判断网络类型

ConnectivityManager connectivityManager = (ConnectivityManager) this.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();

        if(networkInfo==null){
            Toast.makeText(this,"没有可用网络",Toast.LENGTH_SHORT).show();
        }
        else if(networkInfo.getType()==ConnectivityManager.TYPE_WIFI){
            Toast.makeText(this,"wifi网络",Toast.LENGTH_SHORT).show();
        }
        else if(networkInfo.getType()==ConnectivityManager.TYPE_MOBILE){
            Toast.makeText(this,"手机网络",Toast.LENGTH_SHORT).show();
        }

注意要添加权限：

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />