Hi Greg, wow. Thanks a lot for such detailed information.
I have been trying to do what i described above with View and Animation, just like you said. and it seems to work just fine, though currently doesn't look so good as "ZoomControls" :) maybe i should use some images in the Views instead of pure text. Thanks again and it helps a lot~:) Fu On Apr 5, 2:26 pm, Greg Krimer <[email protected]> wrote: > Hi, > > A good place to start is to look at the ApiDemos application to see if > there is anything there close to what you want. The best I found is > com.example.android.apis.view.Animation2, which uses a ViewFlipper to > transition from one view to another with various animations. It's not > exactly what we want, because we actually want to fade in/out a single > view. But Animation2 does give us the names of the fading animations: > android.R.anim.fade_in and android.R.anim.fade_out. > > You can apply an animation to any view (and its children) by calling > startAnimation(). So ... > > myView.startAnimation(AnimationUtils.loadAnimation(mContext, > android.R.anim.fade_in)) > > ... would fade in the view and ... > > myView.startAnimation(AnimationUtils.loadAnimation(mContext, > android.R.anim.fade_out)) > > ... would fade it out. > > The trick is that when the animation ends we want to change the > visibility of the view. If we are fading in then at the end of the > animation we want to make the view visible. If we are fading out then > at the end of the animation we want to make the view invisible. > > Luckily, views have a onAnimationEnd() method that is called when the > animation terminates. We can override this method and change the > visibility of the view as appropriate. Because we want to override a > method we will need a custom view. Our custom view might have methods > like this: > > public void fadeIn() { > startAnimation(AnimationUtils.loadAnimation(mContext, > android.R.anim.fade_in)); > mVisibilityOnAnimationEnd = VISIBLE; > } > > public void fadeOut() { > startAnimation(AnimationUtils.loadAnimation(mContext, > android.R.anim.fade_out)); > mVisibilityOnAnimationEnd = INVISIBLE; > } > > @Override public void onAnimationEnd() { > super.onAnimationEnd(); // make sure to chain up to > superclass > method > setVisibility(mVisibilityOnAnimationEnd); > } > > private int mVisibilityOnAnimationEnd; > > Anyway, that's the simplest way I can think of doing this. Anyone have > other ideas? > > Now, we still need to figure out what View to extend. Every view > accepts the onClick event, so we can extend ImageView. But the zoom > control has two clickable images, so more likely we will need to > extend a view group such as LinearLayout. > > Getting our view to appear now just requires calling fadeIn() and > getting our view to disappear just requires calling fadeOut(). To get > the view to disappear after a delay create a Handler and either send > it a message with a delay or post a runnable with a delay. > > Hope that gets you started. > > Greg > > On Apr 4, 1:48 am, AllSet <[email protected]> wrote: > > > > > i am trying to make a control which looks like the ZoomControls. > > > it is supposed to show up when clicking in a certain area and > > disappear a few seconds later. > > > also it should accept the onClick event. > > > but i don't know exactly how to realize such a control. > > > could anybody help me? > > > thanks in advance! --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~----------~----~----~----~------~----~------~--~---
