Android は比例レイアウトの自動メンテナンスを実装します

package com.boeyu.test;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

public class WalxLayout extends FrameLayout implements View.OnLayoutChangeListener {

    private Context mContext;
    //private int mWrapMode;
    private float mWrapScale;
    private Boolean mLandscape;
    private OnOrientationListener onOrientationListener;

    public WalxLayout(@NonNull Context context) {
        super(context);
        init(context, null);
    }

    public WalxLayout(@NonNull Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        init(context, attrs);
    }

    public WalxLayout(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init(context, attrs);
    }

    private void init(Context context, AttributeSet attrs) {
        mContext = context;
        TypedArray array = mContext.obtainStyledAttributes(attrs, R.styleable.WalxLayout);
        mWrapScale = array.getFloat(R.styleable.WalxLayout_wrap_scale, 0);
    }


    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        if (mWrapScale > 0) {
            int widthSize = MeasureSpec.getSize(widthMeasureSpec);
            int widthMode = MeasureSpec.getMode(widthMeasureSpec);
            int heightSize = MeasureSpec.getSize(heightMeasureSpec);
            int heightMode = MeasureSpec.getMode(heightMeasureSpec);
            if (widthMode == MeasureSpec.EXACTLY && heightMode == MeasureSpec.EXACTLY) {
                print("onMeasure", widthSize, widthMode, heightSize, heightMode);
                float parentScale = (float) widthSize / heightSize;
                if (mWrapScale > parentScale) {
                    int height = (int) (widthSize / mWrapScale);
                    super.onMeasure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY));
                } else {
                    int width = (int) (heightSize * mWrapScale);
                    super.onMeasure(MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY), heightMeasureSpec);
                }
                return;
            }
        }
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();
        View parent = (View) getParent();
        if (parent != null) {
            parent.addOnLayoutChangeListener(this);
        }
    }

    private static void print(String name, Object... values) {
        StringBuilder builder = new StringBuilder();
        for (Object value : values) {
            builder.append(value).append(", ");
        }
        Log.i("WALX2020", builder.toString());
    }

    public void setOnOrientationListener(OnOrientationListener onOrientationListener) {
        this.onOrientationListener = onOrientationListener;
    }

    @Override
    public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
        int width = right - left - v.getPaddingLeft() - v.getPaddingRight();
        int height = bottom - top - v.getPaddingTop() - v.getPaddingBottom();
        boolean isLandscape = width > height;
        if (mLandscape == null || mLandscape != isLandscape) {
            mLandscape = isLandscape;
            if (onOrientationListener != null) {
                onOrientationListener.onOrientationChanged(this, mLandscape);
            }
        }
    }

    public interface OnOrientationListener {
        void onOrientationChanged(View view, boolean isLandscape);
    }
}

<declare-styleable name="WalxLayout">
        <attr name="wrap_scale" format="float" />
    </declare-styleable>

<com.boeyu.test.WalxLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#80000000"
        android:layout_gravity="center"
        app:wrap_mode="all"
        app:wrap_scale="1.6">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_margin="20dp"
            android:background="#80ff0000"
            android:padding="10dp"
            android:orientation="vertical">

            <View
                android:layout_width="match_parent"
                android:layout_height="0dp"
                android:background="#8000ff00"
                android:layout_weight="1"/>

            <View
                android:layout_width="match_parent"
                android:layout_height="0dp"
                android:background="#800000ff"
                android:layout_weight="1"/>

        </LinearLayout>
    </com.boeyu.test.WalxLayout>

 

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_layout);

        WalxLayout mWalxLayout = findViewById(R.id.mWalxLayout);
        mWalxLayout.setOnOrientationListener(this);
    }

    @Override
    public void onOrientationChanged(View view, boolean isLandscape) {
        Toast.makeText(this, isLandscape ? "横屏" : "竖屏", Toast.LENGTH_SHORT).show();
    }