Question

我为Action Bar创建了一个自定义布局：我在Activity上添加了这段代码：

LayoutInflater inflater = (LayoutInflater)getSystemService (Context.LAYOUT_INFLATER_SERVICE);
View actionBarView = inflater.inflate (R.layout.main_actionbar, null);  
getSupportActionBar ().setCustomView (actionBarView);

和main_actionbar.xml布局：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:style="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/white" >

    <RelativeLayout
        android:id="@+id/leftIcons"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_toLeftOf="@+id/empty"
        android:paddingTop="4dp"
        android:paddingBottom="4dp"
        android:background="@drawable/uiclickable_gray_states"
        android:layout_alignParentLeft="true" >

        <ImageView
            android:id="@+id/back"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:gravity="center_vertical"
            android:layout_marginRight="5dp"
            android:src="@drawable/icon_back" />

        <!-- The problem is here -->
        <ImageView
            android:id="@+id/thumbnail"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_toRightOf="@+id/back"
            android:paddingTop="5dp"
            android:paddingBottom="5dp"
            android:src="@drawable/bg"
            android:scaleType="fitXY"
            android:adjustViewBounds="true" />

    </RelativeLayout>

    <View 
        android:id="@+id/empty"
        android:layout_width="100dp"
        android:layout_height="match_parent"
        android:background="@color/black_transparent"
        android:layout_alignParentRight="true" />

</RelativeLayout>

我的问题是，我希望@+id/thumbnail将其高度设为match_parent，并让它的宽度等于高度。意思是：height == match_parent AND width == height，所以我可以有一个方形图像。

似乎这不能通过xml完成，所以我创建了（在网络上的一些教程的帮助下）ImageView的子类并做了这个但没有任何积极的结果：

@Override
protected void onMeasure (int widthMeasureSpec, int heightMeasureSpec) {
    //int width = measureWidth (widthMeasureSpec);
    int height = measureHeight (heightMeasureSpec);
    setMeasuredDimension (height, height);
}

private int measureHeight (int measureSpecHeight) {
    int result;
    int specMode = MeasureSpec.getMode (measureSpecHeight);
    int specSize = MeasureSpec.getSize (measureSpecHeight);

    if (specMode == MeasureSpec.EXACTLY) {
        // We were told how big to be
        result = specSize;
    } else if (specMode == MeasureSpec.AT_MOST) {
        // The child can be as large as it wants up to the specified size.
        result = specSize;
    } else {
        // Measure the text  (beware: ascent is a negative number)
        result = canvasSize;
    }

    return  (result + 2);
}

我在那里做错了吗？谢谢。

Wrap_content在RelativeLayout上不起作用：操作栏自定义视图

0 个答案: