始终将浮动操作按钮置于顶部

Question

我有Mainactivity，一个片段和BlogRecycleadapter用Blog帖子填充片段。

Inside Mainactivity，我有浮动动作按钮。但是，当我运行应用程序时，它隐藏在blogRecycleadapter的项目下面。

如何将浮动操作按钮始终放在顶部？

我的主要活动布局是

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<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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=".Main2Activity">

    <android.support.v7.widget.Toolbar
        android:id="@+id/main_toolbar"
        app:titleTextAppearance="@style/Toolbar.TitleText"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/colorPrimary"
        android:theme="@style/ThemeOverlay.AppCompat.Light"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"></android.support.v7.widget.Toolbar>



    <android.support.design.widget.BottomNavigationView
        android:id="@+id/mainBottomNav"
        android:background="@color/colorblog"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:menu="@menu/bottom_menu"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/add_post_btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="16dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        android:clickable="true"
        android:layout_gravity="bottom|end"
        android:focusable="true"
        android:visibility="visible"
        app:elevation="6dp"
        app:layout_constraintBottom_toTopOf="@+id/mainBottomNav"
        app:layout_constraintEnd_toEndOf="parent"
        app:srcCompat="@mipmap/action_add" />


    <FrameLayout
        android:id="@+id/main_container"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintBottom_toTopOf="@+id/mainBottomNav"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/main_toolbar"
        app:layout_constraintVertical_bias="1.0">

    </FrameLayout>

</android.support.constraint.ConstraintLayout>

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我的片段布局是，

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<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".HomeFragment">

    <!-- TODO: Update blank fragment layout -->

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

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我的blogRecycleadapter类是

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<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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="wrap_content">

    <android.support.v7.widget.CardView
        android:id="@+id/main_blog_post"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:padding="20dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <android.support.constraint.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <ImageView
                android:id="@+id/blog_like_btn"
                android:layout_width="32dp"
                android:layout_height="32dp"
                android:layout_marginBottom="8dp"
                android:layout_marginStart="16dp"
                android:layout_marginLeft="16dp"
                android:layout_marginTop="8dp"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintStart_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@+id/blog_desc"
                app:srcCompat="@mipmap/action_like_gray" />

            <de.hdodenhof.circleimageview.CircleImageView
                android:id="@+id/blog_user_image"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginLeft="8dp"
                android:layout_marginStart="16dp"
                android:layout_marginTop="16dp"
                android:src="@drawable/profile_placeholder"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent" />

            <TextView
                android:id="@+id/blog_user_name"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginLeft="8dp"
                android:layout_marginStart="8dp"
                android:layout_marginTop="16dp"
                android:text="Username"
                android:textStyle="bold"
                app:layout_constraintStart_toEndOf="@+id/blog_user_image"
                app:layout_constraintTop_toTopOf="parent" />

            <TextView
                android:id="@+id/blog_date"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginLeft="8dp"
                android:layout_marginStart="8dp"
                android:text="Blog Post Date"
                app:layout_constraintStart_toEndOf="@+id/blog_user_image"
                app:layout_constraintTop_toBottomOf="@+id/blog_user_name" />

            <ImageView
                android:id="@+id/blog_image"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_marginTop="16dp"
                android:scaleType="centerCrop"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@+id/blog_user_image"
                app:srcCompat="@drawable/image_placeholder" />

            <TextView
                android:id="@+id/blog_desc"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_marginEnd="16dp"
                android:layout_marginStart="16dp"
                android:layout_marginTop="16dp"
                android:text="Lorem ipsum dolor sit amet, soluta regione urbanitas vis in, qui elit populo ut. "
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@+id/blog_image" />

            <TextView
                android:id="@+id/blog_like_count"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginBottom="8dp"
                android:layout_marginLeft="8dp"
                android:layout_marginStart="8dp"
                android:layout_marginTop="8dp"
                android:text="0 Likes"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintStart_toEndOf="@+id/blog_like_btn"
                app:layout_constraintTop_toBottomOf="@+id/blog_desc" />




        </android.support.constraint.ConstraintLayout>
    </android.support.v7.widget.CardView>

</android.support.constraint.ConstraintLayout>

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Answer 1

您可以增加高程，直到它在底部导航上可见。 提升高于8dp并尝试。

<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">

<android.support.v7.widget.Toolbar
    android:id="@+id/main_toolbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentStart="true"
    android:layout_alignParentTop="true"
    android:background="@color/colorPrimary"
    android:theme="@style/ThemeOverlay.AppCompat.Light" />


<android.support.design.widget.BottomNavigationView
    android:id="@+id/mainBottomNav"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    app:menu="@menu/bottom_bar_menu" />

<android.support.design.widget.FloatingActionButton
    android:id="@+id/add_post_btn"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/mainBottomNav"
    android:layout_alignParentRight="true"
    android:layout_marginRight="20dp"
    android:clickable="true"
    android:focusable="true"
    android:visibility="visible"
    app:elevation="10dp" />


<FrameLayout
    android:id="@+id/main_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_above="@+id/mainBottomNav"
    android:layout_below="@+id/main_toolbar">

</FrameLayout>

</RelativeLayout>

只需在主容器中加载你的片段..希望这个工作

Answer 2

试试这个主要活动布局：

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<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form id="ajaxForm" onsubmit="return false" >
  <input id="firstname" class="firstname" name="firstname" type="text" />
  <input type="text" name="date" class="date" id="date" />
  
  <input type="submit" value="submit">
</form>

<div id="ajaxData"></div>

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希望这有帮助。

Answer 3

尝试这样（反转FramLayout和FloatingActionButton的位置）：

   import { Component, OnInit, Input } from '@angular/core';
   @Input() data: any;


   constructor(dataService: DataService)
   {
     console.log(this.data); // undefined
   }


   ngOnInit()
   {
     console.log(this.data) // works here
   }