Is it possible to do a simple image view parallax

问题:

Hello lets say I have a layout which contains the following

    <ScrollView
        android:id="@+id/scroll"
        android:layout_below="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@+id/button">

        <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <ImageView
            android:id="@+id/image"
            android:layout_width="match_parent"
            android:layout_height="240dp"
            android:scaleType="centerCrop"
            android:src="@drawable/android" />
        <View android:id="@+id/anchor"
            android:layout_width="match_parent"
            android:layout_height="240dp" />
        <TextView
            android:id="@+id/body"
            android:layout_below="@+id/anchor"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@android:color/white"
            android:textColor="@android:color/black"
            android:paddingBottom="@dimen/activity_vertical_margin"
            android:paddingLeft="@dimen/activity_horizontal_margin"
            android:paddingRight="@dimen/activity_horizontal_margin"
            android:paddingTop="@dimen/activity_vertical_margin"
            android:text="@string/sample" />
    </RelativeLayout>

    </ScrollView>

is it possible to use coordinator layout to make the image view move with half the speed of the scroll view as it scrolls up or down.

回答1:

Probably not an intended use of CoordinatorLayout, but I believe I achieved your intended effect by doing the following:

<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"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">

<android.support.design.widget.AppBarLayout
    android:id="@+id/appbar"
    android:layout_width="match_parent"
    android:layout_height="300px"
    android:fitsSystemWindows="true"
    android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

    <android.support.design.widget.CollapsingToolbarLayout
        android:id="@+id/collapsing_toolbar"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true"
        app:layout_scrollFlags="scroll|exitUntilCollapsed">

        <ImageView
            android:id="@+id/backdrop"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:paddingTop="?attr/actionBarSize"
            android:fitsSystemWindows="true"
            android:scaleType="centerCrop"
            app:layout_collapseMode="parallax"/>

        <android.support.v7.widget.Toolbar
            android:id="@+id/myToolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:layout_collapseMode="pin"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light">
            <TextView android:id="@+id/textViewTitle"  
                android:layout_width="match_parent"
                android:layout_height="wrap_content"/>
            </android.support.v7.widget.Toolbar>
    </android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>

<android.support.v4.widget.NestedScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">

    <!-- my content that scrolls over the backdrop image -->

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

回答2:

Few libraries that can help you with Parallax:

• ParallaxEveryWhere (Demo app on playstore):Example

• ParallaxScrollView

• nirhart's parallaxScroll
• AKparallax

Particularly ParallaxEveryWhere is impressive. But you should adopt on bases of your usage.