UIPopoverController使用

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h2 tt, h2 code {
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h3 tt, h3 code {
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h4 tt, h4 code {
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h5 tt, h5 code {
font-size: inherit; }

h6 tt, h6 code {
font-size: inherit; }

h1 {
font-size: 28px;
color: black; }

h2 {
font-size: 24px;
border-bottom: 1px solid #cccccc;
color: black; }

h3 {
font-size: 18px; }

h4 {
font-size: 16px; }

h5 {
font-size: 14px; }

h6 {
color: #777777;
font-size: 14px; }

p, blockquote, ul, ol, dl, li, table, pre {
margin: 15px 0; }

hr {
background: transparent url(data:image/png;base64,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) repeat-x 0 0;
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body > h2:first-child {
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body > h1:first-child {
margin-top: 0;
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body > h1:first-child + h2 {
margin-top: 0;
padding-top: 0; }
body > h3:first-child, body > h4:first-child, body > h5:first-child, body > h6:first-child {
margin-top: 0;
padding-top: 0; }

a:first-child h1, a:first-child h2, a:first-child h3, a:first-child h4, a:first-child h5, a:first-child h6 {
margin-top: 0;
padding-top: 0; }

h1 p, h2 p, h3 p, h4 p, h5 p, h6 p {
margin-top: 0; }

li p.first {
display: inline-block; }
li {
margin: 0; }
ul, ol {
padding-left: 30px; }

ul :first-child, ol :first-child {
margin-top: 0; }

dl {
padding: 0; }
dl dt {
font-size: 14px;
font-weight: bold;
font-style: italic;
padding: 0;
margin: 15px 0 5px; }
dl dt:first-child {
padding: 0; }
dl dt > :first-child {
margin-top: 0; }
dl dt > :last-child {
margin-bottom: 0; }
dl dd {
margin: 0 0 15px;
padding: 0 15px; }
dl dd > :first-child {
margin-top: 0; }
dl dd > :last-child {
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blockquote {
border-left: 4px solid #dddddd;
padding: 0 15px;
color: #777777; }
blockquote > :first-child {
margin-top: 0; }
blockquote > :last-child {
margin-bottom: 0; }

table {
padding: 0;border-collapse: collapse; }
table tr {
border-top: 1px solid #cccccc;
background-color: white;
margin: 0;
padding: 0; }
table tr:nth-child(2n) {
background-color: #f8f8f8; }
table tr th {
font-weight: bold;
border: 1px solid #cccccc;
margin: 0;
padding: 6px 13px; }
table tr td {
border: 1px solid #cccccc;
margin: 0;
padding: 6px 13px; }
table tr th :first-child, table tr td :first-child {
margin-top: 0; }
table tr th :last-child, table tr td :last-child {
margin-bottom: 0; }

img {
max-width: 100%; }

span.frame {
display: block;
overflow: hidden; }
span.frame > span {
border: 1px solid #dddddd;
display: block;
float: left;
overflow: hidden;
margin: 13px 0 0;
padding: 7px;
width: auto; }
span.frame span img {
display: block;
float: left; }
span.frame span span {
clear: both;
color: #333333;
display: block;
padding: 5px 0 0; }
span.align-center {
display: block;
overflow: hidden;
clear: both; }
span.align-center > span {
display: block;
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margin: 13px auto 0;
text-align: center; }
span.align-center span img {
margin: 0 auto;
text-align: center; }
span.align-right {
display: block;
overflow: hidden;
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span.align-right > span {
display: block;
overflow: hidden;
margin: 13px 0 0;
text-align: right; }
span.align-right span img {
margin: 0;
text-align: right; }
span.float-left {
display: block;
margin-right: 13px;
overflow: hidden;
float: left; }
span.float-left span {
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span.float-right {
display: block;
margin-left: 13px;
overflow: hidden;
float: right; }
span.float-right > span {
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text-align: right; }

code, tt {
margin: 0 2px;
padding: 0 5px;
white-space: nowrap;
border: 1px solid #eaeaea;
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border-radius: 3px; }

pre code {
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.highlight pre {
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border: 1px solid #cccccc;
font-size: 13px;
line-height: 19px;
overflow: auto;
padding: 6px 10px;
border-radius: 3px; }

pre {
background-color: #f8f8f8;
border: 1px solid #cccccc;
font-size: 13px;
line-height: 19px;
overflow: auto;
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sup {
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* {
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@media screen and (min-width: 914px) {
body {
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margin:0 auto;
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}
@media print {
table, pre {
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pre {
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-->

---

1.简介

• 1.1 什么是UIPopverController?
  • 是iPad开发中常见的一种控制器.
  • 跟其他控制器不一样的是,它直接继承自NSObject,并非继承自UIViewController.
  • 它只占用部分屏幕控件来呈现信息,而且显示在屏幕的最前面.

---

2.使用步骤

• 要想显示一个UIPopverController,需要经过下列步骤:
  • 设置内容控制器
    • 由于 UIPopverController 直接继承自 NSObject,不具备可视化的能力.
    • 因此, UIPopverController上面的内容必须由另外一个继承自UIViewController的控制器来提供,这个控制器成为"内容控制器".
  • 设置内容的尺寸
    • 显示出来占据多少屏幕空间
  • 设置内容的位置
    • 从哪个地方冒出来

---

3.设置内容控制器

• 设置内容控制器有3种方法:

  • 1.在初始化UIPopoverController的时候传入一个内容控制器
    • - (id)initWithContentViewController:(UIViewController *)viewController;

  • 2.@property (nonatomic, retain) UIViewController *contentViewController;

  • 3.- (void)setContentViewController:(UIViewController *)viewController animated:(BOOL)animated;

---

4.设置内容的尺寸

• 设置内容的尺寸有两种方法:
  • @property (nonatomic) CGSize popoverContentSize;
  • - (void)setPopoverContentSize:(CGSize)size animated:(BOOL)animated;

---

5.设置显示的位置

• 设置显示的位置有两种方法:

  • 1.围绕着一个UIBarButtonItem显示（箭头指定那个UIBarButtonItem）
  • (void)presentPopoverFromBarButtonItem:(UIBarButtonItem *)item permittedArrowDirections:(UIPopoverArrowDirection)arrowDirections animated:(BOOL)animated;
  • item ：围绕着哪个UIBarButtonItem显示
  • arrowDirections ：箭头的方向

  • animated ：是否通过动画显示出来

  • 2.围绕着某一块特定区域显示（箭头指定那块特定区域）

  • (void)presentPopoverFromRect:(CGRect)rect inView:(UIView *)view permittedArrowDirections:(UIPopoverArrowDirection)arrowDirections animated:(BOOL)animated;

  • rect ：指定箭头所指区域的矩形框范围（位置和尺寸）

  • view ：rect参数是以view的左上角为坐标原点（0，0）

  • arrowDirections ：箭头的方向

  • animated ：是否通过动画显示出来

  • 

---

6.rect和view参数

---

7.常见报错

• 在popover的使用过程中，经常会遇到这个错误 -[UIPopoverController dealloc] reached while popover is still visible. 错误的大体意思是：popover在仍旧可见的时候被销毁了（调用了dealloc）

• 

• 从错误可以得出的结论:

  • 当popover仍旧可见的时候，不准销毁popover对象
  • 在销毁popover对象之前，一定先让popover消失（不可见）

---

8.通过内容控制器设置内容尺寸

• 内容控制器可以自行设置自己在popover中显示的尺寸

  • 在iOS 7之前 @property (nonatomic,readwrite) CGSize contentSizeForViewInPopover;
  • 从iOS 7开始 @property (nonatomic) CGSize preferredContentSize;

---

9.常见属性

• 代理对象 @property (nonatomic, assign) id delegate;

• 是否可见 @property (nonatomic, readonly, getter=isPopoverVisible) BOOL popoverVisible;

• 箭头方向 @property (nonatomic, readonly) UIPopoverArrowDirection popoverArrowDirection;

• 关闭popover（让popover消失）

• (void)dismissPopoverAnimated:(BOOL)animated;

---

10.防止点击UIPopoverController区域外消失

• 默认情况下 只要UIPopoverController显示在屏幕上，UIPopoverController背后的所有控件默认是不能跟用户进行正常交互的 点击UIPopoverController区域外的控件，UIPopoverController默认会消失

• 要想点击UIPopoverController区域外的控件时不让UIPopoverController消失，解决办法是设置passthroughViews属性 @property (nonatomic, copy) NSArray *passthroughViews; 这个属性是设置当UIPopoverController显示出来时，哪些控件可以继续跟用户进行正常交互。这样的话，点击区域外的控件就不会让UIPopoverController消失了

---

11.如何在iPhone中实现popover的效果

• UIPopoverController这个类是只能用在iPad中的.
• 要想在iPhone中实现popover效果，必须得自定义view.