requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.activity_main); 看一下退出时打出的log,查一下文档你大概也就能明白了,初学要先学会看log。 requestWindowFeature 需要在setContentView后调用,因为他会调用Window的requestFeature方法。public boolean requestFeature (int featureId)Added in API level 1 Enable extended screen features. This must be called before setContentView(). May be called as many times as desired as long as it is before setContentView(). If not called, no extended features will be available. You can not turn off a feature once it is requested. You canot use other title features with FEATURE_CUSTOM_TITLE.
This must be called before setContentView() 也就是说requestWindowFeature是在setContentView前调用,不是之后
This must be called before setContentView() 也就是说requestWindowFeature是在setContentView前调用,不是之后 是的,打错了
11-16 13:54:39.170: D/AndroidRuntime(28897): Shutting down VM 11-16 13:54:39.170: W/dalvikvm(28897): threadid=1: thread exiting with uncaught exception (group=0x415a5d88) 11-16 13:54:39.170: E/AndroidRuntime(28897): FATAL EXCEPTION: main 11-16 13:54:39.170: E/AndroidRuntime(28897): Process: com.example.booktest, PID: 28897 11-16 13:54:39.170: E/AndroidRuntime(28897): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.booktest/com.example.booktest.MainActivity}: java.lang.NullPointerException 11-16 13:54:39.170: E/AndroidRuntime(28897): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2248) 11-16 13:54:39.170: E/AndroidRuntime(28897): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2298) 11-16 13:54:39.170: E/AndroidRuntime(28897): at android.app.ActivityThread.access$800(ActivityThread.java:144) 11-16 13:54:39.170: E/AndroidRuntime(28897): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1246) 11-16 13:54:39.170: E/AndroidRuntime(28897): at android.os.Handler.dispatchMessage(Handler.java:102) 11-16 13:54:39.170: E/AndroidRuntime(28897): at android.os.Looper.loop(Looper.java:212) 11-16 13:54:39.170: E/AndroidRuntime(28897): at android.app.ActivityThread.main(ActivityThread.java:5151) 11-16 13:54:39.170: E/AndroidRuntime(28897): at java.lang.reflect.Method.invokeNative(Native Method) 11-16 13:54:39.170: E/AndroidRuntime(28897): at java.lang.reflect.Method.invoke(Method.java:515) 11-16 13:54:39.170: E/AndroidRuntime(28897): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:877) 11-16 13:54:39.170: E/AndroidRuntime(28897): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:693) 11-16 13:54:39.170: E/AndroidRuntime(28897): at dalvik.system.NativeStart.main(Native Method) 11-16 13:54:39.170: E/AndroidRuntime(28897): Caused by: java.lang.NullPointerException 11-16 13:54:39.170: E/AndroidRuntime(28897): at com.example.booktest.MainActivity.onCreate(MainActivity.java:29) 11-16 13:54:39.170: E/AndroidRuntime(28897): at android.app.Activity.performCreate(Activity.java:5231) 11-16 13:54:39.170: E/AndroidRuntime(28897): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) 11-16 13:54:39.170: E/AndroidRuntime(28897): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2212) 11-16 13:54:39.170: E/AndroidRuntime(28897): ... 11 more 11-16 13:54:41.710: I/Process(28897): Sending signal. PID: 28897 SIG: 9
setContentView(R.layout.activity_main);
看一下退出时打出的log,查一下文档你大概也就能明白了,初学要先学会看log。
requestWindowFeature 需要在setContentView后调用,因为他会调用Window的requestFeature方法。public boolean requestFeature (int featureId)Added in API level 1
Enable extended screen features. This must be called before setContentView(). May be called as many times as desired as long as it is before setContentView(). If not called, no extended features will be available. You can not turn off a feature once it is requested. You canot use other title features with FEATURE_CUSTOM_TITLE.
是的,打错了
11-16 13:54:39.170: W/dalvikvm(28897): threadid=1: thread exiting with uncaught exception (group=0x415a5d88)
11-16 13:54:39.170: E/AndroidRuntime(28897): FATAL EXCEPTION: main
11-16 13:54:39.170: E/AndroidRuntime(28897): Process: com.example.booktest, PID: 28897
11-16 13:54:39.170: E/AndroidRuntime(28897): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.booktest/com.example.booktest.MainActivity}: java.lang.NullPointerException
11-16 13:54:39.170: E/AndroidRuntime(28897): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2248)
11-16 13:54:39.170: E/AndroidRuntime(28897): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2298)
11-16 13:54:39.170: E/AndroidRuntime(28897): at android.app.ActivityThread.access$800(ActivityThread.java:144)
11-16 13:54:39.170: E/AndroidRuntime(28897): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1246)
11-16 13:54:39.170: E/AndroidRuntime(28897): at android.os.Handler.dispatchMessage(Handler.java:102)
11-16 13:54:39.170: E/AndroidRuntime(28897): at android.os.Looper.loop(Looper.java:212)
11-16 13:54:39.170: E/AndroidRuntime(28897): at android.app.ActivityThread.main(ActivityThread.java:5151)
11-16 13:54:39.170: E/AndroidRuntime(28897): at java.lang.reflect.Method.invokeNative(Native Method)
11-16 13:54:39.170: E/AndroidRuntime(28897): at java.lang.reflect.Method.invoke(Method.java:515)
11-16 13:54:39.170: E/AndroidRuntime(28897): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:877)
11-16 13:54:39.170: E/AndroidRuntime(28897): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:693)
11-16 13:54:39.170: E/AndroidRuntime(28897): at dalvik.system.NativeStart.main(Native Method)
11-16 13:54:39.170: E/AndroidRuntime(28897): Caused by: java.lang.NullPointerException
11-16 13:54:39.170: E/AndroidRuntime(28897): at com.example.booktest.MainActivity.onCreate(MainActivity.java:29)
11-16 13:54:39.170: E/AndroidRuntime(28897): at android.app.Activity.performCreate(Activity.java:5231)
11-16 13:54:39.170: E/AndroidRuntime(28897): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
11-16 13:54:39.170: E/AndroidRuntime(28897): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2212)
11-16 13:54:39.170: E/AndroidRuntime(28897): ... 11 more
11-16 13:54:41.710: I/Process(28897): Sending signal. PID: 28897 SIG: 9