package webabcd.util;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
import org.apache.http.protocol.HTTP;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
// 以一个实例，即异步下载，来演示 Android 的异步消息处理（用 Handler 的方式） public class DownloadManagerAsync {
public DownloadManagerAsync() {
}
// 实例化自定义的 Handler EventHandler mHandler =
new EventHandler(
this);
// 按指定 url 地址下载文件到指定路径 public void download(
final String url,
final String savePath) {
new Thread(
new Runnable() {
public void run() {
try {
sendMessage(FILE_DOWNLOAD_CONNECT);
URL sourceUrl =
new URL(url);
URLConnection conn = sourceUrl.openConnection();
InputStream inputStream = conn.getInputStream();
int fileSize = conn.getContentLength();
File savefile =
new File(savePath);
if (savefile.exists()) {
savefile.delete();
}
savefile.createNewFile();
FileOutputStream outputStream =
new FileOutputStream(
savePath,
true);
byte[] buffer =
new byte[1024];
int readCount = 0;
int readNum = 0;
int prevPercent = 0;
while (readCount < fileSize && readNum != -1) {
readNum = inputStream.read(buffer);
if (readNum > -1) {
outputStream.write(buffer);
readCount = readCount + readNum;
int percent = (
int) (readCount * 100 / fileSize);
if (percent > prevPercent) {
// 发送下载进度信息 sendMessage(FILE_DOWNLOAD_UPDATE, percent,
readCount);
prevPercent = percent;
}
}
}
outputStream.close();
sendMessage(FILE_DOWNLOAD_COMPLETE, savePath);
}
catch (Exception e) {
sendMessage(FILE_DOWNLOAD_ERROR, e);
Log.e(
"MyError", e.toString());
}
}
}).start();
}
// 读取指定 url 地址的响应内容 public void download(
final String url) {
new Thread(
new Runnable() {
public void run() {
try {
sendMessage(FILE_DOWNLOAD_CONNECT);
URL sourceUrl =
new URL(url);
URLConnection conn = sourceUrl.openConnection();
conn.setConnectTimeout(3000);
BufferedReader reader =
new BufferedReader(
new InputStreamReader(conn.getInputStream(),
HTTP.UTF_8));
String line =
null;
StringBuffer content =
new StringBuffer();
while ((line = reader.readLine()) !=
null) {
content.append(line);
}
reader.close();
sendMessage(FILE_DOWNLOAD_COMPLETE, content.toString());
}
catch (Exception e) {
sendMessage(FILE_DOWNLOAD_ERROR, e);
Log.e(
"MyError", e.toString());
}
}
}).start();
}
// 向 Handler 发送消息 private void sendMessage(
int what, Object obj) {
// 构造需要向 Handler 发送的消息 Message msg = mHandler.obtainMessage(what, obj);
// 发送消息 mHandler.sendMessage(msg);
}
private void sendMessage(
int what) {
Message msg = mHandler.obtainMessage(what);
mHandler.sendMessage(msg);
}
private void sendMessage(
int what,
int arg1,
int arg2) {
Message msg = mHandler.obtainMessage(what, arg1, arg2);
mHandler.sendMessage(msg);
}
private static final int FILE_DOWNLOAD_CONNECT = 0;
private static final int FILE_DOWNLOAD_UPDATE = 1;
private static final int FILE_DOWNLOAD_COMPLETE = 2;
private static final int FILE_DOWNLOAD_ERROR = -1;
// 自定义的 Handler private class EventHandler
extends Handler {
private DownloadManagerAsync mManager;
public EventHandler(DownloadManagerAsync manager) {
mManager = manager;
}
// 处理接收到的消息 @Override
public void handleMessage(Message msg) {
switch (msg.what) {
case FILE_DOWNLOAD_CONNECT:
if (mOnDownloadConnectListener !=
null)
mOnDownloadConnectListener.onDownloadConnect(mManager);
break;
case FILE_DOWNLOAD_UPDATE:
if (mOnDownloadUpdateListener !=
null)
mOnDownloadUpdateListener.onDownloadUpdate(mManager,
msg.arg1);
break;
case FILE_DOWNLOAD_COMPLETE:
if (mOnDownloadCompleteListener !=
null)
mOnDownloadCompleteListener.onDownloadComplete(mManager,
msg.obj);
break;
case FILE_DOWNLOAD_ERROR:
if (mOnDownloadErrorListener !=
null)
mOnDownloadErrorListener.onDownloadError(mManager,
(Exception) msg.obj);
break;
default:
break;
}
}
}
// 定义连接事件 private OnDownloadConnectListener mOnDownloadConnectListener;
public interface OnDownloadConnectListener {
void onDownloadConnect(DownloadManagerAsync manager);
}
public void setOnDownloadConnectListener(OnDownloadConnectListener listener) {
mOnDownloadConnectListener = listener;
}
// 定义下载进度更新事件 private OnDownloadUpdateListener mOnDownloadUpdateListener;
public interface OnDownloadUpdateListener {
void onDownloadUpdate(DownloadManagerAsync manager,
int percent);
}
public void setOnDownloadUpdateListener(OnDownloadUpdateListener listener) {
mOnDownloadUpdateListener = listener;
}
// 定义下载完成事件 private OnDownloadCompleteListener mOnDownloadCompleteListener;
public interface OnDownloadCompleteListener {
void onDownloadComplete(DownloadManagerAsync manager, Object result);
}
public void setOnDownloadCompleteListener(
OnDownloadCompleteListener listener) {
mOnDownloadCompleteListener = listener;
}
// 定义下载异常事件 private OnDownloadErrorListener mOnDownloadErrorListener;
public interface OnDownloadErrorListener {
void onDownloadError(DownloadManagerAsync manager, Exception e);
}
public void setOnDownloadErrorListener(OnDownloadErrorListener listener) {
mOnDownloadErrorListener = listener;
}
}