Android 顶部对齐宽度撑满高度等比例缩放及限制最大最小高度

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一示例
在这里插入图片描述

二代码

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="match_parent"android:layout_height="match_parent"><com.example.test.ui.video.ui.image.topfit.TopFitImageViewandroid:id="@+id/imageView"android:layout_width="match_parent"android:layout_height="wrap_content"android:background="@color/purple_200"android:scaleType="fitXY" /><LinearLayoutandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:orientation="vertical"><Buttonandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:onClick="largeWidthStretch"android:text="2/1宽高比" /><Buttonandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:onClick="equalWidthStretch"android:text="1/1宽高比" /></LinearLayout></FrameLayout>

package com.example.test.ui.video.ui.image.topfitimport android.content.Context
import android.graphics.Bitmap
import android.util.AttributeSetclass TopFitImageView : androidx.appcompat.widget.AppCompatImageView {constructor(context: Context?) : super(context!!)constructor(context: Context?, attrs: AttributeSet?) : super(context!!, attrs)constructor(context: Context?, attrs: AttributeSet?, defStyleAttr: Int) : super(context!!,attrs,defStyleAttr)val minWHRatio = 1val maxWHRatio = 2override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {val drawable = drawableif (drawable != null) {val whRatio = drawable.intrinsicWidth.toFloat() / drawable.intrinsicHeight.toFloat()val width = MeasureSpec.getSize(widthMeasureSpec)var height = (width / whRatio).toInt()if (whRatio > maxWHRatio) {height = width / maxWHRatio} else if (whRatio < minWHRatio) {height = width}setMeasuredDimension(width, height)} else {super.onMeasure(widthMeasureSpec, heightMeasureSpec)}}override fun setImageBitmap(bm: Bitmap?) {if (bm != null && bm.width > 0 && bm.height > 0) {var height = bm.heightval whRatio = bm.width / bm.height
//            if (whRatio > maxWHRatio) {
//                height = bm.width / maxWHRatio
//            } elseif (whRatio < minWHRatio) {height = bm.width}super.setImageBitmap(Bitmap.createBitmap(bm, 0, 0, bm.width, height))return}super.setImageBitmap(bm)}}