ImageListActivity.java

package com.applite.androiduniversalimageloaderdemo;

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

import com.applite.androiduniversalimageloaderdemo.Constants.Extra;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.display.FadeInBitmapDisplayer;
import com.nostra13.universalimageloader.core.display.RoundedBitmapDisplayer;
import com.nostra13.universalimageloader.core.listener.ImageLoadingListener;
import com.nostra13.universalimageloader.core.listener.SimpleImageLoadingListener;

public class ImageListActivity extends AbsListViewBaseActivity {
	DisplayImageOptions options; //配置图片加载及显示选项
	String[] imageUrls;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.ac_image_list);
		//获取url数组
		Bundle bundle = getIntent().getExtras();
		imageUrls = bundle.getStringArray(Extra.IMAGES);

		//配置图片加载及显示选项（还有一些其他的配置，查阅doc文档吧）
		options = new DisplayImageOptions.Builder()
			.showStubImage(R.drawable.ic_stub)    //在ImageView加载过程中显示图片
			.showImageForEmptyUri(R.drawable.ic_empty)  //image连接地址为空时
			.showImageOnFail(R.drawable.ic_error)  //image加载失败
			.cacheInMemory(true)  //加载图片时会在内存中加载缓存
			.cacheOnDisc(true)   //加载图片时会在磁盘中加载缓存
			.displayer(new RoundedBitmapDisplayer(20))  //设置用户加载图片task(这里是圆角图片显示)
			.build();

		listView = (ListView) findViewById(android.R.id.list);
		//绑定适配器
		listView.setAdapter(new ItemAdapter());
		listView.setOnItemClickListener(new OnItemClickListener() {
			@Override
			public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
				startImagePagerActivity(position);
			}
		});
	}

	@Override
	public void onBackPressed() {
		AnimateFirstDisplayListener.displayedImages.clear();
		super.onBackPressed();
	}

	private void startImagePagerActivity(int position) {
		Intent intent = new Intent(this, ImagePagerActivity.class);
		intent.putExtra(Extra.IMAGES, imageUrls);
		intent.putExtra(Extra.IMAGE_POSITION, position);
		startActivity(intent);
	}

	/**自定义图片适配器**/
	class ItemAdapter extends BaseAdapter {

		private ImageLoadingListener animateFirstListener = new AnimateFirstDisplayListener();

		private class ViewHolder {
			public TextView text;
			public ImageView image;
		}

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

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

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

		@Override
		public View getView(final int position, View convertView, ViewGroup parent) {
			View view = convertView;
			final ViewHolder holder;
			if (convertView == null) {
				view = getLayoutInflater().inflate(R.layout.item_list_image, parent, false);
				holder = new ViewHolder();
				holder.text = (TextView) view.findViewById(R.id.text);
				holder.image = (ImageView) view.findViewById(R.id.image);
				view.setTag(holder);
			} else {
				holder = (ViewHolder) view.getTag();
			}

			holder.text.setText("Item " + (position + 1));

			//Adds display image task to execution pool. Image will be set to ImageView when it's turn.
			imageLoader.displayImage(imageUrls[position], holder.image, options, animateFirstListener);

			return view;
		}
	}

	/**图片加载监听事件**/
	private static class AnimateFirstDisplayListener extends SimpleImageLoadingListener {

		static final List<String> displayedImages = Collections.synchronizedList(new LinkedList<String>());

		@Override
		public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
			if (loadedImage != null) {
				ImageView imageView = (ImageView) view;
				boolean firstDisplay = !displayedImages.contains(imageUri);
				if (firstDisplay) {
					FadeInBitmapDisplayer.animate(imageView, 500); //设置image隐藏动画500ms
					displayedImages.add(imageUri); //将图片uri添加到集合中
				}
			}
		}
	}
}