Block传值的实现

时间：2015-09-08 15:22:38 阅读：126 评论：0 收藏：0 [点我收藏+]

标签：

还是跟上一篇委托传值demo一样的，大家可以对比一下；block传值也是一定要在跳转的方法里调用。代码如下：

ViewController.h

1 #import <UIKit/UIKit.h>
2 
3 @interface ViewController : UIViewController
4 
5 
6 @end

ViewController.m

 1 #import "ViewController.h"
 2 #import "MoneyPickerView.h"
 3 @interface ViewController ()<UITableViewDataSource,UITableViewDelegate>
 4 {
 5     UITableView *_tableView;
 6 }
 7 @property (nonatomic,strong)NSString *cellString;
 8 @property (nonatomic,strong)MoneyPickerView *pickerView;
 9 @end
10 
11 @implementation ViewController
12 
13 - (void)viewDidLoad {
14     [super viewDidLoad];
15     self.view.backgroundColor = [UIColor whiteColor];
16     _tableView = [[UITableView alloc]initWithFrame:self.view.bounds style:UITableViewStylePlain];
17     _tableView.delegate = self;
18     _tableView.dataSource = self;
19     _tableView.tableFooterView = [[UIView alloc]init];
20     [self.view addSubview:_tableView];
21 }
22 
23 
24 #pragma mark uitableview协议方法
25 - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
26     return 3;
27 }
28 
29 
30 
31 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
32     static NSString *identify = @"Cell";
33     UITableViewCell *cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:identify];//如果重用，把数据加载到重写的cell里，不然刷新会重复加载。
34     if (indexPath.row == 0) {
35         cell.textLabel.text = @"点击加载数据";
36     }
37     if (indexPath.row == 1) {
38         cell.textLabel.text = @"数据如下";
39     }
40     if (indexPath.row == 2) {
41         cell.textLabel.text = _cellString;
42     }
43     return cell;
44 }
45 
46 
47 
48 - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
49 {
50     [tableView deselectRowAtIndexPath:indexPath animated:YES];
51     if (indexPath.row == 0) {
52         _pickerView = [[MoneyPickerView alloc]initWithFrame:CGRectMake(0, 300, CGRectGetWidth(self.view.bounds), CGRectGetMaxY(self.view.bounds) - 300)];
53         //BLOck回调 并刷新界面
54         [_pickerView sendMoneyWithBlock:^(NSString *moneyString) {
55             _cellString = moneyString;
56             [_tableView reloadData];
57         }];
58         [self.view addSubview:_pickerView];//加载试图
59     }
60 }
61 
62 
63 @end

MoneyPickerView.h

1 #import <UIKit/UIKit.h>
2 typedef void (^MyBlock)(NSString *moneyString);//block


3 @interface MoneyPickerView : UIView

4 @property (nonatomic,readwrite)  NSInteger currentValue;
5 @property (nonatomic,copy) MyBlock  returnBlock;
6 - (void)sendMoneyWithBlock:(MyBlock)block;
7 @end

MoneyPickerView.m

  1 #import "MoneyPickerView.h"
  2 @interface MoneyPickerView ()<UIPickerViewDelegate,UIPickerViewDataSource>
  3 @property (nonatomic, copy) void (^backValue)(NSString *strValue);
  4 @property (nonatomic,strong) UIPickerView *pickerView;
  5 @property (nonatomic,strong)  NSMutableArray *objectArray;
  6 @end
  7 @implementation MoneyPickerView
  8 
  9 - (instancetype)initWithFrame:(CGRect)frame{
 10     self = [super initWithFrame:frame];
 11     if (self) {
 12         self.backgroundColor = [UIColor whiteColor];
 13         [self addDayPickerView];
 14         [self loadPickerDataSource];
 15         [self loadSelfView];
 16         [_pickerView selectRow:_currentValue inComponent:0 animated:NO];
 17     }
 18     return self;
 19 }
 20 
 21 #pragma mark 加载界面
 22 //加载button
 23 -(void)loadSelfView{
 24     UIButton *canselButton = [[UIButton alloc]initWithFrame:CGRectMake(20, 10, 40, 70)];
 25     canselButton.backgroundColor = [UIColor clearColor];
 26     [canselButton setTitle:@"取消" forState:UIControlStateNormal];
 27     [canselButton setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];
 28     [canselButton addTarget:self action:@selector(cancelButtonPressed:) forControlEvents:UIControlEventTouchUpInside];
 29     [self addSubview:canselButton];
 30     
 31     UIButton *surelButton = [[UIButton alloc]initWithFrame:CGRectMake(CGRectGetMaxX(self.bounds) - 20 - 35, 10, 40, 70)];
 32     surelButton.backgroundColor = [UIColor clearColor];
 33     [surelButton setTitle:@"确定" forState:UIControlStateNormal];
 34     [surelButton setTitleColor:[UIColor blueColor] forState:UIControlStateNormal];
 35     [surelButton addTarget:self action:@selector(sureButtonPressed:) forControlEvents:UIControlEventTouchUpInside];
 36     [self addSubview:surelButton];
 37 }
 38 
 39 /**
 40  *  加载数据源
 41  */
 42 - (void)loadPickerDataSource{
 43     _objectArray = [[NSMutableArray alloc]init];
 44     for (NSInteger idx = 0; idx<=60 ;idx++) {
 45         NSString *value = [NSString stringWithFormat:@"支付宝%ld元",(long)idx];
 46         [_objectArray addObject:value];
 47     }
 48 }
 49 
 50 /**
 51  *  初始化pickerview
 52  */
 53 - (void)addDayPickerView{
 54     _pickerView = [[UIPickerView alloc]init];
 55     _currentValue = 0;
 56     _pickerView.delegate = self;
 57     [self addSubview:_pickerView];
 58 }
 59 
 60 - (void)sendMoneyWithBlock:(MyBlock)block{
 61     self.returnBlock = block;
 62 //    self.returnBlock(@"d");
 63 }
 64 
 65 #pragma mark 自定义方法
 66 /**
 67  *  确定按钮
 68  *
 69  *  @param sender button事件
 70  */
 71 - (void)sureButtonPressed:(UIButton *)sender{
 72     if (self.returnBlock) {
 73     self.returnBlock(_objectArray[_currentValue]);
 74     }
 75     [self removeFromSuperview];
 76 }
 77 
 78 
 79 
 80 /**
 81  *  取消按钮
 82  *
 83  *  @param sender
 84  */
 85 - (void)cancelButtonPressed:(UIButton *)sender{
 86     [self removeFromSuperview];
 87 }
 88 
 89 #pragma mark pickerView协议方法
 90 //返回的列数
 91 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
 92     return 1;
 93 }
 94 //选择的行数
 95 - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{
 96     _currentValue = row;
 97 }
 98 
 99 // returns the # of rows in each component..
100 - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
101     return _objectArray.count;
102 }
103 
104 //没列的数据
105 - (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
106 {
107     return [_objectArray objectAtIndex:row];
108 }
109 
110 
111 @end

------------>下面是一个更简单的demo代码

ViewController.h

1 #import <UIKit/UIKit.h>
2 
3 @interface ViewController : UIViewController
4 
5 
6 @end

ViewController.m

 1 #import "ViewController.h"
 2 #import "SecondViewController.h"
 3 @interface ViewController ()
 4 @property(nonatomic,strong)UIButton  *buttonToTwo;
 5 @property(nonatomic,strong)UILabel   *textLabel;
 6 @end
 7 
 8 @implementation ViewController
 9 
10 - (void)viewDidLoad {
11     [super viewDidLoad];
12     self.view.backgroundColor = [UIColor whiteColor];
13     
14     _buttonToTwo = [[UIButton alloc]initWithFrame:CGRectMake(100, 200, 100, 40)];
15     [_buttonToTwo setTitle:@"跳转" forState:UIControlStateNormal];
16     [_buttonToTwo setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
17     [_buttonToTwo addTarget:self action:@selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside];
18     [self.view addSubview:_buttonToTwo];
19     
20     _textLabel = [[UILabel alloc]initWithFrame:CGRectMake(100, 100, 100, 40)];
21     _textLabel.textColor = [UIColor redColor];
22     _textLabel.backgroundColor = [UIColor grayColor];
23     [self.view addSubview:_textLabel];
24 }
25 
26 
27 //跳转方法
28 -(void)buttonPressed:(UIButton *)sender{
29     SecondViewController *second = [[SecondViewController alloc]init];
30     [second sendString:^(NSString *sendString) {
31         _textLabel.text = sendString;
32     }];
33     [self presentViewController:second animated:YES completion:nil];
34 }
35 
36 @end

SecondViewController.h

1 #import <UIKit/UIKit.h>
2 
3 @interface SecondViewController : UIViewController
4 
5 typedef void (^MyBlock)(NSString *sendString);
6 @property (nonatomic,copy)MyBlock backBlock;
7 -(void)sendString:(MyBlock)block;
8 @end


SecondViewController.m

 1 #import "SecondViewController.h"
 2 
 3 @interface SecondViewController ()
 4 @property(nonatomic,strong)UIButton     *buttonToOne;
 5 @property(nonatomic,strong)UITextField  *textField;
 6 
 7 @end
 8 
 9 @implementation SecondViewController
10 
11 - (void)viewDidLoad {
12     [super viewDidLoad];
13     self.view.backgroundColor = [UIColor purpleColor];
14     _buttonToOne = [[UIButton alloc]initWithFrame:CGRectMake(100, 200, 100, 40)];
15     [_buttonToOne setTitle:@"跳转" forState:UIControlStateNormal];
16     [_buttonToOne setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
17     [_buttonToOne addTarget:self action:@selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside];
18     [self.view addSubview:_buttonToOne];
19 
20     _textField = [[UITextField alloc]initWithFrame:CGRectMake(100, 100, 200, 40)];
21     _textField.layer.borderWidth = 1.0;
22     _textField.layer.borderColor = [UIColor grayColor].CGColor;
23     _textField.textAlignment = NSTextAlignmentLeft;
24     _textField.textColor  = [UIColor redColor];
25     [self.view addSubview:_textField];
26 }
27 
28 - (void)sendString:(MyBlock)block{
29     self.backBlock = block;
30 }
31 
32 //跳转方法
33 -(void)buttonPressed:(UIButton *)sender{
34     if (self.backBlock) {
35         self.backBlock(_textField.text);
36     }
37     [self.presentingViewController dismissViewControllerAnimated:YES completion:nil];
38 }
39 
40 @end

Block传值的实现

标签：

原文地址：http://www.cnblogs.com/yang99/p/4791680.html

踩

(0)

评论一句话评论（0）

分享档案

更多>

2021年07月29日 (22)
2021年07月28日 (40)
2021年07月27日 (32)
2021年07月26日 (79)
2021年07月23日 (29)
2021年07月22日 (30)
2021年07月21日 (42)
2021年07月20日 (16)
2021年07月19日 (90)
2021年07月16日 (35)

周排行