比例矩形RatioLayout

在开发中有很多场景需要使用的比例矩形，比如图片必须保持一定的宽高比才不会变形。但是如果在gridview中按列排列，如果只是指定了列数的话，在不同分辨率的手机下，每个item的宽度是不定的，直接导致了在高度也不好设置。因此只能自定义按照一定比例的矩形布局才行。

<RatioRectLayout

   android:layout_width="match_parent"

   android:layout_height="wrap_content">

    <ImageView

       android:id="@+id/video_thumb"

       android:layout_width="match_parent"

       android:layout_height="match_parent"

       android:scaleType="fitXY"/>

</RatioRectLayout>

 

import android.content.Context;

import android.util.AttributeSet;

import android.widget.RelativeLayout;

 

/**

 * Created by zhendanon 5/21/2016.

 */

 

public class RatioRectLayout extends RelativeLayout {

    publicRatioRectLayout(Context context, AttributeSet attrs, int defStyle) {

        super(context,attrs, defStyle);

    }

 

    publicRatioRectLayout(Context context, AttributeSet attrs) {

        super(context,attrs);

    }

 

    public RatioRectLayout(Contextcontext) {

       super(context);

    }

 

   @SuppressWarnings("unused")

    @Override

    protected voidonMeasure(int widthMeasureSpec, int heightMeasureSpec) {

        // For simpleimplementation, or internal size is always 0.

        // We dependon the container to specify the layout size of

        // our view.We can't really know what it is since we will be

        // adding andremoving different arbitrary views and do not

        // want thelayout to change as this happens.

       setMeasuredDimension(getDefaultSize(0, widthMeasureSpec),

               getDefaultSize(0, heightMeasureSpec));

 

        // Childrenare just made to fill our space.

        intchildWidthSize = getMeasuredWidth();

        intchildHeightSize = getMeasuredHeight();

 

       widthMeasureSpec = MeasureSpec.makeMeasureSpec(childWidthSize,

               MeasureSpec.EXACTLY);

        // width :height = 2 : 3; 这里就是控制比例的地方

       heightMeasureSpec = MeasureSpec.makeMeasureSpec(childWidthSize * 3>> 1,

                MeasureSpec.EXACTLY);

       super.onMeasure(widthMeasureSpec, heightMeasureSpec);

    }

}

特此记录