现在的网络非常的普遍，虽然网络只有，有网没网，wifi还是手机流量4种情况，但是设计到项目，你就要考虑的多了，app打开之后没网或者是，还没进去没网，没网的时候，项目会不会崩，等等一系列的问题，总之，一个网络工具类能给我们解决很多问题。
`import android.app.Activity;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.LocationManager;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.support.v7.app.AlertDialog;
import android.telephony.TelephonyManager;
import android.util.Log;
import java.util.List;
/**
* 跟网络相关的工具类
*
* @author zhy
*/
public class NetUtils {
// 没有连接
public static final int NETWORN_NONE = 0;
// wifi连接
public static final int NETWORN_WIFI = 1;
// 手机网络数据连接
public static final int NETWORN_2G = 2;
public static final int NETWORN_3G = 3;
public static final int NETWORN_4G = 4;
public static final int NETWORN_MOBILE = 5;
private NetUtils() {
/* cannot be instantiated */
throw new UnsupportedOperationException("cannot be instantiated");
}
/**
* 判断网络是否连接
*
* @param context
* @return
*/
public static boolean isConnected(Context context) {
ConnectivityManager connectivity = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
// 如果仅仅是用来判断网络连接
if (null != connectivity) {
NetworkInfo info = connectivity.getActiveNetworkInfo();
if (null != info && info.isConnected()) {
if (info.getState() == NetworkInfo.State.CONNECTED) {
return true;
}
}
}
return false;
}
/**
* 判断GPS是否打开
*
* @param context
* @return
*/
public static boolean isGpsEnabled(Context context) {
LocationManager lm = ((LocationManager) context
.getSystemService(Context.LOCATION_SERVICE));
List<String> accessibleProviders = lm.getProviders(true);
return accessibleProviders != null && accessibleProviders.size() > 0;
}
/**
* 判断是否是3G网络
* @param context
* @return
*/
public static boolean is3rd(Context context) {
ConnectivityManager cm = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkINfo = cm.getActiveNetworkInfo();
if (networkINfo != null
&& networkINfo.getType() == ConnectivityManager.TYPE_MOBILE) {
return true;
}
return false;
}
/**
* 判断是wifi还是3g网络,用户的体现性在这里了，wifi就可以建议下载或者在线播放。
*
* @param context
* @return
*/
public static boolean isWifi(Context context) {
ConnectivityManager cm = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkINfo = cm.getActiveNetworkInfo();
if (networkINfo != null
&& networkINfo.getType() == ConnectivityManager.TYPE_WIFI) {
return true;
}
return false;
}
/**
* 打开网络设置界面
*/
public static void openSetting(final Activity activity) {
Log.e("netutils", "我是网络1111");
final AlertDialog.Builder builder = new AlertDialog.Builder(activity);
builder.setTitle("开启网络服务");
builder.setMessage("网络没有连接，请到设置进行网络设置！");
builder.setPositiveButton("确定",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
if (android.os.Build.VERSION.SDK_INT > 10) {
// 3.0以上打开设置界面，也可以直接用ACTION_WIRELESS_SETTINGS打开到wifi界面
activity.startActivity(new Intent(
android.provider.Settings.ACTION_SETTINGS));
} else {
activity.startActivity(new Intent(
android.provider.Settings.ACTION_WIRELESS_SETTINGS));
}
dialog.cancel();
}
});
builder.setNegativeButton("取消",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
Log.e("netutils", "我是网络");
}
});
builder.show();
}
/**
* 返回当前网络连接类型
*
* @param context 上下文
* @return
*/
public static int getNetworkState(Context context) {
ConnectivityManager connManager = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
if (null == connManager)
return NETWORN_NONE;
NetworkInfo activeNetInfo = connManager.getActiveNetworkInfo();
if (activeNetInfo == null || !activeNetInfo.isAvailable()) {
return NETWORN_NONE;
}
// Wifi
NetworkInfo wifiInfo = connManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
if (null != wifiInfo) {
NetworkInfo.State state = wifiInfo.getState();
if (null != state)
if (state == NetworkInfo.State.CONNECTED || state == NetworkInfo.State.CONNECTING) {
return NETWORN_WIFI;
}
}
// 网络
NetworkInfo networkInfo = connManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
if (null != networkInfo) {
NetworkInfo.State state = networkInfo.getState();
String strSubTypeName = networkInfo.getSubtypeName();
if (null != state)
if (state == NetworkInfo.State.CONNECTED || state == NetworkInfo.State.CONNECTING) {
switch (activeNetInfo.getSubtype()) {
case TelephonyManager.NETWORK_TYPE_GPRS: // 联通2g
case TelephonyManager.NETWORK_TYPE_CDMA: // 电信2g
case TelephonyManager.NETWORK_TYPE_EDGE: // 移动2g
case TelephonyManager.NETWORK_TYPE_1xRTT:
case TelephonyManager.NETWORK_TYPE_IDEN:
return NETWORN_2G;
case TelephonyManager.NETWORK_TYPE_EVDO_A: // 电信3g
case TelephonyManager.NETWORK_TYPE_UMTS:
case TelephonyManager.NETWORK_TYPE_EVDO_0:
case TelephonyManager.NETWORK_TYPE_HSDPA:
case TelephonyManager.NETWORK_TYPE_HSUPA:
case TelephonyManager.NETWORK_TYPE_HSPA:
case TelephonyManager.NETWORK_TYPE_EVDO_B:
case TelephonyManager.NETWORK_TYPE_EHRPD:
case TelephonyManager.NETWORK_TYPE_HSPAP:
return NETWORN_3G;
case TelephonyManager.NETWORK_TYPE_LTE:
return NETWORN_4G;
default://有机型返回16,17
//中国移动 联通 电信 三种3G制式
if (strSubTypeName.equalsIgnoreCase("TD-SCDMA") || strSubTypeName.equalsIgnoreCase("WCDMA") || strSubTypeName.equalsIgnoreCase("CDMA2000")) {
return NETWORN_3G;
} else {
return NETWORN_MOBILE;
}
}
}
}
return NETWORN_NONE;
}
}下面给大家介绍一下使用方法。我是在类里面写了一个方法，放在了第一次进入app的那个页面，我是在activity的onCreat方法里面，
private void initNet() {
boolean connected = NetUtils.isConnected(FirstActivity.this);
if (connected) {
boolean wifi = NetUtils.isWifi(FirstActivity.this);
boolean rd = NetUtils.is3rd(FirstActivity.this);
if (wifi) {
ToastUtils.makeShortToast(FirstActivity.this, "WIFI已经连接");
} else if (rd) {
ToastUtils.makeShortToast(FirstActivity.this, "手机流量已经连接");
} else {
ToastUtils.makeShortToast(FirstActivity.this, "网络连接不可用，请检查网络设置");
NetUtils.openSetting(FirstActivity.this);
}
} else {
ToastUtils.makeShortToast(FirstActivity.this, "网络连接不可用，请检查网络设置");
NetUtils.openSetting(FirstActivity.this);
}
}