// 代码地址: https://github.com/CoderMJLee/MJRefresh
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// 代码地址: http://code4app.com/ios/%E5%BF%AB%E9%80%9F%E9%9B%86%E6%88%90%E4%B8%8B%E6%8B%89%E4%B8%8A%E6%8B%89%E5%88%B7%E6%96%B0/52326ce26803fabc46000000
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// MJRefreshHeader.m
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// MJRefreshExample
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//
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// Created by MJ Lee on 15/3/4.
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// Copyright (c) 2015年 小码哥. All rights reserved.
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//
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#import "MJRefreshHeader.h"
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@interface MJRefreshHeader()
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@property (assign, nonatomic) CGFloat insetTDelta;
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@end
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@implementation MJRefreshHeader
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#pragma mark - 构造方法
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+ (instancetype)headerWithRefreshingBlock:(MJRefreshComponentRefreshingBlock)refreshingBlock
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{
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MJRefreshHeader *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)headerWithRefreshingTarget:(id)target refreshingAction:(SEL)action
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{
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MJRefreshHeader *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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#pragma mark - 覆盖父类的方法
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- (void)prepare
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{
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[super prepare];
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// 设置key
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self.lastUpdatedTimeKey = MJRefreshHeaderLastUpdatedTimeKey;
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// 设置高度
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self.mj_h = MJRefreshHeaderHeight;
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}
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- (void)placeSubviews
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{
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[super placeSubviews];
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// 设置y值(当自己的高度发生改变了，肯定要重新调整Y值，所以放到placeSubviews方法中设置y值)
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self.mj_y = - self.mj_h - self.ignoredScrollViewContentInsetTop;
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}
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- (void)scrollViewContentOffsetDidChange:(NSDictionary *)change
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{
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[super scrollViewContentOffsetDidChange:change];
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// 在刷新的refreshing状态
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if (self.state == MJRefreshStateRefreshing) {
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if (self.window == nil) return;
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// sectionheader停留解决
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CGFloat insetT = - self.scrollView.mj_offsetY > _scrollViewOriginalInset.top ? - self.scrollView.mj_offsetY : _scrollViewOriginalInset.top;
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insetT = insetT > self.mj_h + _scrollViewOriginalInset.top ? self.mj_h + _scrollViewOriginalInset.top : insetT;
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self.scrollView.mj_insetT = insetT;
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self.insetTDelta = _scrollViewOriginalInset.top - insetT;
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return;
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}
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// 跳转到下一个控制器时，contentInset可能会变
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_scrollViewOriginalInset = self.scrollView.contentInset;
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// 当前的contentOffset
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CGFloat offsetY = self.scrollView.mj_offsetY;
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// 头部控件刚好出现的offsetY
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CGFloat happenOffsetY = - self.scrollViewOriginalInset.top;
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// 如果是向上滚动到看不见头部控件，直接返回
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// >= -> >
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if (offsetY > happenOffsetY) return;
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// 普通 和 即将刷新 的临界点
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CGFloat normal2pullingOffsetY = happenOffsetY - self.mj_h;
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CGFloat pullingPercent = (happenOffsetY - offsetY) / self.mj_h;
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if (self.scrollView.isDragging) { // 如果正在拖拽
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self.pullingPercent = pullingPercent;
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if (self.state == MJRefreshStateIdle && offsetY < normal2pullingOffsetY) {
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// 转为即将刷新状态
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self.state = MJRefreshStatePulling;
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} else if (self.state == MJRefreshStatePulling && offsetY >= normal2pullingOffsetY) {
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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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{
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MJRefreshCheckState
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// 根据状态做事情
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if (state == MJRefreshStateIdle) {
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if (oldState != MJRefreshStateRefreshing) return;
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// 保存刷新时间
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[[NSUserDefaults standardUserDefaults] setObject:[NSDate date] forKey:self.lastUpdatedTimeKey];
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[[NSUserDefaults standardUserDefaults] synchronize];
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// 恢复inset和offset
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[UIView animateWithDuration:MJRefreshSlowAnimationDuration animations:^{
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self.scrollView.mj_insetT += self.insetTDelta;
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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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} else if (state == MJRefreshStateRefreshing) {
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dispatch_async(dispatch_get_main_queue(), ^{
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[UIView animateWithDuration:MJRefreshFastAnimationDuration animations:^{
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CGFloat top = self.scrollViewOriginalInset.top + self.mj_h;
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// 增加滚动区域top
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self.scrollView.mj_insetT = top;
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// 设置滚动位置
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[self.scrollView setContentOffset:CGPointMake(0, -top) 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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}
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#pragma mark - 公共方法
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- (void)endRefreshing
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{
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dispatch_async(dispatch_get_main_queue(), ^{
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self.state = MJRefreshStateIdle;
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});
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}
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- (NSDate *)lastUpdatedTime
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{
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return [[NSUserDefaults standardUserDefaults] objectForKey:self.lastUpdatedTimeKey];
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}
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@end
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