android GridView 的使用 实现多项选择

今天小研究了一下GridView,目的是为了实现 下面的效果(GridView多项选择):

首先,在布局文件添加GridView ,创建适配器的items...

具体的都在注释里边了,下面是 程序源码 片段,由于xml文件比较简单,故不在贴出.

MainActivity.java

package com.app.gridview;

import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.GridView;

public class MainActivity extends Activity {
	static  MainActivity  instance;//实例
	GridView gridView1;//声明对象
	MyGridViewAdapter adapter;//声明适配器

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		instance =this;
		//获得组件
		gridView1  =(GridView) findViewById(R.id.gridView1);
		gridView1.setNumColumns(2);
		//获得适配器
		adapter  = new MyGridViewAdapter(instance);
		//设置适配器到组件
		gridView1.setAdapter(adapter);
		//添加监听
		gridView1.setOnItemClickListener(new OnItemClickListener() {

			@Override
			public void onItemClick(AdapterView<?> parent, View view,
					int position, long id) {
				//更改显示
				adapter.changeState(position);
			}
		});
	}
}

自定义适配器 MyGridViewAdapter.java

package com.app.gridview;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.LayerDrawable;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;

public class MyGridViewAdapter extends BaseAdapter {
	Context context;
	boolean isCheck;// 选中
	Boolean boo[] = {false, false, false, false, false};

	int imgsid[] = {R.drawable.aa_badge_ad, R.drawable.aa_badge_award,
			R.drawable.aa_badge_exclusive, R.drawable.aa_badge_gift,
			R.drawable.aa_badge_new,};
	public MyGridViewAdapter(Context context) {
		this.context = context;
		isCheck = false;
	}

	@Override
	public int getCount() {
		return imgsid.length;
	}

	@Override
	public Object getItem(int position) {
		return imgsid[position];
	}

	@Override
	public long getItemId(int position) {
		return position;
	}

	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		ImageView imageView;
		if (convertView == null) {
			imageView = new ImageView(context);
			imageView.setLayoutParams(new GridView.LayoutParams(200, 200));// 设置ImageView对象布局
			imageView.setAdjustViewBounds(false);// 设置边界对齐
			imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);// 设置刻度的类型
			imageView.setPadding(8, 8, 8, 8);// 设置间距
		} else {
			imageView = (ImageView) convertView;
		}
		imageView.setImageDrawable(makeBmp(imgsid[position], boo[position]));
		// imageView.setImageResource(imgsid[position]);//为ImageView设置图片资源
		return imageView;
	}

	private LayerDrawable makeBmp(int id, boolean isChosen) {
		Bitmap bitmap = ((BitmapDrawable) context.getResources()
				.getDrawable(id)).getBitmap();

		// 根据isChosen来选取对勾的图片
		Bitmap seletedBmp;
		if (isChosen == true) {
			seletedBmp = BitmapFactory.decodeResource(context.getResources(),
					R.drawable.btncheck_yes);
		} else {
			seletedBmp = BitmapFactory.decodeResource(context.getResources(),
					R.drawable.btncheck_no);
		}

		// 使 Drawable叠加层（合成图片)
		Drawable[] array = new Drawable[2];
		array[0] = new BitmapDrawable(bitmap);
		array[1] = new BitmapDrawable(seletedBmp);
		// 层图形对象
		LayerDrawable mLayerDrawable = new LayerDrawable(array);// 参数为上面的Drawable数组
		/*
		 * Specify modifiers to the bounds for the drawable[index].索引号 left += l
		 * top += t; right -= r; bottom -= b;
		 */
		mLayerDrawable.setLayerInset(0, 0, 0, 0, 0); // 第一个参数0代表数组的第一个元素
		mLayerDrawable.setLayerInset(1, 88, 0, 0, 88);// 第一个参数1代表数组的第二个元素
		return mLayerDrawable; // 返回合成后的图
	}
	/*
	 * 被点击的时候调用,改变点击后的状态
	 */
	public void changeState(int position) {

		if (isCheck == false) {
			if (position < boo.length) {
				boo[position] = !boo[position];
				isCheck = !isCheck;
			}
		} else {
			if (position < boo.length) {
				boo[position] = !boo[position];
				isCheck = !isCheck;
			}
		}
		// 调用适配器的更新状态方法
		notifyDataSetChanged();
	}
}