史上最简洁的UITableView Sections 展示包含NSDicionary 的NSArray

这个最典型的就是电话本，然后根据A－Z分组, 当然很多例子，不过现在发现一个很简洁易懂的：

1. 准备数据，定义一个dictionary来显示所有的内容，这个dictionary对应的value全是数组

也就是：

A －> A1, A2... 

B  -> B1, B2...

...

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1	NSMutableDictionary *sections;

2. 创建所有的Keys

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BOOL found;     // Loop through the books and create our keys     for (NSDictionary *book in self.books) //self.books 就是包含NSDictionary的数组     {         NSString *c = [[book objectForKey:@"title"] substringToIndex:1];            found = NO;            for (NSString *str in [self.sections allKeys])         {             if ([str isEqualToString:c])             {                 found = YES;             }         }            if (!found)         {             [self.sections setValue:[[NSMutableArray alloc] init] forKey:c];         }     }

 3. 把Key对应的空数组填满，这个很简单应该能看懂

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for (NSDictionary *book in self.books)     {         [[self.sections objectForKey:[[book objectForKey:@"title"] substringToIndex:1]] addObject:book];     }

 4. 下面就排序

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for (NSString *key in [self.sections allKeys])     {         [[self.sections objectForKey:key] sortUsingDescriptors:[NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@"title" ascending:YES]]];     }

 

5. 有了上面的方法之后，就执行UITableView必须的方法

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#pragma mark - #pragma mark Table view data source    - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {     return [[self.sections allKeys] count]; }    - (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {     return [[[self.sections allKeys] sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)] objectAtIndex:section]; }    - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {     return [[self.sections valueForKey:[[[self.sections allKeys] sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)] objectAtIndex:section]] count]; }    - (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView {     return [[self.sections allKeys] sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)]; }- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {        static NSString *CellIdentifier = @"Cell";        UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];     if (cell == nil) {         cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];     }        NSDictionary *book = [[self.sections valueForKey:[[[self.sections allKeys] sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)] objectAtIndex:indexPath.section]] objectAtIndex:indexPath.row];        cell.textLabel.text = [book objectForKey:@"title"];     cell.detailTextLabel.text = [book objectForKey:@"description"];        return cell; }

 差不多了，这个是我见过最简洁的例子了。

参考：http://www.icodeblog.com/2010/12/10/implementing-uitableview-sections-from-an-nsarray-of-nsdictionary-objects/