feat(android): add stopAnimation() to View

[m1ga]

JIRA: https://jira.appcelerator.org/browse/AC-5931

Optional Description:

Android has no possibility to cancel/stop animations like moving an object from left to right before the duration is over. This PR adds a stopAnimation() method to Ti.UI.View

const win = Ti.UI.createWindow();

const lbl = Ti.UI.createLabel({
	text: "-",
	width: Ti.UI.SIZE,
	height: Ti.UI.SIZE
});

const view = Ti.UI.createView({
	backgroundColor: 'red',
	height: 100,
	width: 100,
	top: 0,
	left: 0
});

const btn1 = Ti.UI.createButton({
	title: 'Animate',
	width: 100,
	height: 40,
	bottom: 20,
	left: 10
});
btn1.addEventListener('click', function() {
	view.left = 0;
	view.animate(ani);
});

const btn2 = Ti.UI.createButton({
	title: 'Cancel',
	width: 100,
	height: 40,
	bottom: 20,
	right: 10
});
btn2.addEventListener('click', function() {
	view.stopAnimation();
	view.left = 0;
});

const ani = Ti.UI.createAnimation({
	left: 100,
	duration: 3000
})

ani.addEventListener("start", function() {
	lbl.text = "start";
});

ani.addEventListener("complete", function() {
	lbl.text = "complete";
})

ani.addEventListener("cancel", function() {
	lbl.text = "cancel";
})

win.add([view, btn1, btn2, lbl]);
win.open();

[build]

	Fails
🚫	🔬 There are library changes, but no changes to the unit tests. That's OK as long as you're refactoring existing code, but will require an admin to merge this PR. Please see README.md#unit-tests for docs on unit testing.
🚫	😥 npm test failed. See below for details.

	Warnings
⚠️	🔍 Can't find junit reports at ./junit.*.xml, skipping generating JUnit Report.

	Messages
📖	🎉 Another contribution from our awesome community member, m1ga! Thanks again for helping us make Titanium SDK better. 👍
📖	> titanium-mobile@8.1.0 test /Users/build/jenkins/workspace/ium-sdk_titanium_mobile_PR-10130 > grunt Running "appcJs:src:lintOnly" (appcJs) task Running "eslint:src" (eslint) task /Users/build/jenkins/workspace/ium-sdk_titanium_mobile_PR-10130/build/packager.js 316:17 warning Avoid calling back inside of a promise promise/no-callback-in-promise 317:19 warning Avoid calling back inside of a promise promise/no-callback-in-promise /Users/build/jenkins/workspace/ium-sdk_titanium_mobile_PR-10130/build/scons-xcode-test.js 27:3 warning Each then() should return a value or throw promise/always-return /Users/build/jenkins/workspace/ium-sdk_titanium_mobile_PR-10130/build/utils.js 154:3 warning Avoid using promises inside of callbacks promise/no-promise-in-callback 154:3 warning Avoid using promises inside of callbacks promise/no-promise-in-callback 154:63 warning Each then() should return a value or throw promise/always-return 155:4 warning Avoid calling back inside of a promise promise/no-callback-in-promise 157:4 warning Avoid calling back inside of a promise promise/no-callback-in-promise 175:59 warning Each then() should return a value or throw promise/always-return 176:4 warning Avoid calling back inside of a promise promise/no-callback-in-promise 178:4 warning Avoid calling back inside of a promise promise/no-callback-in-promise 189:3 warning Avoid using promises inside of callbacks promise/no-promise-in-callback 189:3 warning Avoid using promises inside of callbacks promise/no-promise-in-callback 189:51 warning Each then() should return a value or throw promise/always-return 190:4 warning Avoid calling back inside of a promise promise/no-callback-in-promise 192:4 warning Avoid calling back inside of a promise promise/no-callback-in-promise 203:71 warning Each then() should return a value or throw promise/always-return 205:4 warning Avoid calling back inside of a promise promise/no-callback-in-promise 206:17 warning Avoid calling back inside of a promise promise/no-callback-in-promise 218:71 warning Each then() should return a value or throw promise/always-return 220:4 warning Avoid calling back inside of a promise promise/no-callback-in-promise 258:10 warning Each then() should return a value or throw promise/always-return 261:18 warning Avoid calling back inside of a promise promise/no-callback-in-promise /Users/build/jenkins/workspace/ium-sdk_titanium_mobile_PR-10130/iphone/cli/commands/_build.js 6364:79 warning 'out' is defined but never used no-unused-vars /Users/build/jenkins/workspace/ium-sdk_titanium_mobile_PR-10130/iphone/cli/hooks/frameworks.js 61:5 warning Expected catch() or return promise/catch-or-return 61:34 warning Avoid calling back inside of a promise promise/no-callback-in-promise 428:5 warning Each then() should return a value or throw promise/always-return ✖ 27 problems (0 errors, 27 warnings) Running "checkFormat:ios" (checkFormat) task Running "checkFormat:android" (checkFormat) task Fatal error: Error: Formatting incorrect on "android/titanium/src/java/org/appcelerator/titanium/proxy/TiViewProxy.java", proposed changes: <?xml version='1.0'?> <replacements xml:space='preserve' incomplete_format='false'> <replacement offset='21498' length='1'>&#10; </replacement> </replacements> � npm ERR! Test failed. See above for more details.

Generated by 🚫 dangerJS against 0766c04

[sgtcoolguy]

Hey @m1ga Thanks for yet another PR!

Some general thoughts:

• It feels odd to be calling this on the view itself, but I suppose we don't really return an object to call this on otherwise (we don't return something like a Promise to represent the operation). We could potentially call it on a Ti.UI.Animation object that you passed into Ti.UI.View#animate. Makes me curious how this would play with an animation that transitions to a second view...
• It also doesn't really give you control over exactly which animation it'd try and stop. I suppose only one animation per view at a time is executing given our API.
• Nor is there any feedback as to whether/when it gets canceled. Seems like for parity there should be a 'canceled' event fired when an animation is canceled. Or maybe at least a boolean return value for this method to indicate that it will attempt to cancel (i.e. if we know there's no animation or it finished already we'd return false)? I don't see a nice backwards-compatible way to modify the complete event to denote an animation was canceled/stopped.

[m1ga]

@sgtcoolguy thanks for your feedback! As far as I remember you can do animate(null) on iOS to stop an animation, so that would be another way to stop the animation on Android. But I have to check that.
Yes, since there is only one animation playing I thought it would be good to stop it on the view. But I'm open for the Ti.UI.Animation way! Just means that you have to keep track of the animation object. In my case I couldn't access it in the 2nd button.
A callback sounds like a good idea. I'll add a cancelled event, so we have start, complete and cancelled to listen for.

[m1ga]

I think I can't make something like animation.stop() since it looks like that there is no connection between TiAnimation (just storing the parameters) and the actual TiAnimationBuilder that is created from the view where the animation is created

[sgtcoolguy]

@m1ga Sorry about the delay in responding!

Ok, yeah it makes sense that We call stopAnimation() on the view then. I'd still like to see some sort of feedback/mechanism like a callback to handle when an animation is canceled.

Also, my OCD hates that both canceled and cancelled are technically correct, and looking at our API docs I do not see that we stuck with one over the other...

[m1ga]

Added the cancel event, updated the example, added the JIRA ticket

[jquick-axway]

@m1ga, calling View.animate() should stop an existing animation too. On iOS, it does. On Android, the previous animation will continue to animate until its duration has ended, which causes the 2nd given animation to be ignored . This is a pre-existing bug in Titanium and not an issue on your end, but this is good opportunity to fix it. Thanks.

Edit:
Actually, let me see if it's possible to do "tweening" between the 2 animations. That would be better than stopping the animation. It's not particularly valuable on Android "yet" since we only support a "linear" animation, but I'd like us to support "easing" style animations on Android in the near future, like iOS.

[m1ga]

@jquick-axway I've added animate() to call stop, too. Should I remove stopAnimation()?

[jquick-axway]

Should I remove stopAnimation()?

Good question... because I'm wondering if setting View.animate() to null would be a good alternative to stopping an animation. Currently, setting it to null will throw an exception on Android, but we can change that behavior. On iOS, a null animation argument is simply ignored, but doesn't stop the current animation (we can change that too).

Side Note:
I've been experimenting with animations this week. Your fix to the View.animate() method solves an edge case where a translation/scale animation needs to change when the app orientation changes. So, thanks for this. :)

[m1ga]

great...my master branch is broken after testing the github issue PR 😞 need to fix that
edit: fixed!