package com.dodoyota.weicom.net; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.lang.ref.SoftReference; import java.net.URL; import java.util.HashMap; import java.util.Map; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import android.graphics.drawable.Drawable; import android.os.Environment; import android.os.Handler; import android.util.Log; import com.weibo.sdk.android.util.FormatTools; import com.weibo.sdk.android.util.MD5Utils; /** * 异步加载图片 * @author 高元东 * @mailto [email protected] * 2013-6-20 下午9:58:57 */ public class AsyncImageLoader { public Map<String, SoftReference<Drawable>> imageCache = new HashMap<String, SoftReference<Drawable>>(); private static ExecutorService executorService = Executors.newFixedThreadPool(5); private final Handler handler = new Handler(); /*** * 异步加载图片 * @mailto [email protected] * 2013-6-20 下午10:01:34 * @param imageUrl * @param callback * @return */ public Drawable loadDrawable(final String imageUrl, final ImageCallback callback) { // 如果缓存过就从缓存中取出数据 if (imageCache.containsKey(MD5Utils.encode(imageUrl))) { SoftReference<Drawable> softReference = imageCache.get(MD5Utils.encode(imageUrl)); if (softReference.get() != null) { Log.i("imageloader", "从缓存中获取图片"); return softReference.get(); } } //sdcard 可用使用 if(this.checkSdcard()) { Drawable drawable = null; File dir = new File(Environment.getExternalStorageDirectory()+"/weicom"); if(!dir.exists()) { dir.mkdir(); } File header = new File(dir, MD5Utils.encode(imageUrl)); if(header.exists()) { FileInputStream fileInputStream = null; try { fileInputStream = new FileInputStream(header); //从sdcard 中取数据 drawable = Drawable.createFromStream(fileInputStream, "ayscimage"); Log.i("imageloader", "从sdcard获取图片"); if(!imageCache.containsKey(MD5Utils.encode(imageUrl))) { //在sdcard 中取出的图片放在缓存中 imageCache.put(MD5Utils.encode(imageUrl), new SoftReference<Drawable>(drawable)); } return drawable; } catch (Exception e) { e.printStackTrace(); } } } // 缓存中没有图像,则从网络上取出数据,并将取出的数据缓存到内存中 executorService.submit(new Runnable() { public void run() { try { final Drawable drawable = loadImageFromUrl(imageUrl); imageCache.put(imageUrl, new SoftReference<Drawable>( drawable)); Log.i("imageloader", "将图片保存在缓存中"); /*** * 保存在sdcard 中 */ if(checkSdcard()) { File dir = new File(Environment.getExternalStorageDirectory()+"/weicom"); if(!dir.exists()) { dir.mkdir(); } File header = new File(dir, MD5Utils.encode(imageUrl)); FileOutputStream fileOutputStream = new FileOutputStream(header); FormatTools formatTools = FormatTools.getInstance(); byte[] by = formatTools.Drawable2Bytes(drawable); fileOutputStream.write(by); fileOutputStream.flush(); Log.i("imageloader", "将图片保存在sdcard "); } handler.post(new Runnable() { public void run() { callback.imageLoaded(drawable); } }); } catch (Exception e) { throw new RuntimeException(e); } } }); return null; } /*** * 按照 url 从网络上获取 图片 * @mailto [email protected] * 2013-6-20 下午10:00:40 * @param imageUrl * @return */ protected Drawable loadImageFromUrl(String imageUrl) { try { Log.i("imageloader", "从网络中获取图片"); return Drawable.createFromStream(new URL(imageUrl).openStream(), "iamgeSync"); } catch (Exception e) { throw new RuntimeException(e); } } /*** * 检查sdcard 是否可用 * @mailto [email protected] * 2013-6-20 下午10:08:18 * @return */ private boolean checkSdcard() { String status = Environment.getExternalStorageState(); if(status.equals(Environment.MEDIA_MOUNTED)) { return true; } return false; } /*** * 对外开放的接口 * @author 高元东 * @mailto [email protected] * 2013-6-20 下午10:00:03 */ public interface ImageCallback { public void imageLoaded(Drawable imageDrawable); } }
listview 图片异步加载 的实现并缓存到内存 和本地sdcard 中
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转载自qq466862016.iteye.com/blog/1890901
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