网络是否可用

public static boolean isNetworkAvailable(Context context) {
if (context != null) {
ConnectivityManager mConnectivityManager = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo mNetworkInfo = mConnectivityManager.getActiveNetworkInfo();
if (mNetworkInfo != null) {
return mNetworkInfo.isAvailable();
}
}
return false;
}

protected  void isNetworkAvailable() {
if(!StringUtils.isNetworkAvailable(this)) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("没有网络!");
builder.setTitle("提示");
builder.setCancelable(false);
builder.setPositiveButton("重新尝试", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
isNetworkAvailable();
dialog.dismiss();
}
});
builder.create().show();
}else {
initData();
}
}