一个可自定义固定寬高比的 ImageView。
在图片尺寸已知的情况下，加载大量图片时使用固定的寬高比的 ImageView。
setMeasuredDimension 方法决定了 View 大小，在 onMeasure 重设 ImageView 的大小。
class FixedImageView(context: Context, attrs: AttributeSet) : AppCompatImageView(context, attrs) {
private var widthWeight = 1
private var heightWeight = 1
init {
val a = context.obtainStyledAttributes(attrs, R.styleable.FixedImageView)
widthWeight = a.getInteger(R.styleable.FixedImageView_widthWeight, 1)
heightWeight = a.getInteger(R.styleable.FixedImageView_heightWeight, 1)
a.recycle()
}
fun setWidthAndHeightWeight(widthWeight: Int, heightWeight: Int) {
this.widthWeight = widthWeight
this.heightWeight = heightWeight
}
override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec)
val width = this.measuredWidth
val height = width * heightWeight / widthWeight
setMeasuredDimension(width + paddingLeft + paddingRight, height + paddingTop + paddingBottom)
}
}