Android 流式布局 FloatLayout自定义控件

实现效果

FloatLayout自定义控件

自定义view继承ViewGroup,重写onMeasure()，onLayout()方法。可根据子元素宽度动态测量宽高

onMeasure()

    resultWidth = paddingLeft + paddingRight
    measuredChildCount = 0
    for (i in 0 until count) {
        if (mMaxMode == NUMBER) {
            // 超出最多数量，则不再继续
            if (measuredChildCount > mMaximum) {
                break
            }
        } else if (mMaxMode == LINES) {
            // 超出最大行数，则不再继续
            if (1 > mMaximum) {
                break
            }
        }
        val child = getChildAt(i)
        if (child.visibility == View.GONE) {
            continue
        }
        val childLayoutParams = child.layoutParams
        val childWidthMeasureSpec = getChildMeasureSpec(
            widthMeasureSpec,
            paddingLeft + paddingRight, childLayoutParams.width
        )
        val childHeightMeasureSpec = getChildMeasureSpec(
            heightMeasureSpec,
            paddingTop + paddingBottom, childLayoutParams.height
        )
        child.measure(childWidthMeasureSpec, childHeightMeasureSpec)
        resultWidth += child.measuredWidth
        maxLineHeight = maxLineHeight.coerceAtLeast(child.measuredHeight)
        measuredChildCount++
    }
    if (measuredChildCount > 0) {
        resultWidth += mChildHorizontalSpacing * (measuredChildCount - 1)
    }
    resultHeight = maxLineHeight + paddingTop + paddingBottom
    if (mItemNumberInEachLine.isNotEmpty()) {
        mItemNumberInEachLine[lineIndex] = count
    }
    if (mWidthSumInEachLine.isNotEmpty()) {
        mWidthSumInEachLine[0] = resultWidth
    }
}
setMeasuredDimension(resultWidth, resultHeight)
val meausureLineCount = lineIndex + 1
if (lineCount != meausureLineCount) {
    if (mOnLineCountChangeListener != null) {
        mOnLineCountChangeListener!!.onChange(lineCount, meausureLineCount)
    }
    lineCount = meausureLineCount
}

onLayout

val childMaxRight = parentWidth - paddingRight
var childPositionX = paddingLeft
var childPositionY = paddingTop
var lineHeight = 0
val childCount = childCount
var layoutChildCount = 0
for (i in 0 until childCount) {
    val child = getChildAt(i)
    if (child.visibility == View.GONE) {
        continue
    }
    if (layoutChildCount < measuredChildCount) {
        val childw = child.measuredWidth
        val childh = child.measuredHeight
        if (childPositionX + childw > childMaxRight) {
            // 换行
            childPositionX = paddingLeft
            childPositionY += lineHeight + mChildVerticalSpacing
            lineHeight = 0
        }
        child.layout(
            childPositionX,
            childPositionY,
            childPositionX + childw,
            childPositionY + childh
        )
        childPositionX += childw + mChildHorizontalSpacing
        lineHeight = lineHeight.coerceAtLeast(childh)
        layoutChildCount++
    } else {
        child.layout(0, 0, 0, 0)
    }
}

具体使用

xml

<com.chen.floatview.view.FloatLayout
    android:id="@+id/floatLayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="10dp"
    android:gravity="left"//对齐方式
    android:maxLines="2"//最多行数
    app:childHorizontalSpacing="10dp"//水平间距
    app:childVerticalSpacing="10dp"//垂直间距
    app:maxNumber="10" //最大size
/>

adapter

floatLayout.setAdapter(object : FloatLayout.FloatAdapter() {
    override fun getCount(): Int {
        return mData.size
    }

    override fun getLayoutID(): Int {
        return R.layout.item_float
    }

    override fun onBindView(v: View, position: Int) {
        v.findViewById<TextView>(R.id.tv_name).text = mData[position]
    }

})

demo地址

Github-FloatLayout