Objective-c 下拉刷新,上拉加載實現原理

#pragma mark+++++++++++++++++++下拉刷新原理+++++++++++++++++++

• (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView { NSLog(@"scrollViewX:%f scrollViewY:%f",scrollView.contentOffset.x ,scrollView.contentOffset.y); if (scrollView.contentOffset.y <-60) { [UIView animateWithDuration:0.2 animations:^{ self.allTableView.contentInset = UIEdgeInsetsMake(40.0f, 0.0f, 0.0f, 0.0f); } completion:^(BOOL finished){

  /**
         *  發起網絡請求,請求刷新數據
         */
        [_dataSource requestListAllData:^(NSArray *array)
         {
             _allDataSource = [[NSMutableArray alloc]initWithArray:array];
             //刷新
             [_allTableView reloadData];
             self.pag=2;
             [UIView animateWithDuration:0.2 animations:^{
                 self.allTableView.contentInset = UIEdgeInsetsMake(0.0f, 0.0f, 0.0f, 0.0f);
             }];
         }];
  
  
    }];

  } } #pragma mark+++++++++++++++++++上拉加載原理+++++++++++++++++++

• (void)scrollViewDidEndDragging:(UIScrollView )scrollView willDecelerate:(BOOL)decelerate { NSLog(@"%f",scrollView.contentOffset.y); NSLog(@"%f",scrollView.frame.size.height); NSLog(@"%f",scrollView.contentSize.height); /*

  • 關鍵-->

  • scrollView一開始並不存在偏移量,可是會設定contentSize的大小,因此contentSize.height永遠都會比contentOffset.y高一個手機屏幕的

  • 高度;上拉加載的效果就是每次滑動到底部時,再往上拉的時候請求更多,那個時候產生的偏移量,就能讓contentOffset.y + 手機屏幕尺寸高大於這

  • 個滾動視圖的contentSize.height */ if (scrollView.contentOffset.y + scrollView.frame.size.height >= scrollView.contentSize.height) { NSLog(@"%d %s",LINE,FUNCTION); [UIView commitAnimations];

    [UIView animateWithDuration:1.0 animations:^ { //frame發生的偏移量,距離底部往上提升60(可自行設定) self.allTableView.contentInset = UIEdgeInsetsMake(0, 0, 0, 0); } completion:^(BOOL finished) { __weak typeof(self) weakSelf = self; [_dataSource addListAllDataWithPag:weakSelf.pag Data:^(NSArray *array) { [weakSelf.allDataSource addObjectsFromArray:array]; [weakSelf.allTableView reloadData]; weakSelf.pag+=1;

    }];

    }];

  } }