以下代码实现的效果：下滑到某一高度后自动隐藏掉
原始效果1
原始效果2 慢慢的下滑
原始效果3 隐藏消失
#pragma mark -- UIView animateWithDuration
- (void)initTestBtn
{_testBtn = [[UIButton alloc]initWithFrame:CGRectMake(15, 230, kDEVICEWIDTH-30, 45)];_testBtn.backgroundColor = [UIColor grayColor];[_testBtn addTarget:self action:@selector(commitClick) forControlEvents:UIControlEventTouchUpInside];[_testBtn setTitle:@"提交" forState:UIControlStateNormal];_testBtn.titleLabel.textColor = [UIColor whiteColor];_testBtn.layer.cornerRadius = 4;[self.view addSubview:_testBtn];// _testView = [[UIView alloc]initWithFrame:CGRectMake(15, 300, kDEVICEWIDTH-30, 45)];
// _testView.backgroundColor = [UIColor grayColor];
//
// [self.view addSubview:_testView];// [_testView addSubview:_testBtn];
}- (void)testAnimateWithDuration
{/*typeof(self) 是获取到self的类型,这样定义出的weakSelf就是和self一个类型的, 加上__weak是建立一个若引用,整句就是给self定义了一个若引用性质的替身;这个一般用在使用block时会用到,因为block会copy它内部的变量,可能会造成引用循环,使用__weak性质的self替代self,可以切断block对self的引用,避免循环引用*/__weak __typeof(self) weakSelf = self;CGRect _tempCG = _testBtn.frame;_tempCG.origin.y = 360;[UIView animateWithDuration:1.5animations:^{//_testBtn.frame = CGRectMake(15, kDEVICEHEIGHT, kDEVICEWIDTH-30, 45);_testBtn.frame = _tempCG;}completion:^(BOOL finished){_testBtn.hidden = YES;}];
}