Ошибка FloatingActionButton

Question

Я пытаюсь использовать библиотеку FAB (https://github.com/makovkastar/FloatingActionButton), я сделал это, как написано в инструкции, но это не работает. Что я делаю не так? Здесь ошибка, что у меня есть:

> FATAL EXCEPTION: main 
>                  java.lang.RuntimeException: Unable to start activity 
> ComponentInfo{com.myapp/com.myapp.MainActivity}: 
> java.lang.NullPointerException 
>                   at 
> android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 
>                   at 
> android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 
>                   at android.app.ActivityThread.access$600(ActivityThread.java:141) 
>                   at 
> android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 
>                   at android.os.Handler.dispatchMessage(Handler.java:99) 
>                   at android.os.Looper.loop(Looper.java:137) 
>                   at android.app.ActivityThread.main(ActivityThread.java:5041) 
>                   at java.lang.reflect.Method.invokeNative(Native Method) 
>                   at java.lang.reflect.Method.invoke(Method.java:511) 
>                   at 
> com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
>                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
>                   at dalvik.system.NativeStart.main(Native Method) 
>                  Caused by: java.lang.NullPointerException 
>                   at 
> com.myapp.frags.FirstFragment.onCreateView(FirstFragment.java:91) 
>                   at android.app.Fragment.performCreateView(Fragment.java:1695) 
>                   at 
> android.app.FragmentManagerImpl.moveToState(FragmentManager.java:885) 
>                   at 
> android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1057) 
>                   at android.app.BackStackRecord.run(BackStackRecord.java:682) 
>                   at 
> android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1435) 
>                   at android.app.Activity.performStart(Activity.java:5113) 
>                   at 
> android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2153) 
>                   at 
> android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)  
>                   at android.app.ActivityThread.access$600(ActivityThread.java:141)  
>                   at 
> android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)  
>                   at android.os.Handler.dispatchMessage(Handler.java:99)  
>                   at android.os.Looper.loop(Looper.java:137)  
>                   at android.app.ActivityThread.main(ActivityThread.java:5041)  
>                   at java.lang.reflect.Method.invokeNative(Native Method)  
>                   at java.lang.reflect.Method.invoke(Method.java:511)  
>                   at 
> com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)  
>                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)  
>                   at dalvik.system.NativeStart.main(Native Method) 

**My Fragment layout:** 
    <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:id="@+id/first_frg_layout" 
    xmlns:fab="http://schemas.android.com/apk/res-auto" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 

    > 



<RelativeLayout 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:id="@+id/mRelative" 

    xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_alignParentTop="true" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentStart="true" 
    > 
    <android.support.design.widget.CoordinatorLayout 
     android:layout_height="match_parent" 
     android:layout_width="match_parent"> 

     <FrameLayout 
      android:id="@+id/content_frame" 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" > 

      <com.melnykov.fab.FloatingActionButton 
       android:id="@+id/fab" 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:layout_gravity="bottom|right" 
       android:layout_margin="16dp" 
       android:src="@drawable/ic_done" 
       fab:fab_colorNormal="@color/primary" 
       /> 
     </FrameLayout> 


     <android.support.v7.widget.RecyclerView 
      android:id="@+id/my_recycler_view" 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" 

      android:scrollbars="vertical" 
      android:layout_alignParentTop="true" 

      android:layout_alignParentLeft="true" 
      android:layout_alignParentStart="true" /> 

</android.support.design.widget.CoordinatorLayout> 






</RelativeLayout> 

Мой фрагмент кода:

mRecyclerView = (RecyclerView) rootView.findViewById(R.id.my_recycler_view); 
     FloatingActionButton fab = (FloatingActionButton) rootView.findViewById(R.id.fab); 
     fab.attachToRecyclerView(mRecyclerView); 

Answer 1

Почему вы используете библиотеку 3rd партии, когда есть FAB от Google, используя библиотеку поддержки?

гляньте here

Вы можете прикрепить его к ListView или Recycler подобное:

<android.support.design.widget.CoordinatorLayout 
    android:id="@+id/main_content" 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 

      <ListView 
       android:id="@+id/lvToDoList" 
       android:layout_width="match_parent" 
       android:layout_height="match_parent"></ListView> 

      <android.support.design.widget.FloatingActionButton 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:layout_gravity="bottom|right" 
       android:layout_margin="16dp" 
       android:src="@drawable/ic_done" 
       app:layout_anchor="@id/lvToDoList" 
       app:layout_anchorGravity="bottom|right|end" /> 

</android.support.design.widget.CoordinatorLayout> 

Вы можете создать то, что когда-либо behaivior вы хотите для FAB, например:

public class ScrollAwareFABBehavior extends FloatingActionButton.Behavior { 
    // ... 

    @Override 
    public void onNestedScroll(CoordinatorLayout coordinatorLayout, FloatingActionButton child, 
      View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed) { 
     super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, 
       dyUnconsumed); 

     if (dyConsumed > 0 && child.getVisibility() == View.VISIBLE) { 
      child.hide(); 
     } else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) { 
      child.show(); 
     } 
    } 

    // ... 
}