Keep current slider position when rotate device

[rr-hung-nguyen]

I want to keep current slider status when the device rotated. So i create new slider and set left-right position for this:
self.mySAVideoRangeSlider.leftPosition = self.startTime * ratio;
self.mySAVideoRangeSlider.rightPosition = self.stopTime * ratio;
But it worked incorrect, slider's position is wrong. Are there any solution for my problem? Thanks so much.