.GONE and .VISIBLE resets when flipping the phone

Question

I made two buttons, one is visible and one is hidden. When clicking on the visible button it disappear and the other gets visible (it works), however, when I flip the phone to the side (landscape mode) everything gets "reset" so I have to press the button again to get it invisible and the other visible, thats not what I want, the action should be the same however I have the phone, "straight" or "flipped". How is this solved easiest?

                    Button mButton = (Button)findViewById(R.id.button1);
    mButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Button butt1 = (Button) findViewById(R.id.button1);
            butt1.setVisibility(View.GONE);
            Button butt2 = (Button) findViewById(R.id.button2)  ;
            butt2.setVisibility(View.VISIBLE);
        }
    });

https://stackoverflow.com/questions/13022677/save-state-of-activity-when-orientation-changes-android — MMG, May 01 '20 at 10:20
save the last visibility state on `onSaveInstanceState ` and restore them back on your buttons on `onCreate` — etomun, May 01 '20 at 10:31

score 0 · Answer 1 · answered May 01 '20 at 10:30

0

When you rotate your phone, the Activity is destroyed and recreated. You need to maintain state information in a class variable, such as by overriding onStop, and then read this information in your onCreate or onResume methods.

answered May 01 '20 at 10:30

codebod

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ドラゴンハートゼクモル · Accepted Answer · 2020-05-01T20:56:46.757

What you need is to be able to save the state of the buttons elsewhere. I can name two that you can use: SharedPreferences or ViewModel.

In your case, I suggest creating a ViewModel class that will hold the state of your buttons.

CustomViewModel class

import androidx.lifecycle.ViewModel;

public class CustomViewModel extends ViewModel {
    public boolean button1_gone;
}

Then in your activity:

final CustomViewModel model = new ViewModelProvider(this).get(CustomViewModel.class);

if (model.button1_gone) {
    Button butt1 = findViewById(R.id.button1); // I know that butt1 is redundant here
    butt1.setVisibility(View.GONE);
    Button butt2 = findViewById(R.id.button2);
    butt2.setVisibility(View.VISIBLE);
    model.button1_gone = true;
}

Button mButton = findViewById(R.id.button1);
mButton.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        Button butt1 = findViewById(R.id.button1);
        butt1.setVisibility(View.GONE);
        Button butt2 = findViewById(R.id.button2);
        butt2.setVisibility(View.VISIBLE);
        model.button1_gone = true;
    }
});

Also, don't forget to add these dependencies in your app gradle (The one with app and not the one with your project's name):

def lifecycle_version = "2.2.0"
implementation "androidx.lifecycle:lifecycle-extensions:$lifecycle_version"
implementation "androidx.lifecycle:lifecycle-common-java8:$lifecycle_version"

Note: You need to add those dependencies or else you won't get the proper constructor for the ViewModelProvider that takes only one argument.

To know more about ViewModel, go here: https://developer.android.com/topic/libraries/architecture/viewmodel

IMPORTANT: Don't ever declare UI controllers variables inside your ViewModel as it will cause memory leaks. UI controllers are TextView, Button, etc.

.GONE and .VISIBLE resets when flipping the phone

2 Answers2