iOS開發UIPickerView經常使用屬性方法

時間 2019-11-16

標籤 ios 開發 uipickerview 經常使用屬性方法欄目 iOS 简体版

原文原文鏈接

//數組

// ViewController.m佈局

// UIPickerViewAll字體

#import "ViewController.h"動畫

@interface ViewController ()atom

@end代理

@implementation ViewControllercomponent

/*orm

UIPickView控件經常使用的方法和屬性：ci

(1) - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView; 返回PickerView的列數get

(2) - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component;

返回PickView的component列對應的行數

(3) - (nullable NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component;

返回每一列每一行的內容

(4) - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component;

用戶選中PickView的某一列和某一行時會調用該方法

(5) - (nullable NSAttributedString *)pickerView:(UIPickerView *)pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component

修改PickView中component列row行的文本的樣式

(6) - (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(nullable UIView *)view 該方法返回的UIView的控件將直接做爲UIPickView對應的component 列row行的列表項

(7) - (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component 設置component列對應的行高

(8) - (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component

該方法設置component列對應的寬度

(9) - (void)selectRow:(NSInteger)row inComponent:(NSInteger)component animated:(BOOL)animated

該方法設置選中的UIPickView 第component列row行項，最後一個參數animated表明是否要用到動畫

(10) @property(nonatomic,readonly) NSInteger numberOfComponents;

獲取UIPickerView指定列中包含的列表項的數量，該屬性是隻讀的

//簡單實用

//- (void)viewDidLoad

//{

// [super viewDidLoad];

// //獲取須要展現的數據

// [self loadData];

// // 初始化pickerView

// self.pickerView = [[UIPickerView alloc]initWithFrame:CGRectMake(0, 50, self.view.bounds.size.width, 200)];

// [self.view addSubview:self.pickerView];

// //指定數據源和委託

// self.pickerView.delegate = self;

// self.pickerView.dataSource = self;

//}

//#pragma mark 加載數據

//-(void)loadData

//{

// //須要展現的數據以數組的形式保存

// self.letter = @[@"aaa",@"bbb",@"ccc",@"ddd"];

// self.number = @[@"111",@"222",@"333",@"444"];

//}

//#pragma mark UIPickerView DataSource Method 數據源方法

////指定pickerview有幾個錶盤

//-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView

//{

// return 2;//第一個展現字母、第二個展現數字

//}

////指定每一個錶盤上有幾行數據

//-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component

//{

// NSInteger result = 0;

// switch (component) {

// case 0:

// result = self.letter.count;//根據數組的元素個數返回幾行數據

// break;

// case 1:

// result = self.number.count;

// break;

// default:

// break;

// }

// return result;

//}

//#pragma mark UIPickerView Delegate Method 代理方法

////指定每行如何展現數據（此處和tableview相似）

//-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component

//{

// NSString * title = nil;

// switch (component) {

// case 0:

// title = self.letter[row];

// break;

// case 1:

// title = self.number[row];

// break;

// default:

// break;

// }

// return title;

//}

#pragma mark 兩個聯動

- (void)viewDidLoad

{

[super viewDidLoad];

//加載數據

[self loadData];

//指定委託

self.pickerView.delegate = self;

self.pickerView.dataSource = self;

}

//加載數據

-(void)loadData

{

NSString * path = [[NSBundle mainBundle]pathForResource:@"area" ofType:@"plist"];

self.provinces = [NSArray arrayWithContentsOfFile:path];

self.cities = [NSArray arrayWithArray:self.provinces[0][@"Cities"]];

//label的佈局約束

self.label = [[UILabel alloc]initWithFrame:CGRectZero];

self.label.translatesAutoresizingMaskIntoConstraints = NO;

self.label.backgroundColor = [UIColor groupTableViewBackgroundColor];

self.label.textColor = [UIColor greenColor];

self.label.font = [UIFont systemFontOfSize:30];

[self.label setTextAlignment:NSTextAlignmentCenter];

[self.view addSubview:self.label];

NSArray * labelTop = [NSLayoutConstraint constraintsWithVisualFormat:@"V:[_pickerView]-30-[_label(50)]" options:0 metrics:nil views:NSDictionaryOfVariableBindings(_pickerView,_label)];

NSArray * labelH = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-20-[_label]-20-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(_label)];

[self.view addConstraints:labelTop];

[self.view addConstraints:labelH];

}

//有幾個錶盤（component）

-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView

{

return 2;

}

//沒個錶盤有幾行數據（rows）

-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component

{

NSInteger rows = 0;

switch (component) {

case 0:

rows = self.provinces.count;//根據plist文件中的數據返回rows

break;

case 1:

rows = self.cities.count;

break;

default:

break;

}

return rows;

}

//每行的標題

-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component

{

NSString * title = nil;

switch (component) {

case 0:

title = self.provinces[row][@"State"];

break;

case 1:

title = self.cities[row][@"city"];

break;

default:

break;

}

return title;

}

//選中時回調的委託方法，在此方法中實現省份和城市間的聯動

-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component

{

switch (component) {

case 0://選中省份錶盤時，根據row的值改變城市數組，刷新城市數組，實現聯動

self.cities = self.provinces[row][@"Cities"];

[self.pickerView reloadComponent:1];

break;

case 1:

self.label.text = [NSString stringWithFormat:@"%@%@",self.provinces[[self.pickerView selectedRowInComponent:0]][@"State"],self.cities[[self.pickerView selectedRowInComponent:1]][@"city"]];//若是選中第二個

break;

default:

break;

}

//修改pickerview的title樣式

//#pragma mark pickerView Method

//- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView

//{

// return 1;//錶盤數量

//}

////判斷是哪一個pickerview，返回相應的rows

//- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component