自定义view的屏幕适配方案

自定义一个计算屏幕缩放比例的单例类，用于获取屏幕的横向和水平方向的缩放比例。

package com.example.screenadaptation;

import android.content.Context;
import android.util.DisplayMetrics;
import android.view.WindowManager;

public class ScreenAdaptationUtils {
    //设计稿的宽高像素
    private static final int STANDARD_WITH = 720;
    private static final int STANDARD_HEIGHT = 1280;

    private static ScreenAdaptationUtils screenAdaptationUtils;
    private int mDisplayWith;
    private int mDisplayHeight;

    private ScreenAdaptationUtils(Context context) {
        //获取屏幕宽高
        if (mDisplayHeight == 0 || mDisplayWith == 0) {
            WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
            if (windowManager != null) {
                DisplayMetrics displayMetrics = new DisplayMetrics();
                windowManager.getDefaultDisplay().getMetrics(displayMetrics);

                if (displayMetrics.widthPixels > displayMetrics.heightPixels) {
                    //如果横向宽度大于 竖直高度，那就是横屏状态
                    mDisplayWith = displayMetrics.heightPixels;
                    mDisplayHeight = displayMetrics.widthPixels;
                } else {
                    mDisplayHeight = displayMetrics.heightPixels;
                    mDisplayWith = displayMetrics.widthPixels - getStatusBarHight(context);
                }
            }
        }
    }

    //获取屏幕状态栏的高度
    private int getStatusBarHight(Context context) {
        int resId = context.getResources().getIdentifier("status_bar_height", "dimen", "android");
        if (resId > 0) {
            return context.getResources().getDimensionPixelSize(resId);
        }
        return 0;
    }

    public static ScreenAdaptationUtils getScreenAdaptationUtils(Context context) {

        if (screenAdaptationUtils == null) {
            synchronized (ScreenAdaptationUtils.class) {
                if (screenAdaptationUtils == null) {
                    screenAdaptationUtils = new ScreenAdaptationUtils(context.getApplicationContext());
                }
            }
        }
        return screenAdaptationUtils;
    }


    //获取横向的缩放比例
    public float getHorizontalScale() {
        return mDisplayWith / STANDARD_WITH;
    }

    //获取垂直方向的缩放比例
    public float getVerticalScale() {
        return mDisplayHeight / STANDARD_HEIGHT;
    }

}

 

实用例子：

package com.example.screenadaptation;

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.widget.RelativeLayout;

public class MyLayout extends RelativeLayout {
    private boolean flag;
    public MyLayout(Context context) {
        super(context);
    }

    public MyLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MyLayout(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        if (!flag){
            float ScaleX = ScreenAdaptationUtils.getScreenAdaptationUtils(getContext()).getHorizontalScale();
            float ScaleY = ScreenAdaptationUtils.getScreenAdaptationUtils(getContext()).getVerticalScale();

            int viewCount = getChildCount();
            for (int i = 0; i < viewCount; i++) {
                View view = getChildAt(i);
                LayoutParams params = (LayoutParams) view.getLayoutParams();
                params.width = (int) (params.width*ScaleX);
                params.height = (int) (params.height * ScaleY);

                params.leftMargin = (int) (params.leftMargin * ScaleX);
                params.rightMargin = (int) (params.rightMargin * ScaleX);

                params.topMargin = (int) (params.topMargin * ScaleY);
                params.bottomMargin = (int) (params.bottomMargin * ScaleY);
            }


        }else {
            flag = true;
        }
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }
}