浮动操作按钮不在右下角

Question

My FAB for some reason won't go to the bottom right corner of the screen as usual. I'm inside a fragment and that fragment is a coordinator layout (I don't know if this is a good practice or not).

Here is the layout xml code:

<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.gigstudios.polls.fragment.MyPollsFragment">

    <LinearLayout
        android:id="@+id/linear_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

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

    </LinearLayout>

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin"
        android:src="@drawable/ic_add_white_36dp"
        app:fabSize="normal"
        app:layout_anchor="@id/linear_layout"
        app:layout_anchorGravity="bottom|right|end" />

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

And for some reason the FAB ends up in the top right instead of the bottom right. Does anyone know what I'm doing wrong?

Btw the xml preview has always shown the fab button in the bottom right corner but when I run it on my phone it's in the top right instead.

Edit: Here's my main_activity xml to show where I'm putting the fragment (The "container" FrameLayout).

<android.support.design.widget.CoordinatorLayout 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"
    android:background="@color/colorGrey">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

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

    <android.support.v4.widget.NestedScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/colorGrey"
        android:layout_marginTop="?attr/actionBarSize">

        <FrameLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:id="@+id/container">
        </FrameLayout>
    </android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>

Answer 1

The issue is coming due to android.support.v4.widget.NestedScrollView add one more field android:fillViewport="true". Issue was coming as your android:fillViewport="true". Issue was coming as your NestedScrollView` was not expanding to match parent or take available space. Working fine tested with my code

<android.support.v4.widget.NestedScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/colorPrimary"
    android:fillViewport="true"
    android:layout_marginTop="?attr/actionBarSize">
</android.support.v4.widget.NestedScrollView>

Answer 2

Remove the lines

app:layout_anchor="@id/linear_layout"
app:layout_anchorGravity="bottom|right|end"

on your FloatingActionButton . They aren't doing anything (since you are anchoring to a view that fills the entire CoordinatorLayout ). This will cause your layout_gravity to be respected and your FloatingActionButton will be placed in the bottom right corner of the CoordinatorLayout .

Answer 3

从浮动操作按钮xml代码中删除android:layout_gravity="bottom|end" ......它会起作用