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1、【无线互联】EGORefreshTableHeaderView下拉刷新 原理在IOS中,经常会使用到下拉刷新UITableView中的数据，比如新浪的客户端，我们就是使用下拉刷新方式来更新微博数据。所以这次主要是对EGORefreshTableHeaderView下拉刷新原理进行分析。在EGORefreshTableHeaderView中只支持英文，通过修改文中_statusLabel.text的内容，可以支持这种那个英文，例如_statusLabel.text = NSLocalizedString(下拉刷新,Release to refresh status); UITableView继承
2、于UIScrollView，所以可以使用UIScrollView中y的位移量contentOffset.y 计算用户当前下拉的位置，从而判断是否开始刷新数据。首先在TableView视图中，我们首先给视图添加一个view用来显示下拉刷新的状态，我们可以把它叫做refreshHeardView。在普通状态下，我们看不到refreshHeardView，因此我们可以将其frame设置到屏幕以外；当用户下拉列表时refreshHeardView就会一点一点显示出来。普通状态下，contentOffset.y = 0；当用户下拉时，contentOffsetu6.y的值不断变小，refreshHear
3、dView上显示的箭头朝下，内容为:下拉加载.;当contentOffset.y = 40000 37. if (UIScreen mainScreen respondsToSelector:selector(scale) 38. layer.contentsScale = UIScreen mainScreen scale; 39. 40. #endif 41.42. self layer addSublayer:layer; 43. _arrowImage=layer; 44.45. UIActivityIndicatorView *view = UIActivityIndicatorVi
4、ew alloc initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray; 46. view.frame = CGRectMake(25.0f, frame.size.height - 38.0f, 20.0f, 20.0f); 47. self addSubview:view; 48. _activityView = view; 49. view release; 50.51.52. self setState:EGOOPullRefreshNormal; 53.54. 55.56. return self; 57.58
5、. - (id)initWithFrame:(CGRect)frame if (self = super initWithFrame:frame) self.autoresizingMask = UIViewAutoresizingFlexibleWidth;self.backgroundColor = UIColor colorWithRed:226.0/255.0 green:231.0/255.0 blue:237.0/255.0 alpha:1.0;UILabel *label = UILabel alloc initWithFrame:CGRectMake(0.0f, frame.s
6、ize.height - 30.0f, self.frame.size.width, 20.0f);label.autoresizingMask = UIViewAutoresizingFlexibleWidth;label.font = UIFont systemFontOfSize:12.0f;label.textColor = TEXT_COLOR;label.shadowColor = UIColor colorWithWhite:0.9f alpha:1.0f;label.shadowOffset = CGSizeMake(0.0f, 1.0f);label.backgroundCo
7、lor = UIColor clearColor;label.textAlignment = NSTextAlignmentCenter;self addSubview:label;_lastUpdatedLabel=label;label release;label = UILabel alloc initWithFrame:CGRectMake(0.0f, frame.size.height - 48.0f, self.frame.size.width, 20.0f);label.autoresizingMask = UIViewAutoresizingFlexibleWidth;labe
8、l.font = UIFont boldSystemFontOfSize:13.0f;label.textColor = TEXT_COLOR;label.shadowColor = UIColor colorWithWhite:0.9f alpha:1.0f;label.shadowOffset = CGSizeMake(0.0f, 1.0f);label.backgroundColor = UIColor clearColor;label.textAlignment = NSTextAlignmentCenter;self addSubview:label;_statusLabel=label;label release;CALayer *layer = CALayer layer;layer.frame = CGRectMake(25.0f, frame.size.height - 65.0f, 30.0f, 55.0f);layer.contentsGravity = kCAGravityResizeAspect;layer.contents = (id)UIImage imageNamed:blueArrow.png.CGImage;#if _IPHONE_OS_VERSION_MAX_ALLOWED = 40000if
