//

//  ViewController.m

//  回到顶部

//

//  Created by Apple on 15/11/4.

//  Copyright © 2015年 Apple. All rights reserved.

//

#import "ViewController.h"

@interface ViewController () <UITableViewDelegate,UITableViewDataSource>

@property(nonatomic, strong)UITableView        *tableView;

@property (nonatomic, strong) UIButton * topBtn;

@property (nonatomic, assign) CGFloat lastContentOffset;

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

    self.tableView = [[UITableView alloc] initWithFrame:CGRectMake(, , self.view.frame.size.width, self.view.frame.size.height)];

    self.tableView.delegate = self;

    self.tableView.dataSource = self;

    [self.view addSubview:_tableView];

    // 添加回到顶部按钮

    _topBtn = [UIButton buttonWithType:UIButtonTypeCustom];

    _topBtn.frame = CGRectMake(self.view.frame.size.width-, self.view.frame.size.height-, , );

    [_topBtn setBackgroundImage:[UIImage imageNamed:@"nearby_return_top_btn"] forState:UIControlStateNormal];

    [_topBtn addTarget:self action:@selector(backToTopButton) forControlEvents:UIControlEventTouchUpInside];

    _topBtn.clipsToBounds = YES;

    _topBtn.hidden = YES;

    [self.view addSubview:_topBtn];

}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section

{

    return ;

}

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

{

    static NSString *CMainCell = @"CMainCell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CMainCell];

    if (cell == nil) {

        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CMainCell];

    }

    cell.textLabel.text =[NSString stringWithFormat:@"测试广本%u",indexPath.row];

    return cell;

}

// MARK:  计算偏移量

- (void)scrollViewDidScroll:(UIScrollView *)scrollView

{

    //MARK:列表滑动偏移量计算

    CGPoint point = [self.tableView contentOffset];

    if (point.y >= self.tableView.frame.size.height) {

        self.topBtn.hidden = NO;

        [self.view bringSubviewToFront:self.topBtn];

    } else {

        self.topBtn.hidden = YES;

    }

}

//MARK: 点击移动到顶部

- (void)backToTopButton{

    [self.tableView setContentOffset:CGPointMake(, ) animated:YES];

}

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

@end