Menangkap Bintang

*This time I will tell you about my frustrating students

I have this one class, the second grade of junior high school.
The students in this class is very lazy, and they seem not to have any will to study.
I've done many things to solve this problem, but nothing seems to work.

Oh, I forgot to say that this only happens to the male students, meanwhile I have no problems with the female ones.

To give a more vivid insight of what is really going on in the class, I'd better tell something happened yesterday.
So, it was time for my subject. I was on the way to the classroom when I say 2 male students were still eating something in the 'canteen' (it's not really a canteen really, it's just someone selling snacks near the classroom). I told them to get in the class, since the break time had been over several minutes ago. But you know what happened? They insisted not to come to the class. I waited for some minutes more, and they still didn't want to come. So, I've lost my temper. I told them to just stay outside and not to come to the class. They HAPPILY did that.
This is not the first time, you know. It happened many times, and I'm sure will happen again and again.
And then, I came into the class and found only the female students and 2 male students. A few minutes later, came the other male students. I let them in. But what they always do in the class is talking, and talking, and talking, nothing more. Every time I ask them stop talking, they will immediately sleep. Gosh!!
I took this pictures yesterday, have a look, so that you know how I feel.
And please give me solutions if you can.