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;
@Override
protected 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);
}

@Override
protected 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);
    }
}

}