1. Basic controls for iOS development and basic controls for ios development

1. Basic controls for iOS development and basic controls for ios development
I. UIView

1. Common Properties of UIView

@property(nonatomic) CGRect            frame;@property(nonatomic) CGRect            bounds;@property(nonatomic) CGPoint           center;@property(nonatomic) CGAffineTransform transform;@property(nonatomic,readonly) UIView       *superview;@property(nonatomic,readonly,copy) NSArray *subviews;@property(nonatomic,readonly) UIWindow     *window;

Supplement:

// View content mode @ property (nonatomic) UIViewContentMode contentMode;

Generally, this parameter is set to UIViewContentModeCenter. The image size remains the original size.

* Differences between frame, bounds, and center :*

* Frame: uses the upper-left corner of the parent control as the coordinate origin. You can determine the origin and size of the Control. * bounds: uses the upper-left corner as the coordinate origin, you can determine the size of the control * center: you can determine the control position * Note: OC does not allow modification of object structure attribute members

2. transform attributes

You can use transform to modify the position scaling and rotation of the control.
1> Create a transform attribute

CGAffineTransform CGAffineTransformMakeTranslation(CGFloat tx,  CGFloat ty) ;CGAffineTransform CGAffineTransformMakeScale(CGFloat sx, CGFloat sy);CGAffineTransform CGAffineTransformMakeRotation(CGFloat angle)

2> overlay the transform

CGAffineTransform CGAffineTransformTranslate(CGAffineTransform t, CGFloat tx, CGFloat ty);CGAffineTransform CGAffineTransformScale(CGAffineTransform t, CGFloat sx, CGFloat sy);CGAffineTransform CGAffineTransformRotate(CGAffineTransform t, CGFloat angle);

3> clear the previously set transform attributes

view.transform = CGAffineTransformIdentity;

Supplement: Coordinate Transformation

CGPoint * newpoint = [view1 convertPoint: <# (CGPoint) #> toView: view2]; Convert coordinates from view1 to view2 // CGRect * newRect = [view1 convertPoint: <# (CGPoint) #> fromView: view2]; // convert coordinates from view2 to view1CGPoint. The former is frame, the former is subviewCGPoint, and the former is bounds.

3. Common Methods of UIView

- (void)addSubview:(UIView*)view;- (void)removeFromSuperView;- (UIView*)viewWithTag:(NSInteger)tag;

1> meal adding (Listening to the process of adding sub-controls)

// Add a subcontrol-(void) didAddSubview :( UIView *) subview; // remove the subcontrol-(void) willRemoveSubview :( UIView *) subview; // to add to parent control-(void) willMoveToSuperview :( UIView *) newSuperview; // Add to control-(void) didMoveToSuperview;

4. UIView for simple animation

Two animation Methods
1> headers and tails

[UIView beginAnimations: nil context: nil]; // The animation to be executed [UIView commitAnimations];

2> Block type

[UIView animateWithDuration: 0.5 animations: ^ {// code of the animation to be executed}];

**

Ii. UIButton

**

• Features: displays images, texts, and clicks in response to listener events
• Four statuses:

1> normal--> UIControlStateNormal2> highlighted-->UIControlStateHighlighted3> selected-->UIControlStateSelected4> disabled-->UIControlStateDisabled

1. common attributes

@property(nonatomic,readonly,retain) NSString *currentTitle;@property(nonatomic,readonly,retain) UIColor  *currentTitleColor;@property(nonatomic,readonly,retain) UIImage  *currentImage;@property(nonatomic,readonly,retain) UIImage  *currentBackgroundImage;

2. Common attribute settings

- (void)setTitle:(NSString *)title forState:(UIControlState)state;- (void)setTitleColor:(UIColor *)color forState:(UIControlState)state;- (void)setImage:(UIImage *)image forState:(UIControlState)state;- (void)setBackgroundImage:(UIImage *)image forState:(UIControlState)state;btn.titleLabel.font = [UIFont systemFontOfSize:13];

3. Obtain attributes

- (NSString *)titleForState:(UIControlState)state;- (UIColor *)titleColorForState:(UIControlState)state;- (UIImage *)imageForState:(UIControlState)state;- (UIImage *)backgroundImageForState:(UIControlState)state;

4. manually create UIButton code

UIButton * btn = [UIButton buttonWithType: bytes]; [btn setBackgroundImage: [UIImage imageNamed: @ "btn_01"] forstate: UIControlStateNormal]; [btn setTitle: @ "Click me" forstate: UIControlStateNormal]; [btn settitleColor: [UIColor redColor] forstate: UIControlStateNormal]; [btn addTarget: self action: @ selector (btnClick) forControlEvents: UIcontrolEventTouchUpInside];

5. layout of the UIControl Control

@property(nonatomic) UIControlContentVerticalAlignment contentVerticalAlignment;@property(nonatomic) UIControlContentHorizontalAlignment contentHorizontalAlignment;

3. UIImageView

1. Frame Animation attributes and Methods
1> attributes

// Sequence frame image array @ property (nonatomic, copy) NSArray * animationImages; // duration of Frame Animation @ property (nonatomic) NSTimeInterval animationDuration; // Number of frames of animation execution @ property (nonatomic) NSInteger animationRepeatCount;

2> Method

- (void)startAnimating;- (void)stopAnimating;- (BOOL)isAnimating;

2. Two loading methods of UIImagede:

1> cache (the memory occupied by the program will remain in the Program)

+ (UIImage*)imageNamed:(NSString*)name;

2> no cache (the memory occupied by images will be cleared after some specific operations)

+ (UIImage*)imageWithContentsOfFile:(NSString*)path;- (id)initWithContentsOfFile:(NSString*)path;

Supplement:

// Rendering mode. You can change the color of the original image-(UIImage *) imageWithRenderingMode :( UIImageRenderingMode) renderingMode

Iv. UILabel

1. Attributes

text font textColor textAlignment

2. UIFont setting method

// System default font + (UIFont *) systemFontOfSize :( CGFloat) fontSize; // bold + (UIFont *) boldSystemFontOfSize :( CGFloat) fontSize; // italic + (UIFont *) italicSystemFontOfSize :( CGFloat) fontSize;

V. UIAlertViewt prompt box

The Controller UIViewController complies with the proxy protocol of UIAlertView.

<UIAlertViewDelegate>

1. Create

[[UIAlertView alloc] initWithTitle: @ "title" message: @ "message" delegate: self cancelButtonTitle: @ "title of the cancel button" otherButtonTitles: @ "Other button Title 1", @ "Other button Title 2" nil] show];

2. Implement proxy Methods

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{}

6. UIActionSheet

1. The controller UIViewController complies with the proxy protocol of UIActionSheet.

<UIActionSheetDelegate>

2. Create

UIActionSheet * sheet = [[UIActionSheet alloc] initWithTitle: @ "are you sure you want to log out? "Delegate: self cancelButtonTitle: @" cancel "destructiveButtonTitle: @" OK "otherButtonTitles: nil, nil];

3. Display

[sheet showInView:self.view];

4. Implement proxy Methods

- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex{}

VII. UITextField

1. You can use the UITextField proxy method to listen to the button clicking at the bottom right corner of the keyboard.
1> become the UITextField proxy

self.textField.delegate = self;

2> comply with the UITextFieldDelegate Protocol to implement proxy Methods

- (BOOL)textFieldShouldReturn:(UITextField*)textField;

3> put a view on the left of UITextField (input box for keyboard)

self.textField.leftView = [[UIView alloc] initWithFrame:CGRectMake(0,0,8,0)];self.textField.leftViewMode = UITextFieldViewModeAlways;

2. Listen to UITextField to determine whether the text box has input.

// Listener notification [[nsicationicationcenter defacenter center] addObserver: self selector: @ selector (textChange) name: UITextFieldTextDidChangeNotification object: self. accountField]; // listens to the method executed when input is present-(void) textChange {}// removes the listener-(void) dealloc {[[nsicationicationcenter defacenter center] removeObserve: self];}

3. Add events (UITextField also inherits from UIControl)

[self.accountField addTarget:self action:@selector(textChange) forControlEvents:UIControlEventEditingChanged];

8. Pop-up and exit the keyboard

1. Remove the keyboard

1> cancel the responder

[self.textField resignFirstResponder];

2> no keyboard input is allowed for the view of the entire controller.

[self.view endEditing:YES];

2. keyboard pop-up

[self.textField becomeFirstResponder];

IX. Supplement:

1. Comparison of JPG and PNG image formats

JPG: the compression ratio is relatively high. It is usually used for photos and web pages. It is lossy compression. during decompression, the CPU consumption is high.
PNG: high compression, lossless compression, and high decompression efficiency. It is recommended to use

2. Use of weak and strong

1> Why does the UI control use weak:

The UI control should be added to the _ view attribute of UIViewController (addSubview: method), where addSubview: the operation is a strong reference, so there is no need to set the UI control to strong reference again in the UIViewController attribute.

2> Why is the delegate proxy weak:

The UI control that is strongly referenced in the UIViewController. Its proxy is generally set to the Controller's own UIViewController. If you set the delegate proxy to strong, it is a circular reference, which may cause memory leakage.

Copyright Disclaimer: This article is an original article by the blogger and cannot be reproduced without the permission of the blogger.