[JAVA] Change the layout when rotating with onConfigurationChanged

What I wanted to do

I wanted to display the ImageView image on the full screen (with the same aspect ratio) and place the button directly below, but ... If you rotate it horizontally, the button will be hidden, and if you change the layout according to the horizontal screen, the position of the button will shift when you rotate it vertically. I wanted to have only one xml for the layout, so I decided to dynamically resize the ImageView in the source.

What i did

Layout

--Layout uses ConstraintLayout --ImageView settings: --Size (in portrait orientation): - height: wrap_content
- width: 0dp(match constraint) --Size (in landscape orientation): - height: 0dp(match constraint)
- width: wrap_content --Specify ʻandroid: adjustViewBounds = trueto maintain the aspect ratio of the drawing --Specify ʻapp: layout_constraintVertical_chainStyle = "packed"to attach buttons

Activity --Added ʻandroid: configChanges =" orientation | screenSize " to Activity in the manifest. Make it possible to detect vertical and horizontal rotation. --When the vertical and horizontal orientation changes, ʻonConfigurationChanged is called. In that, the layout of ImageView was updated.

Source

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:adjustViewBounds="true"
        android:padding="8dp"
        app:layout_constraintBottom_toTopOf="@+id/button"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.0"
        app:layout_constraintVertical_chainStyle="packed"
        app:srcCompat="@drawable/ic_launcher_background" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="8dp"
        android:text="Button"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imageView" />

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.java

public class MainActivity extends AppCompatActivity {
    ImageView imageView;
    Button button;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //UI acquisition
        imageView = findViewById(R.id.imageView);
        button = findViewById(R.id.button);
        //For the time being, get the orientation at startup
        int orientation = getResources().getConfiguration().orientation;
        UpdateLayout(orientation); //Layout update
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        int orientation = newConfig.orientation; //Get orientation
        UpdateLayout(orientation); //Layout update
    }

    /**
     *Layout update
     * @param orientation orientation
     */
    protected void UpdateLayout(int orientation){
        //ImageView LayoutParam acquisition
        LayoutParams param = imageView.getLayoutParams();
        if (orientation == Configuration.ORIENTATION_PORTRAIT) {
            //In portrait orientation
            Log.d("UpdateLayout", "Vertical orientation");
            param.height = LayoutParams.WRAP_CONTENT;
            param.width = 0;
        }
        else if (orientation == Configuration.ORIENTATION_LANDSCAPE) {
            //When facing sideways
            Log.d("UpdateLayout", "Sideways");
            param.height = 0;
            param.width = LayoutParams.WRAP_CONTENT;
        }
        imageView.setLayoutParams(param);
    }
}

Reference article

Determine whether it is landscape or portrait on Android Display the full screen width on Android while maintaining the aspect ratio of the image https://techblog.zozo.com/entry/constraint_layout