Question

android 开发问题

12717-12717/com.lmx.lmxClock E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.lmx.lmxClock, PID: 12717
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.lmx.lmxClock/com.lmx.lmxClock.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TabHost.setup()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5257)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TabHost.setup()' on a null object reference
at com.lmx.lmxClock.MainActivity.onCreate(MainActivity.java:18)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5257)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

Answer 1

NullPointerException，空指针，java里面最好解决也是最容易出现的问题。
错误原因是你调用了空对象的属性或者方法，导致空指针。
把你报错的代码截图贴出来，帮你分析一下。

Answer 2

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TabHost.setup()' on a null object reference
at com.lmx.lmxClock.MainActivity.onCreate(MainActivity.java:18)

空指针异常？去百度TabHost怎么用吧，搜一些demo 学习下

追问

我也是完全按照网上的教程来的，不知道怎么就出这个问题了。。