RecyclerView

RecyclerView:
优点:
提供了一种插拔式的体验,高度解耦,异常灵活
用法:
1.通过布局管理器LayoutManager控制其显示方式
2.通过ItemDecoration控制Item的间隔(可绘制)
3.通过ItemAnimator控制Item的增删动画
首先在build.gradle中添加依赖:

implementation 'com.android.support:recyclerview-v7:28.0.0'

版本号因人而异,我的是28,然后建立item_view.xml,设置其子项显示的布局:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="80dp">

    <TextView
        android:id="@+id/textView"
        android:gravity="center"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</android.support.constraint.ConstraintLayout>

设置activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.fitsoft.MainActivity">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</android.support.constraint.ConstraintLayout>

MainActivity:

package com.fitsoft;

import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    RecyclerView recyclerView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        recyclerView = findViewById(R.id.recycler_view);
        //设置线性布局管理器
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(linearLayoutManager);

        //设置适配器
        MyAdapter myAdapter = new MyAdapter();
        recyclerView.setAdapter(myAdapter);
    }

    private class MyAdapter extends RecyclerView.Adapter{

        MyViewHolder viewHolder;

        @NonNull
        @Override
        public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
            //绑定布局
            View itemView = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.item_view, viewGroup, false);
            //绑定布局里面的元素
            //由于RecyclerView.ViewHolder是静态抽象类,不能实例化,只能新建一个类来继承
            viewHolder = new MyViewHolder(itemView);
            return viewHolder;
        }

        @Override
        public void onBindViewHolder(@NonNull RecyclerView.ViewHolder viewHolder, int i) {
            //这里的viewHolder其实就是我们新建的MyViewHolder类的一个对象,这里进行强制转换
            //数据的处理都在这个函数里面
            ((MyViewHolder) viewHolder).textView.setText("编号:"+i);
        }

        @Override
        public int getItemCount() {
            //返回子项的个数
            return 30;
        }

        private class MyViewHolder extends RecyclerView.ViewHolder{
            //继承这个静态抽象类,使之可以被绑定
            private TextView textView;
            MyViewHolder(@NonNull View itemView) {
                super(itemView);
                textView = itemView.findViewById(R.id.textView);
            }
        }
    }
}

注释很详细。
效果图:

(图片被loli删除)

posted @ 2019-09-24 19:27  干翻苍穹  阅读(249)  评论(0编辑  收藏  举报