序文

最近浪漫心饱满，所以写了个心形控件。能够将一切内容约束故意形，而且支撑两种心形，运用起来很简单，就当成FrameLayout就行了。 让一切都浪漫起来

效果

下面顺次展现的是：

1. 包裹ScrollView ，形状为桃心
2. 包裹ScrollView，形状为圆心
3. 包裹WebView，形状为圆心

代码

LoveLayout

首要代码就是下面的。

package com.example.myapplication;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Path;
import android.util.AttributeSet;
import android.widget.FrameLayout;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
/**
 * <pre>
 * Created by zhuguohui
 * Date: 2023/6/6
 * Time: 10:26
 * Desc:爱心Layout
 * </pre>
 */
public class LoveLayout extends FrameLayout {
    private Path path1;
    private int heardType;
    public LoveLayout(@NonNull Context context) {
        super(context);
    }
    public LoveLayout(@NonNull Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.LoveLayout);
        heardType = array.getInt(R.styleable.LoveLayout_HeardType,0);
        array.recycle();
    }
    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);
        if(heardType==0) {
            getHeardPath();
        }else{
            getHeardPath2();
        }
    }
    private void getHeardPath(){
        int px = getMeasuredWidth() / 2;
        int py = getMeasuredHeight() / 2;
        path1=new Path();
        path1.moveTo(px, py);
        float rate=getMeasuredWidth()*1.0f/34;
        // 依据心形函数画图
        for (double i = 0; i < 2 * Math.PI; i += 0.001) {
            float x = (float) (16 * Math.sin(i) * Math.sin(i) * Math.sin(i));
            float y = (float) (13 * Math.cos(i) - 5 * Math.cos(2 * i) - 2 * Math.cos(3 * i) - Math.cos(4 * i));
            x *= rate;
            y *= rate;
            x = px - x;
            y = py - y;
            path1.lineTo(x, y);
        }
    }
    private void getHeardPath2(){
//        f(x)=sqrt(1-(abs(x)-1)^2)
//        h(x)=-2*sqrt(1-0.5*abs(x))
        path1=getPathByMathFunction(x -> (float) Math.sqrt(1-Math.pow((Math.abs(x)-1),2)));
        Path path2=getPathByMathFunction(x->(float) (-2* Math.sqrt(1-0.5*Math.abs(x))));
        path1.moveTo(0,getMeasuredHeight()*1.0f/2);
        path1.addPath(path2);
    }
    private interface MathFunction{
        float call(float x);
    }
    private Path getPathByMathFunction(MathFunction function){
       Path path=new Path();
        path.moveTo(0,getMeasuredHeight()*1.0f/2);
        int px = getMeasuredWidth() / 2;
        int py = getMeasuredHeight() / 2;
        float scale=getMeasuredWidth()*1.0f/4;
        for(float i=-2;i<=2;i+=0.01){
            float x=i;
            float y= function.call(x);
            x*=scale;
            y*=scale;
            x=px-x;
            y=py-y;
            path.lineTo(x,y);
        }
        return path;
    }
    @Override
    protected void dispatchDraw(Canvas canvas) {
        int save = canvas.save();
        canvas.clipPath(path1);
        super.dispatchDraw(canvas);
        canvas.restoreToCount(save);
    }
}

xml特点

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="LoveLayout">
        <attr name="HeardType">
            <!-- 桃心 -->
            <enum name="PeachHeart" value="0" />
            <!-- 圆一点的心 -->
            <enum name="CircularHeart" value="1" />
        </attr>
    </declare-styleable>
</resources>

数学原理

圆心是按照以下公式实现的，桃心是网上找到的代码改的，没找到公司。

运用

很简单，当成FrameLayout包裹就行了。