public void computeScroll() {
if (mDecelerationVelocity.x == 0.f && mDecelerationVelocity.y == 0.f)
return; // There's no deceleration in progress
final long currentTime = AnimationUtils.currentAnimationTimeMillis();
mDecelerationVelocity.x *= mChart.getDragDecelerationFrictionCoef();
mDecelerationVelocity.y *= mChart.getDragDecelerationFrictionCoef();
final float timeInterval = (float) (currentTime - mDecelerationLastTime) / 1000.f;
float distanceX = mDecelerationVelocity.x * timeInterval;
float distanceY = mDecelerationVelocity.y * timeInterval;
mDecelerationCurrentPoint.x += distanceX;
mDecelerationCurrentPoint.y += distanceY;
MotionEvent event =
MotionEvent.obtain(
currentTime,
currentTime,
MotionEvent.ACTION_MOVE,
mDecelerationCurrentPoint.x,
mDecelerationCurrentPoint.y,
0);
performDrag(event);
event.recycle();
mMatrix = mChart.getViewPortHandler().refresh(mMatrix, mChart, false);
mDecelerationLastTime = currentTime;
if (Math.abs(mDecelerationVelocity.x) >= 0.01 || Math.abs(mDecelerationVelocity.y) >= 0.01)
Utils.postInvalidateOnAnimation(
mChart); // This causes computeScroll to fire, recommended for this by Google
else {
// Range might have changed, which means that Y-axis labels
// could have changed in size, affecting Y-axis size.
// So we need to recalculate offsets.
mChart.calculateOffsets();
mChart.postInvalidate();
stopDeceleration();
}
}
@SuppressLint("ClickableViewAccessibility")
@Override
public boolean onTouch(View v, MotionEvent event) {
if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(event);
if (event.getActionMasked() == MotionEvent.ACTION_CANCEL) {
if (mVelocityTracker != null) {
mVelocityTracker.recycle();
mVelocityTracker = null;
}
}
if (mTouchMode == NONE) {
mGestureDetector.onTouchEvent(event);
}
if (!mChart.isDragEnabled() && (!mChart.isScaleXEnabled() && !mChart.isScaleYEnabled()))
return true;
// Handle touch events here...
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
stopDeceleration();
saveTouchStart(event);
break;
case MotionEvent.ACTION_POINTER_DOWN:
if (event.getPointerCount() >= 2) {
mChart.disableScroll();
saveTouchStart(event);
// get the distance between the pointers on the x-axis
mSavedXDist = getXDist(event);
// get the distance between the pointers on the y-axis
mSavedYDist = getYDist(event);
// get the total distance between the pointers
mSavedDist = spacing(event);
if (mSavedDist > 10f) {
if (mChart.isPinchZoomEnabled()) {
mTouchMode = PINCH_ZOOM;
} else {
if (mSavedXDist > mSavedYDist) mTouchMode = X_ZOOM;
else mTouchMode = Y_ZOOM;
}
}
// determine the touch-pointer center
midPoint(mTouchPointCenter, event);
}
break;
case MotionEvent.ACTION_MOVE:
if (mTouchMode == DRAG) {
mChart.disableScroll();
performDrag(event);
} else if (mTouchMode == X_ZOOM || mTouchMode == Y_ZOOM || mTouchMode == PINCH_ZOOM) {
mChart.disableScroll();
if (mChart.isScaleXEnabled() || mChart.isScaleYEnabled()) performZoom(event);
} else if (mTouchMode == NONE
&& Math.abs(
distance(event.getX(), mTouchStartPoint.x, event.getY(), mTouchStartPoint.y))
> 5f) {
if (mChart.hasNoDragOffset()) {
if (!mChart.isFullyZoomedOut() && mChart.isDragEnabled()) mTouchMode = DRAG;
else {
if (mChart.isHighlightPerDragEnabled()) performHighlightDrag(event);
}
} else if (mChart.isDragEnabled()) {
mTouchMode = DRAG;
}
}
break;
case MotionEvent.ACTION_UP:
final VelocityTracker velocityTracker = mVelocityTracker;
final int pointerId = event.getPointerId(0);
velocityTracker.computeCurrentVelocity(1000, Utils.getMaximumFlingVelocity());
final float velocityY = velocityTracker.getYVelocity(pointerId);
final float velocityX = velocityTracker.getXVelocity(pointerId);
if (Math.abs(velocityX) > Utils.getMinimumFlingVelocity()
|| Math.abs(velocityY) > Utils.getMinimumFlingVelocity()) {
if (mTouchMode == DRAG && mChart.isDragDecelerationEnabled()) {
stopDeceleration();
mDecelerationLastTime = AnimationUtils.currentAnimationTimeMillis();
mDecelerationCurrentPoint = new PointF(event.getX(), event.getY());
mDecelerationVelocity = new PointF(velocityX, velocityY);
Utils.postInvalidateOnAnimation(
mChart); // This causes computeScroll to fire, recommended for this by Google
}
}
if (mTouchMode == X_ZOOM
|| mTouchMode == Y_ZOOM
|| mTouchMode == PINCH_ZOOM
|| mTouchMode == POST_ZOOM) {
// Range might have changed, which means that Y-axis labels
// could have changed in size, affecting Y-axis size.
// So we need to recalculate offsets.
mChart.calculateOffsets();
mChart.postInvalidate();
}
mTouchMode = NONE;
mChart.enableScroll();
if (mVelocityTracker != null) {
mVelocityTracker.recycle();
mVelocityTracker = null;
}
break;
case MotionEvent.ACTION_POINTER_UP:
Utils.velocityTrackerPointerUpCleanUpIfNecessary(event, mVelocityTracker);
mTouchMode = POST_ZOOM;
break;
case MotionEvent.ACTION_CANCEL:
mTouchMode = NONE;
break;
}
// Perform the transformation, update the chart
// if (needsRefresh())
mMatrix = mChart.getViewPortHandler().refresh(mMatrix, mChart, true);
return true; // indicate event was handled
}