Add support for folders on home screen

[esensar]

This adds very basic support for folders on home screen. They are created by dragging icons on top of each other. These folders have a static folder icon right now.

[esensar]

This should be ready to test now.

There are improvements that could be made:

• Folder icons - either allow some kind of customization or generate it based on icons inside of it
• Animations - currently when dropping items inside the folder, other items can get rearranged if new icon is dropped in the middle - this looks really jumpy right now since there are no animations at all
• Folder opening animation could look nice too

The logic for moving items around isn't perfect at the moment. It can happen sometimes that gaps appear in folders.

[tibbi]

the folder definitely needs to show icons instead of the generic folder icon. And other UI improvements are needed too, but it seems to work fine and going in the right direction :)

[tibbi]

I created a folder with 2 icons and then after dragging the second icon out of the folder to dismiss it, the app crashed
Process: com.simplemobiletools.launcher.debug, PID: 9105
java.lang.IllegalArgumentException: Cannot round NaN value.
at kotlin.math.MathKt__MathJVMKt.roundToInt(MathJVM.kt:1165)
at com.simplemobiletools.launcher.views.HomeScreenGrid.getFolderRect(HomeScreenGrid.kt:1500)
at com.simplemobiletools.launcher.views.HomeScreenGrid.onDraw(HomeScreenGrid.kt:1096)
at android.view.View.draw(View.java:24406)
at android.view.View.updateDisplayListIfDirty(View.java:23267)
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:4732)
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:4704)
at android.view.View.updateDisplayListIfDirty(View.java:23214)
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:4732)
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:4704)
at android.view.View.updateDisplayListIfDirty(View.java:23214)
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:4732)
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:4704)
at android.view.View.updateDisplayListIfDirty(View.java:23214)
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:4732)
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:4704)
at android.view.View.updateDisplayListIfDirty(View.java:23214)
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:4732)
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:4704)
at android.view.View.updateDisplayListIfDirty(View.java:23214)
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:4732)
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:4704)
at android.view.View.updateDisplayListIfDirty(View.java:23214)
at android.view.ThreadedRenderer.updateViewTreeDisplayList(ThreadedRenderer.java:777)
at android.view.ThreadedRenderer.updateRootDisplayList(ThreadedRenderer.java:783)
at android.view.ThreadedRenderer.draw(ThreadedRenderer.java:881)
at android.view.ViewRootImpl.draw(ViewRootImpl.java:5647)
at android.view.ViewRootImpl.performDraw(ViewRootImpl.java:5330)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:4486)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:3116)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:10885)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1301)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1309)
at android.view.Choreographer.doCallbacks(Choreographer.java:923)
at android.view.Choreographer.doFrame(Choreographer.java:852)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:1283)
at android.os.Handler.handleCallback(Handler.java:942)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loopOnce(Looper.java:226)
at android.os.Looper.loop(Looper.java:313)
at android.app.ActivityThread.main(ActivityThread.java:8757)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:604)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1067)

[esensar]

The crash should be fixed now, but I think I will need to do some further work on handling these changes, since there are some thing happening asynchronously and I think there is room for such race conditions right now.

[tibbi]

check the conflicts please

[esensar]

Not sure if I should work on animations when placing items inside folders (when reordering items after new one has been placed in the folder). Other than that, this is ready for testing.

[tibbi]

lets add a small vibration on long pressing a folder, like at long pressing an icon

[tibbi]

if you have 2 lines of icons in the folder, the vertical empty space between them is too big

[tibbi]

no need to add new animations now, lets focus on making it work well first

[tibbi]

alright, this seems to work just fine to me now :)