绘制拖动翅膀动画-优快云博客

本文链接：https://blog.youkuaiyun.com/iteye_15383/article/details/82123761

本文介绍了一种在Android中实现的特殊UI效果——拖动时显示翅膀动画的方法。该动画会在用户拖动屏幕上的元素时出现，并随着元素的移动而变化。文章详细描述了如何根据当前的操作状态和屏幕位置来启动和更新动画，以及如何绘制左右两侧的辅助图像。

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private void drawWingsImg(Canvas canvas) {
if (workspace.isScrollerFinished()) {
if (mDragging) {
if (transferAt == null) {
startWingsAnimation(WINGS_START_VECTOR, WINGS_END_VECTOR, WINGS_INCREMENT, WINGS_SLEEP_TIME);
}

if (!transferAt.isAlive() && needWingsAnimation) {
if (changeWingsAnimationState) {
if (transferAtListener.getAnimationState() == DragLayerAnimationThread.MOVE_IN
&& transferAt.getCurrentScale() > WINGS_START_VECTOR) {
startWingsAnimation(transferAt.getCurrentScale(), WINGS_START_VECTOR, WINGS_INCREMENT,
WINGS_MOVE_IN_SLEEP_TIME);
} else if (transferAtListener.getAnimationState() == DragLayerAnimationThread.MOVE_OUT
&& transferAt.getCurrentScale() < WINGS_END_VECTOR) {
startWingsAnimation(transferAt.getCurrentScale(), WINGS_END_VECTOR, WINGS_INCREMENT,
WINGS_MOVE_OUT_SLEEP_TIME);
}
} else {
startWingsAnimation(WINGS_START_VECTOR, WINGS_END_VECTOR, WINGS_INCREMENT, WINGS_SLEEP_TIME);
}
}
} else {
if (transferAt != null) {
if (transferAt.isAlive()) {
transferAt.setAnimationState(AnimationThread.STATE_ZOOM_OUT);

} else if (needWingsAnimation && transferAt.getCurrentScale() != WINGS_START_VECTOR) {

startWingsAnimation(transferAt.getCurrentScale(), WINGS_START_VECTOR, WINGS_INCREMENT,
WINGS_SLEEP_TIME);
}
} else {
return;
}
}

int currentScreen = workspace.getCurrentScreen();
int currentGroup = workspace.getCurrentGroup();

if (currentScreen != 0 || currentGroup != 0) {
drawLeftDragImg(canvas);
}

if (currentScreen != 1
|| currentGroup != GroupInfoProvider.getInstance(getContext()).getGroupCount() - 1) {
drawRightDragImg(canvas);
}
}
}

private void drawLeftDragImg(Canvas canvas) {
int offset = getDragWingsOffset();
Drawable leftDragNormal = getResources().getDrawable(R.drawable.left_drag_normal);
Drawable leftDrag = getResources().getDrawable(R.drawable.left_drag);
Bitmap arrowheadLeftNormal = BitmapFactory.decodeResource(getResources(), R.drawable.arrowhead_left_normal);
Bitmap arrowheadLeft = BitmapFactory.decodeResource(getResources(), R.drawable.arrowhead_left_active);

canvas.save();
canvas.translate(transferAt.getCurrentScale(), 0);
if (mScrollState == SCROLL_WAITING_IN_ZONE && mScrollRunnable.mDirection == SCROLL_LEFT) {

leftDrag.setBounds(0, offset, SCROLL_ZONE_IMG_WIDTH, offset + calculate.getDragWingsHeight());
leftDrag.draw(canvas);

canvas.drawBitmap(arrowheadLeft, (SCROLL_ZONE_IMG_WIDTH - arrowheadLeft.getWidth()) / 2, getHeight() / 2
- arrowheadLeft.getHeight() / 2, imgPaint);
} else {
leftDragNormal.setBounds(0, offset, SCROLL_ZONE_IMG_WIDTH, offset + calculate.getDragWingsHeight());
leftDragNormal.draw(canvas);

canvas.drawBitmap(arrowheadLeftNormal, (SCROLL_ZONE_IMG_WIDTH - arrowheadLeftNormal.getWidth()) / 2, getHeight() / 2
- arrowheadLeftNormal.getHeight() / 2, imgPaint);
}
canvas.restore();
}

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