Sharedpreferences in android

Well, I am beginner in Android and java, but I'm trying to learn.

My question is. I have these methods in my class (to save and load Sharedpreferences):

private String Load_pref(String key){
    SharedPreferences sharedPreferences = getPreferences(MODE_PRIVATE);
    String strSavedMem1 = sharedPreferences.getString(key, "");        
    return strSavedMem1;
   } 

public void Save_pref(String key, 开发者_StackOverflowString value){
    SharedPreferences sharedPreferences = getPreferences(MODE_PRIVATE);
    SharedPreferences.Editor editor = sharedPreferences.edit();
    editor.putString(key, value);
    editor.commit();
   }

Well, Its work well, but I would call these methods from another class (other screen activity). I tried to do this in my other activity:

            MyActivity1 A = new MyActivity1();
            A.Save_pref("ACCOUNT","Myname"); 

The code compiles without problem, but the program crashes in this part of the code. Someone could help me solve this problem?

Thanks, Alexandre

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Creating an instance of the activity just to access a set of shared preferences is extremely heavyweight. Notice they're called Shared Preferences :) Really what you want to do is call PreferenceManager.getDefaultSharedPreferences(). Rather than repeat the whole solution, I'll just link you to where this has already been explained on StackOverflow, here. Enjoy!