在两个活动之间切换而不会丢失数据

Question

Just want to switch between activities and doesn't want to loose information on any activities.For example:

I have one activity ie activity_one which has one listview , load thousands of data from webservice. now I have another activity ie activity_two which has one listview , load thousands of data from webservice.

when i move from activity_one to activity_two then activity_one data lost and vice versa.

when its loaded once then don't want to do it again while application is running.

Answer 1

You can retain data between activities using onSaveInstanceState and onRestoreInstanceState.

here is an example demo

float[] localFloatArray = {3.14f, 2.718f, 0.577f};
String localUserName = "Euler";

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    //Save the relevant information
    outState.putString("name", localUserName);
    outState.putFloatArray("array", localFloatArray);
}


@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
     //Restore the relevant information
    localUserName = savedInstanceState.getString("name");
    localFloatArray = savedInstanceState.getFloatArray("array");
}

Answer 2

The real thing is how do you move between those two activities. Maybe you are finishing them when you switch. If that's the case you can save the info in a static ArrayList and on the onCreate method you can check if the length of it is 0, if it is 0 then try to load the data, else load the data from the ArrayList .