Button["ahoj",Print["au"]]

RadioButton[x,True]

x=0

y=1

Panel[Slider[Dynamic[x+y,(x=#)&],{0,20}]]

Dynamic[x]

Dynamic[y]

Slider[Dynamic[x],{-20,20}]
Slider[Dynamic[x],{20,-20}]

Slider[Dynamic[x],#]&/@{{-20,20},{20,-20}}

InputField[Dynamic[x,{(x=Floor[#])&,If[IntegerQ[#1],x=#1,x=Floor[#1]]&}],Number]

Dynamic[x//FullForm]

x=5

InputField[Dynamic[z],Background->Dynamic[If[IntegerQ[z],White,Red]]]

Dynamic[Column[
RadioButton[Dynamic[x],#]& /@Range[z]
]
]
Dynamic[x]

Column@Range[5]//FullForm

Panel[
Column[{
"prvni radek",
Row[{"x = ",InputField[x]}]
}]
]

RadioButtonBar[Dynamic[x],{1,2,3,4}]