Android:可以使用 wrap_content 设置 SlidingDrawer 的高度吗? [英] Android: can height of SlidingDrawer be set with wrap_content?

问题描述

我正在尝试实现一个 SlidingDrawer，它将占据整个屏幕宽度，但其高度由其内容动态确定:换句话说，标准 fill_parent 布局宽度的行为和高度的 wrap_content 行为.这正是我在布局 XML 中指定的方式(见下文)，但滑动抽屉始终打开至全屏高度.我的内容的高度各不相同，但通常只有屏幕高度的一半左右，所以我最终在它下面有一个很大的间隙.我希望内容整齐地位于屏幕底部.

I'm trying to implement a SlidingDrawer that will occupy the full screen width, but whose height is determined dynamically by its contents: in other words, standard fill_parent layout behaviour for the width and wrap_content for the height. That's exactly how I've specified it in the layout XML (see below) but the sliding drawer always opens to the full screen height. The height of my content varies, but typically it's only about half the screen height, so I end up with a big gap underneath it. What I'd like is for the content to sit neatly on the bottom of the screen.

我已经尝试了所有我能想到的方法来修复它，但到目前为止没有任何效果.如果我将 SlidingDrawer 的 layout_height 设置为特定值(例如 160dip)，它会起作用，但这不是我需要的:它必须是动态的.当然，我已经确保所有子元素的高度也设置为 wrap_content.

I've tried everything I can think of to fix it but nothing's worked so far. If I set the SlidingDrawer's layout_height to a specific value (e.g. 160dip) it works, but that's not what I need: it has to be dynamic. Of course I've made sure all the child elements have their height set to wrap_content too.

关于 SlidingDrawer 的文档对此有点含糊，我也找不到任何可以实现我所追求的示例.如果有人能看到我哪里出错了，我将非常感谢您的帮助！

The documentation on SlidingDrawer is a bit vague on this and I haven't been able to find any examples that do what I'm after either. If anyone can see where I'm going wrong I'd really appreciate your help!

<RelativeLayout
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <ViewFlipper
        android:id="@+id/ImageFlipper"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >

        <ImageView
            android:id="@+id/imageView0"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:scaleType="centerCrop" />

        <ImageView
            android:id="@+id/imageView1"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:scaleType="centerCrop" />

        <ImageView
            android:id="@+id/imageView2"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:scaleType="centerCrop" />

    </ViewFlipper>

    <SlidingDrawer
        android:id="@+id/infoDrawer"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:handle="@+id/infoDrawerHandle"
        android:content="@+id/infoDrawerContent"
        android:allowSingleTap="false"
        android:layout_alignParentBottom="true"
        android:orientation="vertical" >

        <!-- Sliding drawer handle -->
        <ImageView
            android:id="@id/infoDrawerHandle"
            android:src="@drawable/info_handle_closed"
            android:layout_width="wrap_content" 
            android:layout_height="wrap_content" />

        <!-- Sliding drawer content: a scroller containing a group of text views
        laid out in a LinearLayout -->
        <ScrollView
            android:id="@id/infoDrawerContent"
            android:background="@drawable/info_background"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:fillViewport="false" >

            <LinearLayout
                android:id="@id/infoDrawerContent"
                android:orientation="vertical"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:paddingRight="5dip" >

                <TextView
                    android:id="@+id/infoTitle"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textColor="#ffffff"
                    android:textSize="16dip"
                    android:textStyle="bold" />

                <TextView
                    android:id="@+id/infoCreator"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textColor="#ffffff"
                    android:textSize="14dip"
                    android:textStyle="italic"
                    android:paddingBottom="10dip" />

                <TextView
                    android:id="@+id/infoDescription"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textColor="#ffffff"
                    android:textSize="14dip"
                    android:paddingBottom="10dip" />

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textColor="#ffcc00"
                    android:textSize="14dip"
                    android:textStyle="bold"
                    android:text="@string/heading_pro_tip" />

                <TextView
                    android:id="@+id/infoProTip"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textColor="#ffcc00"
                    android:textSize="14dip" />

            </LinearLayout>    

        </ScrollView>

    </SlidingDrawer>

</RelativeLayout>

推荐答案

SlidingDrawer 类的onMeasure() 方法基本上将布局模式覆盖到了fill_parent，这是为什么 layout_height="wrap_content" 不起作用.

The onMeasure() method of the SlidingDrawer class basically overrides the layout modes to fill_parent, this is why layout_height="wrap_content" is not working.

为了解决这个问题，您可以使用重新实现的 onMeasure() 方法扩展 SlidingDrawer，该方法遵循 layout_width 和 layout_height 属性.然后，您可以通过将 <SlidingDrawer ...> 替换为 <fully.qualified.package.ClassName ...> 在您的 XML 布局中使用此自定义类.

To get around this, you can extend SlidingDrawer with a re-implemented onMeasure() method that honors the layout_width and layout_height attributes. You can then use this custom class in your XML layout by replacing <SlidingDrawer ...> with <fully.qualified.package.ClassName ...>.

请注意，由于抽屉将不再填充父布局，因此您必须将其包含在 LinearLayout 中，并将重力属性设置为抽屉应位于的边缘.

Note that since the drawer will no longer be filling the parent layout, you will have to enclose it in a LinearLayout with the gravity attribute set to the edge where the drawer should be.

下面是我为此目的创建的一个类和一个示例布局.

Below are a class I have created for this purpose and an example layout.

WrappingSlidingDrawer 类:

WrappingSlidingDrawer class :

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.widget.SlidingDrawer;


public class WrappingSlidingDrawer extends SlidingDrawer {

    public WrappingSlidingDrawer(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        int orientation = attrs.getAttributeIntValue("android", "orientation", ORIENTATION_VERTICAL);
        mTopOffset = attrs.getAttributeIntValue("android", "topOffset", 0);
        mVertical = (orientation == SlidingDrawer.ORIENTATION_VERTICAL);
    }

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

        int orientation = attrs.getAttributeIntValue("android", "orientation", ORIENTATION_VERTICAL);
        mTopOffset = attrs.getAttributeIntValue("android", "topOffset", 0);
        mVertical = (orientation == SlidingDrawer.ORIENTATION_VERTICAL);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

        int widthSpecMode = MeasureSpec.getMode(widthMeasureSpec);
        int widthSpecSize =  MeasureSpec.getSize(widthMeasureSpec);

        int heightSpecMode = MeasureSpec.getMode(heightMeasureSpec);
        int heightSpecSize =  MeasureSpec.getSize(heightMeasureSpec);

        if (widthSpecMode == MeasureSpec.UNSPECIFIED || heightSpecMode == MeasureSpec.UNSPECIFIED) {
            throw new RuntimeException("SlidingDrawer cannot have UNSPECIFIED dimensions");
        }

        final View handle = getHandle();
        final View content = getContent();
        measureChild(handle, widthMeasureSpec, heightMeasureSpec);

        if (mVertical) {
            int height = heightSpecSize - handle.getMeasuredHeight() - mTopOffset;
            content.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(height, heightSpecMode));
            heightSpecSize = handle.getMeasuredHeight() + mTopOffset + content.getMeasuredHeight();
            widthSpecSize = content.getMeasuredWidth();
            if (handle.getMeasuredWidth() > widthSpecSize) widthSpecSize = handle.getMeasuredWidth();
        }
        else {
            int width = widthSpecSize - handle.getMeasuredWidth() - mTopOffset;
            getContent().measure(MeasureSpec.makeMeasureSpec(width, widthSpecMode), heightMeasureSpec);
            widthSpecSize = handle.getMeasuredWidth() + mTopOffset + content.getMeasuredWidth();
            heightSpecSize = content.getMeasuredHeight();
            if (handle.getMeasuredHeight() > heightSpecSize) heightSpecSize = handle.getMeasuredHeight();
        }

        setMeasuredDimension(widthSpecSize, heightSpecSize);
    }

    private boolean mVertical;
    private int mTopOffset;
}

示例布局(假设 WrappingSlidingDrawer 在包 com.package 中):

Example layout (assuming WrappingSlidingDrawer is in package com.package) :

<FrameLayout android:layout_width="fill_parent"
             android:layout_height="fill_parent">
    ... stuff you want to cover at full-size ...
    <LinearLayout android:layout_width="fill_parent"
              android:layout_height="fill_parent"
              android:gravity="bottom"
              android:orientation="vertical">
        <com.package.WrappingSlidingDrawer android:layout_width="fill_parent"
                           android:layout_height="wrap_content"
                           android:content="@+id/content"
                           android:handle="@+id/handle">
            ... handle and content views ...
        </com.package.WrappingSlidingDrawer>
    </LinearLayout>
</FrameLayout>

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