4

我是 Android 中的 Fragment 的新手，我指的是 Fragments 演示示例提供了 supprotv4 兼容性库。

谁能解释为什么(@+android:id/realtabcontent , @android:id/tabcontent)Android Support4Demos 的 FragmentTabs.java 示例中有两个框架布局。

FragmentTabs.java 调用setContentView(R.layout.fragment_tabs);方法和下面的布局文件一样。

fragment_tabs.xml

    <TabHost xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@android:id/tabhost"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical" >

            <TabWidget
                android:id="@android:id/tabs"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_weight="0"
                android:orientation="horizontal" />

            <FrameLayout
                android:id="@android:id/tabcontent"
                android:layout_width="0dp"
                android:layout_height="0dp"
                android:layout_weight="0" />

            <FrameLayout
                android:id="@+android:id/realtabcontent"
                android:layout_width="match_parent"
                android:layout_height="0dp"
                android:layout_weight="1" />
        </LinearLayout>

    </TabHost>

提前致谢

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1 回答 1

4

在浏览完示例后，我发现以下评论FragmentsTabs.java

 /**
 * This is a helper class that implements a generic mechanism for
 * associating fragments with the tabs in a tab host. It relies on a trick.
 * Normally a tab host has a simple API for supplying a View or Intent that
 * each tab will show. This is not sufficient for switching between
 * fragments. So instead we make the content part of the tab host 0dp high
 * (it is not shown) and the TabManager supplies its own dummy view to show
 * as the tab content. It listens to changes in tabs, and takes care of
 * switch to the correct fragment shown in a separate content area whenever
 * the selected tab changes.
 */
于 2012-09-08T18:35:26.353 回答