[TIMOB-26168] Android: Fix initializing of scrollbars

[garymathews]

• Scrollbars do not show in Titanium.UI.ScrollView
• Works around a Google bug where scrollbars are not initialized

TEST CASE

const win = Ti.UI.createWindow({ backgroundColor: 'gray' }),
      scrollView = Ti.UI.createScrollView({
          showVerticalScrollIndicator: true,
          width: Ti.UI.FILL,
          height: Ti.UI.FILL
      }),
      view = Ti.UI.createLabel({
          backgroundColor: 'blue',
          width: Ti.UI.FILL,
          height: 1000,
          text: Array(16).join('SCROLL ')
      });

scrollView.add(view);

win.add(scrollView);
win.open();

• Scrollbar should be visible when scrolling

JIRA Ticket

[ComputerTinker]

Gary, thanks for this fix. I attempted to cherrypick it, apply it to the 7.2.x branch, and test it out. The SDK I compiled works great on Android 6, however when I run in Android 4.1 it crashes with the following errors:

[ERROR] : dalvikvm: Could not find class 'android.graphics.drawable.RippleDrawable', referenced from method org.appcelerator.titanium.view.TiUIView.applyTouchFeedback
[WARN] : dalvikvm: VFY: unable to resolve new-instance 207 (Landroid/graphics/drawable/RippleDrawable;) in Lorg/appcelerator/titanium/view/TiUIView;
[WARN] : dalvikvm: threadid=1: thread exiting with uncaught exception (group=0xb116c228)
[ERROR] : TiApplication: (main) [38,38] Sending event: exception on thread: main msg:java.lang.RuntimeException: Unable to start activity ComponentInfo{APP_NAME/org.appcelerator.titanium.TiActivity}: java.lang.NullPointerException; Titanium 7.2.1,2018/07/02 16:49,undefined
[ERROR] : TiApplication: java.lang.RuntimeException: Unable to start activity ComponentInfo{edu.bju.logia/org.appcelerator.titanium.TiActivity}: java.lang.NullPointerException

Perhaps when I compile locally the results differ from the official build process? Is there a way I could get access to the SDK build you generated for this patch?

[garymathews]

@ComputerTinker Nice catch! Although it looks to be unrelated to this change. I've added the fix anyway.

[jquick-axway]

@ComputerTinker, perhaps you had a bad merge? Where it was crashing was already guarded with canApplyTouchFeedback() which checked the API Level.

Also, are you setting the touchFeedback property on a ScrollView? I don't think that would normally work with ScrollViews since they're designed to use "intercepted" touch events.

[jquick-axway]

CR: Pass

[ComputerTinker]

@garymathews for some reason your fix didn't work. I don't know why there's a difference between "min target android version" and "min android version" in the compatibility matrix, but to my untrained eyes it seems as though we're forced to compile with >= v23 even though the code will run with >= v16, so perhaps that's why the (Build.VERSION.SDK_INT >= 21) check isn't catching it?

@jquick-axway I made sure to do a fresh checkout of 7.2.X and cherrypicked just Gary's two patches (which only update two files) so the code seems fine to me. I'm not setting touchFeedback on the ScrollView that I know of. The XML looks like this:

[ComputerTinker]

I thought I would be smart and just comment out the RippleDrawable bits in TiUIView.java, however after doing that the app still blows up, although this time in a slightly different way. The following error jumps out at me:

Could not find class 'android.graphics.drawable.RippleDrawable', referenced from method android.support.v7.widget.AppCompatImageHelper.hasOverlappingRendering

[ComputerTinker]

One last thing I'll mention is that my app works fine when I compile it against 7.2.0.GA (it's just that there are no scrollbars), so it seems as though a recent patch has broken Android 4.x support in the 7.2.X branch.

[jquick-axway]

I still think this is a bad merge. Instead of cherrypicking the changes over. Just copy and paste the TiUIScrollView.java file over to 7.2.x. That's all that's needed.

Edit:
And make sure to do a clean build too. I suspect you must have switched from "master" to "7_2_X" and it wasn't a clean switch over. You may have remnants of the newest Google support libraries/resources from master mixed in with 7.2.x, because the error you are running into is related to resources included with Google's support libraries and has nothing to do with this PR's code change.

[garymathews]

@ComputerTinker You could replace titanium-ui.jar in your 7.2.0 SDK with titanium-ui.jar

[ComputerTinker]

@garymathews thanks for the jar file, and sorry about the delayed response.

I tried replacing the existing titanium-ui.jar file in /Users/USER_NAME/Library/Application Support/Titanium/mobilesdk/osx/7.2.0.GA/android/modules/ with the one you provided. Then I uninstalled the old version of my app, did a Project->Clean and built again in Appcelerator Studio, but unfortunately my program blew up immediately upon launch. Parsing through the log I see a bunch of errors related to transitions, and then:

[ERROR] : dalvikvm: Could not find class 'android.graphics.drawable.RippleDrawable', referenced from method org.appcelerator.titanium.view.TiUIView.applyTouchFeedback

[ERROR] : dalvikvm: Could not find class 'android.graphics.drawable.RippleDrawable', referenced from method android.support.v7.widget.AppCompatImageHelper.hasOverlappingRendering

[ERROR] : TiApplication: (main) [358,358] Sending event: exception on thread: main msg:java.lang.NullPointerException; Titanium 7.2.0,2018/06/07 05:21,undefined
[ERROR] : TiApplication: java.lang.NullPointerException
[ERROR] : TiApplication: at android.widget.ScrollBarDrawable.setAlpha(ScrollBarDrawable.java:221)
[ERROR] : TiApplication: at android.view.View.onDrawScrollBars(View.java:11268)
[ERROR] : TiApplication: at android.view.View.draw(View.java:13464)
[ERROR] : TiApplication: at android.widget.FrameLayout.draw(FrameLayout.java:467)
[ERROR] : TiApplication: at android.support.v4.widget.NestedScrollView.draw(NestedScrollView.java:1815)
[ERROR] : TiApplication: at android.view.View.getDisplayList(View.java:12409)
[...]

I can post the entire log if you like, but I think it's largely similar to the one I posted earlier.

If I put the old .jar file back and repeat the clean and recompile process, my app works again.

[lokeshchdhry]

@garymathews , I am seeing the same issue as @ComputerTinker , on android 4.1 app is stuck at splash

[garymathews]

@lokeshchdhry Updated PR

[ComputerTinker]

@garymathews, it works!! I did a fresh checkout of 7_2_X and applied your updated PR and now my app no longer longer crashes and I have scrollbars. Thank you!

[jquick-axway]

CR: Pass

[build]

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