简介
承上一篇我的iOS入门第一课，本次要记录的是一年前读raywenderlich的基本教程的第二个app，Checklists.主要功能是用来记录个人的一些提醒事项。如下：
主要界面.png
下面主要讲我学到了什么：
一、基本控件
UITableView, UITableView, UITableView!
重点知识：
- 导航控制器的概念 UINavigationController
- 控制器之间的消息回传 delegate
- UITableView的delegate、dataSource
- 操作tableView的cell，删除cell，增加cell
- 删除cell要做两件事情，一是删除数据，二是删除tableView上的cell
-(void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
[self.dataModel.lists removeObjectAtIndex:indexPath.row];
[self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:(UITableViewRowAnimationAutomatic)];
}
- 动态增加cell，用storyboard的话首先要把tableViewCell布局放好，然后在控制器创建引用，接着就可以用代码操作cell了
在storyboard布局一个隐藏的cell.png
@property (weak, nonatomic) IBOutlet UITableViewCell *datePickerCell;
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
if (section == 1 && _datePickerVisible) {
return 3;
}else {
return [super tableView:tableView numberOfRowsInSection:section];
}
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
if (indexPath.section == 1 && indexPath.row == 2) {
return self.datePickerCell;
}else {
return [super tableView:tableView cellForRowAtIndexPath:indexPath];
}
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
if (indexPath.section == 1 && indexPath.row == 2) {
return 217;
}else {
return [super tableView:tableView heightForRowAtIndexPath:indexPath];
}
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
[self.textField resignFirstResponder];
if (indexPath.section == 1 && indexPath.row == 1) {
if (!self.datePickerVisible) {
[self showDatePicker];
}else {
[self hideDatePicker];
}
}
}
- (NSInteger)tableView:(UITableView *)tableView indentationLevelForRowAtIndexPath:(NSIndexPath *)indexPath {
if (indexPath.section == 1 && indexPath.row == 2) {
indexPath = [NSIndexPath indexPathForRow:0 inSection:indexPath.section];
}
return [super tableView:tableView indentationLevelForRowAtIndexPath:indexPath];
}
- (void)showDatePicker {
self.datePickerVisible = YES;
NSIndexPath *indexPathDateRow = [NSIndexPath indexPathForRow:1 inSection:1];
NSIndexPath *indexPathDatePicker = [NSIndexPath indexPathForRow:2 inSection:1];
UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:indexPathDateRow];
cell.detailTextLabel.textColor = cell.detailTextLabel.tintColor;
[self.tableView beginUpdates];
[self.tableView insertRowsAtIndexPaths:@[indexPathDatePicker] withRowAnimation:(UITableViewRowAnimationFade)];
[self.tableView reloadRowsAtIndexPaths:@[indexPathDateRow] withRowAnimation:(UITableViewRowAnimationNone)];
[self.tableView endUpdates];
[self.datePicker setDate:self.dueDate animated:NO];
}
- (void)hideDatePicker {
if (self.datePickerVisible) {
self.datePickerVisible = NO;
NSIndexPath *indexPathDateRow = [NSIndexPath indexPathForRow:1 inSection:1];
NSIndexPath *indexPathDatePicker = [NSIndexPath indexPathForRow:2 inSection:1];
UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:indexPathDateRow];
cell.detailTextLabel.textColor = [[UIColor alloc] initWithWhite:0 alpha:0.5];
[self.tableView beginUpdates];
[self.tableView reloadRowsAtIndexPaths:@[indexPathDateRow] withRowAnimation:(UITableViewRowAnimationNone)];
[self.tableView deleteRowsAtIndexPaths:@[indexPathDatePicker] withRowAnimation:(UITableViewRowAnimationFade)];
[self.tableView endUpdates];
}
}
不得不说动态增加一个cell需要做很多事情。。。
- textField的delegate, 当用户有输入时把done按钮变为可用
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSString *oldString = textField.text;
NSString *newString = [oldString stringByReplacingCharactersInRange:range withString:string];
self.doneBarButton.enabled = newString.length > 0;
return YES;
}
- 本地通知UILocalNotification
- 第一次时需要获取本地通知权限
UIUserNotificationSettings *setting = [UIUserNotificationSettings settingsForTypes:UIUserNotificationTypeSound | UIUserNotificationTypeAlert categories:nil];
[[UIApplication sharedApplication] registerUserNotificationSettings:setting];
- 设置本地通知
-(void)scheduleNotification {
UILocalNotification *existingNotification = [self notificationForThisItem];
if (existingNotification) {
[[UIApplication sharedApplication] cancelLocalNotification:existingNotification];
}
if (_shouldRemind && [_dueDate compare:[NSDate new]] != NSOrderedAscending ) {
UILocalNotification *notification = [UILocalNotification new];
notification.fireDate = _dueDate;
notification.timeZone = [NSTimeZone defaultTimeZone];
notification.alertBody = _text;
notification.soundName = UILocalNotificationDefaultSoundName;
notification.userInfo = @{@"ItemID": @(_itemID)};
[[UIApplication sharedApplication] scheduleLocalNotification:notification];
}
}
-(UILocalNotification *)notificationForThisItem {
NSArray *notifications = [UIApplication sharedApplication].scheduledLocalNotifications;
for (UILocalNotification *notification in notifications) {
NSInteger itemID = (NSInteger)notification.userInfo[@"ItemID"];
if (itemID == self.itemID) {
return notification;
}
}
return nil;
}
- 发通知的对象销毁时取消通知
-(void)dealloc {
if ([self notificationForThisItem]) {
[[UIApplication sharedApplication] cancelLocalNotification:[self notificationForThisItem]];
}
}
- 本地存储，使用对象归档为plist文件做本地存储
- 必须给模型实现NSCoding协议，实现两个方法
-(instancetype)initWithCoder:(NSCoder *)aDecoder {
if (self = [super init]) {
_name = [aDecoder decodeObjectForKey:@"Name"];
_iconName = [aDecoder decodeObjectForKey:@"IconName"];
_items = [aDecoder decodeObjectForKey:@"Items"];
}
return self;
}
-(void)encodeWithCoder:(NSCoder *)aCoder {
[aCoder encodeObject:_name forKey:@"Name"];
[aCoder encodeObject:_iconName forKey:@"IconName"];
[aCoder encodeObject:_items forKey:@"Items"];
}
- 归档到Document文件夹中
-(void)saveChecklists {
NSMutableData *data = [NSMutableData data];
NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
[archiver encodeObject:_lists forKey:@"Checklists"];
[archiver finishEncoding];
[data writeToFile:[self dataFilePath] atomically:YES];
}
-(NSString *)documentsDirectory {
return [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
}
-(NSString *)dataFilePath {
return [[self documentsDirectory] stringByAppendingPathComponent:@"Checklists.plist"];
}
- 程序重新启动时在init方法调用loadChecklists初始化模型加载本地数据
-(void)loadChecklists {
NSString *path = [self dataFilePath];
if ([[NSFileManager defaultManager] fileExistsAtPath:path]) {
NSData *data = [NSData dataWithContentsOfFile:path];
NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
_lists = [unarchiver decodeObjectForKey:@"Checklists"];
[unarchiver finishDecoding];
[self sortChecklists]; //排序
}
}
- 在AppDelegate中初始化DataModel, 并在代理方法中保存数据
-(void)applicationDidEnterBackground:(UIApplication *)application {
[self saveData];
}
-(void)applicationWillTerminate:(UIApplication *)application {
[self saveData];
}
-(void)saveData {
[self.dataModel saveChecklists];
}
总结
此app设计的目的只有一个，就是熟悉tableView的操作，在往后开发的任何一个app里都离不开这个最基本的控件，但现实开发中更多涉及到的是处理动态cell，与xib组合，不同的cell和内容，tableView的header和footer,下拉刷新，如何优化tableView，动态计算cell的高度，MVVM等。革命尚未完成，同志仍需努力。
源代码传送门
卧薪藏胆，三千越甲可吞吴。