Android多行多列效果 Android自定义ViewGroup多行多列效果

时间:2021-09-02 卖炭少年炭治郎人气:0

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先看下效果图

每行两个子孩子

每行一个子孩子

实现思路

自定义viewGroup,实现测量和布局，使控件适应业务场景。

测量

根据父控件的宽度，平均分给每个子孩子固定的宽度。高度就是行数乘以一个子孩子的高度，再加上空隙的高度。

根据子孩子个数计算行数

val rows = if (childCount % perLineChild == 0) {
            childCount / perLineChild
        } else {
            childCount / perLineChild + 1
        }

代码示例

override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
        val width = MeasureSpec.getSize(widthMeasureSpec)
        for (i in 0 until childCount) {
            val child: View = getChildAt(i)
            if (child.visibility != GONE) {
                val lp = child.layoutParams
                val childWidthMeasureSpec = getChildMeasureSpec(
                    widthMeasureSpec,
                    0, (width - (perLineChild - 1) * space) / perLineChild
                )
                val childHeightMeasureSpec = getChildMeasureSpec(
                    heightMeasureSpec,
                    0, lp.height
                )
                child.measure(childWidthMeasureSpec, childHeightMeasureSpec)
            }
        }
        val rows = if (childCount % perLineChild == 0) {
            childCount / perLineChild
        } else {
            childCount / perLineChild + 1
        }
        if (childCount > 0) {
            setMeasuredDimension(
                width,
                getChildAt(0).measuredHeight * rows + (rows - 1) * space
            )
        }
    }

布局

需要注意摆放的顺序和位置，每行摆放固定的个数，达到个数之后换行继续摆放

代码示例

override fun onLayout(changed: Boolean, l: Int, t: Int, r: Int, b: Int) {
        var left = l
        var top = t
        children.forEachIndexed { index, view ->
            if (index % perLineChild == 0) {
                left = 0
                if (index != 0) {
                    top += view.measuredHeight
                    top+=space
                }
                view.layout(left, top, view.measuredWidth + left, top + view.measuredHeight)
            } else {
                view.layout(left, top, view.measuredWidth + left, top + view.measuredHeight)
            }
            left += view.measuredWidth
            left += space
        }
    }

完整代码

class MultiLineViewG @JvmOverloads constructor(
    context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
) : ViewGroup(context, attrs, defStyleAttr) {

    var perLineChild = 2

    /**
     * 子孩子之间的空隙
     */
    var space = 10

    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
        val width = MeasureSpec.getSize(widthMeasureSpec)
        for (i in 0 until childCount) {
            val child: View = getChildAt(i)
            if (child.visibility != GONE) {
                val lp = child.layoutParams
                val childWidthMeasureSpec = getChildMeasureSpec(
                    widthMeasureSpec,
                    0, (width - (perLineChild - 1) * space) / perLineChild
                )
                val childHeightMeasureSpec = getChildMeasureSpec(
                    heightMeasureSpec,
                    0, lp.height
                )
                child.measure(childWidthMeasureSpec, childHeightMeasureSpec)
            }
        }
        val rows = if (childCount % perLineChild == 0) {
            childCount / perLineChild
        } else {
            childCount / perLineChild + 1
        }
        if (childCount > 0) {
            setMeasuredDimension(
                width,
                getChildAt(0).measuredHeight * rows + (rows - 1) * space
            )
        }
    }

    override fun onLayout(changed: Boolean, l: Int, t: Int, r: Int, b: Int) {
        var left = l
        var top = t
        children.forEachIndexed { index, view ->
            if (index % perLineChild == 0) {
                left = 0
                if (index != 0) {
                    top += view.measuredHeight
                    top+=space
                }
                view.layout(left, top, view.measuredWidth + left, top + view.measuredHeight)
            } else {
                view.layout(left, top, view.measuredWidth + left, top + view.measuredHeight)
            }
            left += view.measuredWidth
            left += space
        }
    }
}

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