iOS development common Code Snippets collation

1. Code that determines whether the mailbox is formatted correctly

Using regular expression validation-(BOOL) Isvalidateemail: (NSString *) email{nsstring *emailregex = @ "[A-z0-9a-z._%+-][email protected][ A-za-z0-9.-]+\\. [A-za-z] {2,4} "; Nspredicate *emailtest = [Nspredicate predicatewithformat:@ "Self matches%@", Emailregex];return [emailTest Evaluatewithobject:email];}

2. Image compression
Usage: UIImage *yourimage= [self imagewithimagesimple:image scaledtosize:cgsizemake (210.0, 210.0)];

Compress picture-(uiimage*) Imagewithimagesimple: (uiimage*) Image scaledtosize: (cgsize) newsize{//Create a graphics image Contextuigraphicsbeginimagecontext (newSize);//Tell the old image to draw in this newcontext, with the desired//new size[ Image Drawinrect:cgrectmake (0,0,newsize.width,newsize.height)];//Get The new image from the contextuiimage* newimage = U Igraphicsgetimagefromcurrentimagecontext ();//End the Contextuigraphicsendimagecontext ();//Return The new Image.return NewImage;}

3. Pro-Test the available image upload code

-(Ibaction) Uploadbutton: (ID) Sender {UIImage *image = [UIImage imagenamed:@ "1.jpg"];//Picture name NSData *imagedata = UIImageJPEGRepresentation (image,0.5);//Compression ratio NSLog (@ "number of bytes:%i", [imageData length]);//post urlnsstring *urlstring = @ " Http://192.168.1.113:8090/text/UploadServlet ";//server address//setting up the Request object Nownsmutableurlrequest *request = [[Nsmutableurlrequest alloc] init]; [Request Seturl:[nsurl urlwithstring:urlstring]; [Request sethttpmethod:@ "POST"];//nsstring *boundary = [NSString stringwithstring:@ "--------------------------- 14737809831466499882746641449 "]; NSString *contenttype = [NSString stringwithformat:@ "multipart/form-data;boundary=%@", boundary]; [Request Addvalue:contenttype Forhttpheaderfield: @ "Content-type"]; Nsmutabledata *body = [Nsmutabledata data]; [Body appenddata:[[nsstring stringwithformat:@ "\r\n--%@\r\n", boundary] datausingencoding:nsutf8stringencoding]]; [Body appenddata:[[nsstring stringwithstring:@ "content-disposition:form-data; name=\" userfile\ "; filename=\" 2.png\ "\ r \ n"] datausingencoding:nsutf8stringencoding]; Uploaded image name [body appenddata:[[nsstring stringwithstring:@ "content-type:application/octet-stream\r\n\r\n"] Datausingencoding:nsutf8stringencoding]]; [Body Appenddata:[nsdata Datawithdata:imagedata]; [Body appenddata:[[nsstring stringwithformat:@ "\r\n--%@--\r\n", boundary] datausingencoding:nsutf8stringencoding] ; [Request sethttpbody:body];//NSLog (@ "1-body:%@", body); NSLog (@ "2-request:%@", request); NSData *returndata = [nsurlconnection sendsynchronousrequest:request returningresponse:nil Error:nil]; NSString *returnstring = [[NSString alloc] Initwithdata:returndata encoding:nsutf8stringencoding]; NSLog (@ "3-Test output:%@", returnstring);

4. Load images to ImageView

UIImage *myimage = [UIImage imagenamed:@ "1.jpg"]; [ImageView Setimage:myimage]; [Self.view Addsubview:imageview];

5. Working with the Gallery
Select album:

Uiimagepickercontrollersourcetypesourcetype=uiimagepickercontrollersourcetypecamera;if (![ Uiimagepickercontrollerissourcetypeavailable:uiimagepickercontrollersourcetypecamera]) {sourceType= Uiimagepickercontrollersourcetypephotolibrary;} Uiimagepickercontroller * Picker = [[Uiimagepickercontrolleralloc]init];p icker.delegate = self;picker.allowsEditing= Yes;picker.sourcetype=sourcetype; [Self presentmodalviewcontroller:picker animated:yes];

Select Complete:

-(void) Imagepickercontroller: (uiimagepickercontroller*) Pickerdidfinishpickingmediawithinfo: (NSDictionary *) info {[Picker dismissmodalviewcontrolleranimated:yes]; UIImage * Image=[info Objectforkey:uiimagepickercontrollereditedimage]; [Self performselector: @selector (selectpic:) withobject:imageafterdelay:0.1];} -(void) Selectpic: (uiimage*) Image{nslog (@ "image%@", image); imageView = [[Uiimageview alloc] initwithimage:image]; Imageview.frame = CGRectMake (0, 0, image.size.width, image.size.height); [Self.viewaddSubview:imageView]; [Self Performselectorinbackground: @selector (Detect:) Withobject:nil];}

detect the method that you define for yourself, edit the effect you want to achieve after selecting a photo
Cancel selection:

-(void) Imagepickercontrollerdidcancel: (uiimagepickercontroller*) Picker{[picker Dismissmodalviewcontrolleranimated:yes];}

6. Skip to the next view

Nextwebview = [[Webviewcontroller alloc] initwithnibname:@ "Webviewcontroller" bundle:nil]; [Self Presentmodalviewcontroller:nextwebview animated:yes];//Create a Uibarbuttonitem right button uibarbuttonitem *rightButton = [[Uibarbuttonitem alloc] initwithtitle:@ "right" style:uibarbuttonitemstyledone target:self action: @selector ( Clickrightbutton)]; [Self.navigationitem Setrightbarbuttonitem:rightbutton]; Set Navigationbar Hide Self.navigationController.navigationBarHidden = Yes;//ios Development Uilabel Multiline text wrap (auto-fold line) UIView * Footerview = [[UIView alloc]initwithframe:cgrectmake (10, 100, 300, 180)]; UILabel *label = [[UILabel alloc]initwithframe:cgrectmake]];label.text = @ "Hello world! Hello world! Hello world! Hello world! Hello world! Hello world! Hello world! Hello world! Hello world! Hello world! Hello world! Hello world! Hello world! Helloworld! "; /Background color is red Label.backgroundcolor = [uicolor redcolor];//set font color to white label.textcolor = [Uicolor whitecolor];// Text centered display label.textalignment = uitextalignmentcenter;//Auto Wrap settingLabel.linebreakmode = Uilinebreakmodewordwrap;label.numberoflines = 0; 

7. Code generation button

CGRect frame = CGRectMake (0, 400, 72.0, 37.0); UIButton *button = [UIButton buttonwithtype:uibuttontyperoundedrect];button.frame = frame; [Button settitle:@ "newly added buttons" Forstate:uicontrolstatenormal];button.backgroundcolor = [Uicolor Clearcolor];button.tag = 2000; [Button addtarget:self action: @selector (buttonclicked:) forcontrolevents:uicontroleventtouchupinside]; [Self.view Addsubview:button];

8. Make a control appear in the center of the View
(a control, such as Label,view) Label.center = Self.view.center;

9. Good-looking word processing

Take the Textlabel of the cell in TableView as an example:

Cell.backgroundcolor = [uicolorscrollviewtexturedbackgroundcolor];//Sets the font of the text Cell.textLabel.font = [Uifont fontwithname:@ "Americantypewriter" size:100.0f];//set the color of the text Cell.textLabel.textColor = [Uicolor orangecolor];// Sets the background color of the text Cell.textLabel.shadowColor = [Uicolor whitecolor];//sets the display position of the text cell.textLabel.textAlignment = Uitextalignmentcenter;

10. Hide Status Bar
The reader may know an easy way to add a viewdidload to the program.

[[UIApplication Sharedapplication]setstatusbarhidden:yes Animated:no];

11. Change the Alertview background

Uialertview *thealert = [[[Uialertviewalloc] initwithtitle:@ "atention" message: @ "I ' m a chinese!" delegate:nilcancelbuttontitle:@ "Cancel" otherbuttontitles:@ "Okay", Nil] autorelease]; [Thealert show]; UIImage *theimage = [uiimageimagenamed:@ "lovechina.png"];theimage = [Theimage stretchableimagewithleftcapwidth:0 TOPCAPHEIGHT:0]; Cgsize thesize = [Thealert frame].size; Uigraphicsbeginimagecontext (thesize); [Theimage Drawinrect:cgrectmake (5, 5, thesize.width-10, thesize.height-20)];//the size of this place to adjust itself to fit the size of the alertview background color. Theimage = Uigraphicsgetimagefromcurrentimagecontext (); Uigraphicsendimagecontext (); theAlert.layer.contents = (ID) [Theimage cgimage];

12. Keyboard Transparency

Textfield.keyboardappearance = Uikeyboardappearancealert;

network activity on the status bar whether the wheel rotates

[UIApplication sharedapplication].networkactivityindicatorvisible, the default value is No.

13. Capturing Screen Images
Create a bitmap-based graphics context and specify a size of Cgsizemake (200,400)

Uigraphicsbeginimagecontext (Cgsizemake (200,400))//renderincontext renders the recipient and its child scopes to the specified context [Self.view.layer Renderincontext:uigraphicsgetcurrentcontext ()];//returns a picture based on the current graphics context uiimage *aimage = Uigraphicsgetimagefromcurrentimagecontext ();//Remove the top of the stack based on the current bitmap's graphics context uigraphicsendimagecontext ();// Returns the data for the specified picture in PNG format ImageData = uiimagepngrepresentation (aimage);

14. Change the background of cell selection

UIView *myview = [[UIView alloc] init];myview.frame = CGRectMake (0, 0, +); myview.backgroundcolor = [Uicolorcolorwith Patternimage:[uiimage imagenamed:@ "0006.png"]];cell.selectedbackgroundview = MyView;

15. Displaying images

CGRect myimagerect = CGRectMake (0.0f, 0.0f, 320.0f, 109.0f); Uiimageview *myimage = [[Uiimageview alloc] initwithframe:myimagerect]; [MyImage setimage:[uiimage imagenamed:@ "myimage.png"]];myimage.opaque = YES; Opaque is transparent [self.view addsubview:myimage];

16. Can make the picture fit the box size (no confirmation)

Nsstring*imagepath = [[NSBundle mainbundle] pathforresource:@ "Xcodecrash" oftype:@ "PNG"]; UIImage *image = [[UIImage Alloc]initwithcontentsoffile:imagepath]; UIImage *newimage= [Image transformwidth:80.f HEIGHT:240.F]; Uiimageview *imageview = [[Uiimageview alloc]initwithimage:newimage]; [Newimagerelease]; [Image release]; [Self.view Addsubview:imageview];

17. Implement the code to jump by clicking on the image: Generate a button with a background image and bind the desired event to the button!

UIButton *imgbutton=[[uibutton alloc]initwithframe:cgrectmake (0, 0, 120, 120)]; [Imgbutton setbackgroundimage: (UIImage *) [Self.imgarray ObjectAtIndex:indexPath.row] Forstate:uicontrolstatenormal];imgbutton.tag=[indexpath row]; [Imgbutton addtarget:self Action: @selector (ButtonClick:) forcontrolevents:uicontroleventtouchupinside];

iOS development common Code Snippets collation