Android选项卡主机错误

我使用的是Android Studio，我正试图根据本教程制作一个带有ViewPager的TabHost

但我有一个问题，我无法确定

主要的_activity.xml代码：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.subhi.navtabs.MainActivity">


    <TabHost
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/tabHost"
       >



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

            <HorizontalScrollView
                android:layout_width="match_parent"
                android:id="@+id/h_Scroll_View"
                android:layout_height="wrap_content">


                <TabWidget
                    android:id="@android:id/tabs"
                    android:fillViewport="true"
                    android:scrollbars="none"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"></TabWidget>

            </HorizontalScrollView>



            <FrameLayout
                android:id="@android:id/tabcontent"
                android:layout_width="match_parent"
                android:layout_height="match_parent">

                <android.support.v4.view.ViewPager
                    android:layout_width="match_parent"
                    android:id="@+id/viewpager"
                    android:layout_height="match_parent"></android.support.v4.view.ViewPager>
            </FrameLayout>
        </LinearLayout>
    </TabHost>
</RelativeLayout>

这是原木猫：

    02-09 08:35:36.925 2501-2501/? E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.subhi.navtabs, PID: 2501
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.subhi.navtabs/com.subhi.navtabs.MainActivity}: java.lang.NullPointerException
         at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
         at android.app.ActivityThread.access$800(ActivityThread.java:135)
         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
         at android.os.Handler.dispatchMessage(Handler.java:102)
         at android.os.Looper.loop(Looper.java:136)
         at android.app.ActivityThread.main(ActivityThread.java:5017)
         at java.lang.reflect.Method.invokeNative(Native Method)
         at java.lang.reflect.Method.invoke(Method.java:515)
         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
         at dalvik.system.NativeStart.main(Native Method)
    Caused by: java.lang.NullPointerException
         at com.subhi.navtabs.MainActivity.initTabHost(MainActivity.java:37)
         at com.subhi.navtabs.MainActivity.onCreate(MainActivity.java:28)
         at android.app.Activity.performCreate(Activity.java:5231)
         at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
         at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245) 
         at android.app.ActivityThread.access$800(ActivityThread.java:135) 
         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196) 
         at android.os.Handler.dispatchMessage(Handler.java:102) 
         at android.os.Looper.loop(Looper.java:136) 
         at android.app.ActivityThread.main(ActivityThread.java:5017) 
         at java.lang.reflect.Method.invokeNative(Native Method) 
         at java.lang.reflect.Method.invoke(Method.java:515) 
         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) 
         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) 
         at dalvik.system.NativeStart.main(Native Method) 
    02-09 08:35:36.925 1268-1438/? W/ActivityManager:   Force finishing activity com.subhi.navtabs/.MainActivity
    02-09 08:35:37.145 1268-1438/? D/dalvikvm: GC_FOR_ALLOC freed 1812K, 26% free 12136K/16264K, paused 10ms, total 10ms
    02-09 08:35:37.665 1268-1283/? W/ActivityManager: Activity pause timeout for ActivityRecord{b1549268 u0 com.subhi.navtabs/.MainActivity t6 f}
    02-09 08:35:37.735 1402-1402/? W/EGL_emulation: eglSurfaceAttrib not implemented

我不知道哪里出了问题，如果有人能帮我的话

tabHost（带大写字母“H”）与tabHost不同

您的

TabHost

id是

“@+id/TabHost”

，您正在

findViewById（）

方法中使用

android.R.id.TabHost

这就是

findViewById（）

返回空对象的原因

---

要解决此问题，只需更改：

从java代码中

tabHost=（tabHost）findviewbyd（android.R.id.tabHost）

to
tabHost=（tabHost）findviewbyd（R.id.tabHost）

或
从xml，
android:id=“@+id/tabHost”
到
android:id=“@android:id/tabHost”

package com.subhi.navtabs;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

/**
 * Created by subhi on 2/9/2016.
 */
public class Fragment1 extends Fragment {


    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View v=inflater.inflate(R.layout.fragment1_layout,container,false);
        return v;
    }
}

    02-09 08:35:36.925 2501-2501/? E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.subhi.navtabs, PID: 2501
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.subhi.navtabs/com.subhi.navtabs.MainActivity}: java.lang.NullPointerException
         at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
         at android.app.ActivityThread.access$800(ActivityThread.java:135)
         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
         at android.os.Handler.dispatchMessage(Handler.java:102)
         at android.os.Looper.loop(Looper.java:136)
         at android.app.ActivityThread.main(ActivityThread.java:5017)
         at java.lang.reflect.Method.invokeNative(Native Method)
         at java.lang.reflect.Method.invoke(Method.java:515)
         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
         at dalvik.system.NativeStart.main(Native Method)
    Caused by: java.lang.NullPointerException
         at com.subhi.navtabs.MainActivity.initTabHost(MainActivity.java:37)
         at com.subhi.navtabs.MainActivity.onCreate(MainActivity.java:28)
         at android.app.Activity.performCreate(Activity.java:5231)
         at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
         at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245) 
         at android.app.ActivityThread.access$800(ActivityThread.java:135) 
         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196) 
         at android.os.Handler.dispatchMessage(Handler.java:102) 
         at android.os.Looper.loop(Looper.java:136) 
         at android.app.ActivityThread.main(ActivityThread.java:5017) 
         at java.lang.reflect.Method.invokeNative(Native Method) 
         at java.lang.reflect.Method.invoke(Method.java:515) 
         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) 
         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) 
         at dalvik.system.NativeStart.main(Native Method) 
    02-09 08:35:36.925 1268-1438/? W/ActivityManager:   Force finishing activity com.subhi.navtabs/.MainActivity
    02-09 08:35:37.145 1268-1438/? D/dalvikvm: GC_FOR_ALLOC freed 1812K, 26% free 12136K/16264K, paused 10ms, total 10ms
    02-09 08:35:37.665 1268-1283/? W/ActivityManager: Activity pause timeout for ActivityRecord{b1549268 u0 com.subhi.navtabs/.MainActivity t6 f}
    02-09 08:35:37.735 1402-1402/? W/EGL_emulation: eglSurfaceAttrib not implemented