Question

这里发生了什么？看起来FAB正在贪婪（左侧屏幕截图），然后当我打开调试菜单中的“显示布局边界”时，它会正常工作（右侧屏幕截图）。

activity_main.xml：

  <?xml version="1.0" encoding="utf-8"?>
    <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"
        android:fitsSystemWindows="true"
        tools:context="com.registrationmax.recordbook.MainActivity">

        <android.support.design.widget.AppBarLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/appBar"
            android:theme="@style/AppTheme.AppBarOverlay">

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

        <include layout="@layout/content_main" />

        <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="@android:drawable/ic_input_add"
            android:tint="#ffffff" />
    </android.support.design.widget.CoordinatorLayout>

content_main.xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="com.registrationmax.recordbook.MainActivity"
    tools:showIn="@layout/activity_main">

    <ListView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/experience_listView"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_alignParentTop="true" />
</RelativeLayout>

自定义列表项的布局：

<?xml version="2.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="?android:attr/listPreferredItemHeight"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin">

    <ImageView
        android:id="@+id/experience_list_item_photo"
        android:layout_width="wrap_content"
        android:layout_height="fill_parent"
        android:contentDescription="TODO"
        android:layout_alignParentTop="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true" />

    <TextView
        android:id="@+id/experience_list_item_description"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignWithParentIfMissing="true"
        android:gravity="center_vertical"
        android:text="Description (Line 1)"
        android:textSize="16sp"
        android:layout_marginTop="4dip"
        android:layout_alignParentTop="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true" />

    <TextView
        android:id="@+id/experience_list_item_date"
        android:layout_width="fill_parent"
        android:layout_height="26dip"
        android:ellipsize="marquee"
        android:singleLine="true"
        android:text="Description (Line 2)"
        android:textSize="12sp"
        android:layout_below="@+id/experience_list_item_description"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

</RelativeLayout>

Answer 1

您需要从activity_main.xml布局中删除layout_gravity并使用 layout_anchor和layout_anchorGravity如下所示

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

<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    app:layout_anchor="@id/include_main_layout"
    app:layout_anchorGravity="bottom|end"
    android:src="@android:drawable/ic_input_add"
    android:tint="#ffffff" />

您可以阅读更多相关信息here

浮动操作按钮周围不需要的空格

1 个答案: