IOS开发基础知识--碎片15

要转为nsdata自定义对象要遵循<NSCoding>的协议,然后实现encodeWithCoder，initwithcode对属性转化,实例如下:HMShop.h#import <Foundation/Foundation.h>@interface HMShop : NSObject <NSCoding>@PRoperty (nonatomic, copy) NSString *name;@property (nonatomic, assign) double  price;@endHMShop.m#import "HMShop.h"@implementation HMShop- (void)encodeWithCoder:(NSCoder *)encoder{    [encoder encodeObject:self.name forKey:@"name"];    [encoder encodeDouble:self.price forKey:@"price"];}- (id)initWithCoder:(NSCoder *)decoder{    if (self = [super init]) {        self.name = [decoder decodeObjectForKey:@"name"];        self.price = [decoder decodeDoubleForKey:@"price"];    }    return self;}- (NSString *)description{    return [NSString stringWithFormat:@"%@ <-> %f", self.name, self.price];}@end操作:- (void)addShops{    NSMutableArray *shops = [NSMutableArray array];    for (int i = 0; i<100; i++) {        HMShop *shop = [[HMShop alloc] init];        shop.name = [NSString stringWithFormat:@"商品--%d", i];        shop.price = arc4random() % 10000;                NSData *data = [NSKeyedArchiver archivedDataWithRootObject:shop];        [self.db executeUpdateWithFormat:@"INSERT INTO t_shop(shop) VALUES (%@);", data];    }}- (void)readShops{    FMResultSet *set = [self.db executeQuery:@"SELECT * FROM t_shop LIMIT 10,10;"];    while (set.next) {        NSData *data = [set objectForColumnName:@"shop"];        HMShop *shop = [NSKeyedUnarchiver unarchiveObjectWithData:data];        NSLog(@"%@", shop);    }}＊把对象转成nsdata的理由，因为在存入数据库时会变成字符串，不利转化，所以先把其序列化转化成nsdata，然后存进数据库，取出时同样先为nsdata再转化；

DetailsViewController *details = [[DetailsViewController alloc] init];    details.photo = self.photo;    details.delegate = self;    [self addChildViewController:details];     CGRect frame = self.view.bounds;    frame.origin.y = 110;    details.view.frame = frame;    [self.view addSubview:details.view];    [details didMoveToParentViewController:self];

在子控制器创建一个协议，然后在其内部对它进行处理传参子控制器.h@protocol DetailsViewControllerDelegate- (void)didSelectPhotoAttributeWithKey:(NSString *)key;@end@interface DetailsViewController : UITableViewController@property (nonatomic, strong) Photo *photo;@property (nonatomic, weak) id <DetailsViewControllerDelegate> delegate;@end子控制器.m- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{    NSString *key = self.keys[(NSUInteger) indexPath.row];    //对它进行传参，让其在父控制器去实现    [self.delegate didSelectPhotoAttributeWithKey:key]; }父控制器.m@interface PhotoViewController () <DetailsViewControllerDelegate>@end然后(得到参数，进行原本子控制器要进行的操作)：- (void)didSelectPhotoAttributeWithKey:(NSString *)key{    DetailViewController *detailViewController = [[DetailViewController alloc] init];    detailViewController.key = key;    [self.navigationController pushViewController:detailViewController animated:YES];}

//进度值改变 增加kvo 传值 key为fractionCompleted- (void)setProgress:(NSProgress *)progress{    if (_progress) {        [_progress removeObserver:self forKeyPath:@"fractionCompleted"];    }    _progress = progress;    if (_progress) {        [_progress addObserver:self forKeyPath:@"fractionCompleted" options:NSKeyValueObservingOptionNew context:nil];    }}//消息kvo消息- (void)dealloc{    if (_progress) {        [_progress removeObserver:self forKeyPath:@"fractionCompleted"];    }    _progress = nil;}#pragma mark KVO- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context{    if ([keyPath isEqualToString:@"fractionCompleted"]) {        NSProgress *progress = (NSProgress *)object;        NSProgress *cellProgress = _offsourecebean.cDownloadTask.progress;        BOOL belongSelf = NO;        if (cellProgress && cellProgress == progress) {            belongSelf = YES;        }        dispatch_async(dispatch_get_main_queue(), ^{            if (self) {                [self showProgress:progress belongSelf:belongSelf];            }        });    } else {        [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];    }}＊注意增加监听后在不用时要进行消除，移除观察，其中addObserver可以是其它对象，然后在其内部实现observeValueForKeyPath这个协议；增加监听时可以设置options类型，也可以多类型一起；比如NSKeyValueObservingOptionNew|NSKeyValueObservingOptionOld;当被监听的对象发生变化时，会马上通知监听对象，使它可以做出一些响应，比如视图的更新；

UITableview的开发中经常要自定义Cell右侧的AccessoryView，把他换成带图片的按钮，并在用户Tap时判断出是哪个自定义按钮被按下了。创建自定义按钮，并设为AccessoryViewif (cell == nil) {     cell = [[UITableView alloc] initWithStyle:UITableViewCellStyleDefault                                  reuseIdentifier:identifier];        UIImage *image= [ UIImage imageNamed:@"delete.png" ];    UIButton *button = [ UIButton buttonWithType:UIButtonTypeCustom ];    CGRect frame = CGRectMake( 0.0 , 0.0 , image.size.width , image.size.height );    button. frame = frame;    [button setBackgroundImage:image forState:UIControlStateNormal ];    button. backgroundColor = [UIColor clearColor ];    [button addTarget:self action:@selector(buttonPressedAction  forControlEvents:UIControlEventTouchUpInside];     cell. accessoryView = button; } 如果将Button加入到cell.contentView中，也是可以的。cell.contentView addSubview:button];在Tap时进行判断，得到用户Tap的Cell的IndexPath- (void)buttonPressedAction  id)sender {    UIButton *button = (UIButton *)sender;    (UITableViewCell*)cell = [button superview];    int row = [myTable indexPathForCell:cell].row; } 对于加到contentview里的Button(UITableViewCell*)cell = [[button superview] superview];

#import "MyselfViewController.h"@interface MyselfViewController ()@property (nonatomic, retain) NSMutableArray *datasource;@end@implementation MyselfViewController-(void)dealloc {    [_datasource release];    [super dealloc];}-(NSMutableArray *)datasource {    if (!_datasource) {        self.datasource = [NSMutableArray arrayWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"MyselfList" ofType:@"plist"]];    }    return _datasource;}-(instancetype)init {    self = [super initWithStyle:UITableViewStyleGrouped];    if (self) {    }    return self;}- (void)viewDidLoad {    [super viewDidLoad];    [self.tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:@"cell"];    self.tableView.rowHeight = 70;    self.navigationItem.title = @"我的";}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}#pragma mark - Table view data source- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {    return self.datasource.count;}- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {    // Return the number of rows in the section.    return [self.datasource[section] count];}- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"cell" forIndexPath:indexPath];    NSDictionary *dict = [self.datasource[indexPath.section] objectAtIndex:indexPath.row];    cell.textLabel.text = dict[@"title"];    cell.imageView.image = [UIImage imageNamed:dict[@"imageName"]];    if (indexPath.section == 2 && indexPath.row == 0) {        cell.accessoryView = [[[UISwitch alloc] init] autorelease];    } else {        cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;    }        return cell;}@end