下面列出了android.view.View#OVER_SCROLL_ALWAYS 实例代码,或者点击链接到github查看源代码,也可以在右侧发表评论。
public static int parseOverScrollMode(String jsOverScrollMode) {
if (jsOverScrollMode == null || jsOverScrollMode.equals(AUTO)) {
return View.OVER_SCROLL_IF_CONTENT_SCROLLS;
} else if (jsOverScrollMode.equals(OVER_SCROLL_ALWAYS)) {
return View.OVER_SCROLL_ALWAYS;
} else if (jsOverScrollMode.equals(OVER_SCROLL_NEVER)) {
return View.OVER_SCROLL_NEVER;
} else {
throw new JSApplicationIllegalArgumentException("wrong overScrollMode: " + jsOverScrollMode);
}
}
@Override
public void computeScroll() {
if (mScroller.computeScrollOffset()) {
int oldX = getScrollX();
int oldY = getScrollY();
int x = mScroller.getCurrX();
int y = mScroller.getCurrY();
if (oldX != x || oldY != y) {
final int range = getScrollRange();
final int overscrollMode = getOverScrollMode();
final boolean canOverscroll = overscrollMode == View.OVER_SCROLL_ALWAYS
|| (overscrollMode == View.OVER_SCROLL_IF_CONTENT_SCROLLS && range > 0);
overScrollByCompat(x - oldX, y - oldY, oldX, oldY, 0, range,
0, 0, false);
if (canOverscroll) {
ensureGlows();
if (y <= 0 && oldY > 0) {
mEdgeGlowTop.onAbsorb((int) mScroller.getCurrVelocity());
} else if (y >= range && oldY < range ) {
mEdgeGlowBottom.onAbsorb((int) mScroller.getCurrVelocity());
}
}
} else if (!isFling){
//回弹过程中有可能会相同,也需要刷新
//Log.i("you", "postInvalidate...");
postInvalidate();
}
}
}
/**
* Pull leftover touch scroll distance into one of the edge glows as appropriate.
*
* @param x Current X scroll offset
* @param y Current Y scroll offset
* @param oldX Old X scroll offset
* @param oldY Old Y scroll offset
* @param maxX Maximum range for horizontal scrolling
* @param maxY Maximum range for vertical scrolling
*/
public void pullGlow(int x, int y, int oldX, int oldY, int maxX, int maxY) {
// Only show overscroll bars if there was no movement in any direction
// as a result of scrolling.
if (oldX == mHostView.getScrollX() && oldY == mHostView.getScrollY()) {
// Don't show left/right glows if we fit the whole content.
// Also don't show if there was vertical movement.
if (maxX > 0) {
final int pulledToX = oldX + mOverScrollDeltaX;
if (pulledToX < 0) {
mEdgeGlowLeft.onPull((float) mOverScrollDeltaX / mHostView.getWidth());
if (!mEdgeGlowRight.isFinished()) {
mEdgeGlowRight.onRelease();
}
} else if (pulledToX > maxX) {
mEdgeGlowRight.onPull((float) mOverScrollDeltaX / mHostView.getWidth());
if (!mEdgeGlowLeft.isFinished()) {
mEdgeGlowLeft.onRelease();
}
}
mOverScrollDeltaX = 0;
}
if (maxY > 0 || mHostView.getOverScrollMode() == View.OVER_SCROLL_ALWAYS) {
final int pulledToY = oldY + mOverScrollDeltaY;
if (pulledToY < 0) {
mEdgeGlowTop.onPull((float) mOverScrollDeltaY / mHostView.getHeight());
if (!mEdgeGlowBottom.isFinished()) {
mEdgeGlowBottom.onRelease();
}
} else if (pulledToY > maxY) {
mEdgeGlowBottom.onPull((float) mOverScrollDeltaY / mHostView.getHeight());
if (!mEdgeGlowTop.isFinished()) {
mEdgeGlowTop.onRelease();
}
}
mOverScrollDeltaY = 0;
}
}
}
/**
* Absorb leftover fling velocity into one of the edge glows as appropriate.
*
* @param x Current X scroll offset
* @param y Current Y scroll offset
* @param oldX Old X scroll offset
* @param oldY Old Y scroll offset
* @param rangeX Maximum range for horizontal scrolling
* @param rangeY Maximum range for vertical scrolling
* @param currentFlingVelocity Current fling velocity
*/
public void absorbGlow(int x, int y, int oldX, int oldY, int rangeX, int rangeY,
float currentFlingVelocity) {
if (rangeY > 0 || mHostView.getOverScrollMode() == View.OVER_SCROLL_ALWAYS) {
if (y < 0 && oldY >= 0) {
mEdgeGlowTop.onAbsorb((int) currentFlingVelocity);
if (!mEdgeGlowBottom.isFinished()) {
mEdgeGlowBottom.onRelease();
}
} else if (y > rangeY && oldY <= rangeY) {
mEdgeGlowBottom.onAbsorb((int) currentFlingVelocity);
if (!mEdgeGlowTop.isFinished()) {
mEdgeGlowTop.onRelease();
}
}
}
if (rangeX > 0) {
if (x < 0 && oldX >= 0) {
mEdgeGlowLeft.onAbsorb((int) currentFlingVelocity);
if (!mEdgeGlowRight.isFinished()) {
mEdgeGlowRight.onRelease();
}
} else if (x > rangeX && oldX <= rangeX) {
mEdgeGlowRight.onAbsorb((int) currentFlingVelocity);
if (!mEdgeGlowLeft.isFinished()) {
mEdgeGlowLeft.onRelease();
}
}
}
}
/**
* Pull leftover touch scroll distance into one of the edge glows as appropriate.
*
* @param x Current X scroll offset
* @param y Current Y scroll offset
* @param oldX Old X scroll offset
* @param oldY Old Y scroll offset
* @param maxX Maximum range for horizontal scrolling
* @param maxY Maximum range for vertical scrolling
*/
public void pullGlow(int x, int y, int oldX, int oldY, int maxX, int maxY) {
// Only show overscroll bars if there was no movement in any direction
// as a result of scrolling.
if (oldX == mHostView.getScrollX() && oldY == mHostView.getScrollY()) {
// Don't show left/right glows if we fit the whole content.
// Also don't show if there was vertical movement.
if (maxX > 0) {
final int pulledToX = oldX + mOverScrollDeltaX;
if (pulledToX < 0) {
mEdgeGlowLeft.onPull((float) mOverScrollDeltaX / mHostView.getWidth());
if (!mEdgeGlowRight.isFinished()) {
mEdgeGlowRight.onRelease();
}
} else if (pulledToX > maxX) {
mEdgeGlowRight.onPull((float) mOverScrollDeltaX / mHostView.getWidth());
if (!mEdgeGlowLeft.isFinished()) {
mEdgeGlowLeft.onRelease();
}
}
mOverScrollDeltaX = 0;
}
if (maxY > 0 || mHostView.getOverScrollMode() == View.OVER_SCROLL_ALWAYS) {
final int pulledToY = oldY + mOverScrollDeltaY;
if (pulledToY < 0) {
mEdgeGlowTop.onPull((float) mOverScrollDeltaY / mHostView.getHeight());
if (!mEdgeGlowBottom.isFinished()) {
mEdgeGlowBottom.onRelease();
}
} else if (pulledToY > maxY) {
mEdgeGlowBottom.onPull((float) mOverScrollDeltaY / mHostView.getHeight());
if (!mEdgeGlowTop.isFinished()) {
mEdgeGlowTop.onRelease();
}
}
mOverScrollDeltaY = 0;
}
}
}
/**
* Absorb leftover fling velocity into one of the edge glows as appropriate.
*
* @param x Current X scroll offset
* @param y Current Y scroll offset
* @param oldX Old X scroll offset
* @param oldY Old Y scroll offset
* @param rangeX Maximum range for horizontal scrolling
* @param rangeY Maximum range for vertical scrolling
* @param currentFlingVelocity Current fling velocity
*/
public void absorbGlow(int x, int y, int oldX, int oldY, int rangeX, int rangeY,
float currentFlingVelocity) {
if (rangeY > 0 || mHostView.getOverScrollMode() == View.OVER_SCROLL_ALWAYS) {
if (y < 0 && oldY >= 0) {
mEdgeGlowTop.onAbsorb((int) currentFlingVelocity);
if (!mEdgeGlowBottom.isFinished()) {
mEdgeGlowBottom.onRelease();
}
} else if (y > rangeY && oldY <= rangeY) {
mEdgeGlowBottom.onAbsorb((int) currentFlingVelocity);
if (!mEdgeGlowTop.isFinished()) {
mEdgeGlowTop.onRelease();
}
}
}
if (rangeX > 0) {
if (x < 0 && oldX >= 0) {
mEdgeGlowLeft.onAbsorb((int) currentFlingVelocity);
if (!mEdgeGlowRight.isFinished()) {
mEdgeGlowRight.onRelease();
}
} else if (x > rangeX && oldX <= rangeX) {
mEdgeGlowRight.onAbsorb((int) currentFlingVelocity);
if (!mEdgeGlowLeft.isFinished()) {
mEdgeGlowLeft.onRelease();
}
}
}
}
/**
* 滑动功能核心代码
* @param deltaX
* @param deltaY
* @param scrollX
* @param scrollY
* @param scrollRangeX
* @param scrollRangeY
* @param maxOverScrollX
* @param maxOverScrollY
* @param isTouchEvent
* @return
*/
boolean overScrollByCompat(int deltaX, int deltaY,
int scrollX, int scrollY,
int scrollRangeX, int scrollRangeY,
int maxOverScrollX, int maxOverScrollY,
boolean isTouchEvent) {
final int overScrollMode = getOverScrollMode();
final boolean canScrollHorizontal =
computeHorizontalScrollRange() > computeHorizontalScrollExtent();
final boolean canScrollVertical =
computeVerticalScrollRange() > computeVerticalScrollExtent();
final boolean overScrollHorizontal = overScrollMode == View.OVER_SCROLL_ALWAYS
|| (overScrollMode == View.OVER_SCROLL_IF_CONTENT_SCROLLS && canScrollHorizontal);
final boolean overScrollVertical = overScrollMode == View.OVER_SCROLL_ALWAYS
|| (overScrollMode == View.OVER_SCROLL_IF_CONTENT_SCROLLS && canScrollVertical);
int newScrollX = scrollX + deltaX;
if (!overScrollHorizontal) {
maxOverScrollX = 0;
}
//此处修改原码
if (scrollY < 0 && deltaY < 0) {//偏移往下滑动
deltaY /= PULLDOWN_SCROLL;
}
int newScrollY = scrollY + deltaY;
if (!overScrollVertical) {
maxOverScrollY = 0;
}
// Clamp values if at the limits and record
final int left = -maxOverScrollX;
final int right = maxOverScrollX + scrollRangeX;
//此处修改原码
int top;
if (isFling) {
top = - maxOverScrollY;
} else {
top = -getPulldownScroll();
}
final int bottom = maxOverScrollY + scrollRangeY;
boolean clampedX = false;
if (newScrollX > right) {
newScrollX = right;
clampedX = true;
} else if (newScrollX < left) {
newScrollX = left;
clampedX = true;
}
boolean clampedY = false;
if (newScrollY > bottom) {//滑动越出界限
newScrollY = bottom;
clampedY = true;
} else if (newScrollY < top) {
newScrollY = top;
clampedY = true;
}
if (clampedY && isFling) {//这里isFling时才回弹
//Log.i("you", top + " " + bottom + " "+deltaY+" "+newScrollY+" "+getScrollRange());
mScroller.springBack(newScrollX, newScrollY, 0, 0, 0, getScrollRange());
}
onOverScrolled(newScrollX, newScrollY, clampedX, clampedY);
return clampedX || clampedY;
}