Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

https://github.com/BeppiMenozzi/ArcPageIndicator

Android Page Indicator for ViewPager with original animations. It uses an ellipse to dispose indication spots, and can draw a hand, like in old elevators.
https://github.com/BeppiMenozzi/ArcPageIndicator

android android-library android-ui animation animations arc clock ellipse graphics indicator indicators material-design material-ui needle viewpager viewpager-indicator viewpagerindicator viewpagers

Last synced: 1 day ago
JSON representation

Android Page Indicator for ViewPager with original animations. It uses an ellipse to dispose indication spots, and can draw a hand, like in old elevators.

Lists

README 

        
# ArcPageIndicator

Bored of the usual small points or stressed by the space occupied by a tab bar?


Try this elevator-like elegant and original page indicator!

A fully customizable super-easy Page Indicator, with stunning animations and very original and discreet graphics, for Android. Needs a very small screen, perfect when many pages need to be shown and reached in a small time.











- [x] Out-of-the-box working indicator

- [x] Fully customizable and styleable

- [x] Can be programmatically controlled

- [x] Includes rather complex ellipses calculations :-)






An old elevator that inspired this project.



### Setup (Gradle)

In your project's build.gradle file:



    allprojects {

        repositories {

            ...

            maven { url "https://jitpack.io" }

            ...

        }

    }

    

In your Application's or Module's build.gradle file:



    dependencies {

        ...

        compile 'com.github.BeppiMenozzi:ArcPageIndicator:1.0.2'

        ...

    }

    

### Minimal usage

Layout for bottom 180° ellipse:



    ...

    xmlns:app="http://schemas.android.com/apk/res-auto"

    ...

    



Layout for upper-left 90° ellipse:



    ...

    xmlns:app="http://schemas.android.com/apk/res-auto"

    ...

    



### Attributes description

List of attributes with description:



General

apiViewPagerThe ViewPager associated to the Indicator

Arc appearance

apiArcOrientationOrientation of the "belly" of the arc. This parameter also affects if the arc will be 90° (corner arc) or 180° (edge arc)

Spot appearance

apiSpotsColorColor of the spots

apiSelectedSpotColorColor of the selected spot

apiSpotsRadiusSize of the spots

apiSpotsShapeShape of the spots: Circle, RoundedSquare or Square

Spots distribution and movement

apiIntervalMeasureHow spots are distributed on the circumference: constant angle or constant arc length. With constant angle, the spots will not be distributed evenly, because of ellipse's eccentricity. Normally constant arc length is used: being a non-finite math problem, here an approximation function is used, as explained later on.

apiInvertDirectionIf spots will be selected in inverted direction

apiAnimationTypeSee below to detailed explanation of animation types

Hand appearance

apiHandEnabledIf hand is drawn

apiHandColorHand's color

apiHandWidthHand's width

apiHandRelativeLengthHand's relative length starting from center to edges (1 = full length)



### Animation types

List of animation types:



NametoBottomRighttoUpNotes

Color
Color cross-fade


Slide
Simple movement


Pinch
Simple movement
with size reduction


Bump
Simple movement
with size growth.
Might need additional padding



Rotate
Inverted movement of all spots


Rotate Pinch
Inverted movement of all spots
with size reduction


Cover
Spots are filled from inside


Fill
Spots are empty and filled from inside


Surround
Simple movement of a circle
surrounding smaller spots


Necklace
Inverted movement of all spots,
with center spot biggest
and lateral spots smaller


Necklace 2
Inverted movement of all spots,
with selected spot biggest
and farthest spot smallest



Example of hand

Example of rounded squared spots



### New in 1.0.2

* Fixed a crash when the ViewPager was not found

* Added setViewPager(), to attach the Indicator to dynamically created viewpagers, by referring the Object and not the id reference number



### Some maths

This question I made helped me solve the

ellipse's problem. Indeed, finding arcs of constant length on a known ellipse is a problem with a non-finite solution, that needs integrals to be calculated. There were at least 5 approaches to solve this problem with acceptable performance:



* find the points recursively, by iteratively reducing the error until it's close enough to zero. Pros: easy to do. Cons: adds a indetermined (although very small) time to the drawing process

* create a big table of sampled data and storing them to provide a database of pre-calculated solutions. Pros: fastest. Cons: can't work for *any* number of elements

* distribute the points on the radius and project them on the circumference. Pros: very fast. Cons: error still pretty large

* use an approximated function. Pros: fast and good enough. Cons: never perfect

* calculate the elliptic integrals. Pros: perfect. Cons: very very very heavy on performance



I chose to find a good approximated function and that is what you can find inside the code, it's fast enough and the error is near to invisibility. In case you need more performance, you can remove the e6 part of the formula and have a slightly bigger error.



The formula used is the one of the referenced question, and thanks very much to its author, Ng Chung Tak that is both the author of the answer, and the author of the formula itself.



Author

-------

* Beppi Menozzi

* Ng Chung Tak formula's author



License

-------

    The MIT License (MIT)



    Copyright (c) 2016 Beppi Menozzi



    Permission is hereby granted, free of charge, to any person obtaining a copy

    of this software and associated documentation files (the "Software"), to deal

    in the Software without restriction, including without limitation the rights

    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

    copies of the Software, and to permit persons to whom the Software is

    furnished to do so, subject to the following conditions:



    The above copyright notice and this permission notice shall be included in all

    copies or substantial portions of the Software.



    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

    SOFTWARE.