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iphoneandroidscrolltouches

how to achieve same flinging results on android & iphone

I ported a game from iPhone to android. All OpenGL based, and exactly the same calculations for scrolling. I noticed that on the iPhone when scrolling through the game I can scroll faster, and the starting speed as I lifted my finger felt the same as my finger was moving.

However on the android device unfortunatly this was wan not the same. As I lifter my finger when scrolling, the start scroll speed felt slower. Scrolling on the iPhone feels more accurate.

Is there anything special about how the android handles the touches that is differnt than the iPhone? and how can I take advantage of this to achieve a similar feeling as on the iPhone. On the On Android all applications when flinging the speed that I have lifted my finger from doesn't feel the same as how fast my finger moved.

Solution

  • I found it. The android gives a ACTION_MOVE then a ACTION_UP for the same (or close) location. iPhone doesn't do this at all! It just gives a touchesEnded! So if there is motion I will at minimum have 3 points on the android ALWAYS, But on the iPhone its 2 points (touch down, touch up both at different locations)

    The next thing is the ACTION_MOVE AND ACTION_UP don't happen right away, and its significant time interval when calculating the average speed of sampled points.

    Solution: On ACTION_UP, if there is a ACTION_MOVE slide all the seconds stored so that the ACTION_MOVE "happens" when the ACTION_UP occured. Don't put the final touches up point in the speed calculation. And now calculate speed as usual.

    Summary

    On Android if you have moved your finger you get a ACTION_MOVE before a ACTION_UP. And ACTION_UP is roughly at the same location at the ACTION_MOVE making it seem as if the speed at the end is roughly 0. iPhone does not do this, iPhone does not give a touchesMoved for the last touchesEnded (IE touch down, move finger, lift, if you do it fast enough on iPhone you wont get the intermediate event for touchesMoved your finger, where as on the android you do).

    Android / iPhone equivalent's

    1. ACTION_UP = touchesEnded
    2. ACTION_DOWN = touchesBegan
    3. ACTION_MOVE = touchesMoved

    Also I noticed on Android there is some point history functions. I did not use those. I stored touches and there timestamps in my own array.