A ViewPager animator that animates Views within pages as well as views across pages.
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README.md

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Sparkle Motion

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Sparkle Motion is a ViewPager animator that animates Views within pages as well as views across pages.

Sparkle Motion

Overview

Sparkle Motion is an animation library dedicated to animate ViewPager elements.

Sparkle Motion supports cross page animations, meaning that you can animate Views outside of ViewPager based on the ViewPager's scrolling, thus achieve cross-page animations. This is done through Decor and SparkleViewPagerLayout. By using them, you can specify Views that you want to animate through multiple pages, and the animations on them will be controlled by the OnPageChangeListener.

Sparkle Motion can also animate Views within ViewPager. It uses ViewPager's PageTransformer to control the progress of the animations, so that the animated Views respond to the scrolling, and thus provides an interactive effect.

Usage

Add Sparkle Motion as dependency via Gradle:

compile 'com.ifttt:sparklemotion:1.0.1'

JazzHands and RazzleDazzle

Looking for libraries to build awesome keyframe animations like Sparkle Motion on iOS? Check out JazzHands and RazzleDazzle.

Cross Page Animations

One of the main features that Sparkle Motion offers is running cross page animations with ViewPager. Animations that require to be animated across different pages needs to be run on Decor, which is an element within SparkleViewPagerLayout.

SparkleViewPagerLayout

SparkleViewPagerLayout is a custom FrameLayout that controls Decor objects to play ViewPager cross page animations. To use this layout with SparkleMotion, you need to supply a ViewPager as a child View. This can be done in layout xml or through addView() method.

Note that you should only have one ViewPager child in this layout.

Example for layout xml,

<com.ifttt.sparklemotion.SparkleViewPagerLayout
        android:id="@+id/view_pager_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <android.support.v4.view.ViewPager
            android:id="@+id/view_pager"
            android:layout_width="match_parent"
            android:layout_height="match_parent"/>

</com.ifttt.sparklemotion.SparkleViewPagerLayout>

Decor

A Decor is a component that holds information about a View that should be controlled by the ViewPager and animates when there is at least one Animation associated.

Important attributes of a Decor:

  • contentView: required element for a Decor, a View that should be used to animate across pages.
  • page: starting from which page the Decor should be presented, and on which page the Decor should be hidden. Controlled by Page object.
  • layoutBehindViewPage: whether or not the Decor should be drawn behind the ViewPager within SparkleViewPagerLayout.
  • slideOut: if used, this Decor will be scrolled along with the ViewPager at the end of its range, instead of being hidden by the layout.

To build a Decor, simply use Decor.Builder.

To assign an animation to Decor, in your Activity, for example,

SparkleViewPagerLayout viewPagerLayout = (SparkleViewPagerLayout) findViewById(/* view_pager_id */);
View contentView = new View(this);

// Both the animation and the Decor exists in the first page.
Page firstPage = Page.singlePage(0);
AlphaAnimation alphaAnimation = new AlphaAnimation(firstPage, 0f, 1f);

Decor decor = new Decor.Builder(contentView)
		 .setPage(firstPage)
		 .build();
		 
SparkleMotion.with(viewPagerLayout)
		 .animate(alphaAnimation)
		 .on(decor);

a Decor will then be added to your SparkleViewPagerLayout, which will run the alphaAnimation during ViewPager scrolling.

A Decor.Builder supports following methods,

Decor decor = new Decor.Builder(View) // Content View of the Decor, must not be null

                .setPage(Page)        // Set the Page attribute for this Decor, default to Page.allPages()
                                
                .behindViewPage()     // Set to draw the content View behind the ViewPager
                
                .slideIn()		      // Set to scroll with ViewPager before the first visible page
                
                .slideOut()           // Set to scroll with ViewPager after last visible page
                
                .withLayer()          // Set to use hardware layer when animating this Decor's content View
                
                .build();
			

ViewPager Animations

Sparkle Motion can also run animations on Views within the ViewPager. To add an animation to a View using Sparkle Motion,

ViewPager viewPager = (ViewPager) findViewById(/* view_pager_id */);
AlphaAnimation alphaAnimation = new AlphaAnimation(Page.allPages(), 0f, 1f);
SparkleMotion.with(viewPager)
		 .animate(mAnimation)
		 .on(R.id.view_id)

In the code snippet above, AlphaAnimation is a class that Sparkle Motion contains for running alpha animation on View (See here for details about supported animations). R.id.view_id is the id of the View inside the page that is going to run the animation, you can also use Animation.FULL_PAGE instead of specific View id to apply this animation to the page View itself.

Animation

Animation is an abstract class for storing animation information for Sparkle Motion. To animate a View through Sparkle Motion, you need to assign an Animation instance to a View, so that Sparkle Motion will know how to animation it.

To create an instance of Animation, you need to pass an instance of Page, and the animation will be run through the pages that you assign to.

Supported animations

Sparkle Motion provides several animation classes that can be used directly to animate View properties.

  • Basic View animations:
    • AlphaAnimation: animates the alpha property of the target Views.
    • RotationAnimation: animates the rotation property of the target Views.
    • ScaleAnimation: animates the scale X and/or Y properties of the target Views.
    • TranslationAnimation: animates the translation X and/or Y properties of the target Views.
  • PathAnimation: animates the target Views' translation X and Y so that it follows a path.
  • ParallaxAnimation: animates the target Views' translation X to the opposite direction of the ViewPager scrolling to achieve a parallax effect.

Custom animations

Sparkle Motion also supports customized animations through extending Animation class. There are 3 methods in Animation class that you might be interested:

  • onAnimate(View v, float offset, float offsetInPixel): main method to override to provide customized animation.
  • onAnimateOffScreenLeft(View v, float offset, float offsetInPixel) (optional): this method will be called when offset < -1, which means the page is currently to the left of the screen.
  • onAnimateOffScreenRight(View v, float offset, float offsetInPixel)(optional): this method will be called when offset > 1, which means the page is currently to the right of the screen.

There are differences between running an Animation on a View within ViewPager an on a Decor:

  • For View animations, the offset value is ranged within [-1, 1], offsetInPixel is the negative value of the scrolling offset of the entire page in pixel.
  • For Decor animations, the offset value is ranged within [0, 1], offsetInPixel will always be 0 as they are not part of the ViewPager and are not scrolled along with the ViewPager by default.
  • onAnimateOffScreenLeft and onAnimateOffScreenRight will be called on for animations running on Views inside ViewPager.

Page

Both Animation and Decor have an attribute that ties to the index of the pages, controlling whether or not the animation should run or the Decor should be shown. In Sparkle Motion we use a class Page to control such attribute.

Page provides 3 methods to return a Page object that controls the page attribute:

  • allPages(): indicates the animation should be run for all pages, or the Decor should be shown across all pages.
  • singlePage(int): indicates the animation should be run on a specific page or the Decor should be shown on a specific page.
  • pageRange(int, int): indicates the animation should be run on a range of pages or the Decor should be shown on a range of pages.

For Decor, a page stands for the period where the page is still visible. For example, if a Decor has Page.singlePage(0), the Decor is visible from the point where the page at index 0 is the current page, till the page at index 1 is the current page.

For animations that will run on multiple pages, the progress of the animation will be evenly split across the pages. For ViewPager View animation, it might not be necessary to run such animation, as the View will be invisible once the page is scrolled off-screen.

Sparkle Motion and PageTransformer

You can use Sparkle Motion instead of PageTransformer to play regular ViewPager page animations. One example is the ZoomOutAnimation, which takes the PageTransformer implementation and implement as an Animation class. Simply apply this to the entire page to achieve the same effect.

If you need to have a custom PageTransformer for your ViewPager while using Sparkle Motion, you need to call SparkleMotionCompat.setPageTransformer(ViewPager, boolean, PageTransformer) to set your PageTransformer.

Contributors

Contributing

  1. Fork it ( https://github.com/[my-github-username]/SparkleMotion/fork )
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create a new Pull Request

License

Sparkle Motion is available under the MIT license. See the LICENSE file for more info.

Copyright 2015 IFTTT Inc.