Android Studio教程11-RecycleView的使用

目录

• 1. recyclerview
• 2. 实例

1. recyclerview

1.1. add support library

dependencies {
    implementation 'com.android.support:recyclerview-v7:28.0.0'
}

1.2. 将recyclerview添加到布局

此文件命名为：activity_recycle_demo.xml

<?xml version="1.0" encoding="utf-8"?>
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".recycledemoactivity">

    <linearlayout
        android:id="@+id/layout01"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        >

        <button
            android:id="@+id/linearlayout_recycle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="线性布局"/>

        <button
            android:id="@+id/grid_recycle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:text="网格布局"/>

        <button
            android:id="@+id/staggeredlayout_recycle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="瀑布布局"/>

    </linearlayout>


    <android.support.v7.widget.recyclerview
        android:id="@+id/my_recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    </android.support.v7.widget.recyclerview>

</linearlayout>

1.3. 主actiivty中如何调用recycleview对象

recycledemoactivity.java

package com.haoch95.fristapp;

import android.support.v7.app.appcompatactivity;
import android.os.bundle;
import android.support.v7.widget.defaultitemanimator;
import android.support.v7.widget.divideritemdecoration;
import android.support.v7.widget.gridlayoutmanager;
import android.support.v7.widget.linearlayoutmanager;
import android.support.v7.widget.recyclerview;
import android.support.v7.widget.staggeredgridlayoutmanager;
import android.view.menu;
import android.view.menuitem;
import android.view.view;
import android.widget.button;
import android.widget.textview;
import android.widget.toast;

import java.util.arraylist;
import java.util.list;

public class recycledemoactivity extends appcompatactivity {

    private button linearbt, gridbt, starbt;

    private recyclerview mrecyclerview;
    private recycleadapter mmyadapter;
    private recyclerview.layoutmanager mlayoutmanager;
    private list<string> list;


    @override
    protected void oncreate(bundle savedinstancestate) {
        super.oncreate(savedinstancestate);
        setcontentview(r.layout.activity_recycle_demo);

        linearbt = (button)findviewbyid(r.id.linearlayout_recycle);
        gridbt = (button)findviewbyid(r.id.grid_recycle);
        starbt = (button)findviewbyid(r.id.staggeredlayout_recycle);
        // recyclerview的三部曲 01: 获取recyclerview对象
        mrecyclerview = (recyclerview)findviewbyid(r.id.my_recycler_view);

        initdata();

        linearbt.setonclicklistener(new buttonclicked());
        gridbt.setonclicklistener(new buttonclicked());
        starbt.setonclicklistener(new buttonclicked());




//        // 添加水平分割线
//        mrecyclerview.additemdecoration(new divideritemdecoration(this,divideritemdecoration.vertical));

    }

    private void initdata() {
        list = new arraylist<>();
        for (int i=0;i<20;i++){
            list.add("item" + i);
        }
    }

    class buttonclicked implements view.onclicklistener {
        @override
        public void onclick(view v) {
            switch (v.getid()){
                case r.id.linearlayout_recycle:
                    mlayoutmanager = new linearlayoutmanager(getapplicationcontext());
                    break;
                case r.id.grid_recycle:
                    mlayoutmanager = new gridlayoutmanager(getapplicationcontext(),4);
                    break;
                case r.id.staggeredlayout_recycle:
                    //如果传入 staggeredgridlayoutmanager.vertical则该布局支持纵向滑动，那么前面的 4 则指的是 4列。
                    //如果传入 staggeredgridlayoutmanager.horizontal，则该布局支持横向滑动，那么前面的4 则指的是 4行
                    mlayoutmanager = new staggeredgridlayoutmanager(4,staggeredgridlayoutmanager.vertical);
                    break;
                default:
                    mlayoutmanager = new linearlayoutmanager(getapplicationcontext());
                    break;
            }
            //recyclerview的三部曲 02：设置布局管理器
            mrecyclerview.setlayoutmanager(mlayoutmanager);
            mrecyclerview.additemdecoration(new divideritemdecoration(getapplicationcontext(),divideritemdecoration.vertical));
            // recyclerview的三部曲 03： 添加适配器，适配器需要重写
            mmyadapter = new recycleadapter(list, getapplicationcontext());
            mrecyclerview.setadapter(mmyadapter);
            //设置item增加、移除动画
            mrecyclerview.setitemanimator(new defaultitemanimator());

        }
    }

    @override
    public boolean oncreateoptionsmenu(menu menu) {
        getmenuinflater().inflate(r.menu.menu, menu);
        return true;
    }

    @override
    public boolean onoptionsitemselected(menuitem item) {
        switch (item.getitemid()) {
            case r.id.add:
                mmyadapter.adddata(1);
                break;
            case r.id.delete:
                mmyadapter.removedata(1);
                break;
        }
        return true;
    }
}

1.4. 重写定义adapter

recycleadapter

package com.haoch95.fristapp;

import android.content.context;
import android.support.annotation.nonnull;
import android.support.v7.widget.recyclerview;
import android.view.layoutinflater;
import android.view.view;
import android.view.viewgroup;
import android.widget.textview;
import android.widget.toast;

import java.util.list;
import java.util.random;

public class recycleadapter extends recyclerview.adapter<recycleadapter.myviewholder> {

    private list<string> mlist;
    private context context;

    public recycleadapter(list<string> list, context context){
        this.mlist = list;
        this.context = context;
    }

    @override
    public int getitemcount() {
        return mlist.size();
    }


    public class myviewholder extends recyclerview.viewholder {

        public textview mview;

        public myviewholder(@nonnull view itemview) {
            super(itemview);
            mview = itemview.findviewbyid(r.id.text_view);
        }
    }

    //创建viewholder
    //oncreateviewholder方法创建一个viewholder，viewholder可以理解为一条数据的展示布局，这里我们自定义类linearviewholder创建一个只有textview的item
    //这里我们需要创建每条布局使用的layout：recycle_item
    @nonnull
    @override
    public myviewholder oncreateviewholder(@nonnull viewgroup viewgroup, int i) {
        return new myviewholder(layoutinflater.from(viewgroup.getcontext()).inflate(r.layout.recycle_item, viewgroup, false));
    }


    //填充视图
    //onbindviewholder方法为item的ui绑定展示数据
    @override
    public void onbindviewholder(@nonnull final myviewholder holder, final int position) {
        holder.mview.settext(mlist.get(position));

        holder.itemview.setonclicklistener(new view.onclicklistener(){

            @override
            public void onclick(view v) {
                toast.maketext(context, "点击子项"+position, toast.length_short).show();
            }
        });

    }

    public void adddata(int position) {
        mlist.add(position, "insert one");
        notifyiteminserted(position);
    }

    public void removedata(int position) {
        mlist.remove(position);
        notifyitemremoved(position);
    }

    public void clearall(){
        mlist.clear();
        notifydatasetchanged();
    }


}

2. 实例

本节中的所有代码已上传到: