android 网格显示问题

按照教程进行操作
不知道显示怎么成这样的效果
上下两行的间隔太大
而且文字和图片之间的间隔也很大

布局文件也进行了修改
还是不行
有遇到过类似问题的人么

希望您给我一点意见

mainactivity.java

package com.example.imageview;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.R.integer;
import android.R.string;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.GridView;
import android.widget.SimpleAdapter;

public class MainActivity extends Activity {

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

        GridView gridView=(GridView) findViewById(R.id.gridView1);
        int[] imageid=new int[]{R.drawable.img01,R.drawable.img02,R.drawable.img03,
                                R.drawable.img04,R.drawable.img05,R.drawable.img06,
                                R.drawable.img07};
        String[] title=new String[]{"a","b","c","d","e","f","i"};
        List>listitems=new ArrayList>();
        for (int i = 0; i < imageid.length; i++) {
            Map map=new HashMap();
            map.put("image", imageid[i]);
            map.put("title", title[i]);
            listitems.add(map);
        }
        SimpleAdapter adapter=new SimpleAdapter(this, 
                                                listitems, R.layout.items, 
                                                new String[]{"title","image"},
                                                new int[]{R.id.title, R.id.image});
                    gridView.setAdapter(adapter);
        }

    }

activity_main.xml

items.xml