AndoridGridView 自定义适配器 监听事件的使用，实现更换头像功能

// ① 创建自定义布局文件
//② 创建自定义适配器
//③ 创建Activity.xml 布局文件
// ④ 写MainActivity方法 准备数据源
//⑤ 构建适配器对象
// ⑥ 给布局文件添加适配器
// ⑦ 页面跳转
//⑧ 将选中资源id 返回 设置头像

自定义适配器

package com.example.gp11_day12_gridview2.adatper;import java.util.List;import java.util.Map;import com.example.gp11_day12_gridview2.R;import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ImageView;import android.widget.TextView;public class HeadAdapter extends BaseAdapter {    private Context context;    private List<Map<String,Object>> datas;    public HeadAdapter(Context context, List<Map<String, Object>> datas) {        super();        this.context = context;        this.datas = datas;    }    @Override    public int getCount() {        int count = 0;        if(datas!=null)            count = datas.size();        return count;    }    @Override    public Object getItem(int position) {        return datas.get(position);    }    @Override    public long getItemId(int position) {        return position;    }    @Override    public View getView(int position, View convertView, ViewGroup parent) {        ViewHolder holder = null;        if(convertView==null)        {            convertView = LayoutInflater.from(context).inflate(R.layout.item_head, null);            holder = new ViewHolder();            holder.imageHead = (ImageView) convertView.findViewById(R.id.imageView);            holder.textInfo = (TextView) convertView.findViewById(R.id.textView);            convertView.setTag(holder);        }        else            holder = (ViewHolder) convertView.getTag();        Map<String,Object> data = datas.get(position);        holder.imageHead.setImageResource(Integer.parseInt(data.get("headImage").toString()));        holder.textInfo.setText(data.get("headInfo").toString());        return convertView;    }    class ViewHolder    {        ImageView imageHead;        TextView textInfo;    }}

目标界面

package com.example.gp11_day12_gridview2;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import com.example.gp11_day12_gridview2.adatper.HeadAdapter;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.widget.AdapterView;import android.widget.AdapterView.OnItemClickListener;import android.widget.GridView;public class HeadActivity extends Activity {    private GridView gridView;    private List<Map<String,Object>> datas;    private HeadAdapter adapter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_head);        gridView = (GridView) findViewById(R.id.gridView);        datas = new ArrayList<Map<String,Object>>();        int[] heads={R.drawable.img01,R.drawable.img02,R.drawable.img03,                R.drawable.img04,R.drawable.img05,R.drawable.img06,                R.drawable.img07,R.drawable.img08,R.drawable.img09};        Map<String,Object> map = null;        for(int i=0;i<heads.length;i++)        {            map = new HashMap<String,Object>();            map.put("headImage", heads[i]);            map.put("headInfo", "头像"+(i+1));            datas.add(map);        }        adapter = new HeadAdapter(this,datas);        gridView.setAdapter(adapter);        //给GridView添加事件监听        gridView.setOnItemClickListener(new OnItemClickListener() {            @Override            public void onItemClick(AdapterView<?> parent, View view,                    int position, long id) {                //得到被点击的数据项                Map<String,Object> map = datas.get(position);                int imageId = Integer.parseInt(map.get("headImage").toString());                //把图片的资源id返回给上一个activity                Intent content = new Intent();                content.putExtra("imageId", imageId);                setResult(RESULT_OK,content);                finish();            }        });    }}源界面

package com.example.gp11_day12_gridview2;

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.widget.ImageView;

public class MainActivity extends Activity {

private static final int REQUESTCODE = 6;private ImageView imageHead;@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    imageHead = (ImageView) findViewById(R.id.image_head);}//点击按钮时选择头像public void selectHead(View v){    Intent intent = new Intent(this,HeadActivity.class);    startActivityForResult(intent, REQUESTCODE);}@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) {    super.onActivityResult(requestCode, resultCode, data);    if(requestCode==this.REQUESTCODE && resultCode==this.RESULT_OK)    {        int imageid = data.getIntExtra("imageId", R.drawable.ic_launcher);        imageHead.setImageResource(imageid);    }}

}