use "forms"

label = newLabel("Current value: 50")
progressBar = newProgressBar()
progressBar.setValue(50)
progressBar.onChange(def() {
  label.setText("Current value: " + progressBar.getValue())
})
minusBtn = newButton("-1")
minusBtn.onClick(def() = changeProgress(-1))
plusBtn = newButton("+1")
plusBtn.onClick(def() = changeProgress(1))

def changeProgress(delta) {
  value = progressBar.getValue() + delta
  if (value > 100) value = 100
  else if (value < 0) value = 0
  progressBar.setValue(value)
}

window = newWindow("ProgressBar example")
window.add(minusBtn, BorderLayout.WEST)
window.add(progressBar, BorderLayout.CENTER)
window.add(plusBtn, BorderLayout.EAST)
window.add(label, BorderLayout.SOUTH)
window.pack()
window.setLocationByPlatform()
window.setResizable(false)
window.setVisible()