实现android相册网格和gallery功能 实例源码下载

【核心代码】

package com.yl.picture;

import java.io.File;
import java.util.HashMap;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;

public class SuolueActivity extends Activity {
	//声明变量
	private GridView gridView;
	private String path;
	private String sdPath;
	private static HashMap<Integer,Bitmap> imageMaps=new HashMap<Integer,Bitmap>();
	
	public static HashMap<Integer, Bitmap> getImageMaps() {
		return imageMaps;
	}

	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		this.setContentView(R.layout.suolue);
		//根据控件的ID来获取代表控件的对象
		this.gridView=(GridView) this.findViewById(R.id.gridView1);
		//图片存储的准确文件夹
		path=ReadSDPath() "/DCIM/Camera/";
		Log.i("init", path "========");
		//设置图片的大小
		BitmapFactory.Options opt=new BitmapFactory.Options();
		opt.inPreferredConfig = Bitmap.Config.RGB_565;
		//比例缩小2
		opt.inSampleSize=2;
		opt.inPurgeable = true;
		opt.inInputShareable = true;
		//根据路径找到所有的文件的路径存到Bitmap数组中
		File file=new File(path);
		File[] files=file.listFiles();
		for(int i=0;i<files.length;i  ){
			File f=files[i];
			Log.i("path", f.getPath() "----------");
			Bitmap bm=BitmapFactory.decodeFile(f.getPath(),opt);
			imageMaps.put(i, bm);
		}
		//把自定义的适配器加载到gridView中
		this.gridView.setAdapter(new MyAdapter(SuolueActivity.this));
		//点击单张图片显示
		this.gridView.setOnItemClickListener(new GridView.OnItemClickListener(){
			public void onItemClick(AdapterView<?> arg0, View arg1, int postion,
					long arg3) {
				//生成一个Intent对象
				Intent intent=new Intent();
				//通过Intent来从SuolueActivity切换到SuolueDisplayActivity
				intent.setClass(SuolueActivity.this, SuolueDisplayActivity.class);
				//生成一个Bundle对象，用来携带数据
				Bundle bundle=new Bundle();
				//将ID赋值为postion
				bundle.putInt("ID", postion);
				//将要传递的值附加到Intent对象 
				intent.putExtras(bundle);
				//启动该Intent对象，实现跳转
				startActivity(intent);
			}
		});
	}
	//获取SD卡的根路径
	public String ReadSDPath(){
		boolean SDExit=Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED);
		if(SDExit){
			return sdPath=Environment.getExternalStorageDirectory().toString();
		}else{
			return null;
		}
	}
	//自定义适配器实现BaseAdapter
public class MyAdapter extends BaseAdapter{
	private Context context;
	//定义构造方法加入Context参数
	public MyAdapter(Context context){
		this.context=context;
	}
	public int getCount() {
		//返回值为所有图片的个数
		return imageMaps.size();
	}

	public Object getItem(int position) {
		return null;
	}

	public long getItemId(int position) {
		return 0;
	}

	public View getView(int position, View convertView, ViewGroup parent) {
		//定义一个ImageView显示图片
		ImageView imageView;
		if(convertView==null){
			//生成一个imageView对象
			imageView=new ImageView(context);
			//设置ImageView对象布局 
			imageView.setLayoutParams(new GridView.LayoutParams(90,90));
			//设置刻度的类型
			imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
			//设置间距 
			imageView.setPadding(8, 8, 8, 8);
		}else{
			imageView=(ImageView)convertView;
		}
		//为ImageView设置图片资源 
		imageView.setImageBitmap(imageMaps.get(position));
		return imageView;
		}
	}
}