Android中GridView和ArrayAdapter用法实例分析

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.GridView;
import android.widget.TextView;
public class A06Activity extends Activity {
 private TextView tv;
//两个按钮是动态放入GridView的开关，b01是设置GridView为两列格式，并放入4
//个item,b02设置为三列格式，并放入9个Item
 private Button b01,b02;//
 private GridView gv;
 private String[] s1,s2;
 private ArrayAdapter aa;
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    tv=(TextView)findViewById(R.id.tv);
    b01=(Button)findViewById(R.id.button01);
    b02=(Button)findViewById(R.id.button02);
    gv=(GridView)findViewById(R.id.gv);
    s1=new String[]{
     getResources().getString(R.string.str_list01),
     getResources().getString(R.string.str_list02),
     getResources().getString(R.string.str_list03),
     getResources().getString(R.string.str_list04)
    };
    s2=new String[]{
     getResources().getString(R.string.str_list01),
     getResources().getString(R.string.str_list02),
     getResources().getString(R.string.str_list03),
     getResources().getString(R.string.str_list04),
     getResources().getString(R.string.str_list01),
     getResources().getString(R.string.str_list02),
     getResources().getString(R.string.str_list03),
     getResources().getString(R.string.str_list04),
     getResources().getString(R.string.str_list04)
    };
    b01.setOnClickListener(new OnClickListener(){
  @Override
  public void onClick(View v) {
  // TODO Auto-generated method stub
  gv.setNumColumns(2);
  aa=new ArrayAdapter(A06Activity.this,R.layout.list_item_l_small,s1);
  gv.setAdapter(aa);
  gv.setSelection(2);
  gv.refreshDrawableState();
  }
  });
  b02.setOnClickListener(new OnClickListener(){
  @Override
  public void onClick(View v) {
  // TODO Auto-generated method stub
  gv.setNumColumns(2);
  aa=new ArrayAdapter(A06Activity.this,R.layout.list_item_l_small,s2);
  gv.setAdapter(aa);
  }
  });
  //利用GridView的OnClickListener()方法用来捕捉用户单击的是哪个item
  gv.setOnItemClickListener(new OnItemClickListener(){
  @Override
  public void onItemClick(AdapterView<&＃63;> arg0, View arg1, int arg2,
   long arg3) {
  // 判断Adapter中元素的个数，判断被单击的是第几个元素的名称
  switch(aa.getCount()){
  case 4:
   tv.setText(s1[arg2]);
   break;
  case 9:
   tv.setText(s2[arg2]);
   break;
  }
  }
  });
  }
}

<&＃63;xml version="1.0" encoding="utf-8"&＃63;>

  
  
  
  

<&＃63;xml version="1.0" encoding="utf-8"&＃63;>