phetsims/vector-addition

problems with touch snag

Closed this issue · 9 comments

kathy-phet commented

I was doing some brief testing on my phone and I find swipe to pick up working with pulling the vector out of the box, but once it is dropped it looks like I have to hit it directly to pick it up - which is hard on a phone. Is it possible to add swipe to pick up to the vectors?

kathy-phet commented

Also adding same question re "axis dot" control? It is hard to pick up.

pixelzoom commented

allowTouchSnag: true is supposed to be the default for the new scenery DragListener, which is what is used throughout this sim. But I'm having the same difficulty on iPad. I'll have to investigate.

pixelzoom commented

Surprisingly, this is not a problem when dragging vectors out of the toolbox, where DragListener.createForwardingListener is used.

pixelzoom commented

There are 3 places where DragListener is used in this sim:

  • the origin manipulator (uses new DragListener)
  • vectors on the graph (uses new DragListener)
  • vectors in the toolboxes (uses DragListener.createForwardingListener)

I verified that every one of the DragListeners in this sim is created with allowTouchSnag: true.

On my iPad6 + iPadOS 13.1.3, the vectors in the toolbox behave reliably; they can always be snagged. The other cases don't snag almost all of the time, but occasionally do snag. So there's something odd going on here.

@jonathanolson can you please take a look?

pixelzoom commented

@kathy-phet what version of iOS is your phone running?

Reply via Slack: iPhone 7 + iOS 12.4.1

pixelzoom commented

Via Slack:

@kathy-phet notes that touch snag works in 1.0.0-dev.42, but does not work in 1.0.0-dev.43. (I have not confirmed or investigated yet.)

@kathy-phet also confirms that touch snag works from the vector toolbox, but not from the graph.

jonathanolson commented

Looks like it's this PressListener being activated by drags or touches:

      // Clicking in the graph clears the active (selected) vector.
      // No need to remove, exists for the lifetime of the sim.
      this.addInputListener( new PressListener( {
        release: () => { graph.activeVectorProperty.value = null; }
      } ) );

If it's necessary to have this as a PressListener, it should probably have attach: false and pressCursor: null. I'm curious as to why the deselect would be on a release, as a raw { down: ... } listener might be better here?

I tested setting that listener to attach: false and touch-snag then seems to work.

pixelzoom commented

Thanks @jonathanolson.

This problem was introduced by #238.

In the above commit, I've converted to a raw 'down' listener. Vector deselection (by clicking on the graph) now occurs on pointer 'down'. This is consistent with vector selection, which also occurs on 'down'.

@arouinfar please review in master or 1.0.0-dev.49. You'll need an iPad or other touch device.

arouinfar commented

Looks good in dev.49

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