Floating action button not displaying over recycle

问题:

I am trying to get FAB over recyclerview which in my case will cover the whole screen. The FAB wont display even recyclerview is empty. Following is my xml code.

<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/drawer_layout"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    tools:context="com.technistan.ledger.CreateLedger"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <include
            android:id="@+id/tool_bar"
            layout="@layout/tool_bar"
            ></include>


        <FrameLayout
            android:orientation="vertical"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <android.support.v7.widget.RecyclerView
                android:paddingLeft="2dp"
                android:paddingRight="2dp"
                android:id="@+id/recyclerView"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"

                />


            <android.support.design.widget.FloatingActionButton
                android:id="@+id/myFAB"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="bottom|end"
                android:layout_margin="20dp"
                app:elevation="4dp" />


        </FrameLayout>

    </LinearLayout>


    <fragment
        android:id="@+id/fragment_navigation_drawer"
        android:layout_width="280dp"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:layout="@layout/fragment_navigation_drawer"
        android:name="com.technistan.ledger.NavigationDrawerFragment"
        tools:layout="@layout/fragment_navigation_drawer" />


    </android.support.v4.widget.DrawerLayout>

The preview is showing floating button fine like in the below snap; https://www.dropbox.com/s/18u5pt5v6kkkibj/Screen%20Shot%202015-09-13%20at%201.19.20%20PM.png?dl=0

But when i run the app there is no FAB displayed. I had tried many combinations but couldn't succeed. I tried this over listview without navigationdrawer (simple activity and it was working there i.e. displayed over listview).

Any help will be appreciated guys. Thanks

[EDIT:] I think the problem is because of the parent layout i.e. android.support.v4.widget.DrawerLayout, I had copy pasted the code from start of to its end to another empty activity and it shows the floating button over it there. But still unable to figure it out how to resolve this issue, I nee to display floating action button inside the Drawerlayout.

回答1:

Try it like this :

Remove all layouts.

Keep only one parent, that's CoordinatorLayout.

Inside CoordinatorLayout, put both your RecyclerView and FloatingActionButton.

CoordinatorLayout should auto arrange your toolbar, recycler and fab, since is programmed to handle the design support library components.

Here's an example. You can use RecyclerView in place of the FrameLayout (which dynamically loads fragments at runtime). I generally use RecyclerView in another Fragment and load the fragment in here at runtime. This keeps the xml files clean.

<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">

<android.support.design.widget.CoordinatorLayout
    android:id="@+id/layout_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:elevation="0dp">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
            app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" />

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


    <!-- Main layout for fragment placing -->
    <FrameLayout
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" >

    </FrameLayout>

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fabBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_action"
        android:layout_gravity="bottom|right"
        android:layout_marginBottom="@dimen/fab_margin_bottom"
        android:layout_marginRight="@dimen/fab_margin_right"
        app:fab_colorNormal="@color/pink"
        app:fab_colorPressed="@color/pink_pressed"
        app:borderWidth = "0dp" />


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

<!-- Nav drawer -->
<android.support.design.widget.NavigationView
    android:id="@+id/navigation"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:layout_gravity="start"
    app:headerLayout="@layout/nav_header"
    app:itemIconTint="@color/pink_pressed"
    app:itemTextColor="@color/primary_text"
    app:menu="@menu/nav_menu" />

</android.support.v4.widget.DrawerLayout>

回答2:

Try using FrameLayout instead of LinearLayout as your root layout. That worked for me.

回答3:

You could use the LinearLayout, that seems not be the problem.

I'm pretty sure your solution will be fixed by moving the RecyclerView under the FAB button.

In other words, in the XML layout, move the FAB button block of code, over the RecyclerView block of code.

An example:

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/myFAB"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="20dp"
        app:elevation="4dp" />

    <android.support.v7.widget.RecyclerView
        android:paddingLeft="2dp"
        android:paddingRight="2dp"
        android:id="@+id/recyclerView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        />

Order matters due to the way android system draws it's views.

You might see other artifacts but the FAB button should at least be visible now.

回答4:

I had just created a new activity and copy pasted the whole code there and its working fine there. I still dont know the issue that what was wrong. But it worked for me this way. I had compared line by line code in two activities and they are same. Its just that floating action button is displaying in new activity and not in the old.

any ways thanks for all the help from community who tried.

回答5:

It should be because of androidmanifest.xml. When you add a new activity it is automatically added in androidmanifest.xml with right permission.