//
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// MJRefreshTrailer.m
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// MJRefresh
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//
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// Created by kinarobin on 2020/5/3.
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// Copyright © 2020 小码哥. All rights reserved.
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//
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#import "MJRefreshTrailer.h"
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#import "UIView+MJExtension.h"
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#import "UIScrollView+MJRefresh.h"
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#import "UIScrollView+MJExtension.h"
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@interface MJRefreshTrailer()
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@property (assign, nonatomic) NSInteger lastRefreshCount;
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@property (assign, nonatomic) CGFloat lastRightDelta;
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@end
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@implementation MJRefreshTrailer
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#pragma mark - 构造方法
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+ (instancetype)trailerWithRefreshingBlock:(MJRefreshComponentAction)refreshingBlock {
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MJRefreshTrailer *cmp = [[self alloc] init];
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cmp.refreshingBlock = refreshingBlock;
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return cmp;
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}
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+ (instancetype)trailerWithRefreshingTarget:(id)target refreshingAction:(SEL)action {
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MJRefreshTrailer *cmp = [[self alloc] init];
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[cmp setRefreshingTarget:target refreshingAction:action];
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return cmp;
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}
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- (void)scrollViewContentOffsetDidChange:(NSDictionary *)change {
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[super scrollViewContentOffsetDidChange:change];
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// 如果正在刷新，直接返回
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if (self.state == MJRefreshStateRefreshing) return;
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_scrollViewOriginalInset = self.scrollView.mj_inset;
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// 当前的contentOffset
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CGFloat currentOffsetX = self.scrollView.mj_offsetX;
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// 尾部控件刚好出现的offsetX
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CGFloat happenOffsetX = [self happenOffsetX];
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// 如果是向右滚动到看不见右边控件，直接返回
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if (currentOffsetX <= happenOffsetX) return;
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CGFloat pullingPercent = (currentOffsetX - happenOffsetX) / self.mj_w;
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// 如果已全部加载，仅设置pullingPercent，然后返回
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if (self.state == MJRefreshStateNoMoreData) {
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self.pullingPercent = pullingPercent;
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return;
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}
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if (self.scrollView.isDragging) {
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self.pullingPercent = pullingPercent;
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// 普通 和 即将刷新 的临界点
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CGFloat normal2pullingOffsetX = happenOffsetX + self.mj_w;
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if (self.state == MJRefreshStateIdle && currentOffsetX > normal2pullingOffsetX) {
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self.state = MJRefreshStatePulling;
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} else if (self.state == MJRefreshStatePulling && currentOffsetX <= normal2pullingOffsetX) {
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// 转为普通状态
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self.state = MJRefreshStateIdle;
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}
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} else if (self.state == MJRefreshStatePulling) {// 即将刷新 && 手松开
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// 开始刷新
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[self beginRefreshing];
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} else if (pullingPercent < 1) {
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self.pullingPercent = pullingPercent;
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}
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}
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- (void)setState:(MJRefreshState)state {
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MJRefreshCheckState
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// 根据状态来设置属性
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if (state == MJRefreshStateNoMoreData || state == MJRefreshStateIdle) {
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// 刷新完毕
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if (MJRefreshStateRefreshing == oldState) {
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[UIView animateWithDuration:self.slowAnimationDuration animations:^{
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if (self.endRefreshingAnimationBeginAction) {
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self.endRefreshingAnimationBeginAction();
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}
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self.scrollView.mj_insetR -= self.lastRightDelta;
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// 自动调整透明度
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if (self.isAutomaticallyChangeAlpha) self.alpha = 0.0;
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} completion:^(BOOL finished) {
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self.pullingPercent = 0.0;
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if (self.endRefreshingCompletionBlock) {
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self.endRefreshingCompletionBlock();
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}
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}];
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}
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CGFloat deltaW = [self widthForContentBreakView];
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// 刚刷新完毕
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if (MJRefreshStateRefreshing == oldState && deltaW > 0 && self.scrollView.mj_totalDataCount != self.lastRefreshCount) {
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self.scrollView.mj_offsetX = self.scrollView.mj_offsetX;
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}
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} else if (state == MJRefreshStateRefreshing) {
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// 记录刷新前的数量
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self.lastRefreshCount = self.scrollView.mj_totalDataCount;
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[UIView animateWithDuration:self.fastAnimationDuration animations:^{
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CGFloat right = self.mj_w + self.scrollViewOriginalInset.right;
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CGFloat deltaW = [self widthForContentBreakView];
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if (deltaW < 0) { // 如果内容宽度小于view的宽度
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right -= deltaW;
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}
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self.lastRightDelta = right - self.scrollView.mj_insetR;
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self.scrollView.mj_insetR = right;
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// 设置滚动位置
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CGPoint offset = self.scrollView.contentOffset;
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offset.x = [self happenOffsetX] + self.mj_w;
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[self.scrollView setContentOffset:offset animated:NO];
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} completion:^(BOOL finished) {
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[self executeRefreshingCallback];
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}];
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}
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}
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- (void)scrollViewContentSizeDidChange:(NSDictionary *)change {
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[super scrollViewContentSizeDidChange:change];
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// 内容的宽度
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CGFloat contentWidth = self.scrollView.mj_contentW + self.ignoredScrollViewContentInsetRight;
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// 表格的宽度
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CGFloat scrollWidth = self.scrollView.mj_w - self.scrollViewOriginalInset.left - self.scrollViewOriginalInset.right + self.ignoredScrollViewContentInsetRight;
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// 设置位置和尺寸
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self.mj_x = MAX(contentWidth, scrollWidth);
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}
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- (void)placeSubviews {
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[super placeSubviews];
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self.mj_h = _scrollView.mj_h;
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// 设置自己的宽度
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self.mj_w = MJRefreshTrailWidth;
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}
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- (void)willMoveToSuperview:(UIView *)newSuperview {
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[super willMoveToSuperview:newSuperview];
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if (newSuperview) {
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// 设置支持水平弹簧效果
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_scrollView.alwaysBounceHorizontal = YES;
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_scrollView.alwaysBounceVertical = NO;
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}
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}
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#pragma mark . 链式语法部分 .
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- (instancetype)linkTo:(UIScrollView *)scrollView {
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scrollView.mj_trailer = self;
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return self;
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}
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#pragma mark - 刚好看到上拉刷新控件时的contentOffset.x
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- (CGFloat)happenOffsetX {
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CGFloat deltaW = [self widthForContentBreakView];
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if (deltaW > 0) {
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return deltaW - self.scrollViewOriginalInset.left;
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} else {
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return - self.scrollViewOriginalInset.left;
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}
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}
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#pragma mark 获得scrollView的内容 超出 view 的宽度
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- (CGFloat)widthForContentBreakView {
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CGFloat w = self.scrollView.frame.size.width - self.scrollViewOriginalInset.right - self.scrollViewOriginalInset.left;
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return self.scrollView.contentSize.width - w;
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}
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@end
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