Touch Input for Mobile Scripting

• Began: A finger has just begun touching the screen
• Moved: The finger has moved position, without breaking contact with the screen, since it was last polled
• Stationary: The finger has remained in position without breaking contact with the screen since it was last polled (not used in this workflow)
• Ended: The finger is no longer touching the screen
• Cancelled: Tracking for this touch has been cancelled (not used in this workflow)

• For this demonstration, we’ll need to use Unity’s UI. This isn’t a requirement to use mobile touch, but we’re using it for our purposes in displaying the touch phase. On line 4, type:

using UnityEngine.UI;

• Now we’ll declare our data members. Beginning on line 7, type:

public Text phaseDisplayText;
private Touch theTouch;
private float timeTouchEnded;
private float displayTime = .5f;

• In Update, beginning on line 14, type:

if (Input.touchCount > 0)
{
	theTouch = Input.GetTouch(0);
	phaseDisplayText.text = theTouch.phase.ToString();

	if (theTouch.phase == TouchPhase.Ended)
	{
		timeTouchEnded = Time.time;
	}
}

else if (Time.time - timeTouchEnded > displayTime)
{
	phaseDisplayText.text = “”;
}

• TouchPhaseDisplay is now complete. (Figure 01) Save changes and return to the Unity Editor.

Select image to expand

Figure 01: The completed TouchPhaseDisplay script

• Back in the Unity Editor, from the GameObject dropdown, select Create Empty, name it TouchDisplay, and attach the Touch Phase Display component.
• From the GameObject dropdown select UI > Text, making sure that it clearly displays the following test phrase with the Game display resolution set to that of your mobile device: Stationary
• Drag the newly created UI Text object into the slot marked Debug Text in the Touch Phase Display component of TouchDisplay. (Figure 02)

Select image to expand

Figure 02: The name will change with each exercise, but all three will use the display text.

• Build and run your project on your physical or emulated mobile device. Tap the screen and note the status display. Try moving your finger while touching the screen, or just holding it in one place.
• Exit the demonstration.

• On line 4, type:

using UnityEngine.UI;

• Beginning on line 7, type:

public Text directionText;

private Touch theTouch;
private Vector2 touchStartPosition, touchEndPosition;
private string direction;

• In Update, beginning on line 17, type:

if (Input.touchCount > 0)
{
	theTouch = Input.GetTouch(0);

	if (theTouch.phase == TouchPhase.Began)
	{
		touchStartPosition = theTouch.position;
	}

	else if (theTouch.phase == TouchPhase.Moved || theTouch.phase == TouchPhase.Ended)
	{
		touchEndPosition = theTouch.position;

		float x = touchEndPosition.x - touchStartPosition.x;
		float y = touchEndPosition.y - touchStartPosition.y;

		if (Mathf.Abs(x) == 0 && Mathf.Abs(y) == 0)
		{
			direction = “Tapped”;
		}

		else if (Mathf.Abs(x) > Mathf.Abs(y))
		{
			direction = x > 0 ? “Right” : “Left”;
		}

		else
		{
			direction = y > 0 ? “Up” : “Down”;
		}
	}
}

directionText.text = direction;

• VirtualDPad is now complete. (Figure 03) Save changes and return to the Unity Editor.

Select image to expand

Figure 03: The completed VirtualDPad script

• In the hierarchy window, right click TouchDisplay and select Rename. Type DpadTester. In the Inspector, click the gear in the upper right corner of the Touch Phase Display component, or right click Touch Phase Display (Script), and select Remove Component. (Figure 04)

Select image to expand

Figure 04

• Add the Virtual D Pad component and drag the UI text into the Direction Text slot.
• Build and run your project on your physical or emulated mobile device. Try tapping the screen and lifting your finger or stylus without moving it. Swipe in different directions and notice how even the smallest movement in any direction registers a direction. In an actual game, you would probably want to have a minimum change in touch position before movement is registered, and/or scale movement by how far the virtual D-pad is moved.
• Exit the demonstration.

• On line 4, type:

using UnityEngine.UI;

• Beginning on line 7, type:

public Text multiTouchInfoDisplay;

private int maxTapCount = 0;
private string multiTouchInfo;
private touch theTouch;

• In Update, beginning on line 15, type:

multiTouchInfo = string.Format(“Max tap count: {0}\n”, maxTapCount);

if (Input.touchCount > 0)
{
	for (int i = 0; i < Input.touchCount; i++)
	{
		theTouch = Input.GetTouch(i);
		
		multiTouchInfo +=
			string.Format(“Touch {0} - Position {1} - Tap Count: {2} - Finger ID: {3}\nRadius: {4} ({5}%)\n”,
			i, theTouch.position, theTouch.tapCount, theTouch.fingerId, theTouch.radius,
			((theTouch.radius/(theTouch.radius + theTouch.radiusVariance)) * 100f).ToString(“F1”));

		if (theTouch.tapCount > maxTapCount)
		{
			maxTapCount = theTouch.tapCount;
		}
	}
}

multiTouchInfoDisplay.text = multiTouchInfo;

• MultiTouchDisplay is now complete. (Figure 05) Rename DPadTester to MultiTouch as in earlier exercises. Remove the Virtual D Pad component and add Multi Touch Display. Finally, add the Multi Touch Display component to MultiTouch and drag the UI text object into the Multi Touch Info Display slot.

Select image to expand

Figure 05: the completed MultiTouchDisplay script

• Build and run your project on your physical or emulated Android device. Using as many fingers as you can, experiment with mixing the order in which you touch and lift fingers. Try holding three or more fingers on the screen, then temporarily lifting one of the middle (in the sequence of touches) fingers. Watch how the position coordinates jump, but Unity is able to tell which finger was lifted, indicated by the finger ID. Try getting the tap count past 100. Notice how each finger contributes only to its own tap count. Using just a single touch, the tap count times out and resets to zero briefly after a touch ends. What strategy can you use with multiple touches to keep it from resetting? Try rolling your fingertip on the screen as if you were being fingerprinted, or just barely tapping the screen and monitoring how the radius changes.
• When you’re ready, exit the exercise application.