对BaseAdapter和ViewHolder的封装

最新推荐文章于 2021-05-25 22:37:25 发布

mChenys

最新推荐文章于 2021-05-25 22:37:25 发布

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分类专栏： Android 文章标签： android

本文链接：https://blog.youkuaiyun.com/mChenys/article/details/49848591

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本文介绍了一种自定义BaseAdapter的实现方式，通过创建MyBaseAdapter和BaseHolder两个抽象类来简化Adapter的编写过程。文章提供了MainActivity测试示例，展示了如何使用自定义Adapter填充ListView，并附带了item_list.xml布局文件。

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项目结构如下:

其中MyBaseAdapter和BaseHolder是2个抽象类,分别是对BaseAdapter和ViewHolder的封装.MainActivity为测试类.

1.MyBaseAdapter类

package com.example.mchenys.mybaseadapterdemo.adapter;

import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;

import com.example.mchenys.mybaseadapterdemo.holder.BaseHolder;

import java.util.List;

/**
 * 自定义BaseAdapter的基类
 * Created by mChenys on 2015/11/15.
 */
public abstract class MyBaseAdapter<T> extends BaseAdapter {
    private List<T> mData;

    public MyBaseAdapter(List<T> data) {
        mData = data;
    }

    @Override
    public int getCount() {
        return mData == null ? 0 : mData.size();
    }

    @Override
    public T getItem(int position) {
        return mData == null ? (T) null : mData.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        BaseHolder holder;
        if (null == convertView) {
            holder = getBaseHolder(position);
            convertView = holder.getConvertView();
        } else {
            holder = (BaseHolder) convertView.getTag();
        }
        holder.setData(getItem(position));
        return convertView;
    }

    /**
     * 由子类去实现获取BaseHolder的方法
     *
     * @param position
     * @return BaseHolder
     */
    public abstract BaseHolder getBaseHolder(int position);
}

2.BaseHolder类

package com.example.mchenys.mybaseadapterdemo.holder;

import android.view.View;

/**
 * 自定义BaseHolder的基类
 * Created by mChenys on 2015/11/15.
 */
public abstract class BaseHolder<T> {
    private View mRootView;
    private T mData;

    public BaseHolder() {
        //初始化item的根布局
        mRootView = initItemLayout();
        //绑定holder到当前根布局中
        mRootView.setTag(this);
    }


    /**
     * 获取item的根布局
     *
     * @return
     */
    public View getConvertView() {
        return mRootView;
    }

    /**
     * 设置item的数据
     *
     * @param t 具体的数据
     */
    public void setData(T t) {
        mData = t;
        refreshView(t);
    }

    /**
     * 获取显示的数据
     *
     * @return
     */
    public T getmData() {
        return mData;
    }

    /**
     * 由子类去实现刷新界面数据的方法
     *
     * @param t 具体的数据
     */
    public abstract void refreshView(T t);

    /**
     * 由具体的子类去实现初始化listView Item的根布局
     *
     * @return
     */
    public abstract View initItemLayout();
}

3.MainActivity测试类

package com.example.mchenys.mybaseadapterdemo;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.ListView;
import android.widget.TextView;

import com.example.mchenys.mybaseadapterdemo.adapter.MyBaseAdapter;
import com.example.mchenys.mybaseadapterdemo.holder.BaseHolder;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private List<String> mData = new ArrayList<>();
    private ListView mListView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mListView = new ListView(this);
        setContentView(mListView);
        initData();
        showListView();
    }

    /**
     * 显示ListView
     */
    private void showListView() {
        mListView.setAdapter(new MyBaseAdapter<String>(mData) {
            @Override
            public BaseHolder getBaseHolder(int position) {

                return new BaseHolder<String>() {
                    private TextView tvInfo;

                    @Override
                    public View initItemLayout() {
                        View view = View.inflate(MainActivity.this, R.layout.item_list, null);
                        tvInfo = (TextView) view.findViewById(R.id.id_tv_info);
                        return view;
                    }

                    @Override
                    public void refreshView(String s) {
                        tvInfo.setText(s);
                    }
                };
            }
        });
    }

    /**
     * 初始化测试数据
     */
    private void initData() {
        for (int i = 0; i < 20; i++) {
            mData.add("测试数据:" + i);
        }
    }
}

4.item_list.xml文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:id="@+id/id_tv_info"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:padding="10dp" />
</LinearLayout>

5.测试效果