teacher_tab.setup(this.getLocalActivityManager())报空指针，希望各位帮忙看看

qq_42955997 2019-06-19 03:20:51
因为想在一个TabHost的其中一个标签页下面在添加一个TabHost，就在网上找了相关帖子模仿，结果遇到“Did you forget to call 'public voidsetup(LocalActivityManager activityGroup)？”这样的错误，网上说继承ActivityGroup，或者TabActivity 而不是 activity

加入 activitytabHost.setup(this.getLocalActivityManager());就可以了，但是这样改了之后teacher_tab.setup(this.getLocalActivityManager());这一句又会报空指针错误“java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TabHost.setup(android.app.LocalActivityManager)' on a null object reference”。
下面是java代码


public class TeacherActivity extends ActivityGroup {



    private Context context = TeacherActivity.this;

    private List<CourseSummary> listMyCourses = new ArrayList<>();

    void getMyCourses(){

        List<CourseSummary> mycourses = CMSClient.getMyCourses(SystemConfig.username);

        listMyCourses.clear();

        for(CourseSummary c : mycourses) {

            listMyCourses.add(c);

        }

    }



    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        TabHost teacher_tab = findViewById(R.id.tabhost_teacher);

        teacher_tab.setup(this.getLocalActivityManager());

//        TabHost teacher_tab = getTabHost();

//        LayoutInflater.from(this).inflate(R.layout.activity_teacher_main,teacher_tab.getTabContentView(),true);



        teacher_tab.addTab(teacher_tab.newTabSpec("taba").setIndicator("我的课程").setContent(R.id.teacher_mycourses));

        teacher_tab.addTab(teacher_tab.newTabSpec("tabb").setIndicator("课程维护").setContent(new Intent(this,TeacherActivity_courserepair.class)));

        teacher_tab.addTab(teacher_tab.newTabSpec("tabc").setIndicator("课表查看").setContent(R.id.teacher_coursetable));



        //我的课程标签页

        ListView listview_mycourses = findViewById(R.id.list_view_teacher_course);

        getMyCourses();

        for(int i = 0; i < listMyCourses.size(); i++){

            Log.i("cmstag",listMyCourses.get(i).courseName);

        }

        MyCoursesAdapter mdp = new MyCoursesAdapter(context, R.layout.listview_sub_mycourse, listMyCourses);

        listview_mycourses.setAdapter(mdp);

        listview_mycourses.setOnItemClickListener(new AdapterView.OnItemClickListener() {

            @Override

            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                CourseSummary myCourse = listMyCourses.get(position);

                Intent intent = new Intent(context,CourseDetailsActivity.class);

                intent.putExtra("course_id",myCourse.courseId);

                context.startActivity(intent);

            }

        });



        //标签切换事件处理，setOnTabChangedListener

        teacher_tab.setOnTabChangedListener(new TabHost.OnTabChangeListener(){

            @Override

            public void onTabChanged(String tabId) {

                if (tabId.equals("taba")) {   //第一个标签



                }

                if (tabId.equals("tabb")) {   //课程维护



                }

                if (tabId.equals("tabc")) {   //课表查看



                }

            }

        });

    }

}


这里是错误信息


E/AndroidRuntime: FATAL EXCEPTION: main

    Process: cn.edu.njrts.cms, PID: 8947

    java.lang.RuntimeException: Unable to start activity ComponentInfo{cn.edu.njrts.cms/cn.edu.njrts.cms.TeacherActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TabHost.setup(android.app.LocalActivityManager)' on a null object reference

        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2665)

        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726)

        at android.app.ActivityThread.-wrap12(ActivityThread.java)

        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477)

        at android.os.Handler.dispatchMessage(Handler.java:102)

        at android.os.Looper.loop(Looper.java:154)

        at android.app.ActivityThread.main(ActivityThread.java:6119)

        at java.lang.reflect.Method.invoke(Native Method)

        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)

        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TabHost.setup(android.app.LocalActivityManager)' on a null object reference

        at cn.edu.njrts.cms.TeacherActivity.onCreate(TeacherActivity.java:38)

        at android.app.Activity.performCreate(Activity.java:6679)

        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)

        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2618)

        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726) 

        at android.app.ActivityThread.-wrap12(ActivityThread.java) 

        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477) 

        at android.os.Handler.dispatchMessage(Handler.java:102) 

        at android.os.Looper.loop(Looper.java:154) 

        at android.app.ActivityThread.main(ActivityThread.java:6119) 

        at java.lang.reflect.Method.invoke(Native Method) 

        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 

        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) 

Application terminated.


下面是日志信息


2019-06-19 15:18:49.672 9813-9813/cn.edu.njrts.cms I/System.out: connect to server success!

2019-06-19 15:18:49.675 1384-1433/? W/audio_hw_generic: Not supplying enough data to HAL, expected position 57444609 , only wrote 57444480

2019-06-19 15:18:49.678 9813-9813/cn.edu.njrts.cms I/System.out: {"password":"1111","username":"10001"}

2019-06-19 15:18:49.690 9813-9813/cn.edu.njrts.cms I/System.out: server reply: {"msg":"OK","jsonStr":"{\"teacherId\":\"10001\",\"username\":\"10001\",\"password\":\"1111\",\"name\":\"张乐乐\",\"state\":0}"}

2019-06-19 15:18:49.696 1688-4449/? I/ActivityManager: START u0 {cmp=cn.edu.njrts.cms/.TeacherActivity} from uid 10083 on display 0

2019-06-19 15:18:49.719 9813-9813/cn.edu.njrts.cms D/AndroidRuntime: Shutting down VM

    

    

    --------- beginning of crash

2019-06-19 15:18:49.719 9813-9813/cn.edu.njrts.cms E/AndroidRuntime: FATAL EXCEPTION: main

    Process: cn.edu.njrts.cms, PID: 9813

    java.lang.RuntimeException: Unable to start activity ComponentInfo{cn.edu.njrts.cms/cn.edu.njrts.cms.TeacherActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TabHost.setup(android.app.LocalActivityManager)' on a null object reference

        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2665)

        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726)

        at android.app.ActivityThread.-wrap12(ActivityThread.java)

        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477)

        at android.os.Handler.dispatchMessage(Handler.java:102)

        at android.os.Looper.loop(Looper.java:154)

        at android.app.ActivityThread.main(ActivityThread.java:6119)

        at java.lang.reflect.Method.invoke(Native Method)

        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)

        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TabHost.setup(android.app.LocalActivityManager)' on a null object reference

        at cn.edu.njrts.cms.TeacherActivity.onCreate(TeacherActivity.java:38)

        at android.app.Activity.performCreate(Activity.java:6679)

        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)

        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2618)

        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726) 

        at android.app.ActivityThread.-wrap12(ActivityThread.java) 

        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477) 

        at android.os.Handler.dispatchMessage(Handler.java:102) 

        at android.os.Looper.loop(Looper.java:154) 

        at android.app.ActivityThread.main(ActivityThread.java:6119) 

        at java.lang.reflect.Method.invoke(Native Method) 

        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 

        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) 

2019-06-19 15:18:49.720 1688-4450/? W/ActivityManager:   Force finishing activity cn.edu.njrts.cms/.TeacherActivity

2019-06-19 15:18:49.723 1688-4450/? W/ActivityManager:   Force finishing activity cn.edu.njrts.cms/.MainActivity

2019-06-19 15:18:49.766 1688-10315/? I/OpenGLRenderer: Initialized EGL, version 1.4

2019-06-19 15:18:49.766 1688-10315/? D/OpenGLRenderer: Swap behavior 1

2019-06-19 15:18:49.766 1688-10315/? W/OpenGLRenderer: Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...

2019-06-19 15:18:49.766 1688-10315/? D/OpenGLRenderer: Swap behavior 0

2019-06-19 15:18:49.770 1688-10315/? D/EGL_emulation: eglCreateContext: 0x9af30f20: maj 3 min 0 rcv 3

2019-06-19 15:18:49.779 1688-10315/? D/EGL_emulation: eglMakeCurrent: 0x9af30f20: ver 3 0 (tinfo 0x8bb7f860)

2019-06-19 15:18:49.782 1688-10315/? E/eglCodecCommon: glUtilsParamSize: unknow param 0x00008cdf

2019-06-19 15:18:49.782 1688-10315/? E/eglCodecCommon: glUtilsParamSize: unknow param 0x00008824

2019-06-19 15:18:49.789 1688-10315/? D/EGL_emulation: eglMakeCurrent: 0x9af30f20: ver 3 0 (tinfo 0x8bb7f860)

2019-06-19 15:18:50.225 1688-1701/? W/ActivityManager: Activity pause timeout for ActivityRecord{8a01dc1 u0 cn.edu.njrts.cms/.TeacherActivity t383 f}

2019-06-19 15:18:50.302 2262-2473/? D/EGL_emulation: eglMakeCurrent: 0x97c23780: ver 3 0 (tinfo 0x84cb7050)

2019-06-19 15:18:50.370 2262-2262/? I/OptInState: There is a new client and it does not support opt-in. Dropping request.

2019-06-19 15:18:50.382 2262-9842/? W/LocationOracle: No location history
...全文
105 1 打赏 收藏 转发到动态 举报
写回复
用AI写文章
1 条回复
切换为时间正序
请发表友善的回复…
发表回复
eisldkw 2019-06-19
  • 打赏
  • 举报
 回复
帮你顶一下喽
将一个activity转换成一个view并显示
LocalActivityManager类是管理activity的，然后通过startActivity（String id, Intent intent）这个方法获取Window获取当前Window对象，再然后调用getDecorView()方法获取当前activity对应的view，这样就可以使用...
android点滴24:使用TabHost时各种蛋疼的错误
否则会报Did you forget to call 'public void setup (LocalActivityManager activityGroup)'错误，不继承ActivityGroup也会报莫名其妙的NullPointException，即使TabHost类并没有空指针。 转载...
Android中TabHost切换不同的Activity
TabHost在很多应用都会使用到,有时候在TabHost添加的Tab中设置view不能满足需求,因为在view中添加如PreferenceActivity相当困难. 之前在一个应用中需要实现使用TabHost中在多个Tab切换不同的Activity.一个是日志...
ActivityGroup、TabHost之子页面不刷新——getLocalActivityManager() 以及intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR...
TabHost继承自ActivityGroup，以下不再单独列出。 ActivityGroup在第一次创建的时候会完整的执行子Activity或子view的生命周期，但在从其他子activity或子view返回第一个子activity/view时，则不会执行第一个...
创建TabHost的两种方式的简单分析
目前就我所知，创建TabHost有两种方式，第一种是继承TabActivity类，然后用getTabHost方法来得到一个TabHost的实例，然后就可以给这个TabHost添加Tab了。示例代码如下： [java] view plaincopy public.....
Android

80,351

社区成员

91,288

社区内容

发帖
与我相关
我的任务
社区描述
移动平台 Android
androidandroid-studioandroidx 技术论坛（原bbs）
社区管理员
  • Android
  • yechaoa
  • 失落夏天
加入社区
  • 近7日
  • 近30日
  • 至今

加载中

查看更多榜单
社区公告
暂无公告

试试用AI创作助手写篇文章吧

+ 用AI写文章