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app/src/main/java/com/gh/download/DownloadTask.java

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+package com.gh.download;
+
+import java.text.DecimalFormat;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map.Entry;
+
+import android.content.Context;
+import android.os.Handler;
+import android.os.Message;
+
+import com.gh.common.constant.Constants;
+import com.gh.common.util.FileUtils;
+import com.gh.common.util.Trace;
+
+public class DownloadTask implements DownloadListener {
+
+	private DownloadEntry entry;
+	private Handler handler;
+	private Context context;
+	private DownloadThread downloadThread;
+
+	private double currPercent;
+	private long totalSize;
+	private long currSize;
+
+	// 计算下载速度
+	private long lastTime;
+	private long intervalDownloadedSize;
+
+	public DownloadTask(Handler handler, final DownloadEntry entry,
+			Context context) {
+
+		this.entry = entry;
+		this.handler = handler;
+
+		this.context = context;
+		DownloadEntry historyEntry = DownloadDao.getInstance(context).get(
+				entry.getUrl());
+		if (historyEntry != null && historyEntry.getSize() != 0) {
+			// 历史下载任务，初始化数据
+			this.totalSize = entry.getSize();
+			this.currPercent = (int) (entry.getProgress() * 100l / totalSize);
+			Trace.getInstance().debug(DownloadTask.class.getSimpleName(),
+					"DownloadTask==>" + "历史下载任务，初始化数据");
+		} else {
+			// 第一次下载
+			this.currSize = 0;
+			this.currPercent = 0;
+		}
+
+	}
+
+	public void start() {
+		// 从下载历史里获取过去下载的进度信息
+		DownloadEntry downloadEntry = null;
+		downloadEntry = DownloadDao.getInstance(context).get(entry.getUrl());
+
+		if (downloadEntry != null) {
+			entry = downloadEntry;
+			entry.setStatus(DownloadStatus.downloading);
+			Trace.getInstance().debug(
+					DownloadTask.class.getSimpleName(),
+					"start==>" + "load from history:" + entry.getUrl() + "--"
+							+ entry.getProgress() + "," + entry.getSize());
+			currSize = entry.getProgress();
+			currPercent = entry.getPercent();
+		} else {
+			Trace.getInstance().debug(DownloadTask.class.getSimpleName(),
+					"start==>" + "First log into history!");
+
+		}
+
+		downloadThread = new DownloadThread(context, this.entry, this);
+		downloadThread.setPriority(Thread.MAX_PRIORITY);
+		downloadThread.start();
+	}
+
+	@Override
+	public synchronized void onProgressChanged(int len) {
+		currSize += len;
+		double percent = 0;
+		if (entry.getSize() != 0) {
+			percent = currSize * 100.0 / entry.getSize();
+			DecimalFormat df = new DecimalFormat("#.0");
+			percent = Double.parseDouble(df.format(percent));
+		}
+		entry.setProgress(currSize);
+		entry.setPercent(percent);
+
+		if (percent > currPercent) {
+			currPercent = percent;
+			Message msg = handler.obtainMessage();
+			handler.removeMessages(0);
+			msg.what = 0;
+			msg.obj = entry;
+			handler.sendMessage(msg);
+			DownloadDao.getInstance(context).newOrUpdate(entry);
+		}
+
+		// 计算下载速度
+		if (System.currentTimeMillis() - lastTime > Constants.SPEED_CHECK_INTERVAL) {
+			entry.setSpeed(intervalDownloadedSize
+					/ (Constants.SPEED_CHECK_INTERVAL));
+			lastTime = System.currentTimeMillis();
+			intervalDownloadedSize = 0;
+			DownloadDao.getInstance(context).newOrUpdate(entry);
+		} else {
+			intervalDownloadedSize += len;
+		}
+
+		Trace.getInstance()
+				.debug(DownloadTask.class.getSimpleName(),
+						"onProgressChanged==>" + entry.getName() + "**"
+								+ entry.getPercent() + "%**" + entry.getSpeed()
+								+ "k/s");
+	}
+
+	@Override
+	public void onStatusChanged(DownloadStatus status) {
+
+		if (status == DownloadStatus.cancel
+				|| status == DownloadStatus.hijack) {
+			entry.setProgress(0);
+			entry.setPercent(0);
+			FileUtils.deleteFile(entry.getPath());
+			DownloadDao.getInstance(context).delete(entry.getUrl());
+			Trace.getInstance().debug(DownloadTask.class.getSimpleName(),
+					"onStatusChanged==>" + entry.getUrl() + " is calcled!");
+		}
+
+		if (status == DownloadStatus.done) {
+			entry.setSpeed(0);
+			entry.setProgress(entry.getSize());
+			entry.setPercent(100);
+		}
+
+		if (status == DownloadStatus.pause) {
+			entry.setSpeed(0);
+		}
+
+		/*********************** 处理网络异常 ***********************/
+		if (status == DownloadStatus.timeout
+				|| status == DownloadStatus.neterror) {
+			HashMap<String, DownloadTask> map = DataChanger.getInstance().getDownloadingTasks();
+			Iterator<String> iterator = map.keySet().iterator();
+			String key = null;
+			while (iterator.hasNext()) {
+				key = iterator.next();
+				DownloadTask task = map.get(key);
+				if (task != null) {
+					task.pause();
+				}
+				iterator.remove();
+			}
+			for (Entry<String, DownloadEntry> entry : DataChanger.getInstance()
+					.getDownloadEntries().entrySet()) {
+				DataChanger.getInstance().pauseDownloadEntries(entry.getKey());
+				DownloadDao.getInstance(context).newOrUpdate(entry.getValue());
+			}
+
+		}
+
+		entry.setStatus(status);
+		DownloadDao.getInstance(context).newOrUpdate(entry);
+		Message msg = handler.obtainMessage();
+		// handler.removeMessages(1);
+		msg.what = 1;
+		msg.obj = entry;
+		handler.sendMessage(msg);
+		Trace.getInstance().debug(DownloadTask.class.getSimpleName(),
+				"onStatusChanged:" + status);
+	}
+
+	public void cancel() {
+		downloadThread.cancle();
+
+	}
+
+	public void pause() {
+		downloadThread.pause();
+
+	}
+
+	// check download progress
+	// DataChanger notify progress
+}