本次的Demo是通過GridView展示一個List，通過2個按鈕實現GridView從視覺上的增加和減少。

為了方便增加和減少，本次用的儲存結構是List。與String在BaseAdapter一樣，只需要更改BaseAdapter的2個基本函數分別是 getItem(),getCount()

       
public Object getItem(int position) {
        return  mad[position];
	}
public int getCount() {
				
        return mad.length;
	}
    

?

?這是String的 BaseAdapter

      @Override
public Object getItem(int position) {
	// TODO Auto-generated method stub
	return mList.get(position);
                   }
		
@Override
	public int getCount() {
	// TODO Auto-generated method stub
	return mList.size();
                   }
    

      ?
    

?這是List的BaseAdapter

?

?

?

下邊放上整個代碼

      package com.example.onclickgridview;

import java.security.acl.LastOwnerException;
import java.util.ArrayList;
import java.util.List;

import android.R.integer;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Adapter;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.ListAdapter;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {
	
//	作用： 
//	1、對于一個沒有被載入或者想要動態載入的界面, 都需要使用inflate來載入. 
//
//	2、對于一個已經載入的Activity, 就可以使用實現了這個Activiyt的的findViewById方法來獲得其中的界面元素. 
    private LayoutInflater mInflater;
	//創建初始化數據源
	private String[] mad = {"1","2","3","4","5","6","7","8","9"};
	
	private List<String> mList;
	//聲明控件
	private GridView mGridView;
	//聲明adpter
	private Adapter mAdapter;
	
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
	//關聯	
    Button btnAdd = (Button) findViewById(R.id.button1);	
    
    Button btnDel = (Button) findViewById(R.id.button2);	
		
	mGridView = (GridView) findViewById(R.id.gridView1);	
	
	mInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
	
	mList = new ArrayList<String>();
	
	for(int i = 0; i<mad.length;  i++){
		
		mList.add(mad[i]);
    
	}
	
	
	//新建BaseAdapter
	mAdapter = new BaseAdapter() {
		
		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			TextView text;
			ImageView imgview;
			RelativeLayout rLayout;
			//初始化時加載頁面用到的 if里的東西
			 if (convertView == null) {
				 rLayout = (RelativeLayout) mInflater.inflate(R.layout.new_file, parent, false);

		        } else {
		        	rLayout = (RelativeLayout) convertView;
		        }
			String item = (String) getItem(position);
			//設置控件取回的數據
			text = (TextView) rLayout.findViewById(R.id.TextView2);

			text.setText(item);
			
			imgview = (ImageView) rLayout.findViewById(R.id.ImageView1);
			
			imgview.setImageResource(R.drawable.ic_launcher);
			
			
			return rLayout;
		}
		//本次重點 準確返回數據位置的關鍵 必須在getItemID設置對的位置選項默認從0開始
		@Override
		public long getItemId(int position) {
			// TODO Auto-generated method stub
			return position;
		}
		
		@Override
		public Object getItem(int position) {
			// TODO Auto-generated method stub
			return mList.get(position);
		}
		
		@Override
		public int getCount() {
			// TODO Auto-generated method stub
			return mList.size();
		}
	};
	
	mGridView.setAdapter((ListAdapter) mAdapter);
	//監聽事件 對于按下gridView控件的其中一個做出的響應
	mGridView.setOnItemClickListener(new OnItemClickListener() {

		@Override
		public void onItemClick(AdapterView<?> parent, View view, int position,long id) {
			
			Toast.makeText(MainActivity.this, "你選擇了" + (position + 1) + " 號圖片", Toast.LENGTH_SHORT).show();
			
		}
		
		
	});
	//監聽2個按鈕
	btnAdd.setOnClickListener(new Button.OnClickListener(){

		@Override
		public void onClick(View v) {
			//通過對list的長度在選擇累計增加的數值
			int j= mList.size();
			//這里用到了類型轉換
			String s = Integer.toString(j+1);
			mList.add(s);
			mGridView.setAdapter((ListAdapter) mAdapter);
		}
		
		
		
		
	});
	
	btnDel.setOnClickListener(new Button.OnClickListener(){

		@Override
		public void onClick(View v) {
			//通過對list的長度在選擇累計減少的數值
			int z= mList.size();
			//這里用到了類型轉換
			String t = Integer.toString(z);
			mList.remove(t);
			mGridView.setAdapter((ListAdapter) mAdapter);
		}
		
		
		
		
	});
	
	
	
	
	
	
	}
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

}

    

?展示效果

?

?按下Add一次

?

?多次按下Add

?多次按下Delete

?