iOS Development UI Chapter-uipickerview Controls Brief introduction

iOS Development UI Chapter-uipickerview Controls Brief introduction

One. Uipickerview Controls

1. Brief Introduction:

2. Sample Code

TXVIEWCONTROLLER.M file

Created by Xin on 14-10-15.

Copyright (c) 2014 Liang. All rights reserved.

//

#import "TXViewController.h"

@interface Txviewcontroller () <UIPickerViewDataSource,UIPickerViewDelegate>

@property (Weak, nonatomic) Iboutlet Uipickerview *pickerview;

-(ibaction) Randomfood;

@property (nonatomic, strong) Nsarray *foods;

@property (Weak, nonatomic) Iboutlet UILabel *fruitlabel;

@property (Weak, nonatomic) Iboutlet UILabel *mainlabel;

@property (Weak, nonatomic) Iboutlet UILabel *drinklabel;

@end

@implementation Txviewcontroller

-(void) viewdidload

{

[Super Viewdidload];

Additional setup after loading the view, typically from a nib.

Initialization

Self.fruitLabel.text = self.foods[0][0];

Self.mainLabel.text = self.foods[1][0];

Self.drinkLabel.text = self.foods[2][0];

Call the proxy method manually so it can be used for loop, not above

[Self Pickerview:nil didselectrow:0 incomponent:0];

[Self Pickerview:nil didselectrow:0 incomponent:1];

[Self Pickerview:nil didselectrow:0 incomponent:2];

for (int Component = 0; Component < Self.foods.count; component++) {

[Self Pickerview:nil didselectrow:0 incomponent:component];

}

}

Randomly select a food

-(ibaction) Randomfood {

Generate random numbers

Arc4random ()%14; Generates a random number from 0 to 14, [Self.foods[0] count] takes out the No. 0 column of this array, and this array calls the Count method

[Self.pickerview Selectrow:arc4random ()%[self.foods[0] count] incomponent:0 Animated:yes];

[Self.pickerview Selectrow:arc4random ()%[self.foods[1] count] incomponent:1 Animated:yes];

[Self.pickerview Selectrow:arc4random ()%[self.foods[2] count] incomponent:2animated:yes];

Use for loop

for (int component = 0; component < Self.foods.count; component++) {

The total length of the component column array

int count = [Self.foods[component]count];

The previous line number

int oldrow = [Self.pickerview selectedrowincomponent:component];

The first few lines the default new line number is the same as the old line number

int row =oldrow;

Arc4random ()%count equivalent Arc4random_uniform (count);

Make sure the number of rows is different

The previous line number

while (row ==oldrow) {

row = Arc4random ()%count;

}

Let Pickerview actively select column component row

[Self.pickerview selectrow:row incomponent:component Animated:yes];

Set the text of a label

[Self Pickerview:nil didselectrow:row incomponent:component];

}

}

-(Nsarray *) foods

{

if (_foods = = nil) {

_foods = [Nsarray arraywithcontentsoffile:[[nsbundle mainbundle]pathforresource:@ "Foods" ofType:@ "plist"]];

}

return _foods;

}

#pragma mark---data source method

How many columns?

-(Nsinteger) Numberofcomponentsinpickerview: (Uipickerview *) Pickerview

{

return self.foods.count;

}

Column. (Nsinteger) component (Nsinteger) Componentl column shows how many rows

-(Nsinteger) Pickerview: (Uipickerview *) Pickerview numberofrowsincomponent: (Nsinteger) component

{

First remove the array from column component

Nsarray *subfoods = self.foods[component];

return subfoods.count;

}

#pragma mark--proxy method

-(NSString *) Pickerview: (Uipickerview *) Pickerview Titleforrow: (nsinteger) Row forcomponent: (Nsinteger) component

{

First, take out the component column, and in this row of the array

return Self.foods[component][row];

}

Check column component row

-(void) Pickerview: (Uipickerview *) Pickerview Didselectrow: (nsinteger) Row incomponent: (Nsinteger) component

{

NSLog (@ "Selected%d column%d", component, row);

if (component ==0) {

Self.fruitLabel.text = Self.foods[component][row];

}

else if (component ==1)

{

Self.mainLabel.text = Self.foods[component][row];

}

else if (component = = 2)

{

Self.drinkLabel.text = Self.foods[component][row];

}

}

@end

Implementation results:

two. Uipickerview usage1. Common Properties of Uipickerview//data source (used to tell Uipickerview how many columns there are rows)@property (nonatomic,assign)ID<UIPickerViewDataSource>DataSource;//agent (used to tell Uipickerview what to display on every 1 rows of every 1 columns, listen for Uipickerview selection)@property (nonatomic,assign)ID<UIPickerViewDelegate>Delegate;//do you want to display the selected indicator@property (nonatomic) BOOL showsselectionindicator;//How many columns are there altogether?@property (Nonatomic,ReadOnly) Nsinteger numberofcomponents;2. Common methods of Uipickerview//re-refresh all columns- (void) reloadallcomponents;//re-refresh column component- (void) Reloadcomponent: (Nsinteger) component;//the row row of column component is actively selected- (void) SelectRow: (Nsinteger) Row incomponent: (Nsinteger) component animated: (BOOL) animated;//get the currently selected line number in column component-(Nsinteger) Selectedrowincomponent: (Nsinteger) component;3. Data source Method (Uipickerviewdatasource)//How many columns are there altogether?-(Nsinteger) Numberofcomponentsinpickerview: (Uipickerview *) Pickerview;//How many lines are there in column component?-(Nsinteger) Pickerview: (Uipickerview *) Pickerview numberofrowsincomponent: (nsinteger) component;4. Proxy method (Uipickerviewdelegate)//What is the width of column component?-(CGFloat) Pickerview: (Uipickerview *) Pickerview widthforcomponent: (nsinteger) component;//What is the row height of column component ?-(CGFloat) Pickerview: (Uipickerview *) Pickerview rowheightforcomponent: (nsinteger) component;//what text is displayed in column component row-(NSString *) Pickerview: (Uipickerview *) Pickerview Titleforrow: (nsinteger) Row forcomponent: (Nsinteger) component;//section component row row shows what view (content)-(UIView *) Pickerview: (Uipickerview *) Pickerview Viewforrow: (nsinteger) Row forcomponent: (Nsinteger) component Reusingview: (UIView *) view;//column component row of Pickerview was selected- (void) Pickerview: (Uipickerview *) Pickerview Didselectrow: (nsinteger) Row incomponent: (Nsinteger) component;

iOS Development UI Chapter-uipickerview Controls Brief introduction