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流式布局的实现（Kotlin语言）
   
import android.content.Context
import android.util.AttributeSet
import android.util.Log
import android.view.View
import android.view.ViewGroup
import androidx.core.view.isEmpty
class FlowLayout : ViewGroup {
    constructor(context: Context): super(context) {}
    constructor(context: Context, attrs: AttributeSet?): super(context, attrs) {}
    private val space = 30
    var allViews: MutableList
    
      = mutableListOf()
    var everyLineViews: MutableList
     
       = mutableListOf()
    private var allLineHeightList: MutableList
      
        = mutableListOf()
    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
        var maxWidth = 0
        var parentHeight = 0
        var parentWidth = 0
        var currentWidth = space
        var currentHeight = space
        var totalHeight = 0
        allViews.clear()
        everyLineViews.clear()
        super.onMeasure(widthMeasureSpec, heightMeasureSpec)
        val parentMaxWidth = MeasureSpec.getSize(widthMeasureSpec)
        Log.v("zj", "父容器最大宽度：$parentMaxWidth")
        for (i in 0 until childCount) {
            val child = getChildAt(i)
            val lp = child.layoutParams
            val childWidthSpec = getChildMeasureSpec(
                widthMeasureSpec,
                2 * space,
                lp.width
            )
            val childHeightSpec = getChildMeasureSpec(
                heightMeasureSpec,
                2 * space,
                lp.height
            )
            child.measure(childWidthSpec, childHeightSpec)
            if (currentWidth + space + child.measuredWidth <= parentMaxWidth) {
                currentWidth += child.measuredWidth + space
                currentHeight = Math.max(currentHeight, child.measuredHeight + space)
            } else {
                allViews.add(everyLineViews)
                everyLineViews = mutableListOf()
                totalHeight += currentHeight
                allLineHeightList.add(currentHeight)
                maxWidth = Math.max(maxWidth, currentWidth)
                currentHeight = child.measuredHeight + space
                currentWidth = child.measuredWidth + space
            }
            everyLineViews.add(child)
        }
        if (!everyLineViews.isEmpty()) {
            currentWidth = 0
            currentHeight = 0
            for (i in 0 until everyLineViews.size) {
                val child = everyLineViews[i]
                currentWidth += child.measuredWidth + space
                currentHeight = Math.max(currentHeight, child.measuredHeight + space)
            }
            maxWidth = Math.max(maxWidth, currentWidth)
            totalHeight += currentHeight
            allLineHeightList.add(currentHeight)
            allViews.add(everyLineViews)
        }
        parentHeight = totalHeight + space
        parentWidth = maxWidth + space
        setMeasuredDimension(parentWidth, parentHeight)
    }
    override fun onLayout(changed: Boolean, l: Int, t: Int, r: Int, b: Int) {
        var left = space
        var top = space
        var right = 0
        var bottom = 0
        for (i in 0 until allViews.size) {
            for (j in 0 until allViews[i].size) {
                val child = allViews[i][j]
                right = left + child.measuredWidth
                bottom = top + child.measuredHeight
                child.layout(left, top, right, bottom)
                left += child.measuredWidth + space
            }
            top += allLineHeightList[i]
            left = space
        }
    }
}
      
     
    
   
代码解释
   
该代码实现了一个自定义的流式布局View类，主要功能包括:
   
    
    
定义控件之间的间隔（space）
    
    
保存所有子控件的布局信息
    
    
按行布局子控件，自动换行
    
    
计算每行的高度和总体的布局参数
   
代码中的关键逻辑包括：
   
    
    
测量子控件的宽度和高度
    
    
判断是否需要换行
    
    
记录每行的布局信息
    
    
设置父容器的最终尺寸
   
注：代码中使用了测量布局（Layout Measurement）和布局（Layout）过程的标准方法，确保了布局的准确性和兼容性。