplicationDetails appDetails = new ApplicationDetails();
        System.out.println(" app support url " + appDetails.getSupportURL());
    }

}

output 

I/System.out(2242):  app support url null

any help.

Upvotes: 1

Views: 4786

Answers (5)

Pratik
Pratik

Reputation: 30855

Update

As you setting value in Splash screen that object in memory was different and in another activity you creating another object that also different in memory that's why you getting null.

If this was your requirement to init url in splash screen and used in another then there are many ways.

  1. You directly get the string in your activity as you getting in splash screen.
  2. In splash screen make appDetails object as public static so you can access in another activities also
  3. Implement serialization on ApplicationDetails and put this object in putExtra as we put string,int etc value for passing data between activity and get this data using bundle in started activity

Edited

For using single object you need make that object declare as public static in splash screen

public static ApplicationDetails appDetails;

now assign value in splash screen oncreate() and used in another activity or even another class also like this way

public class AboutViewController extends Activity {

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

        // direct use object by class name
        System.out.println(" app support url " + SplashScreen.appDetails.getSupportURL());
    }

}

Upvotes: -2

Mac
Mac

Reputation: 1163

Thanks all for all suggestions. Now I am using only one instance of a class. 

public class ApplicationDetails {

private static ApplicationDetails instance = null;

String supportURL;
String companyURL;
String copyRightText;

// with getter and setter methods 

public static ApplicationDetails getInstance() {
 if (instance == null) {
    instance = new ApplicationDetails();
 }
   return instance;
 }

}

And I am setting and getting like this 

 ApplicationDetails appDetails = ApplicationDetails.getInstance();
 appDetails.setSupportURL(supportURL);

and in activity 

ApplicationDetails appDetails = ApplicationDetails.getInstance();
appDetails.getSupportURL();

Its wrks fine.

Upvotes: 0

Taras Leskiv
Taras Leskiv

Reputation: 1875

You get null, because you create a new object and all fields are initialized to zero.

In your case, I see these fields are going to be the same through application, so you can use a Singleton pattern and instantiate only one object for your application and refer to it later on. You don't need to create a new object each time you refer to it. It would be ok for this class and you can also make them constants. (I guess these variables won't change through execution)

Upvotes: 5

Vivek Khandelwal
Vivek Khandelwal

Reputation: 7849

You can use the shared preference to store data to be used through your application. Here the Context in the constructor is nothing but your Activity.

public class ApplicationDetails {

        public static final String SUPPORT_URL = "support_url"; 
        public static final String COMPANY_URL = "company_url";
        public static final String COPYRIGHT_URL = "copyright_url";

        String supportURL;
        String companyURL;
        String copyRightText;
        private Context context;

        public ApplicationDetails(Context context) {
            super();
            this.context = context;
        }

        private String getPreference(String key)
        {
            return PreferenceManager.getDefaultSharedPreferences(context).getString(key, null);
        }

        private void setPreference(String key, String value)
        {
            PreferenceManager.getDefaultSharedPreferences(context).edit().putString(key, value).commit();
        }

        public String getSupportURL() {
            if(supportURL == null)
                supportURL = getPreference(SUPPORT_URL);
            return supportURL;
        }

        public void setSupportURL(String supportURL) {
            this.supportURL = supportURL;
            setPreference(SUPPORT_URL, supportURL);
        }

        public String getCompanyURL() {
            if(supportURL == null)
                supportURL = getPreference(COMPANY_URL);
            return companyURL;
        }

        public void setCompanyURL(String companyURL) {
            this.companyURL = companyURL;
            setPreference(COMPANY_URL, companyURL);
        }

        public String getCopyRightText() {
            if(copyRightText == null)
                copyRightText = getPreference(COPYRIGHT_URL);
            return copyRightText;
        }

        public void setCopyRightText(String copyRightText) {
            this.copyRightText = copyRightText;
            setPreference(COPYRIGHT_URL, copyRightText);
        }
    }

Upvotes: 0

Aram
Aram

Reputation: 695

As fast solution you can make your supportURL object static, but this isn't good solution. 

public class ApplicationDetails {
static String supportURL;
static String companyURL;
static String copyRightText;

// with getter and setter methods

}

better solution is to pass strings from one activity to another with intents, when you are starting your AboutViewController Activity.

Upvotes: 0

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