IOS Development Guide Chapter 5th Delegating Protocol Data Source Protocol Advanced View Learning

1 The delegate object is responsible for controlling the appearance of the control and reacting to the control's events and states

The data source object is a bridge between the control and the Application data (model), which is generally necessary.

2 selector Uipickerview gives users a choice

1) Date picker Uidatepicker

Set individual properties in the property Inspector-code

-setdateformat: Formatting dates

-stringfromdate: Get Time

-(Ibaction) onclick: (ID) Sender {NSDate* Thedate =self.datePicker.date; Gets the selected date NSLog (@"The date picked is:%@", [Thedate Descriptionwithlocale:[nslocale Currentlocale]]); Returns localization-based date information NSDateFormatter* Dateformatter =[[NSDateFormatter alloc] init]; date format Dateformatter.dateformat=@"YYYY-MM-DD HH:mm:ss"; -setdateformat:
NSLog (@"The date formate is:%@", [Dateformatter stringfromdate:thedate]); Self.label.text=[Dateformatter stringfromdate:thedate]; }

2) General selector Uipickerview Datesource and Delegate

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Viewdidload: To prepare the default (current display data), set the proxy

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Get data: Get home directory +mainbundle

Get Resource Path-pathforresource:oftype:

Get data-initwithcontentsoffile:                    

- (void) viewdidload{[Super Viewdidload]; NSBundle*bundle =[NSBundle Mainbundle]; NSString*plistpath = [Bundle Pathforresource:@"provinces_cities"OfType:@"plist"]; //get all the data in a property list fileNsdictionary *dict =[[Nsdictionary alloc] initwithcontentsoffile:plistpath]; Self.pickerdata=dict; //Province name DataSelf.pickerprovincesdata =[Self.pickerdata AllKeys]; fetch all key values from the dictionary//data for all municipalities in the first province are taken out by defaultNSString *seletedprovince = [Self.pickerprovincesdata objectatindex:0]; Self.pickercitiesdata=[Self.pickerdata objectforkey:seletedprovince]; Self.pickerView.dataSource=Self ; Self.pickerview.Delegate=Self ; }

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A key multiple value values can be placed in an array, and then a dictionary is formed.

Remove all key-Remove the first key-to remove the value corresponding to this key.

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Action method:

-selectedrowincomponent: Returns the number of rows for the selected dial

 -(ibaction) onclick: (id   = [self.pickerview selectedrowincomponent:0  ' Span style= "color: #000000;" >]; The number of rows in the first dial nsinteger row2  = [Self.pickerview selectedrowincomponent:1     ];    NSString  *selected1 = [Self.pickerprovincesdata Objectatindex:row1]; Take data based on number of rows        NSString  *selected2 = [Self.pickercitiesdata Objectatindex:row2]; NSString  *title = [[NSString alloc] Initwithformat:@ " %@,%@ City   "  Selected1,select        ED2];    Self.label.text  = title; }

Implementing the Proxy protocol:

DataSource:

-Numberofcomponentsinpickerview: Returns the number of dials

-pickerview:numberofrowsincomponent: Returns the number of rows per dial

Delegate

-pickerview:titleforrow:forcomponent: Provides display data to a row in a dial

-pickerview:didselectrow:incomponent: Called when the row is selected

-reloadcomponent: Refresh dial and callback display method

#pragmaMark implements the protocol Uipickerviewdatasource Method-(Nsinteger) Numberofcomponentsinpickerview: (Uipickerview *) Pickerview {return 2;}-(Nsinteger) Pickerview: (Uipickerview *) Pickerview numberofrowsincomponent: (Nsinteger) component {if(Component = =0) {//Number of Provinces        return[Self.pickerprovincesdata Count]; } Else{//Number of cities        return[Self.pickercitiesdata Count]; }    }#pragmaMark implements the protocol Uipickerviewdelegate method-(NSString *) Pickerview: (Uipickerview *) Pickerview Titleforrow: (nsinteger) Row forcomponent: (Nsinteger) component {if(Component = =0) {//Select Province Name        return[Self.pickerprovincesdata Objectatindex:row]; } Else{//Select city Name        return[Self.pickercitiesdata Objectatindex:row]; }}- (void) Pickerview: (Uipickerview *) Pickerview Didselectrow: (nsinteger) Row incomponent: (Nsinteger) component {if(Component = =0) {NSString*seletedprovince =[Self.pickerprovincesdata Objectatindex:row]; Nsarray*array =[Self.pickerdata objectforkey:seletedprovince]; Self.pickercitiesdata=Array; [Self.pickerview reloadcomponent: 1 ]; This will callback the above display method}}

3 Collection view (grid view) Uicollectionview

Structure: section, cell (Uicollectionviewcell class, layout defined by Uicollectionviewlayout Class), supplemental view, decorative view, controller (Uicollectionviewcontroller)

Prepare: Add resource-delete viewcontroller-add Collectionviewcontroller to design interface and set to is Initial View controller-Modifying the Viewcontroller class to be a Uicollectionviewcontroller class and associating with the interface-adaptation screen

design and add cells : A cell is a view that allows you to place other views or controls inside it.

Create a new cell class and associate it with the collection View cell of the design interface-set a reusable cell label in the cell property Inspector-Set cell size in the cell Size Inspector-set collection cell in the View dimension Inspector Size value-Customize in Cell view-add constraint

@interface Custom Cell**label;

To implement a trust agreement:

DataSource:

-numberofsectionincollectionview: Number of knots

-collectionview:numberofiteminsection: Number of columns in a section

-collectionview:cellforitematindexpath: Providing display data for cells

-collectionview:viewforsupplementaryelementofkind:atindexpath: Providing display data for supplemental views

- (void) viewdidload{[Super Viewdidload]; //additional setup after loading the view, typically from a nib.NSBundle*bundle =[NSBundle Mainbundle]; NSString*plistpath = [Bundle Pathforresource:@"Events"OfType:@"plist"]; //get all the data in a property list fileNsarray *array =[[Nsarray alloc] initwithcontentsoffile:plistpath]; Self.events=Array; }#pragmamark-uicollectionviewdatasource-(Nsinteger) Numberofsectionsincollectionview: (Uicollectionview *) collectionview{return[Self.events Count]/2;}-(Nsinteger) CollectionView: (Uicollectionview *) CollectionView numberofitemsinsection: (nsinteger) section{return 2;}-(Uicollectionviewcell *) CollectionView: (Uicollectionview *) CollectionView Cellforitematindexpath: (NSIndexPath *) indexpath{ reuse mechanism Cell*cell = [CollectionView dequeuereusablecellwithreuseidentifier:@"Cell"Forindexpath:indexpath]; Nsdictionary*Event= [self.events objectatindex: (indexpath.section*2+Indexpath.row)]; Cell.label.text= [EventObjectforkey:@"name"]; Cell.imageView.image= [UIImage imagenamed:[EventObjectforkey:@"Image"]]; returncell;}#pragmamark-uicollectionviewdelegate-(void) CollectionView: (Uicollectionview *) CollectionView Didselectitematindexpath: (Nsindexpath *) indexpath{nsdictionary*Event= [self.events objectatindex: (indexpath.section*2+Indexpath.row)]; NSLog (@"Select Event Name:%@", [EventObjectforkey:@"name"]);}

IOS Development Guide Chapter 5th Delegating Protocol Data Source Protocol Advanced View Learning