uibutton 初始化

UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    btn.frame = CGRectMake(30, 360, 90, 35);
    //[btn setTitle:@"ZoomIn" forState:UIControlStateNormal];
    //[btn setTitle:@"ZoomIn" forState:UIControlStateHighlighted];
    [btn addTarget:self action:@selector(zoomInAction:) forControlEvents:UIControlEventTouchUpInside];
    [btn setImage:[UIImage imageNamed:@"2.png"] forState:UIButtonTypeCustom];
    //[myScrollView addSubview:img];
    [self.view addSubview:btn];