自定义ViewGroup

最新推荐文章于 2021-12-08 15:31:19 发布

原创最新推荐文章于 2021-12-08 15:31:19 发布 · 371 阅读

CC 4.0 BY-SA版权

本文介绍了一种自定义ViewGroup的实现方式，通过重写onMeasure和onLayout方法来控制子视图的位置和大小。具体实现了四个按钮分别位于屏幕的四个角落。

public class MyViewGroup extends ViewGroup {
    private int width;
    private int height;
    public MyViewGroup(Context context) {
        super(context);
    }

    public MyViewGroup(Context context, AttributeSet attrs) {
        super(context, attrs);

    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        width=getDefaultSize(getSuggestedMinimumWidth(),widthMeasureSpec);
        height=getDefaultSize(getSuggestedMinimumHeight(),heightMeasureSpec);
        measureChildren(width,height);//测量整体的宽和高
    }

    @Override
    protected void onLayout(boolean b, int i, int i1, int i2, int i3) {
    //i,i1为左上角。i2，i3为右下角
        View child1=getChildAt(0);
        View child2=getChildAt(1);
        View child3=getChildAt(2);
        View child4=getChildAt(3);

        if (child1!=null){
            child1.layout(0,0,child1.getMeasuredWidth(),child1.getMeasuredHeight());
        }
        if (child2!=null){
            child2.layout(i2-child2.getMeasuredWidth(),0,i2,child2.getMeasuredHeight());
        }
        if (child3!=null){
            child3.layout(0,i3-child3.getMeasuredHeight(),child3.getMeasuredWidth(),i3);
        }
        if (child4!=null){
            child4.layout(i2-child4.getMeasuredWidth(),i3-child4.getMeasuredHeight(),i2,i3);
        }
    }
}

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent"  tools:context=".MainActivity">

    <com.lingzhuo.test.myviewgroup.MyViewGroup
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <Button
            android:layout_width="150dp"
            android:layout_height="200dp" />
        <Button
            android:layout_width="150dp"
            android:layout_height="200dp" />
        <Button
            android:layout_width="150dp"
            android:layout_height="200dp" />
        <Button
            android:layout_width="150dp"
            android:layout_height="200dp" />
    </com.lingzhuo.test.myviewgroup.MyViewGroup>

</RelativeLayout>