for (int i = 0; i < self.bmb.pieceNumber; i++)
{
    VHSimpleCircleButtonBuilder *builder = [VHSimpleCircleButtonBuilder builder];
    
    // Event block when the boom-button corresponding the builder itself is clicked.
    builder.clickedBlock = ^(int index) {
        // the boom-button is clicked
    };
    [self.bmb addBuilder:builder];
}

...
bmb.boomDelegate = self;
...
- (void)boomMenuButton:(VHBoomMenuButton *)bmb didClickBoomButtonOfBuilder:(VHBoomButtonBuilder *)builder at:(int)index
{
    // If you have implement clickedBlocks for boom-buttons in builders,
    // then you shouldn't add any listener here for duplicate callbacks.
    
    // self.buttonLabel.text = builder.normalImageName;
}
- (void)boomMenuButtonDidClickBackground:(VHBoomMenuButton *)bmb
{
    self.animationLabel.text = @"Click background!!!";
}
- (void)boomMenuButtonWillReboom:(VHBoomMenuButton *)bmb
{
    self.animationLabel.text = @"Will RE-BOOM!!!";
}
- (void)boomMenuButtonDidReboom:(VHBoomMenuButton *)bmb
{
    self.animationLabel.text = @"Did RE-BOOM!!!";
}
- (void)boomMenuButtonWillBoom:(VHBoomMenuButton *)bmb
{
    self.animationLabel.text = @"Will BOOM!!!";
}
- (void)boomMenuButtonDidBoom:(VHBoomMenuButton *)bmb
{
    self.animationLabel.text = @"Did BOOM!!!";
}

bmb.isAnimating  // Whether BMB is animating.
bmb.isBoomed     // Whether BMB is boomed.
bmb.isReBoomed   // Whether BMB is re-boomed.