实例013 隐藏指定的UIView区域

实例说明

本实例的功能是使用UIView的属性hidden来隐藏指定的区域。当属性hidden的值为YES时隐藏UIView，当属性hidden的值为NO时显示UIView。当单击本实例中的“点击”按钮时，会实现文本隐藏和文本显示的转换。

具体实现

实例文件UIkitPrjHide.h的实现代码如下所示。

#import "SampleBaseController.h"
@interface UIKitPrjHide : SampleBaseController
{
 @private
  UILabel* label_;
}
@end

实例文件UIkitPrjHide.m的实现代码如下所示。

#import "UIKitPrjHide.h"
@implementation UIKitPrjHide
#pragma mark ----- Override Methods -----
// finalize
- (void)dealloc {
  [label_ release];
  [super dealloc];
}
- (void)viewDidLoad {
  [super viewDidLoad];
  self.view.backgroundColor = [UIColor blackColor];
  label_ = [[UILabel alloc] initWithFrame:CGRectMake( 0, 0, 320, 200 )];
  label_.textAlignment = UITextAlignmentCenter;
  label_.backgroundColor = [UIColor blackColor];
  label_.textColor = [UIColor whiteColor];
  label_.text = @"I'm here! ";
  [self.view addSubview:label_];
  UIButton* button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
  button.frame = CGRectMake( 0, 0, 100, 40 );
  CGPoint newPoint = self.view.center;
  newPoint.y = self.view.frame.size.height -70;
  button.center = newPoint;
  [button setTitle:@"点击" forState:UIControlStateNormal];
  [button  addTarget:self  action:@selector(buttonDidPush)  forControlEvents:UIControl
EventTouchUpInside];
  [self.view addSubview:button];
}
- (void)buttonDidPush {
  label_.hidden = ! label_.hidden;
}
- (void)touchesEnded:(NSSet*)touches withEvent:(UIEvent*)event {
  [self.navigationController setNavigationBarHidden:NO animated:YES];
}
@end

执行后的效果如图2-16所示，按下图2-16中的“点击”按钮后会隐藏文本，如图2-17所示。

图2-16 执行效果

图2-17 隐藏了文本