在开发过程中,我们常常会碰到一种情况就是,在一个controller里面,经常要放很多复杂的控制,最常用的就是tar切换。tar切换,原理就是在一个controller里面,显示另一个controller的view。
如果发现:控制器的view还在,但是view上面的数据不显示,极大可能是因为:控制器被提前销毁了
- 一个控制器的view是可以随意调整尺寸和位置的
- 一个控制器的view是可以随意添加到其他view中
- 如果将一个控制器的view,添加到其他view中显示,那么要想办法保证控制器不被销毁
- 原则:只要view在,view所在的控制器必须得在,这样才能保证view内部的数据和业务逻辑正常
简单例子
//
// ViewController.m
// 控制器tab切换view显示
//
// Created by jiangys on 15/10/11.
// Copyright © 2015年 Jiangys. All rights reserved.
// #import "ViewController.h" #import "OneViewController.h"
#import "TwoViewController.h"
#import "ThreeViewController.h" @interface ViewController ()
- (IBAction)vc1;
- (IBAction)vc2;
- (IBAction)vc3; /** one */
@property (nonatomic, strong) OneViewController *one;
/** two */
@property (nonatomic, strong) TwoViewController *two;
/** three */
@property (nonatomic, strong) ThreeViewController *three; @end @implementation ViewController - (OneViewController *)one
{
if (!_one) {
self.one = [[OneViewController alloc] init];
self.one.view.frame = CGRectMake(, , , );
}
return _one;
} - (TwoViewController *)two
{
if (!_two) {
self.two = [[TwoViewController alloc] init];
self.two.view.frame = CGRectMake(, , , );
}
return _two;
} - (ThreeViewController *)three
{
if (!_three) {
self.three = [[ThreeViewController alloc] init];
self.three.view.frame = CGRectMake(, , , );
}
return _three;
} - (void)viewDidLoad {
[super viewDidLoad];
// HestViewController *test = [[TestViewController alloc] init];
// test.view.frame = CGRectMake(100, 100, 200, 300);
// test.view.backgroundColor = [UIColor redColor];
// [self.view addSubview:test.view];
// self.test = test; // 如果发现:控制器的view还在,但是view上面的数据不显示,极大可能是因为:控制器被提前销毁了 // 1.一个控制器的view是可以随意调整尺寸和位置的
// 2.一个控制器的view是可以随意添加到其他view中
// 3.如果将一个控制器的view,添加到其他view中显示,那么要想办法保证控制器不被销毁
// 4.原则:只要view在,view所在的控制器必须得在,这样才能保证view内部的数据和业务逻辑正常
} - (IBAction)vc1 {
[self.two.view removeFromSuperview];
[self.three.view removeFromSuperview];
[self.view addSubview:self.one.view];
} - (IBAction)vc2 {
[self.one.view removeFromSuperview];
[self.three.view removeFromSuperview];
[self.view addSubview:self.two.view];
} - (IBAction)vc3 {
[self.two.view removeFromSuperview];
[self.one.view removeFromSuperview];
[self.view addSubview:self.three.view];
}
@end
效果:
上面的做法确实是可以实现了效果,但却隐藏了很多隐患。比如,self.View 屏幕旋转,并不会通知到子控制器。当然还有很多其它的问题。
解决方案:
- 当控制器的view互为父子关系,那么控制器最好也互为父子关系
- 通过addChildViewController添加一个子控制器,那么这个子控制器就会被放到ChildViewControllers数据中,只要self存在,那么ChildViewControllers数组就会一直存在
修改:
//
// ViewController.m
// 控制器tab切换view显示
//
// Created by jiangys on 15/10/11.
// Copyright © 2015年 Jiangys. All rights reserved.
// #import "ViewController.h" #import "OneViewController.h"
#import "TwoViewController.h"
#import "ThreeViewController.h" @interface ViewController ()
- (IBAction)vc1;
- (IBAction)vc2;
- (IBAction)vc3; @end @implementation ViewController - (void)viewDidLoad {
[super viewDidLoad]; // 当控制器的view互为父子关系,那么控制器最好也互为父子关系
OneViewController *one=[[OneViewController alloc] init];
one.view.frame = CGRectMake(, , , );
// 通过addChildViewController添加一个子控制器,那么这个子控制器就会被放到ChildViewControllers数据中
// 只要self存在,那么ChildViewControllers数组就会一直存在
[self addChildViewController:one]; TwoViewController *two=[[TwoViewController alloc] init];
two.view.frame = CGRectMake(, , , );
[self addChildViewController:two]; ThreeViewController *three=[[ThreeViewController alloc] init];
three.view.frame = CGRectMake(, , , );
[self addChildViewController:three]; } - (IBAction)vc1 {
OneViewController *one = self.childViewControllers[];
TwoViewController *two = self.childViewControllers[];
ThreeViewController *three = self.childViewControllers[]; [two.view removeFromSuperview];
[three.view removeFromSuperview];
[self.view addSubview:one.view];
} - (IBAction)vc2 {
OneViewController *one = self.childViewControllers[];
TwoViewController *two = self.childViewControllers[];
ThreeViewController *three = self.childViewControllers[]; [one.view removeFromSuperview];
[three.view removeFromSuperview];
[self.view addSubview:two.view];
} - (IBAction)vc3 {
OneViewController *one = self.childViewControllers[];
TwoViewController *two = self.childViewControllers[];
ThreeViewController *three = self.childViewControllers[]; [two.view removeFromSuperview];
[one.view removeFromSuperview];
[self.view addSubview:three.view];
}
@end