0x00 Preface

Before that, I learned ListView and three adapters, arrayadapter, simpleadapter and simplecusoradapter in Android

This time we mainly focus on BaseAdapter to learn and practice.

0x01 what is BaseAdapter

In short, it is a kind of universal adapter, which we usually inherit.

We will implement it after inheriting

public int getCount(): the number of data sets in the adapter;

public Object getItem(int position): get the data item corresponding to the index in the dataset;

public long getItemId(int position): gets the ID corresponding to the specified row;

public View getView(int position,View convertView,ViewGroup parent): get the display content of no line Item.

After reading these, maybe we don't understand very well, so we need to raise a chestnut at this time.

0x02 example

Code

Main main activity

package com.example.hanlei.baseadapterdemo;

import android.content.Context;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.Toast;

import java.util.LinkedList;
import java.util.List;

public class MainActivity extends AppCompatActivity implements AdapterView.OnItemClickListener {
private List<Animal> mdata=null;
private Context mContext;
private AnimalAdapter mAdapter =null;
private ListView listView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final LayoutInflater inflater=LayoutInflater.from(this);
        View head=inflater.inflate(R.layout.view_header,null,false);
        View end=inflater.inflate(R.layout.view_header,null,false);

        mContext=MainActivity.this;

        listView=findViewById(R.id.lv);

        mdata=new LinkedList<Animal>();

        mdata.add(new Animal("The dog said","Are you a dog?",R.mipmap.p1));
        mdata.add(new Animal("The dog said","Are you a dog?",R.mipmap.p2));
        mdata.add(new Animal("The dog said","Are you a dog?",R.mipmap.p3));
        mdata.add(new Animal("The dog said","Are you a dog?",R.mipmap.p4));

        mAdapter=  new AnimalAdapter((LinkedList<Animal>)mdata, mContext);

        listView.addHeaderView(head);

        listView.addFooterView(end);

        listView.setAdapter(mAdapter);

        listView.setOnItemClickListener(this);
    }


    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
        Toast.makeText(mContext,"You clicked the"+i+"term",Toast.LENGTH_SHORT).show();
    }
}

class

package com.example.hanlei.baseadapterdemo;

/**
 * Created by hanlei on 2018/4/4.
 */

public class Animal {
    private String aName;
    private String aSpeak;
    private int aIcon;

    public Animal()
    {

    }
    public Animal(String aName,String aSpeak,int aIcon)
    {
        this.aName=aName;
        this.aSpeak=aSpeak;
        this.aIcon=aIcon;
    }

    public int getaIcon() {
        return aIcon;
    }

    public String getaName() {
        return aName;
    }

    public String getaSpeak() {
        return aSpeak;
    }

    public void setaIcon(int aIcon) {
        this.aIcon = aIcon;
    }

    public void setaName(String aName) {
        this.aName = aName;
    }

    public void setaSpeak(String aSpeak) {
        this.aSpeak = aSpeak;
    }
}

BaseAdapter

package com.example.hanlei.baseadapterdemo;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AnalogClock;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.LinkedList;

/**
 * Created by hanlei on 2018/4/4.
 */

public class AnimalAdapter extends BaseAdapter {
    private LinkedList <Animal> mData;
    private Context mContext;

    public AnimalAdapter(LinkedList<Animal> mData,Context mContext){
        this.mData=mData;
        this.mContext=mContext;
    }
    //Number of data
    @Override
    public int getCount() {
        return mData.size();
    }
    //Gets the data item of the data set corresponding to the specified index
    @Override
    public Object getItem(int i) {
        return null;
    }
    //Corresponding row ID
    @Override
    public long getItemId(int i) {
        return i;
    }
    //Get the content of each Item
    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        view= LayoutInflater.from(mContext).inflate(R.layout.demo,viewGroup,false);
        ImageView imageView=view.findViewById(R.id.imgtou);
        TextView textView=view.findViewById(R.id.name);
        TextView textView1=view.findViewById(R.id.says);
        imageView.setBackgroundResource(mData.get(i).getaIcon());
        textView.setText(mData.get(i).getaName());
        textView1.setText(mData.get(i).getaSpeak());
        return view;
    }
}

Demonstration