ScaleType属性

截图1：没啥属性，就wrap_content后者设置高宽等，代码就略过

image.png

截图2：ScaleType=fitXY,fitCenter,fitStart,fitEnd

image.png

       <TextView
            android:layout_marginTop="10dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textStyle="bold"
            android:textSize="18sp"
            android:textColor="@color/blue"
            android:text="下面ImageView固定设置：200dp*100dp，并开始加上ScaleType属性了"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="1、scaleTyple=fitXY，显然是缩放到XY高度，被拉伸了"/>
        <ImageView
            android:layout_width="200dp"
            android:layout_height="100dp"
            android:class="lazyload" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC" data-original="@mipmap/namei"
            android:background="@color/pink"
            android:scaleType="fitXY"/>

        <TextView
            android:layout_marginTop="10dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="2、scaleTyple=fitCenter，按比例适配缩放后居中，也是默认形式哦"/>
        <ImageView
            android:layout_width="200dp"
            android:layout_height="100dp"
            android:class="lazyload" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC" data-original="@mipmap/namei"
            android:background="@color/pink"
            android:scaleType="fitCenter"/>

        <TextView
            android:layout_marginTop="10dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="3、scaleTyple=fitStart，按比例适配缩放后左上"/>
        <ImageView
            android:layout_width="200dp"
            android:layout_height="100dp"
            android:class="lazyload" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC" data-original="@mipmap/namei"
            android:background="@color/pink"
            android:scaleType="fitStart"/>

        <TextView
            android:layout_marginTop="10dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="4、scaleTyple=fitEnd，按比例适配缩放后右下"/>
        <ImageView
            android:layout_width="200dp"
            android:layout_height="100dp"
            android:class="lazyload" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC" data-original="@mipmap/namei"
            android:background="@color/pink"
            android:scaleType="fitEnd"/>

截图3：ScaleType=center,centerCrop,centerInside

image.png

       <TextView
            android:layout_marginTop="10dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="5、scaleTyple=center，显然按照默认图大小，画在中间了"/>
        <ImageView
            android:layout_width="200dp"
            android:layout_height="100dp"
            android:class="lazyload" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC" data-original="@mipmap/namei"
            android:background="@color/pink"
            android:scaleType="center"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="用50*50大小试试看，scaleTyple=center，好吧，就一个笑脸了，原图不变，尺寸小就小咯"/>
        <ImageView
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:class="lazyload" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC" data-original="@mipmap/namei"
            android:background="@color/pink"
            android:scaleType="center"/>

        <TextView
            android:layout_marginTop="10dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="6、scaleTyple=centerCrop，这个厉害了，为了等比例适配后还改变了原先控件大小！！"/>
        <ImageView
            android:layout_width="200dp"
            android:layout_height="100dp"
            android:class="lazyload" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC" data-original="@mipmap/namei"
            android:background="@color/pink"
            android:scaleType="centerCrop"/>

        <TextView
            android:layout_marginTop="10dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="7、scaleTyple=centerInside，感觉和center一样啊"/>
        <ImageView
            android:layout_width="200dp"
            android:layout_height="100dp"
            android:class="lazyload" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC" data-original="@mipmap/namei"
            android:background="@color/pink"
            android:scaleType="centerInside"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="用50*50大小试试看，scaleTyple=centerInside，按比例缩小后显示在内部"/>
        <ImageView
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:class="lazyload" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC" data-original="@mipmap/namei"
            android:background="@color/pink"
            android:scaleType="centerInside"/>

截图4：ScaleType=matrix

image.png

       <TextView
            android:layout_marginTop="10dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="8、scaleTyple=matrix，默认尺寸左上排列"/>
        <ImageView
            android:layout_width="200dp"
            android:layout_height="100dp"
            android:class="lazyload" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC" data-original="@mipmap/namei"
            android:background="@color/pink"
            android:scaleType="matrix"/>

ImageView加载图片，代码部分

//4种方式设置图片iv_nm.setImageResource(R.mipmap.namei);
iv_nm.setImageDrawable(getResources().getDrawable(R.mipmap.namei));
iv_nm.setImageBitmap(BitmapFactory.decodeFile("file path"));
iv_nm.setImageURI(Uri.parse("file path"));

作者：Kandy_JS
链接：https://www.jianshu.com/p/cebfaa7f81ac