UITableView(可滚动到顶部和底部)

#import "RootViewController.h"
#define width [UIScreen mainScreen].bounds.size.width
#define height [UIScreen mainScreen].bounds.size.height
#define topH 64
@interface RootViewController ()<UITableViewDataSource,UITableViewDelegate>

@property (nonatomic, strong) UITableView *tableView;
@property (nonatomic, strong) NSMutableArray *rowData;

@end

@implementation RootViewController

- (void)loadView
{
    [super loadView];
    // 初始化view
    UIView *aView = [[UIView alloc] initWithFrame:CGRectMake(, , width, topH)];
    aView.backgroundColor = [UIColor grayColor];
    [self.view addSubview:aView];
    // 初始化leftButton
    SEL leftSel = NSSelectorFromString(@"scrollToTop:");
    UIButton *leftBtn = [self setupButtonWithTitle:@"top" withFrame:CGRectMake(, , , topH - ) withSelector:leftSel];
    [self.view addSubview:leftBtn];
    // 初始化rigthButton
    SEL rightSel = NSSelectorFromString(@"scrollToBottom:");
    UIButton *rightBtn = [self setupButtonWithTitle:@"bottom" withFrame:CGRectMake(width -  - , , , topH-) withSelector:rightSel];
    [self.view addSubview:rightBtn];
    // 初始化_tableView
    self.tableView = [[UITableView alloc] initWithFrame:CGRectMake(, topH,width, height - topH) style:UITableViewStylePlain];
    self.tableView.dataSource = self;
    self.tableView.delegate = self;
    [self.view addSubview:self.tableView];

}
/**
 *  初始化Button
 *
 *  @param aTitle    Button的标题
 *  @param aFrame    Button的框架
 *  @param aSelector Button的方法
 *
 *  @return Button
 */
- (UIButton *)setupButtonWithTitle:(NSString *)aTitle withFrame:(CGRect)aFrame withSelector:(SEL)aSelector
{
    UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    btn.frame = aFrame;
    [btn setTitle:aTitle forState:];
    btn.titleLabel.font = [UIFont systemFontOfSize:];
    [btn addTarget:self action:aSelector forControlEvents:UIControlEventTouchUpInside];
    return btn;
}
- (void)viewDidLoad {
    [super viewDidLoad];
    [self loadData];
}
/**
 *  加载数据
 */
-(void)loadData
{
    if (self.rowData!=nil)
    {
        [self.rowData removeAllObjects];
        self.rowData=nil;

    }
    self.rowData = [[NSMutableArray alloc] init];
    for (int i= ; i<;i++)
    {
        [self.rowData addObject:[NSString stringWithFormat:@"Row: %i",i]];
    }
    [self.tableView reloadData];
}

- (void)scrollToTop:(UIButton *)sender
{
    NSIndexPath *topRow = [NSIndexPath indexPathForRow: inSection:];
    [self.tableView scrollToRowAtIndexPath:topRow atScrollPosition:UITableViewScrollPositionTop animated:YES];
}

- (void)scrollToBottom:(UIButton *)sender
{
    NSIndexPath *bottomRow = [NSIndexPath indexPathForRow:[self.rowData count]- inSection:];
    [self.tableView scrollToRowAtIndexPath:bottomRow atScrollPosition:UITableViewScrollPositionBottom animated:YES];
}

#pragma mark -UITableView delegates-
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return ;
}

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

    return [self.rowData count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = (UITableViewCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    }
    cell.selectionStyle = UITableViewCellSelectionStyleNone;
    cell.textLabel.text = [self.rowData objectAtIndex:indexPath.row];
    return cell;
}

@end