@Override
public void onStart(ConnectedNode connectedNode) {
// Subscribe to the laser scans.
Subscriber<sensor_msgs.LaserScan> laserScanSubscriber =
connectedNode.newSubscriber(laserTopic, sensor_msgs.LaserScan._TYPE);
laserScanSubscriber.addMessageListener(this);
// Subscribe to the command velocity. This is needed for auto adjusting the
// zoom in ZoomMode.VELOCITY_ZOOM_MODE mode.
Subscriber<geometry_msgs.Twist> twistSubscriber =
connectedNode.newSubscriber("cmd_vel", geometry_msgs.Twist._TYPE);
twistSubscriber.addMessageListener(
new MessageListener<geometry_msgs.Twist>() {
@Override
public void onNewMessage(final geometry_msgs.Twist robotVelocity) {
post(
new Runnable() {
@Override
public void run() {
distanceRenderer.currentSpeed(robotVelocity.getLinear().getX());
}
});
}
});
setOnTouchListener(this);
// Load the last saved setting.
distanceRenderer.loadPreferences(this.getContext());
}
@Override
public boolean onTouch(View v, MotionEvent event) {
final int action = event.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_MOVE:
{
// Only zoom when there are exactly 2 contacts on the view.
if (event.getPointerCount() == 2) {
// Get the current distance between the 2 contacts.
double currentContactDistance =
calculateDistance(event.getX(0), event.getY(0), event.getX(1), event.getY(1));
// Calculate the delta between the current contact location and the
// previous contact locations. Then add (a fraction of) that delta to
// the existing normalized value for zoom.
// Using half the width of the view provides an appropriate level of
// sensitivity while zooming.
normalizedZoomValue +=
(currentContactDistance - contactDistance) / (this.getWidth() / 2);
if (normalizedZoomValue > 1) {
normalizedZoomValue = 1;
} else if (normalizedZoomValue < 0) {
normalizedZoomValue = 0;
}
distanceRenderer.setNormalizedZoom((float) normalizedZoomValue);
// Remember the current distance between coordinates for later.
contactDistance = currentContactDistance;
}
break;
}
// When the second contact touches the screen initialize contactDistance
// for the immediate round of interaction.
case MotionEvent.ACTION_POINTER_1_DOWN:
{
contactDistance =
calculateDistance(event.getX(0), event.getY(0), event.getX(1), event.getY(1));
break;
}
}
return true;
}
/**
* Updates the current speed in {@link #distanceRenderer} which then can adjust the zoom level in
* velocity mode.
*
* @param speed The linear velocity of the robot.
*/
public void currentSpeed(double speed) {
distanceRenderer.currentSpeed(speed);
}
/** Unlocks the zoom allowing it to be changed. */
public void unlockZoom() {
distanceRenderer.unlockZoom();
}
/** Prevents changes to the zoom level. */
public void lockZoom() {
distanceRenderer.lockZoom();
}
/**
* Sets the zoom mode to one of the modes in {@link ZoomMode}.
*
* @param mode The zoom mode that must be set.
*/
public void setZoomMode(ZoomMode mode) {
distanceRenderer.setZoomMode(mode);
}
@Override
public void onShutdownComplete(Node node) {
// Save the existing settings before exiting.
distanceRenderer.savePreferences(this.getContext());
}
