扩展的FrameLayout，子视图将不会显示再 [英] Extending FrameLayout, child views won't show anymore

问题描述

这是我的code与的FrameLayout ：

<FrameLayout
        android:layout_width="fill_parent" android:layout_height="wrap_content">
    <ImageView
            android:id="@+id/frameView"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:src="@drawable/image1"
            />
</FrameLayout>

该ImageView的表演很好。

The ImageView show well.

现在我有一个自定义布局从的FrameLayout，例如延长MyFrameLayout。

Now I have a custom layout extends from FrameLayout, e.g. MyFrameLayout.

在MyFrameLayout，我想布局的高度，始终是宽度的一半，所以我的code是：

In MyFrameLayout, I want the height of the layout is always half of the width, so my code is:

public class MyFrameLayout extends FrameLayout {

     // 3 constructors just call super

     @Override
     protected void onMeasure(int widthMeasureSpec,
                         int heightMeasureSpec) {
        int width = MeasureSpec.getSize(widthMeasureSpec);
        int height = (int) (width * 0.5);
        setMeasuredDimension(width, height);
    }
}

然后在XML中使用它：

Then use it in xml:

<com.test.MyFrameLayout
        android:layout_width="fill_parent" android:layout_height="wrap_content">
    <ImageView
            android:id="@+id/frameView"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:src="@drawable/image1"
            />
</com.test.MyFrameLayout>

但是现在内在的ImageView消失了。

But now the inner ImageView disappeared.

我觉得我没有正确实施 onMeasure 或 onLayout 。我想我需要调整孩子们的意见为好。但我不知道现在该做什么。

I think I don't implement onMeasure or onLayout correctly. I guess I need to resize the children views as well. But I don't know what to do now.

更新

每 TheDimasig 的评论，我只是检查我的code和更新我的问题。谢谢

Per TheDimasig's comment, I just checked my code and update my question. Thanks

推荐答案

最简单的方法是改变onMeasure的measurespec，但还是叫超：

The simplest way is to change the measurespec in onMeasure, but still call super:

 @Override
 protected void onMeasure(int widthMeasureSpec,
                     int heightMeasureSpec) {
    int width = MeasureSpec.getSize(widthMeasureSpec);
    int height = (int) (width * 0.5);
    heightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}

这样，你得到你想要的尺寸，但不必手动测量孩子。

This way you get the dimensions you want but don't have to manually measure the children.

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