package cn.com.basic.face.util.bitmap;
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import java.io.InputStream;
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import java.net.HttpURLConnection;
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import java.net.URL;
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import android.graphics.Bitmap;
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import android.graphics.BitmapFactory;
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import android.os.AsyncTask;
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import android.widget.ImageView;
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/**
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* 网络缓存
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*
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* @author Kevin
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*
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*/
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public class NetCacheUtils {
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private LocalCacheUtils mLocalCacheUtils;
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private MemoryCacheUtils mMemoryCacheUtils;
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public NetCacheUtils(LocalCacheUtils localCacheUtils,
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MemoryCacheUtils memoryCacheUtils) {
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mLocalCacheUtils = localCacheUtils;
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mMemoryCacheUtils = memoryCacheUtils;
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}
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/**
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* 从网络下载图片
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*
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* @param ivPic
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* @param url
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*/
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public void getBitmapFromNet(ImageView ivPic, String url) {
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new BitmapTask().execute(ivPic, url);// 启动AsyncTask,
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// 参数会在doInbackground中获取
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}
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/**
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* Handler和线程池的封装
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*
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* 第一个泛型: 参数类型 第二个泛型: 更新进度的泛型, 第三个泛型是onPostExecute的返回结果
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*
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* @author Kevin
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*
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*/
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class BitmapTask extends AsyncTask<Object, Void, Bitmap> {
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private ImageView ivPic;
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private String url;
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/**
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* 后台耗时方法在此执行, 子线程
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*/
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@Override
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protected Bitmap doInBackground(Object... params) {
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ivPic = (ImageView) params[0];
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url = (String) params[1];
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ivPic.setTag(url);// 将url和imageview绑定
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return downloadBitmap(url);
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}
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/**
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* 更新进度, 主线程
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*/
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@Override
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protected void onProgressUpdate(Void... values) {
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super.onProgressUpdate(values);
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}
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/**
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* 耗时方法结束后,执行该方法, 主线程
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*/
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@Override
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protected void onPostExecute(Bitmap result) {
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if (result != null) {
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String bindUrl = (String) ivPic.getTag();
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if (url.equals(bindUrl)) {// 确保图片设定给了正确的imageview
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ivPic.setImageBitmap(result);
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mLocalCacheUtils.setBitmapToLocal(url, result);// 将图片保存在本地
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mMemoryCacheUtils.setBitmapToMemory(url, result);// 将图片保存在内存
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System.out.println("从网络缓存读取图片啦...");
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}
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}
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}
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}
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/**
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* 下载图片
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*
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* @param url
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* @return
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*/
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private Bitmap downloadBitmap(String url) {
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HttpURLConnection conn = null;
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try {
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conn = (HttpURLConnection) new URL(url).openConnection();
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conn.setConnectTimeout(5000);
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conn.setReadTimeout(5000);
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conn.setRequestMethod("GET");
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conn.connect();
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int responseCode = conn.getResponseCode();
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if (responseCode == 200) {
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InputStream inputStream = conn.getInputStream();
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//图片压缩处理
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BitmapFactory.Options option = new BitmapFactory.Options();
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option.inSampleSize = 2;//宽高都压缩为原来的二分之一, 此参数需要根据图片要展示的大小来确定
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option.inPreferredConfig = Bitmap.Config.RGB_565;//设置图片格式
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Bitmap bitmap = BitmapFactory.decodeStream(inputStream, null, option);
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return bitmap;
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}
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} catch (Exception e) {
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e.printStackTrace();
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} finally {
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conn.disconnect();
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}
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return null;
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}
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}
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