iOS Development Basics-Fragmentation 46

1: URL processing with Chinese

http://static.tripbe.com/videofiles/video/My selfie video. mp4nsstring *path  = (__bridge_transfer NSString *) Cfurlcreatestringbyreplacingpercentescapesusingencoding (NULL, (__bridge cfstringref) Model.mp4_url, CFSTR (""), Cfstringconvertnsstringencodingtoencoding (nsutf8stringencoding));

2: take webview height

-(void) Webviewdidfinishload: (UIWebView *) WebView {cgfloat height = [[WebView Stringbyevaluatingjavascriptfromstrin      g:@ "Document.body.offsetHeight"] floatvalue];      CGRect frame = webview.frame;  Webview.frame = CGRectMake (frame.origin.x, FRAME.ORIGIN.Y, frame.size.width, height); }

Another way to take advantage of KVO instance:-(void) viewdidload{//KVO, as an observer, as long as the property "Contentsize" Changes, the callback method inside will notify [_webview.scrollview Addobserver : Self forkeypath:@ "contentsize" Options:nskeyvalueobservingoptionnew Context:null];} callback Method-(void) Observevalueforkeypath: (NSString *) KeyPath Ofobject: (ID) object change: (nsdictionary *) Change context: ( void *) context{if (object = = _webview.scrollview && [keypath isequaltostring:@ "Contentsize"]) {//              To the maximum y-coordinate cgsize size = _webview.scrollview.contentsize; if (Size.Height > 568.0) {//occlusion ad _hidebottomimage = [[Uiimageview alloc] Initwithfr            Ame:cgrectmake (0, size.height-67, ScreenWidth, 67)];            _hidebottomimage.image = [UIImage imagenamed:@ "banner"];        [_webview.scrollview Addsubview:_hidebottomimage]; }} else {//Call the parent class method [Super Observevalueforkeypath:keypath Ofobject:object Change:change Context:    Context]; }}-(void) dealloc{//----> in ARC Environmentcan also call the Dealloc method, but do not need to write [super Dealloc]//Remove KVO, otherwise it will cause resource leakage [_webview.scrollview removeobserver:self forkeypath:@ "Conte Ntsize "];}

partial fillet problem of 3:uiview

UIView *view2 = [[UIView alloc] Initwithframe:cgrectmake (+)];view2.backgroundcolor = [Uicolor Redcolor]; [Self.view Addsubview:view2]; Uibezierpath *maskpath = [Uibezierpath bezierPathWithRoundedRect:view2.bounds byroundingcorners: Uirectcornerbottomleft | Uirectcornerbottomright Cornerradii:cgsizemake (10, 10)]; Cashapelayer *masklayer = [[Cashapelayer alloc] init];masklayer.frame = View2.bounds;masklayer.path = MaskPath.CGPath; View2.layer.mask = masklayer;//where, Byroundingcorners:uirectcornerbottomleft | The uirectcornerbottomright//specifies the corners that need to be rounded corners. The parameter is of type Uirectcorner, and the optional values are: * uirectcornertopleft* uirectcornertopright* uirectcornerbottomleft* uirectcornerbottomright* uirectcornerallcorners

4: Force app to exit directly

-(void) exitapplication {appdelegate *app = [UIApplication sharedapplication].delegate;    UIWindow *window = App.window;    [UIView animatewithduration:1.0f animations:^{window.alpha = 0;    } completion:^ (BOOL finished) {exit (0); }];}

5: Modify placeholder color and size

Textfield.placeholder = @ "Please enter user name";  [TextField setvalue:[uicolor Redcolor] forkeypath:@ "_placeholderlabel.textcolor"]; [TextField Setvalue:[uifont boldsystemfontofsize:16] forkeypath:@ "_placeholderlabel.font"];

6: Cancel the system's return gesture

self.navigationController.interactivePopGestureRecognizer.enabled = NO;

7: Change webview font/ color

UIWebView set font size, color, font: UIWebView Some properties of the font cannot be set by their properties, but only through HTML code after the webview is loaded:

-(void) Webviewdidfinishload: (UIWebView *) WebView {nsstring *str = @ "document.getElementsByTagName (' body ') [0].style].      webkittextsizeadjust= ' 60% ' "; [WebView STRINGBYEVALUATINGJAVASCRIPTFROMSTRING:STR]; or add the following code nsstring *jsstring = [[NSString alloc] initwithformat:@ "DOCUMENT.BODY.STYLE.FONTSIZE=%F;   document.body.style.color=%@ ", Fontsize,fontcolor]; [WebView stringbyevaluatingjavascriptfromstring:jsstring];

8:webview Picture Adaptive Screen

-(void) Webviewdidfinishload: (UIWebView *) WebView {  NSString *js = @ "function Imgautofit () {      var IMGs = document. getElementsByTagName (' img ');      for (var i = 0; i < imgs.length; ++i) {        var img = imgs[i];           Img.style.maxWidth =%f;        }   } ";  JS = [NSString stringwithformat:js, [UIScreen mainscreen].bounds.size.width-20];   [WebView Stringbyevaluatingjavascriptfromstring:js];  [WebView stringbyevaluatingjavascriptfromstring:@ "Imgautofit ()"];}

The difference between 9:bool/bool/boolean/nscfboolean

10:nil/nil/null/nsnull differences

A, nil: general assignment to empty objects;

B, null: A value other than nil is generally assigned to a null value. such as SEL, etc.;

Give me a chestnut (good weight ~):

[Nsapp Beginsheet:sheet
Modalforwindow:mainwindow

Modaldelegate:nil//pointing to an object

Didendselector:null//pointing to a non object/class

Contextinfo:null]; Pointing to a non object/class

C, Nsnull:nsnull only one method: + (NSNULL *) null;

[NSNull NULL] is used to add a non-nil (representing the end of the list) to a null value in Nsarray and Nsdictionary.

Nsmutabledictionary *mutabledictionary = [nsmutabledictionary dictionary];mutabledictionary[@ "someKey"] = [NSNull NULL]; Sets value of NSNull singleton for ' Somekey ' NSLog (@ "Keys:%@", [Mutabledictionary AllKeys]); @[@ "Somekey"]

D, when sending a message to nil, return no, there will be no exception, the program will continue to execute;

You receive an exception when you send a message to an Nsnull object.

11: Sub-class implementation-isequal: and Hash

@interface person@property nsstring *name; @property nsdate *birthday;-(BOOL) Isequaltoperson: (person *) person;@ End@implementation person-(BOOL) Isequaltoperson: (person *) person {  if (!person) {    return NO;  }  BOOL haveequalnames = (!self.name &&!person.name) | | [Self.name IsEqualToString:person.name];  BOOL haveequalbirthdays = (!self.birthday &&!person.birthday) | | [Self.birthday IsEqualToDate:person.birthday];  return haveequalnames && haveequalbirthdays;} #pragma mark-nsobject-(BOOL) IsEqual: (ID) object {  if (self = = object) {    return YES;  }  if (![ Object Iskindofclass:[person class]] {    return NO;  }  return [self Isequaltoperson: (person *) object];} -(Nsuinteger) hash {  return [self.name hash] ^ [self.birthday hash];}

iOS Development Basics-Fragmentation 46