Android 从自定义布局中的子视图读取自定义布局属性

我创建了自己的布局。我定义了一个“good”属性用于其子视图

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="MyLayout">
        <attr name="good" format="boolean" />
    </declare-styleable>
</resources>

现在我想从孩子们那里读这个属性。但是怎么做呢？我在网上搜索过，尝试过一些东西，但似乎不起作用

class MyLayout: LinearLayout
{
    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int)
    {
        setMeasuredDimension(200, 300); // dummy

        for(index in 0 until childCount)
        {
            val child = getChildAt(index);
            val aa = child.context.theme.obtainStyledAttributes(R.styleable.MyLayout);
            val good = aa.getBoolean(R.styleable.MyLayout_good, false)
            aa.recycle();
            Log.d("so", "value = $good")
        }
    }
}

---

添加：以注释作为提示，我发现并修改了我的代码，如下所示，现在我得到了我想要的结果

class MyLayout: LinearLayout
{
    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int)
    {
        setMeasuredDimension(200, 300);

        for(index in 0 until childCount)
        {
            val child = getChildAt(index);
            val p = child.layoutParams as MyLayoutParams;
            Log.d("so", "value = ${p.good}")

        }
    }

    override fun generateDefaultLayoutParams(): LayoutParams
    {
        return MyLayoutParams(context, null);
    }

    override fun generateLayoutParams(attrs: AttributeSet?): LayoutParams
    {
        return MyLayoutParams(context, attrs);
    }

    override fun checkLayoutParams(p: ViewGroup.LayoutParams?): Boolean
    {
        return super.checkLayoutParams(p)
    }

    inner class MyLayoutParams: LayoutParams
    {
        var good:Boolean = false;
        constructor(c: Context?, attrs: AttributeSet?) : super(c, attrs)
        {
            if(c!=null && attrs!=null)
            {
                val a = c.obtainStyledAttributes(attrs, R.styleable.MyLayout);
                good = a.getBoolean(R.styleable.MyLayout_good, false)
                a.recycle()
            }
        }
    }
}

---

您应该在

MyLayout

中使用自定义

LayoutParams

-查看

FrameLayout

、

LinearLayout

、

RelativeLayout

等中使用了哪些

LayoutParams

，

class MyLayout: LinearLayout
{
    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int)
    {
        setMeasuredDimension(200, 300);

        for(index in 0 until childCount)
        {
            val child = getChildAt(index);
            val p = child.layoutParams as MyLayoutParams;
            Log.d("so", "value = ${p.good}")

        }
    }

    override fun generateDefaultLayoutParams(): LayoutParams
    {
        return MyLayoutParams(context, null);
    }

    override fun generateLayoutParams(attrs: AttributeSet?): LayoutParams
    {
        return MyLayoutParams(context, attrs);
    }

    override fun checkLayoutParams(p: ViewGroup.LayoutParams?): Boolean
    {
        return super.checkLayoutParams(p)
    }

    inner class MyLayoutParams: LayoutParams
    {
        var good:Boolean = false;
        constructor(c: Context?, attrs: AttributeSet?) : super(c, attrs)
        {
            if(c!=null && attrs!=null)
            {
                val a = c.obtainStyledAttributes(attrs, R.styleable.MyLayout);
                good = a.getBoolean(R.styleable.MyLayout_good, false)
                a.recycle()
            }
        }
    }
}