Dewey

Introduction

Dewey is an android widget designed to hold an unlimited number of tabs, making it ideal for allowing pagination through a list, hence it being named after The Dewey Decimal System. Most other implementations of this style of widget don't recycle their child views, leading to performance issues even on modern devices for large data-sets.

A demo application included with this repository shows an example of this functionality;

Installing

1. Add the repository;

   repositories {
    maven {
     url 'https://jitpack.io'
    }
   }

2. Add the dependency;

   dependencies {
    compile 'com.TippingCanoe.Dewey:library:0.0.1'
   }

Creating layout

The com.tippingcanoe.dewey.Dewey view is the core of this project. Simply add one to your view;

<com.tippingcanoe.dewey.Dewey
 android:layout_width="match_parent"
 android:layout_height="wrap_content" />

You can also customize certain properties of the view, more on what those properties control later;

<RelativeLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:custom="http://schemas.android.com/apk/res-auto"
 android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.tippingcanoe.dewey.Dewey
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     custom:stripColor="@color/accent_material_light"
        custom:animationDurationMs="@integer/animation_duration_ms"
        custom:cloakColor="@color/background_floating_material_dark"
        custom:minCloakPercentage="@integer/min_cloak_percentage"
        custom:stripHeight="@dimen/strip_height" />

</RelativeLayout>

Setting up views

Once you've got your layout setup, you'll need to find your view;

Dewey dewey = (Dewey) findViewById(R.id.dewey);

Dewey extends android.support.v7.widget.RecyclerView, so you'll need to create and add a new RecyclerView.Adapter. This works the same as any other implementation, so take a look at the example code in the :app module of this repository or familiarize yourself with Google's Documentation;

dewey.setAdapter(new MyAdapter());

public class MyAdapter extends RecyclerView.Adapter<MyViewHolder> {
 ...
}

public class MyViewHolder extends RecyclerView.ViewHolder {
 ...
}

You can also setup a listener on the view to receive notifications when a new page is selected;

dewey.setOnFocusedPositionChangedListener(new Dewey.OnFocusedPositionChangedListener() {
 @Override
 public void onFocusedPositionChanged ( int previousFocusedPosition, int newFocusedPosition ) {
  ...
 }
});

Customizing

This library provides plenty of customization touch points to ensure the effect is right for your application;

• cloakColor
  • The first and last "page" of the list are always visible to the user, pinned at the beginning and end of the list. The "cloak" is rendered behind them to ensure they are legible.
• minCloakPercentage
  • Sets the minimum amount, between 0 and 100 percent, of the background "cloak"s transparency. From this point, it is calculated on a curve.
• stripHeight
  • Sets the height dimension for the current page indication strip.
• stripColor
  • Sets the colour for the current page indication strip.
• animationDurationMs
  • Sets the speed of the animation for changing pages, in milliseconds.

Contact

Love it? Hate it? Want to make changes to it? Contact me at @iainconnor or iainconnor@gmail.com.