Android判断网络是否可用并且开启网络

package com.pocketdigi.webview;


import android.app.Activity;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.net.ConnectivityManager;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.KeyEvent;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;

public class main extends Activity {
    /** Called when the activity is first created. */
    WebView wv;
    ProgressDialog pd;
    Handler handler;

    //检测url
    private boolean isOpenNetwork() {
        ConnectivityManager connManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        if (connManager.getActiveNetworkInfo() != null) {
        return connManager.getActiveNetworkInfo().isAvailable();
        }


        return false;
        }

    private void initMoreGames() {
        String URL_MOREGAMES = "http://www.baidu.com";

        WebView mWebView = (WebView) findViewById(R.id.view_gamesort);

        if (mWebView != null) {
            mWebView.requestFocus();
            WebSettings webSettings = mWebView.getSettings();
            if (webSettings != null) {
                webSettings.setJavaScriptEnabled(true);
                webSettings.setCacheMode(MODE_PRIVATE);
                webSettings.setDefaultTextEncodingName("utf-8");
            }

            // 判断网络是否可用
            if(isOpenNetwork() == true) {
                mWebView.loadUrl(URL_MOREGAMES);
            } else {
                AlertDialog.Builder builder = new AlertDialog.Builder(MoreGamesActivity.this);
                builder.setTitle("没有可用的网络").setMessage("是否对网络进行设置?");

                builder.setPositiveButton("是", new DialogInterface.OnClickListener() {
                    @Override

                    public void onClick(DialogInterface dialog, int which) {
                        Intent intent = null;

                        try {
                            String sdkVersion = android.os.Build.VERSION.SDK;
                            if(Integer.valueOf(sdkVersion) > 10) {
                                intent = new Intent(android.provider.Settings.ACTION_WIRELESS_SETTINGS);
                            }else {
                                intent = new Intent();
                                ComponentName comp = new ComponentName("com.android.settings", "com.android.settings.WirelessSettings");
                                intent.setComponent(comp);
                                intent.setAction("android.intent.action.VIEW");
                            }
                            MoreGamesActivity.this.startActivity(intent);
                        } catch (Exception e) {
                            Log.w(TAG, "open network settings failed, please check...");
                            e.printStackTrace();
                        }
                    }
                }).setNegativeButton("否", new DialogInterface.OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.cancel();
                        finish();
                    }
                }).show();
            }
        } else {
            Log.w(TAG, "mWebView is null, please check...");
        }
    }
    //检测url end
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        init();//执行初始化函数
        loadurl(wv,"http://baidu.com ");
    }

    public void init(){
        // Progress
        pd=new ProgressDialog(main.this);
        pd.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        pd.setMessage("数据载入中，请稍候！");
        // Show/Hide message
        handler=new Handler(){
        public void handleMessage(Message msg)
        {
            //定义一个Handler，用于处理下载线程与UI间通讯
        if (!Thread.currentThread().isInterrupted())
        {
        switch (msg.what)
        {
        case 0:
        pd.show();//显示进度对话框
        break;
        case 1:
        pd.hide();//隐藏进度对话框，不可使用dismiss()、cancel(),否则再次调用show()时，显示的对话框小圆圈不会动。
        break;

        }
        }
        super.handleMessage(msg);
        }
        };
        // WebView
        wv=(WebView)findViewById(R.id.wv);
        wv.getSettings().setJavaScriptEnabled(true);//可用JS
        wv.setScrollBarStyle(0);//滚动条风格，为0就是不给滚动条留空间，滚动条覆盖在网页上
        wv.setWebViewClient(new WebViewClient(){
        public boolean shouldOverrideUrlLoading(final WebView view, final String url) {
        loadurl(view,url);//载入网页
        return true;
        }//重写点击动作,用webview载入

        });
        wv.setWebChromeClient(new WebChromeClient(){
        public void onProgressChanged(WebView view,int progress){//载入进度改变而触发
        if(progress==100){
        handler.sendEmptyMessage(1);//如果全部载入,隐藏进度对话框

        }
        super.onProgressChanged(view, progress);
        }
        });
        }


    public boolean onKeyDown(int keyCode, KeyEvent event) {//捕捉返回键
        if ((keyCode == KeyEvent.KEYCODE_BACK) && wv.canGoBack()) {
            wv.goBack();
            return true;
        }else if(keyCode == KeyEvent.KEYCODE_BACK){
            ConfirmExit();//按了返回键，但已经不能返回，则执行退出确认
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }
    public void ConfirmExit(){//退出确认
        AlertDialog.Builder ad=new AlertDialog.Builder(main.this);
        ad.setTitle("退出");

        ad.setMessage("是否退出商城?");
        ad.setPositiveButton("是", new DialogInterface.OnClickListener() {//退出按钮
            @Override
            public void onClick(DialogInterface dialog, int i) {
                // TODO Auto-generated method stub
                main.this.finish();//关闭activity

            }
        });
        ad.setNegativeButton("否",new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int i) {
                //不退出不用执行任何操作
            }
        });
        ad.show();//显示对话框
    }
    public void loadurl(final WebView view,final String url){
        new Thread(){
            public void run(){

                handler.sendEmptyMessage(0);
                view.loadUrl(url);//载入网页
            }
        }.start();
    }
  }
本文是小崔从一位大师的评论转载过来的，如果有抄袭清告诫小崔删掉。小崔最近在做关于这方面的工程，所以为了方便才自己弄下来的。而且可能有点错误，如有发现请大家指点。