http://www.cnblogs.com/loulijun/archive/2012/02/03/2337230.html 原文地址
许多联网应用都在开始运行的时候检查当前网络状态，如果没有开启则去开启它，记录一下以前写程序时的网络检查，发现人的记忆力真是有限，总是隔段时间久忘记，所以记录下来是最好的记忆。
我们可以在一开始启动程序的时候检查网络连接状况，如果没有开启则弹出对话框设置网络
首先需要加入权限
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>
<uses-permission android:name="android.permission.INTERNET"/>
检查网络状态代码如下
public boolean CheckNetworkState() { boolean flag = false; ConnectivityManager manager = (ConnectivityManager)getSystemService( Context.CONNECTIVITY_SERVICE); if(manager.getActiveNetworkInfo() != null) { flag = manager.getActiveNetworkInfo().isAvailable(); } if(!flag) { AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setIcon(android.R.drawable.ic_dialog_alert); builder.setTitle(R.string.netstate); builder.setMessage(R.string.setnetwork); builder.setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { // TODO Auto-generated method stub Intent mIntent = new Intent("/"); ComponentName comp = new ComponentName("com.android.settings", "com.android.settings.WirelessSettings"); mIntent.setComponent(comp); mIntent.setAction("android.intent.action.VIEW"); startActivity(mIntent); } }); builder.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.cancel(); } }); builder.create(); builder.show(); } return flag; }
效果如下，用户可以点击确定来设置网络，比如启动wifi
如果希望网络连接时做一些事情的话，需要判断当前网络状态是否为true，为真则进行一些操作，否则设置网络。还可以用另外一种方式，其实差不多
//setnetwork public void setNetwork() { AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setIcon(android.R.drawable.ic_dialog_alert); builder.setTitle(R.string.netstate); builder.setMessage(R.string.setnetwork); builder.setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { // TODO Auto-generated method stub Intent mIntent = new Intent("/"); ComponentName comp = new ComponentName("com.android.settings", "com.android.settings.WirelessSettings"); mIntent.setComponent(comp); mIntent.setAction("android.intent.action.VIEW"); startActivity(mIntent); } }); builder.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.cancel(); } }); builder.create(); builder.show(); } //NETWORK public boolean isNetworkAvailable() { Context context = getApplicationContext(); ConnectivityManager connect = (ConnectivityManager)context.getSystemService( Context.CONNECTIVITY_SERVICE); if(connect==null) { return false; }else//get all network info { NetworkInfo[] info = connect.getAllNetworkInfo(); if(info!=null) { for(int i=0;i<info.length;i++) { if(info[i].getState()==NetworkInfo.State.CONNECTED) { return true; } } } } return false; }
然后通过判断如果当前状态可用则执行相关代码，不可用则设置网络
if(isNetworkAvailable()) { 相关代码 }else { setNetwork(); }
可以通过ConnectivityManager获取当前网络连接状态，通过状态值判别当前网络连接
NetworkInfo info = conMan.getActiveNetworkInfo(); if(info !=null && info.getType() == ConnectivityManager.TYPE_MOBILE) { // NETWORK_TYPE_EVDO_A是电信3G //NETWORK_TYPE_EVDO_A是中国电信3G的getNetworkType //NETWORK_TYPE_CDMA电信2G是CDMA //移动2G卡 + CMCC + 2//type = NETWORK_TYPE_EDGE //联通的2G经过测试 China Unicom 1 NETWORK_TYPE_GPRS if(info.getSubtype() == TelephonyManager.NETWORK_TYPE_GPRS || info.getSubtype() == TelephonyManager.NETWORK_TYPE_CDMA || info.getSubtype() == TelephonyManager.NETWORK_TYPE_EDGE){ System.out.println("mobile connected"); } else{ System.out.println("type:"+info.getSubtype()); System.out.println("not mobile"); } }else System.out.println("not mobile connected");
通过getType的值可以得到以下2g|3g网络
networktype 1~15分别为：联通2G，移动2G，电信2G，电信3G，电信3G，电信3G，联通3G，联通3G，LTE，IDEN,HSUPA,HSPA,HSPAP
