使用Storyboard为自定义子视图添加动画，以便从iOS 5中的屏幕底部飞入

Question

我正在尝试模拟键盘出现的动画，只使用自定义子视图，它会向用户显示三个按钮。有什么方法可以用故事板来完成这个（即无需以编程方式创建子视图）？

Answer 1

快速回答

是的，虽然您将以编程方式设置一些子视图属性。你想要做的是你的UIViewController调用：

[UIView animateWithDuration:animations:completion:]

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详细示例

在任何方法的一侧应该调出键盘尝试以下内容：

CGFloat windowWidth = self.mainView.frame.size.width;
CGFloat windowHeight = self.mainView.frame.size.height;

// center myCustomSubview along the x direction, and put myCustomSubview just below the screen when UIViewController initially gets onto the screen
CGPoint offScreenBelow = CGPointMake(windowWidth/2, windowHeight + (myCustomView.frame.size.y/2));
CGPoint onScreen = CGPointMake(windowWidth/2,windowHeight/2); 
// change the second argument of the CGPointMake function to alter the final height of myCustomSubview

// start myCustomSubview offscreen
myCustomSubview.center = offScreenBelow;
// make sure to add myCustomSubview to the UIViewController's view's subviews
[self.view addSubview:myCustomSubview];
float duration = 1.0; // change this value to make your animation slower or faster. (units in seconds)

// animate myCustomSubview onto the screen
[UIView animateWithDuration:duration
                 animations:^{
                     myCustomSubview.center = onScreen;
                 }
                 completion:^(BOOL finished){
                     // add anything you want to be done as soon as the animation is finished here
                 }];

确保在'viewDidAppear：'之后或在其中调用方法。 当你想在屏幕上关闭myCustomSubview动画时，请确保在你的UIViewController中执行以下操作：

// set offscreen position same way as above
CGFloat windowWidth = self.mainView.frame.size.width;
CGFloat windowHeight = self.mainView.frame.size.height;

CGPoint offScreenBelow = CGPointMake(windowWidth/2, windowHeight + (myCustomView.frame.size.y/2));

// myCustomSubview is on screen already. time to animate it off screen
[UIView animateWithDuration:duration // remember you can change this for animation speed
                 animations:^{
                     myCustomSubview.center = offScreenBelow;
                 }
                 completion:^(BOOL finished){
                     [myCustomSubview removeFromSuperView];
                 }];

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如果您的子视图未显示

与处理子视图时一样，确保框架设置正确，子视图已添加到具有addSubview:的超级视图，子视图不是nil（并且已正确初始化），并且子视图的alpha或opacity属性设置为0。