先讲需求：
APP中所有界面支持竖屏，只有在一个界面，点击一个btn之后变成横屏，再点就是竖屏。
在网上找了一些方法，发现实现不了，遂问了一个做过这个功能的朋友，得到朋友的支持之后，顺利解决这一问题，我这里将demo附上。
首先，看效果图：
点击横屏.gif
在这里因为是要全局界面都是支持竖屏，其他的不支持，在Xcode里面的配置
Xcode配置
然后就是在AppDelegate中添加属性和方法，
添加属性
在AppDelegate中添加方法
一下是viewController中，即需要转换屏幕方向的.m文件的代码：
#import "ViewController.h"
#import "AppDelegate.h"
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
// _currentOrient = [UIApplication sharedApplication].statusBarOrientation;
UIButton * button = [UIButton buttonWithType:UIButtonTypeCustom];
[button setTitle:@"转一转" forState:UIControlStateNormal];
[button setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
[button addTarget:self action:@selector(changeFrame:) forControlEvents:UIControlEventTouchUpInside];
button.translatesAutoresizingMaskIntoConstraints = NO;
[self.view addSubview:button];
NSLayoutConstraint * centerX = [NSLayoutConstraint constraintWithItem:button attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeCenterX multiplier:1.0 constant:0];
NSLayoutConstraint * centerY = [NSLayoutConstraint constraintWithItem:button attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeCenterY multiplier:1.0 constant:0];
NSLayoutConstraint * width = [NSLayoutConstraint constraintWithItem:button attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0 constant:100];
NSLayoutConstraint * height =[NSLayoutConstraint constraintWithItem:button attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0 constant:44];
[NSLayoutConstraint activateConstraints:@[centerX,centerY,width,height]];
centerY.active = YES;
centerX.active = YES;
width.active = YES;
height.active = YES;
}
// 允许自动旋转
-(BOOL)shouldAutorotate{
return YES;
}
// 横屏时是否将状态栏隐藏
-(BOOL)prefersStatusBarHidden{
return NO;
}
-(void)changeFrame:(UIButton *)btn{
btn.selected = !btn.selected;
if (btn.selected) {
[self forceOrientationLandscapeWith:self];
}else{
[self forceOrientationPortraitWith:self];
}
}
// 横屏 home键在右边
-(void)forceOrientationLandscapeWith:(UIViewController *)VC{
AppDelegate *appdelegate=(AppDelegate *)[UIApplication sharedApplication].delegate;
appdelegate.isForcePortrait=NO;
appdelegate.isForceLandscape=YES;
[appdelegate application:[UIApplication sharedApplication] supportedInterfaceOrientationsForWindow:VC.view.window];
//强制翻转屏幕，Home键在右边。
[[UIDevice currentDevice] setValue:@(UIInterfaceOrientationLandscapeRight) forKey:@"orientation"];
//刷新
[UIViewController attemptRotationToDeviceOrientation];
}
// 竖屏
- (void)forceOrientationPortraitWith:(UIViewController *)VC{
AppDelegate *appdelegate=(AppDelegate *)[UIApplication sharedApplication].delegate;
appdelegate.isForcePortrait=YES;
appdelegate.isForceLandscape=NO;
[appdelegate application:[UIApplication sharedApplication] supportedInterfaceOrientationsForWindow:VC.view.window];
//强制翻转屏幕
[[UIDevice currentDevice] setValue:@(UIDeviceOrientationPortrait) forKey:@"orientation"];
//刷新
[UIViewController attemptRotationToDeviceOrientation];
}
