view3的跳转按钮无法启动MainActivity，直接跳转也打不开。

来源：2-4 引导页逻辑—引导页逻辑开发

逍遥无解

2017-07-12

07-11 20:39:20.453 26118-26118/? E/memtrack: Couldn't load memtrack module (No such file or directory)

07-11 20:39:20.454 26118-26118/? E/android.os.Debug: failed to load memtrack module: -2

07-11 20:39:21.023 26140-26140/? E/memtrack: Couldn't load memtrack module (No such file or directory)

07-11 20:39:21.023 26140-26140/? E/android.os.Debug: failed to load memtrack module: -2

07-11 20:39:26.977 26174-26174/? E/memtrack: Couldn't load memtrack module (No such file or directory)

07-11 20:39:26.977 26174-26174/? E/android.os.Debug: failed to load memtrack module: -2

07-11 20:39:27.911 18616-18678/? E/NetworkScheduler.SR: Invalid parameter app

07-11 20:39:27.911 18616-18678/? E/NetworkScheduler.SR: Invalid package name : Perhaps you didn't include a PendingIntent in the extras?

07-11 20:39:27.912 21929-22150/? E/Drive.UninstallOperation: Package still installed imooc.com.smartbutler

07-11 20:39:28.196 18616-24931/? E/NetworkScheduler.SR: Invalid parameter app

07-11 20:39:28.196 18616-24931/? E/NetworkScheduler.SR: Invalid package name : Perhaps you didn't include a PendingIntent in the extras?

07-11 20:39:28.424 26271-26271/? E/memtrack: Couldn't load memtrack module (No such file or directory)

07-11 20:39:28.424 26271-26271/? E/android.os.Debug: failed to load memtrack module: -2

07-11 20:39:29.147 1332-1336/? E/SurfaceFlinger: ro.sf.lcd_density must be defined as a build property

[ 07-11 20:39:29.156 26304:26304 D/ ]

HostConnection::get() New Host Connection established 0xab574e40, tid 26304

[ 07-11 20:39:29.158 26304:26304 W/ ]

Unrecognized GLES max version string in extensions: ANDROID_EMU_CHECKSUM_HELPER_v1 ANDROID_EMU_dma_v1

[ 07-11 20:39:29.252 26304:26343 D/ ]

HostConnection::get() New Host Connection established 0xa44e6140, tid 26343

[ 07-11 20:39:29.263 26304:26343 W/ ]

Unrecognized GLES max version string in extensions: ANDROID_EMU_CHECKSUM_HELPER_v1 ANDROID_EMU_dma_v1

07-11 20:39:31.281 26304-26304/imooc.com.smartbutler E/AndroidRuntime: FATAL EXCEPTION: main

Process: imooc.com.smartbutler, PID: 26304

java.lang.RuntimeException: Unable to start activity ComponentInfo{imooc.com.smartbutler/imooc.com.smartbutler.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.app.ActionBar.setElevation(float)' on a null object reference

at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)

at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)

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

at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)

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

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

at android.app.ActivityThread.main(ActivityThread.java:6077)

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

at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)

at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.app.ActionBar.setElevation(float)' on a null object reference

at imooc.com.smartbutler.MainActivity.onCreate(MainActivity.java:43)

at android.app.Activity.performCreate(Activity.java:6662)

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

at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2599)