Android实现检查并下载APK更新、安装APK及获取网络信息的方法

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.text.DecimalFormat;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.conn.ConnectTimeoutException;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.CoreConnectionPNames;
import org.apache.http.util.EntityUtils;
import org.lmw.weather.R;
import org.lmw.weather.entity.AppDetail;
import android.app.AlertDialog;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.app.AlertDialog.Builder;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.DialogInterface.OnCancelListener;
import android.content.DialogInterface.OnClickListener;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager.NameNotFoundException;
import android.net.Uri;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;
public class DownloadManager {
  private static final int DOWN_NOSDCARD = 0;
  private static final int DOWN_UPDATE = 1;
  private static final int DOWN_OVER = 2;
  private static final int DOWN_ERROR=3;
  private static final int DIALOG_TYPE_LATEST = 0;
  private static final int DIALOG_TYPE_FAIL = 1;
  private static final int DIALOG_TYPE_INTERNETERROR = 2;
  private static DownloadManager downloadManager;
  private Context mContext;
  // 通知对话框
  private Dialog noticeDialog;
  // 下载对话框
  private Dialog downloadDialog;
  // 进度条
  private ProgressBar mProgress;
  // 显示下载数值
  private TextView mProgressText;
  // 查询动画
  private ProgressDialog mProDialog;
  // '已经是最新' 或者 '无法获取最新版本' 的对话框
  private Dialog latestOrFailDialog;
  // 返回的安装包url
  private String apkUrl = "";
  // 进度值
  private int progress;
  // 下载线程
  private Thread downLoadThread;
  // 终止标记
  private boolean interceptFlag;
  // 提示语
  private String updateMsg = "";
  // 下载包保存路径
  private String savePath = "";
  // apk保存完整路径
  private String apkFilePath = "";
  // 临时下载文件路径
  private String tmpFilePath = "";
  // 下载文件大小
  private String apkFileSize;
  // 已下载文件大小
  private String tmpFileSize;
  private String curVersiOnName= "";
  private int curVersionCode;
  private AppDetail mDownload;
  private String checkUrl="http://192.168.0.133:8080/lmw/androidMarket/SimpleWeather-20130701093349937/update.xml";
  private Handler mHandler = new Handler() {
 public void handleMessage(Message msg) {
   switch (msg.what) {
   case DOWN_UPDATE:
 mProgress.setProgress(progress);
 mProgressText.setText(tmpFileSize + "/" + apkFileSize);
 break;
   case DOWN_OVER:
 downloadDialog.dismiss();
 installApk();
 break;
   case DOWN_NOSDCARD:
 downloadDialog.dismiss();
 Toast.makeText(mContext, "无法下载安装文件，请检查SD卡是否挂载",Toast.LENGTH_SHORT).show();
 break;
   case DOWN_ERROR:
 downloadDialog.dismiss();
 if(msg.arg1==0){
 Toast.makeText(mContext, "网络不给力啊", Toast.LENGTH_SHORT).show();
 }else if(msg.arg1==1||msg.arg1==2){
 Toast.makeText(mContext, "未找到资源",Toast.LENGTH_SHORT).show();
 }
 break;
   }
 };
  };
  public static DownloadManager getDownloadManager() {
 if (downloadManager == null) {
   downloadManager = new DownloadManager();
 }
 downloadManager.interceptFlag = false;
 return downloadManager;
  }
  public void DownLoader(Context context, AppDetail download) {
 this.mCOntext= context;
 this.mDownload = download;
 showDownloadDialog();
  }
  /**
   * 检查App更新
   * @param context
   * @param isShowMsg
   * 是否显示提示消息
   */
  public void checkAppUpdate(Context context, final boolean isShowMsg,final boolean notmain) {
 this.mCOntext= context;
 getCurrentVersion(mContext);
 if (isShowMsg) {
   if (mProDialog == null)
 mProDialog = ProgressDialog.show(mContext, null, "正在检测，请稍后...",true, true);
   else if (mProDialog.isShowing()|| (latestOrFailDialog != null && latestOrFailDialog.isShowing()))
 return;
 }
 final Handler handler = new Handler() {
   public void handleMessage(Message msg) {
 // 进度条对话框不显示 - 检测结果也不显示
 if (mProDialog != null && !mProDialog.isShowing()) {
   return;
 }
 // 关闭并释放释放进度条对话框
 if (isShowMsg && mProDialog != null) {
   mProDialog.dismiss();
   mProDialog = null;
 }
 // 显示检测结果
 if (msg.what == 1) {
   mDownload = (AppDetail) msg.obj;
   if (mDownload != null) {
  if (curVersionCode