These supply parameters to the parent of this view specifying how it should be arranged. There are many subclasses of ViewGroup.LayoutParams, and these correspond to the different subclasses of ViewGroup that are responsible for arranging their children.
So basically, if you are adding a view to another, you MUST set the LayoutParams of the view to the LayoutParams type that the parent uses, or you will get a runtime error.
我是这样理解的,如果你要将一个view添加到另一个布局中,你必须设定该View的布局参数为其父类所使用的布局参数类型。即要在代码中动态改变某组件的高度,其布局参数类型应该是其父类所使用的布局参数类型。比如:
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<FrameLayout
android:id="@+id/FrameLayout01"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
若想在代码中动态改变FrameLayout的大小,应该这样写:
FrameLayout frameLayout=(FrameLayout) convertView.findViewById(R.id.FrameLayout01);
LinearLayout.LayoutParams ff=new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, height);
frameLayout.setLayoutParams(ff);注:其布局参数类型应该线性布局LinearLayout.LayoutParams的类型,而不是帧布局FrameLayout .LayoutParams
。
http://blog.163.com/smilecatflower_18z/blog/static/19262704520120974119643/
本文探讨了在Android中使用代码动态改变布局高度时遇到的类转换异常问题,并提供了正确设置布局参数的方法。
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