IOS Study Notes 26-iPhone development knowledge collection

 

1. check whether this object or method exists

ResponseToSelector: @ selector

 

2. Delayed asynchronous execution

PeformSelector: withObject: afterDelay

 

3. simulator path:

/[User]/Library/Application Support/iPhone Simulator/4.2/Applications/B0E3EC07-F395-408F-9B94-A5B0BAECBC2E/Documents/personal. plist

 

4. Custom send notification

Send message

NSDictionary * info = [[NSDictionaryalloc] initWithObjectsAndKeys: nil, @ "ret", nil];

[[Nsnotifcencenterdefacenter] postNotificationOnMainThreadWithName: @ "LoginSuccessful" object: self userInfo: info];

Receive messages

[[Nsnotifcencenterdefacenter] addObserver: self selector: @ selector (loginSuccessful :) name: @ "LoginSuccessful" object: nil];

 

1. code used to determine whether the email format is correct

// Use regular expression for verification

-(BOOL) isValidateEmail :( NSString *) email

{

NSString * emailRegex = @ "[A-Z0-9a-z. _ % +-] + @ [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 the image

-(UIImage *) imageWithImageSimple :( UIImage *) image scaledToSize :( CGSize) newSize

{

// Create a graphics image context

UIGraphicsBeginImageContext (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 context

UIImage * newImage = UIGraphicsGetImageFromCurrentImageContext ();

// End the context

UIGraphicsEndImageContext ();

// Return the new image.

Return newImage;

}

3. Test the available image upload code.

-(IBAction) uploadButton :( id) sender {

UIImage * image = [UIImage imageNamed: @ "1.jpg"]; // image name

NSData * imageData = UIImageJPEGRepresentation (image, 0.5); // compression ratio

NSLog (@ "Bytes: % I", [imageData length]);

// Post url

NSString * urlString = @ "http: // 192.168.1.113: 8090/text/UploadServlet ";

// Server address

// Setting up the request object now

NSMutableURLRequest * 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]; // name of the uploaded Image

[Body appendData: [[NSString stringWithString: @ "Content-Type: application/octet-stream \ 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. operations on the Image Library

Select album:

UIImagePickerControllerSourceTypesourceType = UIImagePickerControllerSourceTypeCamera;

If (! [UIImagePickerControllerisSourceTypeAvailable: UIImagePickerControllerSourceTypeCamera]) {

SourceType = UIImagePickerControllerSourceTypePhotoLibrary;

}

UIImagePickerController * picker = [[UIImagePickerControlleralloc] init];

Picker. delegate = self;

Picker. allowsEditing = YES;

Picker. sourceType = sourceType;

[Self presentModalViewController: picker animated: YES];

Selected:

-(Void) imagePickerController :( UIImagePickerController *) pickerdidFinishPickingMediaWithInfo :( NSDictionary *) info

{

[Picker dismissModalViewControllerAnimated: YES];

UIImage * image = [info objectForKey: UIImagePickerControllerEditedImage];

[Self defined mselector: @ 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 validate mselectorinbackground: @ selector (detect :) withObject: nil];

}

Detect is a method defined by the user. The effect to be achieved after the photo is edited and selected

Unselect:

-(Void) imagePickerControllerDIdCancel :( UIImagePickerController *) picker

{

[Picker dismissModalViewControllerAnimated: YES];

}

6. jump to the next View

NextWebView = [[WEBViewController alloc] initWithNibName: @ "WEBViewController" bundle: nil];

[Self presentModalViewController: nextWebView animated: YES];

// Create a button on the Right of UIBarButtonItem

UIBarButtonItem * rightButton = [[UIBarButtonItem alloc] initWithTitle: @ "right" style: UIBarButtonItemStyleDone target: self action: @ selector (clickRightButton)];

[Self. navigationItem setRightBarButtonItem: rightButton];

Set navigationBar to hide

Self. navigationController. navigationBarHidden = YES ;//

Automatic line feed (automatic LINE folding) for multiple lines of UIlabel in iOS development)

UIView * footerView = [[UIView alloc] initWithFrame: CGRectMake (10,100,300,180)];

UILabel * label = [[UILabel alloc] initWithFrame: CGRectMake (10,100,300,150)];

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! ";

// The background color is red.

Label. backgroundColor = [UIColor redColor];

// Set the font color to white

Label. textColor = [UIColor whiteColor];

// Text center display

Label. textAlignment = UITextAlignmentCenter;

// Automatic LINE folding settings

Label. 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: @ "New button" forState: UIControlStateNormal];

Button. backgroundColor = [UIColor clearColor];

Buttons. tag = 2000;

[Button addTarget: self action: @ selector (buttonClicked :) forControlEvents: UIControlEventTouchUpInside];

[Self. view addSubview: button];

8. display a widget in the center of the View

(A control, such as label and View) label. center = self. view. center;

9. Nice-looking text processing

Take the cell textLabel in tableView as an example:

Cell. backgroundColor = [UIColorscrollViewTexturedBackgroundColor];

// Set the text font

Cell. textLabel. font = [UIFont fontWithName: @ "AmericanTypewriter" size: 100366f];

// Set the text color

Cell. textLabel. textColor = [UIColor orangeColor];

// Set the background color of the text

Cell. textLabel. shadowColor = [UIColor whiteColor];

// Set the text display position

Cell. textLabel. textAlignment = UITextAlignmentCenter;

10. Hide the Status Bar

The reader may know a simple method, that is, adding

[[UIApplication sharedApplication] setStatusBarHidden: YES animated: NO];

11. Change the AlertView background

UIAlertView * theAlert = [[UIAlertViewalloc] initWithTitle: @ "Atention"

Message: @ "I'm a Chinese! "

Delegate: nil

CancelButtonTitle: @ "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)]; // adjust the size of this place to adapt to the background color of alertview.

TheImage = UIGraphicsGetImageFromCurrentImageContext ();

UIGraphicsEndImageContext ();

TheAlert. layer. contents = (id) [theImage CGImage];

12. Transparent keyboard

TextField. keyboardAppearance = UIKeyboardAppearanceAlert;

Indicates whether the network active firewheel in the status bar is rotated.

[UIApplication sharedApplication]. networkActivityIndicatorVisible. The default value is NO.

13. capture screen images

// Create a bitmap-based image context and specify the size as CGSizeMake (200,400)

UIGraphicsBeginImageContext (CGSizeMake (200,400 ));

// RenderInContext presents the receiver and Its subrange to the specified context

[Self. view. layer renderInContext: UIGraphicsGetCurrentContext ()];

// Returns an image based on the current image context.

UIImage * aImage = UIGraphicsGetImageFromCurrentImageContext ();

// Remove the image context at the top of the stack based on the current bitmap

UIGraphicsEndImageContext ();

// Return the data of the specified image in png format

ImageData = UIImagePNGRepresentation (aImage );

14. Change the background of the cell.

UIView * myview = [[UIView alloc] init];

Myview. frame = cgrecctmake (0, 0,320, 47 );

Myview. backgroundColor = [UIColorcolorWithPatternImage: [UIImage imageNamed: @ "0006.png"];

Cell. selectedBackgroundView = myview;

15. display images

CGRect myImageRect = CGRectMake (0.0f, 0.0f, 3200000f, 109.0f );

UIImageView * myImage = [[UIImageView alloc] initWithFrame: myImageRect];

[MyImage setImage: [UIImage imageNamed: @ "myImage.png"];

MyImage. opaque = YES; // whether opaque is transparent

[Self. view addSubview: myImage];

16. Adjust the image size to the frame size without 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. Code for clicking an image to jump: generate a button with a background image and bind the button with the desired event!

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];