Android常用控件之GridView使用BaseAdapter

我们可以为GridView添加自定义的Adapter，首先看下用自定义Adapter的显示效果

在布局文件main.xml文件中定义一个GridView控件

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <GridView
        android:id="@+id/gridView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:numColumns="4"
        android:stretchMode="columnWidth" >
    </GridView>

</RelativeLayout>

要使用BaseAdapter首先定义一个类继承BaseAdapter，并重写几个方法

package com.example.gridviewadapterdemo;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.AdapterView.OnItemClickListener;

public class MainActivity extends Activity {

	private GridView gridView = null;
	private 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, R.drawable.img08,
			R.drawable.img09, R.drawable.img10, R.drawable.img11,
			R.drawable.img12, }; // 定义并初始化保存图片id的数组

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

		gridView = (GridView) findViewById(R.id.gridView);
		GridViewAdapter gridViewAdapter = new GridViewAdapter();
		gridView.setAdapter(gridViewAdapter);
		// 为GridView设定监听器
		gridView.setOnItemClickListener(new gridViewListener());
	}

	class gridViewListener implements OnItemClickListener {

		@Override
		public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
				long arg3) {
			// TODO Auto-generated method stub
			System.out.println("arg2 = " + arg2); // 打印出点击的位置
		}
	}

	private class GridViewAdapter extends BaseAdapter {

		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			ImageView imageview; // 声明ImageView的对象
			if (convertView == null) {
				imageview = new ImageView(MainActivity.this); // 实例化ImageView的对象
				imageview.setScaleType(ImageView.ScaleType.CENTER_INSIDE); // 设置缩放方式
				imageview.setPadding(5, 0, 5, 0); // 设置ImageView的内边距
			} else {
				imageview = (ImageView) convertView;
			}
			imageview.setImageResource(imageId[position]); // 为ImageView设置要显示的图片
			return imageview; // 返回ImageView
		}

		/*
		 * 功能：获得当前选项的ID
		 *
		 * @see android.widget.Adapter#getItemId(int)
		 */
		@Override
		public long getItemId(int position) {
			//System.out.println("getItemId = " + position);
			return position;
		}

		/*
		 * 功能：获得当前选项
		 *
		 * @see android.widget.Adapter#getItem(int)
		 */
		@Override
		public Object getItem(int position) {
			return position;
		}

		/*
		 * 获得数量
		 *
		 * @see android.widget.Adapter#getCount()
		 */
		@Override
		public int getCount() {
			return imageId.length;
		}
	}

}

样例代码

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