先看下效果图(布局就随便看看吧 ,重点是效果😂)
finished3.gif
需求:上面的效果图是在用户从应用程序的界面按下Home键退出,过一段时间再从后台切换回来的时候,显示一个密码输入的界面,只有当用户输入了正确的密码才能进入退出前的界面.
需求分析:因为这个密码输入界面可能从任何应用界面弹出,并且需要盖在所有的界面上,所有它适合用一个UIWindow来实现.代码如下
1.创建一个PasswordInputWindow类继承自UIWindow,在.h文件中实现两个方法
@interface PasswordInputWindow : UIWindow
+(PasswordInputWindow *)sharedInstance;
- (void)show;
@end
2.在PasswordInputWindow类的.m文件中实现对应的方法
+(PasswordInputWindow *)sharedInstance{
static id sharedInstance = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
sharedInstance = [[self alloc]initWithFrame:[UIScreen mainScreen].bounds];
});
return sharedInstance;
}
- (id)initWithFrame:(CGRect)frame{
self = [super initWithFrame:frame];
if (self) {
UILabel * label = [[UILabel alloc]initWithFrame:CGRectMake(10, 50, 200, 20)];
label.text = @"请输入密码";
[self addSubview:label];
UITextField * textField = [[UITextField alloc]initWithFrame:CGRectMake(10, 80, 200, 20)];
textField.backgroundColor = [UIColor whiteColor];
textField.secureTextEntry = YES;
[self addSubview:textField];
UIButton * button = [[UIButton alloc]initWithFrame:CGRectMake(10, 110, 200, 44)];
[button setBackgroundColor:[UIColor blueColor]];
button.titleLabel.textColor = [UIColor blackColor];
[button setTitle:@"确定" forState:UIControlStateNormal];
[button addTarget:self action:@selector(compleBtnPressed) forControlEvents:UIControlEventTouchUpInside];
[self addSubview:button];
self.backgroundColor = [UIColor yellowColor];
self.textField = textField;
}
return self;
}
- (void)show{
[self makeKeyWindow];
self.hidden = NO;
}
- (void)compleBtnPressed{
if ([self.textField.text isEqualToString:@"abcd"]) {
[self.textField resignFirstResponder];
[self resignKeyWindow];
self.hidden = YES;
}else{
[self showErrorAlterView];
}
}
- (void)showErrorAlterView{
UIAlertView * view = [[UIAlertView alloc]initWithTitle:nil message:@"密码错误" delegate:nil cancelButtonTitle:@"ok" otherButtonTitles:nil, nil];
[view show];
}
3.我们只需要在应用进入后台的回调函数中,把自己的显示出来即可.
//进入后台
- (void)applicationDidEnterBackground:(UIApplication *)application {
[[PasswordInputWindow sharedInstance]show];
}
总结:支付宝客户端的手势解锁功能,应用的启动介绍页,应用内的弹窗广告等都是利用的UIWindow一个很好的应用.
参考资料:ios开发进阶(唐巧)
