android ImageView 圖片寬度全屏,高度自適應的寫法

<ImageView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:adjustViewBounds="true"
    android:scaleType="fitXY"
    android:src="@drawable/res_version_bg" />

<!-- Set this to true if you want the ImageView to adjust its bounds
     to preserve the aspect ratio of its drawable. -->

如果希望ImageView調整其邊界，請將此設置為true 以保持其可拉伸的長寬比

<attr name="adjustViewBounds" format="boolean" />

把圖片按比例擴大/縮小到View的寬度，顯示在View的上部分位置
 android:scaleType="fitXY"