android网络状态判断(wifi、3G、2G)

首先需要加入权限

代码如下	复制代码
<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

代码如下

复制代码

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

代码如下

复制代码

//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

代码如下	复制代码
if(isNetworkAvailable()) { 相关代码 }else { setNetwork(); }]

这篇文章中已经介绍了网络状态的判断，但是测试后发现用此方法只能够判断WIFI是否连接，而现在的智能机可以是wifi、3G、甚至2G。那么如果用上面的方法就不行了需要进行一下修改，使其在网络不连接（无论wifi、3G、2G）的时候也可以判断。代码如下

代码如下

复制代码

//Check network public void CheckNetworkState() { boolean flag = false; ConnectivityManager manager = (ConnectivityManager)getSystemService( Context.CONNECTIVITY_SERVICE); State mobile = manager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState(); State wifi = manager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState(); //如果3G、wifi、2G等网络状态是连接的，则退出，否则显示提示信息进入网络设置界面 if(mobile == State.CONNECTED||mobile==State.CONNECTING) return; if(wifi == State.CONNECTED||wifi==State.CONNECTING) return; showTips(); } private void showTips() { 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) { // 如果没有网络连接，则进入网络设置界面 startActivity(new Intent(Settings.ACTION_WIRELESS_SETTINGS)); } }); builder.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.cancel(); } }); builder.create(); builder.show(); }

种方式更加简单，也更加有用，当然第一篇也有可取之处，可以加入3G状态检查即可

注意：别忘了加上权限

代码如下	复制代码
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>