用xutils3.0进行下载

写的例子比较简单，是用xutils3.0来进行下载项目更新

1.先通过网络请求，判断版本是否要更新

2.若要更新，则弹出一个弹窗，我用的是系统自带的Dialog，将下载的版本号及下载的内容提示展示出来

3.当用户点击下载时，开始下载，下载时展示一个水平的进度条

4.下载完成后，进度条消失，调用系统安装apk

如下是代码  用到的xutils的jar包是3.3.32版本的

package com.item.weixin;

import java.io.File;

import org.json.JSONException;
import org.json.JSONObject;
import org.xutils.x;
import org.xutils.common.Callback;
import org.xutils.http.RequestParams;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager.NameNotFoundException;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.view.Window;
import android.widget.Button;

/**
 * 设置xutils下载
 * 
 * @author Administrator
 * 
 */
public class LoginActivity extends Activity {
    private Button ll_update;
    private ProgressDialog pDialog;
    private String nowVersion;
    private ProgressDialog progressDialog;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_login);
        ll_update = (Button) findViewById(R.id.btn_login);
        ll_update.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                checkUpdate();
            }
        });
        try {
            PackageInfo packageInfo = getPackageManager().getPackageInfo(
                    getPackageName(), 0);
            nowVersion = packageInfo.versionName;
        } catch (NameNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    /**
     * 下载更新,
     */
    protected void checkUpdate() {
        // TODO Auto-generated method stub
        proDialogShow(LoginActivity.this, "正在查询...");
        RequestParams params = new RequestParams("url");
        x.http().get(params, new Callback.CommonCallback<String>() {

            @Override
            public void onCancelled(CancelledException arg0) {
                // TODO Auto-generated method stub

            }

            @Override
            public void onError(Throwable arg0, boolean arg1) {
                // TODO Auto-generated method stub
                PDialogHide();
                System.out.println("提示网络错误");
            }

            @Override
            public void onFinished() {
                // TODO Auto-generated method stub

            }

            @Override
            public void onSuccess(String arg0) {
                // TODO Auto-generated method stub
                PDialogHide();
                try {
                    JSONObject object = new JSONObject(arg0);
                    boolean success = object.getBoolean("succee");
                    if (success) {
                        String desc = object.getString("desc");
                        String downloadurl = object.getString("downloadurl");
                        String versionname = object.getString("versionname");
                        if (nowVersion.equals(versionname)) {
                            System.out.println("当前版本为最新，不用跟新");
                        } else {
                            // 不同，弹出更新提示对话框
                            setUpDialog(versionname, downloadurl, desc);
                        }
                    }
                } catch (JSONException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * 
     * @param versionname
     *            地址中版本的名字
     * @param downloadurl
     *            下载包的地址
     * @param desc
     *            版本的描述
     */
    protected void setUpDialog(String versionname, final String downloadurl,
            String desc) {
        // TODO Auto-generated method stub
        AlertDialog dialog = new AlertDialog.Builder(this).setCancelable(false)
                .setTitle("下载" + versionname + "版本").setMessage(desc)
                .setNegativeButton("取消", null)
                .setPositiveButton("下载", new DialogInterface.OnClickListener() {

                    @Override
                    public void onClick(DialogInterface arg0, int arg1) {
                        // TODO Auto-generated method stub
                        setDownLoad(downloadurl);
                    }
                }).create();
        dialog.show();
    }

    /**
     * 下载包
     * 
     * @param downloadurl
     *            下载的url
     * 
     */
    @SuppressLint("SdCardPath")
    protected void setDownLoad(String downloadurl) {
        // TODO Auto-generated method stub
        RequestParams params = new RequestParams(downloadurl);
        params.setAutoRename(true);//断点下载
        params.setSaveFilePath("/mnt/sdcard/demo.apk");
        x.http().get(params, new Callback.ProgressCallback<File>() {

            @Override
            public void onCancelled(CancelledException arg0) {
                // TODO Auto-generated method stub
                
            }

            @Override
            public void onError(Throwable arg0, boolean arg1) {
                // TODO Auto-generated method stub
                if(progressDialog!=null && progressDialog.isShowing()){
                    progressDialog.dismiss();
                }
                System.out.println("提示更新失败");
            }

            @Override
            public void onFinished() {
                // TODO Auto-generated method stub
                
            }

            @Override
            public void onSuccess(File arg0) {
                // TODO Auto-generated method stub
                if(progressDialog!=null && progressDialog.isShowing()){
                    progressDialog.dismiss();
                }
                Intent intent = new Intent(Intent.ACTION_VIEW);
                intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                intent.setDataAndType(Uri.fromFile(new File(Environment
                        .getExternalStorageDirectory(), "demo.apk")),
                        "application/vnd.android.package-archive");
                startActivity(intent);
            }

            @Override
            public void onLoading(long arg0, long arg1, boolean arg2) {
                // TODO Auto-generated method stub
                progressDialog.setMax((int)arg0);
                progressDialog.setProgress((int)arg1);
            }

            @Override
            public void onStarted() {
                // TODO Auto-generated method stub
                System.out.println("开始下载");
                progressDialog = new ProgressDialog(LoginActivity.this);
                progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);//设置为水平进行条
                progressDialog.setMessage("正在下载中...");
                progressDialog.setProgress(0);
                progressDialog.show();
            }

            @Override
            public void onWaiting() {
                // TODO Auto-generated method stub
                
            }
        });
    }

    private void proDialogShow(Context context, String msg) {
        pDialog = new ProgressDialog(context);
        pDialog.setMessage(msg);
        // pDialog.setCancelable(false);
        pDialog.show();
    }

    private void PDialogHide() {
        try {
            if (pDialog != null && pDialog.isShowing()) {
                pDialog.dismiss();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}