vlayout

Projects of Tangram

Android

iOS

Project vlayout is a powerful LayoutManager extension for RecyclerView, it provides a group of layouts for RecyclerView. Make it able to handle a complicate situation when grid, list and other layouts in the same recyclerview.

Design

By providing a custom LayoutManager to RecyclerView, VirtualLayout is able to layout child views with different style at single view elegantly. The custom LayoutManager manages a serial of layoutHelpers where each one implements the specific layout logic for a certain position range items. By the way, implementing your custom layoutHelper and provding it to the framework is also supported.

Main Feature

Provide default common layout implementation, decouple the View and Layout. Default layout implementations are:
- LinearLayoutHelper: provide linear layout as LinearLayoutManager.
- GridLayoutHelper: provide grid layout as GridLayoutManager, but with more feature.
- FixLayoutHelper: fix the view at certain position of screen, the view does not scroll with whole page.
- ScrollFixLayoutHelper: fix the view at certain position of screen, but the view does not show until it scrolls to it position.
- FloatLayoutHelper: float the view on top of page, user can drag and drop it.
- ColumnLayoutHelper: perform like GridLayoutHelper but layouts all child views in one line.
- SingleLayoutHelper: contain only one child view.
- OnePlusNLayoutHelper: a custom layout with one child view layouted at left and the others at right, you may not need this.
- StickyLayoutHelper: scroll the view when its position is inside the screen, but fix the view at start or end when its position is outside the screen.
- StaggeredGridLayoutHelper: provide waterfall like layout as StaggeredGridLayoutManager.
LayoutHelpers provided by default can be generally divided into two categories. One is non-fix LayoutHelper such as LinearLayoutHelper, GridLayoutHelper, etc which means the children of these LayoutHelper will be layouted in the flow of parent container and will be scrolled with the container scrolling. While the other is fix LayoutHelper which means the child of these is always fix in parent container.

Usage

Import Library

Please find the latest version in release notes. The newest version has been upload to jcenter and MavenCentral, make sure you have added at least one of these repositories. As follow:

For gradle:

compile ('com.alibaba.android:vlayout:1.2.8@aar') {
	transitive = true
}

Or in maven:
pom.xml

<dependency>
  <groupId>com.alibaba.android</groupId>
  <artifactId>vlayout</artifactId>
  <version>1.2.8</version>
  <type>aar</type>
</dependency>

Initialize LayoutManager

final RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
final VirtualLayoutManager layoutManager = new VirtualLayoutManager(this);

recyclerView.setLayoutManager(layoutManager);

Initialize recycled pool's size

Provide a reasonable recycled pool's size to your recyclerView, since the default value may not meet your situation and cause re-create views when scrolling.

RecyclerView.RecycledViewPool viewPool = new RecyclerView.RecycledViewPool();
recyclerView.setRecycledViewPool(viewPool);
viewPool.setMaxRecycledViews(0, 10);

Attention: the demo code above only modify the recycle pool size of item with type = 0, it you has more than one type in your adapter, you should update recycle pool size for each type.

Set Adapters

You can use DelegateAdapter for as a root adapter to make combination of your own adapters. Just make it extend DelegateAdapter.Adapter and overrides onCreateLayoutHelper method.

DelegateAdapter delegateAdapter = new DelegateAdapter(layoutManager, hasConsistItemType);
recycler.setAdapter(delegateAdapter);

// Then you can set sub- adapters

delegateAdapter.setAdapters(adapters);

// or
CustomAdapter adapter = new CustomAdapter(data, new GridLayoutHelper());
delegateAdapter.addAdapter(adapter);

// call notify change when data changes
adapter.notifyDataSetChanged();

Attention: When hasConsistItemType = true, items with same type value in different sub-adapters share the same type, their view would be reused during scroll. When hasConsistItemType = false, items with same type value in different sub-adapters do not share the same type internally.

The other way to set adapter is extending VirtualLayoutAdapter and implementing it to make deep combination to your business code.

public class MyAdapter extends VirtualLayoutAdapter {
   ......
}

MyAdapter myAdapter = new MyAdapter(layoutManager);

//create layoutHelper list
List<LayoutHelper> helpers = new LinkedList<>();
GridLayoutHelper gridLayoutHelper = new GridLayoutHelper(4);
gridLayoutHelper.setItemCount(25);
helpers.add(gridLayoutHelper);

GridLayoutHelper gridLayoutHelper2 = new GridLayoutHelper(2);
gridLayoutHelper2.setItemCount(25);
helpers.add(gridLayoutHelper2);

//set layoutHelper list to adapter
myAdapter.setLayoutHelpers(helpers);

//set adapter to recyclerView
recycler.setAdapter(myAdapter);

In this way, one thing you should note is that you should call setLayoutHelpers when the data of Adapter changes.

Config proguard

Add following configs in your proguard file if your app is released with proguard.

-keepattributes InnerClasses
-keep class com.alibaba.android.vlayout.ExposeLinearLayoutManagerEx { *; }
-keep class android.support.v7.widget.RecyclerView$LayoutParams { *; }
-keep class android.support.v7.widget.RecyclerView$ViewHolder { *; }
-keep class android.support.v7.widget.ChildHelper { *; }
-keep class android.support.v7.widget.ChildHelper$Bucket { *; }
-keep class android.support.v7.widget.RecyclerView$LayoutManager { *; }

Demo

Demo Project

FAQ

Read FAQ(In Chinese language only now) before submitting issue: FAQ。

Layout Attributes

Each layoutHelper has a few attributes to control its layout style. See this to read more.

Contributing

Before you open an issue or create a pull request, please read Contributing Guide first.

LICENSE

Vlayout is available under the MIT license.

bingcoding/vlayout