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Saving ArrayList in savedInstanceState package

ArrayList is defined at the class level. these are my saveInstance methods:

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putStringArrayList("savedList", list);
}


@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    list=savedInstanceState.getStringArrayList("savedList");
}

but still, when I change the orientation, the ArrayList is empty.

+5
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3 answers

When you use onRestoreInstanceState()to restore the state, it is called after onStart()so that you update the list with the saved state after determining your adapter. Your best option is to restore the list to the onCreate()same as you do, on onRestoreInstanceState(). You can also override the adapter or call notifyDataSetChanged().

+2
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TextView textviewname;
String textname;

 @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);   
          setContentView(R.layout.activity_main);

       //declare the ui like this
    textviewname = (TextView) findViewById(R.id.textviewid);
       if(savedInstanceState==null){
       //the first time the activity was created
       //do the normal flow of the code
       //Example:getting the intent data for(savedList)or processing it
       Intent i = getIntent();
       textname = i.getStringExtra("savetext");
      //or textname="name_data";
       }else{
       //this is called when orientation change occur
       //get the savedata
        list=savedInstanceState.getStringArrayList("savedList");
        textname=savedInstanceState.getString("savetext");
       }

       textviewname.setText(textname);

}   
@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    //saving data when orientation change trigger
    //saving  data before ondestroy happens
//onSaveInstanceState is called before going to another activity or orientation change
    outState.putStringArrayList("savedList", list);
    outState.putString("savetext", textname);
    //all imnportant data saved and can be restored
}


@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    //this is  only called after ondestroy-> oncreate occur
    list=savedInstanceState.getStringArrayList("savedList");
    textname=savedInstanceState.getString("savetext");
    //oncreate->onSaveInstanceState->ondestroy->oncreate->onRestoreInstanceState
}
+3
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list.addAll(savedInstanceState.getStringArrayList("savedList"));


list=savedInstanceState.getStringArrayList("savedList");
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