{"id":292,"date":"2017-03-30T10:02:12","date_gmt":"2017-03-30T10:02:12","guid":{"rendered":"http:\/\/abhiandroid.com\/materialdesign\/?page_id=292"},"modified":"2019-06-14T12:35:24","modified_gmt":"2019-06-14T12:35:24","slug":"recyclerview","status":"publish","type":"page","link":"https:\/\/abhiandroid.com\/materialdesign\/recyclerview","title":{"rendered":"RecyclerView Tutorial With Example In Android Studio"},"content":{"rendered":"

In Android, RecyclerView is an advanced and flexible version of ListView and GridView. It is a container used for\u00a0displaying large amount of data sets that can be scrolled very efficiently by maintaining a limited number of views. RecyclerView was\u00a0introduced in Material Design in API level 21 (Android 5.0 i.e Lollipop).<\/p>\n

\"RecyclerViewThis new widget is a big step for displaying data in Material Design because the ListView and GridView are one of the most commonly used UI widget. In RecyclerView android provides a lots of new features which are not present in existing ListView or GridView.<\/p>\n

Important Note:<\/strong><\/span><\/p>\n

In Android, RecyclerView provides an ability to implement the horizontal, vertical and Expandable List. It is mainly used when we have data collections whose elements can change at run time based on user action or any network events. For using this widget we have to specify the Adapter and Layout Manager.<\/p>\n

Basic RecyclerView XML code:<\/span><\/strong><\/p>\n

<?xml version=\"1.0\" encoding=\"utf-8\"?>\r\n<RelativeLayout xmlns:android=\"http:\/\/schemas.android.com\/apk\/res\/android\"\r\n    xmlns:tools=\"http:\/\/schemas.android.com\/tools\"\r\n    android:layout_width=\"match_parent\"\r\n    android:layout_height=\"match_parent\"\r\n    tools:context=\"abhiandroid.com.recyclerviewexample.MainActivity\">\r\n    <android.support.v7.widget.RecyclerView\r\n        android:id=\"@+id\/recyclerView\"\r\n        android:layout_width=\"match_parent\"\r\n        android:layout_height=\"match_parent\" \/>\r\n<\/RelativeLayout>\r\n<\/pre>\n
Gradle Dependency to use RecyclerView:<\/strong><\/span><\/p>\n
The RecyclerView widget is a part of separate library valid for API 7 level or higher. Add the following dependency in your Gradle build file to use recyclerview.<\/p>\n
Gradle Scripts > build.gradle and inside dependencies<\/strong><\/p>\n
dependencies {\r\n...\r\ncompile \"com.android.support:recyclerview-v7:23.0.1\"\r\n}\r\n<\/pre>\n
Need of RecyclerView In Android<\/strong><\/h4>\n
RecyclerView uses a ViewHolder for storing the reference of the view for one entry in the RecyclerView. When we use ListView or GridView for displaying custom items then we create a custom xml file and then use it inside our Adapter. For this we create a CustomAdapter class and then extends our Base or any other Adapter in it. In getView() method of our Adapter we inflate the item layout xml file and then give the reference of every view by using the unique id’s we provide in our xml file . Once finished we pass that view to the ListView, ready to be drawn, but the truth is that ListView and GridView do only half the job of achieving true memory efficiency.<\/p>\n
ListView\/GridView\u00a0recycle the item layout but don’t keep the reference to the layout children, forcing us to call findViewById() for every child of our item layout for every time we call getView(). This issue causes the scrolling or non responsive problem as it frantically tries to grab references to the view’s we needed.<\/p>\n
With the arrival of RecyclerView everything is changed. RecyclerView still uses Adapter to act as Data source but in this we have to create a ViewHolder to keep the reference of View in memory, so when we need a new view it either creates a new ViewHolder object to inflate the layout and hold those references or it recycles one from existing stack.<\/p>\n
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Components of RecyclerView In Android<\/strong><\/h4>\n
Below we define the mainly used components of a RecyclerView.<\/p>\n
1. Layout Managers:<\/strong><\/span><\/p>\n
In Android a\u00a0RecyclerView needs to have a Layout Manager and an Adapter to be instantiated. Layout Manager is a very new concept introduced in RecyclerView for defining the type of Layout which RecyclerView should use. It Contains the references for all the views that are filled by the data of the entry. We can create a Custom Layout Manager by extending RecyclerView.LayoutManager Class but RecyclerView Provides three types of in-built Layout Managers.<\/p>\n
Linear Layout Manager –<\/strong> It is used for displaying the data items in a horizontal or vertical scrolling List
\nGridLayoutManager –<\/strong> It is used to show the items in grid format
\nStaggeredGridLayoutManager –<\/strong> It is used to show the items in staggered Grid.<\/p>\n
Below\u00a0we explain each type in details:<\/p>\n
Linear Layout Manager<\/strong><\/h4>\n
\"RecyclerView
\nIt is used for displaying the data items in a horizontal or vertical scrolling List. If we need a list(vertical or horizontal) then we need to use LinearLayoutManager with require orientation. In Simple words we can say that we use the LinearLayoutManager for displaying RecyclerView as a ListView.<\/p>\n
Public constructor for LinearLayoutManager<\/strong><\/span><\/p>\n