Android Basics (11)

List-View

• List-View
  • Brief introduction
  • Body
  • Extended Reading

Target group: Android Beginner without foundation
Knowledge Points: The use of Recyclerview
Goal: Use Recyclerview to display list data in a page

Brief introduction

• Recyclerview Layout-related instructions

Body

1. Open the Activity_main.xml file and modify its internal code to resemble the following

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent">    <android.support.v7.widget.RecyclerView        android:id="@+id/recyclerView"        android:layout_width="fill_parent"        android:layout_height="fill_parent" /></RelativeLayout>

• There is a Recyclerview control inside the page, and the next code expands around it

2. Create a new layout file named Item_card.xml, and the internal code is as follows

<linearlayout xmlns:android="Http://schemas.android.com/apk/res/android"  Xmlns:card_view="Http://schemas.android.com/apk/res-auto"android:layout_width="Fill _parent "android:layout_height=" Fill_parent ">                <!--a CardView control with TextView--    <android.support.v7.widget.cardview  android:id  =" @+id/card_view " android:layout_gravity  = "center"  android:layout_width  = "200DP"  android:layout_height  = "200DP"  card_view:cardcornerradius  =" 4DP ";         <TextViewandroid:id="@+id/info_text"android:layout_width="Match _parent "android:layout_height=" match_parent " />                                        </android.support.v7.widget.CardView></linearlayout>

• The layout style that corresponds to each child item

• A new control CardView is used here, go to Build.gradle to add a new code reference, as shown below

dependencies {    compile fileTree(dir‘libs‘, include: [‘*.jar‘])    ‘com.android.support:appcompat-v7:21.0.3‘    ‘com.android.support:cardview-v7:21.0.+‘}

3.Recyclerview is only responsible for UI display and data set processing , in order to specify the specific display of each unit view, we need to specify a layout manager for Recyclerview, the code is as follows

  @Override  protected  void  oncreate  (        Bundle savedinstancestate) {super . OnCreate (savedinstancestate);        Setcontentview (R.layout.activity_main);        Recyclerview Mrecyclerview = (recyclerview) Findviewbyid (R.id.recyclerview); //when the size of each child view does not change in the layout, this sentence can be called to improve performance  Mrecyclerview.sethasfixedsize (true );        //specifies a layout manager  of type Recyclerview for Linearlayoutmanager Linearlayoutmanager Mlayoutmanager = new  linearlayoutmanager (this );     Mrecyclerview.setlayoutmanager (Mlayoutmanager); }

• Linearlayoutmanager is the simplest layout manager, which is the management of linear layouts

• Linearlayoutmanager have both horizontal and vertical orientations

Extended Reading

1. Staggered-Position web format layout Manager
2. CardView's API description

Android Basics (11)