java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead.

[Jay-YaoJie]

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.xc.app/droidninja.filepicker.FilePickerActivity}: java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead. at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2200) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2249) at android.app.ActivityThread.access$800(ActivityThread.java:141) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1212) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:136) at android.app.ActivityThread.main(ActivityThread.java:5113) 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:793) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609) at dalvik.system.NativeStart.main(Native Method) Caused by: java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead. at android.support.v7.app.AppCompatDelegateImpl.setSupportActionBar(AppCompatDelegateImpl.java:345) at android.support.v7.app.AppCompatActivity.setSupportActionBar(AppCompatActivity.java:130) at droidninja.filepicker.BaseFilePickerActivity.onCreate(BaseFilePickerActivity.java:26) at droidninja.filepicker.FilePickerActivity.onCreate(FilePickerActivity.java:26) at android.app.Activity.performCreate(Activity.java:5245) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) at cn.jiguang.a.a.c.a.a.d.callActivityOnCreate(Unknown Source) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2164) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2249)  at android.app.ActivityThread.access$800(ActivityThread.java:141)  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1212)  at android.os.Handler.dispatchMessage(Handler.java:102)  at android.os.Looper.loop(Looper.java:136)  at android.app.ActivityThread.main(ActivityThread.java:5113)  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:793)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609)  at dalvik.system.NativeStart.main(Native Method)  09-30 16:20:58.268 30940-30940/com.xc.app I/Process: Sending signal. PID: 30940 SIG: 9 09-30 16:20:58.268 949-1380/? W/ActivityManager: Force finishing activity com.xc.app/droidninja.filepicker.FilePickerActivity 09-30 16:20:58.268 949-1380/? W/ActivityManager: Force finishing activity com.xc.app/.ui.activity.UpLoadStoreResActivity

[matteogabella]

just add in AppTheme, in you styles.xml

    <item name="windowActionBar">true</item>
    <item name="windowNoTitle">true</item>