-(void)listButton{
    // #define OPTION_BUT_HEIGHT   50
    // #define OPTION_BUT_WIDTH    180 
    // CGSize          _screenSize;            
    // _screenSize               = [UIScreen mainScreen].bounds.size;

    NSInteger numButton = 2;
    NSInteger butIndex0 = 0;
    NSInteger butIndex1 = 1;
    
    UIButton* backButton = [UIButton buttonWithType:UIButtonTypeSystem];
    CGRect frame    = CGRectMake((_screenSize.width - OPTION_BUT_WIDTH)/2, butIndex0*(_screenSize.height - 
    (numButton*OPTION_BUT_HEIGHT))/(numButton+1) + 3*OPTION_BUT_HEIGHT, OPTION_BUT_WIDTH, OPTION_BUT_HEIGHT);

    backButton.frame     = frame;
    [backButton addTarget:self action:@selector(but0Click:) forControlEvents:UIControlEventTouchUpInside];
    [backButton setTitle:@"Button 0" forState:(UIControlState) UIControlStateNormal];
    [backButton.titleLabel setFont:[UIFont fontWithName:@"MarkerFelt-Thin" size:18]];
    [backButton setBackgroundColor:[UIColor brownColor]];
    [backButton setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];
    [self.view addSubview:backButton];

    UIButton* resumeButton = [UIButton buttonWithType:UIButtonTypeSystem];
    CGRect resumeFrame    = CGRectMake((_screenSize.width - OPTION_BUT_WIDTH)/2, butIndex1*(_screenSize.height - 
    (numButton*OPTION_BUT_HEIGHT))/(numButton+1) + 3*OPTION_BUT_HEIGHT, OPTION_BUT_WIDTH, OPTION_BUT_HEIGHT);

    resumeButton.frame = resumeFrame;
    [resumeButton addTarget:self action:@selector(but1Click:) forControlEvents:UIControlEventTouchUpInside];
    [resumeButton setTitle:@"Button 1" forState:(UIControlState) UIControlStateNormal];
    [resumeButton.titleLabel setFont:[UIFont fontWithName:@"MarkerFelt-Thin" size:18]];
    [resumeButton setBackgroundColor:[UIColor greenColor]];
    [resumeButton setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];
    [self.view addSubview:resumeButton];
}