仅在应用程序首次在Android中运行时才使用共享首选项来调用方法吗？

Question

I am working on a wallpaper application in android in which i need to copy few images from assets to SDCARD location for applicaiton. But this process must to be done on application runs 1st time. It must not happen when user use the application in future. I planned to use Shared Preference for this purpose. But not getting success.

I have initialized the preferences as private member of class.

private SharedPreferences preferences=null;
private boolean flagCopy;
//USING Shared Preferences FOR COPY ASSETS------
        if(preferences!=null){
            flagCopy = preferences.getBoolean("COPY_ASSETS", DO_NOT_COPY_ASSESTS);

        }else{
            preferences =getPreferences(MODE_PRIVATE);
            SharedPreferences.Editor editor = preferences.edit();
            editor.putBoolean("COPY_ASSETS", COPY_ASSESTS); // value to store
            editor.commit();
            flagCopy = true;
        }
        if(flagCopy){//IF FLAG IS FALSE THAN COPY THE IMAGES TO SDCARD FROM RES
            CopyAssets();
        }

Answer 1

your preferences object is always null, so it will always go to the second part where you are making flagcopy = true. see below code

 preferences =getPreferences(MODE_PRIVATE);
   if(preferences!=null){
            flagCopy = preferences.getBoolean("COPY_ASSETS", COPY_ASSETS);


   if(flagcopy == COPY_ASSETS){
            SharedPreferences.Editor editor = preferences.edit();
            editor.putBoolean("COPY_ASSETS", DO_NOT_COPY_ASSESTS);
            editor.commit();
            flagCopy = true;
        }

        if(flagCopy){
            CopyAssets();
        }