在android上创建类似iPhone的选项卡栏

android非常新。我浏览了一些网站和官方网站，在登录屏幕后创建了一个选项卡式视图。但是当我创建标签时，它会显示

没有标签为空
。不确定如何创建4个选项卡

这是我的密码

<android.support.v4.app.FragmentTabHost
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:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

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

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

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

</LinearLayout>

我哪里做错了？我需要在屏幕底部有一个选项卡栏。这是我的日志

04-29 05:45:25.126: E/AndroidRuntime(781): FATAL EXCEPTION: main
04-29 05:45:25.126: E/AndroidRuntime(781): java.lang.ClassCastException: com.example.hello.DeliverySitesActivity cannot be cast to android.support.v4.app.Fragment
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.support.v4.app.Fragment.instantiate(Fragment.java:402)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.support.v4.app.FragmentTabHost.doTabChanged(FragmentTabHost.java:339)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.support.v4.app.FragmentTabHost.onAttachedToWindow(FragmentTabHost.java:276)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.View.dispatchAttachedToWindow(View.java:12125)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2450)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2457)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2457)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2457)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1207)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1004)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5481)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.Choreographer.doCallbacks(Choreographer.java:562)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.Choreographer.doFrame(Choreographer.java:532)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.os.Handler.handleCallback(Handler.java:730)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.os.Handler.dispatchMessage(Handler.java:92)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.os.Looper.loop(Looper.java:137)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.app.ActivityThread.main(ActivityThread.java:5103)
04-29 05:45:25.126: E/AndroidRuntime(781):  at java.lang.reflect.Method.invokeNative(Native Method)
04-29 05:45:25.126: E/AndroidRuntime(781):  at java.lang.reflect.Method.invoke(Method.java:525)
04-29 05:45:25.126: E/AndroidRuntime(781):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
04-29 05:45:25.126: E/AndroidRuntime(781):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
04-29 05:45:25.126: E/AndroidRuntime(781):  at dalvik.system.NativeStart.main(Native Method)

FragmentTabHost
要求将片段作为选项卡的内容，但您使用的是活动类而不是片段类作为选项卡的内容

mTabHost.addTab（…DeliverySitesActivity.class…）
请从Logcat发布整个堆栈跟踪。那么，您从哪里得到“没有标记为null的选项卡”？Logcat跟踪被共享您正在获取
ClassCastException
，因为
DeliverySitesActivity
可能不是
片段
而是
活动
我将其更改为片段，但它仍然给出相同的异常
04-29 05:45:25.126: E/AndroidRuntime(781): FATAL EXCEPTION: main
04-29 05:45:25.126: E/AndroidRuntime(781): java.lang.ClassCastException: com.example.hello.DeliverySitesActivity cannot be cast to android.support.v4.app.Fragment
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.support.v4.app.Fragment.instantiate(Fragment.java:402)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.support.v4.app.FragmentTabHost.doTabChanged(FragmentTabHost.java:339)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.support.v4.app.FragmentTabHost.onAttachedToWindow(FragmentTabHost.java:276)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.View.dispatchAttachedToWindow(View.java:12125)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2450)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2457)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2457)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2457)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1207)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1004)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5481)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.Choreographer.doCallbacks(Choreographer.java:562)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.Choreographer.doFrame(Choreographer.java:532)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.os.Handler.handleCallback(Handler.java:730)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.os.Handler.dispatchMessage(Handler.java:92)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.os.Looper.loop(Looper.java:137)
04-29 05:45:25.126: E/AndroidRuntime(781):  at android.app.ActivityThread.main(ActivityThread.java:5103)
04-29 05:45:25.126: E/AndroidRuntime(781):  at java.lang.reflect.Method.invokeNative(Native Method)
04-29 05:45:25.126: E/AndroidRuntime(781):  at java.lang.reflect.Method.invoke(Method.java:525)
04-29 05:45:25.126: E/AndroidRuntime(781):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
04-29 05:45:25.126: E/AndroidRuntime(781):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
04-29 05:45:25.126: E/AndroidRuntime(781):  at dalvik.system.NativeStart.main(Native Method)