我一直坚持这一点,检查了官方指导等。任何教程/从 ActionBar 更改为 ActionBarCompat 的步骤是什么(对于旧版本的工具栏和支持?我已经导入了 appcompat-v7:21.0.+,试过了
getSupportActionBar();
和
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar_actionbar);
setSupportActionBar(toolbar);
在样式中将主题更改为 appcompat 主题...有什么常见的错误要注意或想法吗?
不断收到这种错误:
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.battery.plusfree/com.battery.plusfree.MainCollectionActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2212)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2271)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1205)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5146)
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:732)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:566)
at de.robv.android.xposed.XposedBridge.main(XposedBridge.java:132)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.battery.plusfree.MainCollectionActivity.onCreate(MainCollectionActivity.java:133)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2169)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2271)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1205)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5146)
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:732)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:566)
at de.robv.android.xposed.XposedBridge.main(XposedBridge.java:132)
at dalvik.system.NativeStart.main(Native Method)