iCloud之旅

1、创建BIDTinyPixDocument类

 #import <UIKit/UIKit.h>

 //创建文档类
 @interface TinyPixDocument : UIDocument
 //接收一对行和列索引作为参数
 - (BOOL)stateAtRow:(NSUInteger)row column:(NSUInteger)column;
 //指定的行和列设置特定的状态
 - (void)setState:(BOOL)state atRow:(NSUInteger)row column:(NSUInteger)column;
 //负责切换特定位置处的状态
 - (void)toggleStateAtRow:(NSUInteger)row column:(NSUInteger)column;

 @end

 #import "TinyPixDocument.h"

 //类扩展
 @interface TinyPixDocument ()
 @property (nonatomic,strong) NSMutableData * bitmap;
 @end

 @implementation TinyPixDocument

 //将每个位图初始化为从一个角延伸到另一个角的对角线图案。
 - (id)initWithFileURL:(NSURL *)url
 {
     self = [super initWithFileURL:url];
     if (self) {
         unsigned char startPattern[] = {
             0x01,
             0x02,
             0x04,
             0x08,
             0x10,
             0x20,
             0x40,
             0x80
         };

         self.bitmap = [NSMutableData dataWithBytes:startPattern length:];
     }
     return self;
 }

 //实现读取单个位的状态的方法。实现这个方法只要从字节数组中获取相关字节，然后对其进行位移操作和AND操作，检查是否设置了给定位，相应的返回YES或NO。
 - (BOOL)stateAtRow:(NSUInteger)row column:(NSUInteger)column
 {
     const char * bitmapBytes = [self.bitmap bytes];
     char rowByte = bitmapBytes[row];
     char result = ( << column) & rowByte;
     if (result != ) {
         return YES;
     } else {
         return NO;
     }
 }
 //这个方法正好和上一个相反，用于为给定行和列的位置设置值。
 - (void)setState:(BOOL)state atRow:(NSUInteger)row column:(NSUInteger)column
 {
     char *bitmapBytes = [self.bitmap mutableBytes];
     char *rowByte = &bitmapBytes[row];

     if (state) {
         *rowByte = *rowByte | ( << column);
     } else {
         *rowByte = *rowByte & ~( << column);
     }
 }
 //辅助方法，外部代码使用该方法来切换单个单元的状态。
 - (void)toggleStateAtRow:(NSUInteger)row column:(NSUInteger)column
 {
     BOOL state = [self stateAtRow:row column:column];
     [self setState:!state atRow:row column:column];
 }

 //保存文档时调用
 - (id)contentsForType:(NSString *)typeName error:(NSError **)outError
 {
     NSLog(@"saving document to URL %@", self.fileURL);
     return [self.bitmap copy];
 }
 //系统从存储区加载了数据，并且准备将这个数据提供给文档类的一个实例时，调用此方法。
 - (BOOL)loadFromContents:(id)contents ofType:(NSString *)typeName
                    error:(NSError **)outError
 {
     NSLog(@"loading document from URL %@", self.fileURL);
     self.bitmap = [contents mutableCopy];
     return true;
 }

2、主控制器代码

 #import "BIDMasterViewController.h"
 #import "BIDDetailViewController.h"
 #import "BIDTinyPixDocument.h"

 @interface BIDMasterViewController () <UIAlertViewDelegate>

 @property (weak, nonatomic) IBOutlet UISegmentedControl *colorControl;
 @property (strong, nonatomic) NSArray * documentFilenames;
 @property (strong, nonatomic) BIDTinyPixDocument * chosenDocument;

 @property (strong, nonatomic) NSMetadataQuery * query;
 @property (strong, nonatomic) NSMutableArray * documentURLs;

 @end

 @implementation BIDMasterViewController

 /* original
  //接收一个文件名作为参数，将它和应用的Document目录的文件路径结合起来，然后返回一个指向该文件的URL指针。
 - (NSURL *)urlForFilename:(NSString *)filename {
     NSFileManager * fm = [NSFileManager defaultManager];
     NSArray * urls = [fm URLsForDirectory:NSDocumentDirectory
                                inDomains:NSUserDomainMask];
     NSURL * directoryURL = urls[0];
     NSURL * fileURL = [directoryURL URLByAppendingPathComponent:filename];
     return fileURL;
 }
  */

 - (NSURL *)urlForFilename:(NSString *)filename
 {
     // be sure to insert "Documents" into the path
     NSURL * baseURL = [[NSFileManager defaultManager]
                       URLForUbiquityContainerIdentifier:nil];
     NSURL * pathURL = [baseURL URLByAppendingPathComponent:@"Documents"];
     NSURL * destinationURL = [pathURL URLByAppendingPathComponent:filename];
     return destinationURL;
 }

 /* original

  //也用到了Document目录，用于查找代表现存文档的文件。该方法获取它所找到的文件，并将它们根据创建的时间来排序，以便用户可以以“博客风格”的顺序来查看文档列表（第一个文档是最新的）。文档文件名被存放在documentFilenames属性中，然后重新加载表视图（我们尚未处理）。
 - (void)reloadFiles {
     NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
                                                          NSUserDomainMask, YES);
     NSString *path = paths[0];
     NSFileManager *fm = [NSFileManager defaultManager];

     NSError *dirError;
     NSArray *files = [fm contentsOfDirectoryAtPath:path error:&dirError];
     if (!files) {
         NSLog(@"Encountered error while trying to list files in directory %@: %@",
               path, dirError);
     }
     NSLog(@"found files: %@", files);

     files = [files sortedArrayUsingComparator:
              ^NSComparisonResult(id filename1, id filename2) {
                  NSDictionary *attr1 = [fm attributesOfItemAtPath:
                                         [path stringByAppendingPathComponent:filename1]
                                                             error:nil];
                  NSDictionary *attr2 = [fm attributesOfItemAtPath:
                                         [path stringByAppendingPathComponent:filename2]
                                                             error:nil];
                  return [attr2[NSFileCreationDate] compare: attr1[NSFileCreationDate]];
              }];
     self.documentFilenames = files;
     [self.tableView reloadData];
 }
  */

 - (void)reloadFiles {
     NSFileManager * fileManager = [NSFileManager defaultManager];
     // passing nil is OK here, matches first entitlement
     NSURL * cloudURL = [fileManager URLForUbiquityContainerIdentifier:nil];
     NSLog(@"got cloudURL %@", cloudURL);  // returns nil in simulator

     self.query = [[NSMetadataQuery alloc] init];
     _query.predicate = [NSPredicate predicateWithFormat:@"%K like '*.tinypix'",
                         NSMetadataItemFSNameKey];
     _query.searchScopes = [NSArray arrayWithObject:
                            NSMetadataQueryUbiquitousDocumentsScope];
     [[NSNotificationCenter defaultCenter]
      addObserver:self
      selector:@selector(updateUbiquitousDocuments:)
      name:NSMetadataQueryDidFinishGatheringNotification
      object:nil];
     [[NSNotificationCenter defaultCenter]
      addObserver:self
      selector:@selector(updateUbiquitousDocuments:)
      name:NSMetadataQueryDidUpdateNotification
      object:nil];
     [_query startQuery];
 }

 - (void)updateUbiquitousDocuments:(NSNotification *)notification {
     self.documentURLs = [NSMutableArray array];
     self.documentFilenames = [NSMutableArray array];

     NSLog(@"updateUbiquitousDocuments, results = %@", self.query.results);
     NSArray *results = [self.query.results sortedArrayUsingComparator:
                         ^NSComparisonResult(id obj1, id obj2) {
                             NSMetadataItem *item1 = obj1;
                             NSMetadataItem *item2 = obj2;
                             return [[item2 valueForAttribute:NSMetadataItemFSCreationDateKey] compare:
                                     [item1 valueForAttribute:NSMetadataItemFSCreationDateKey]];
                         }];

     for (NSMetadataItem *item in results) {
         NSURL *url = [item valueForAttribute:NSMetadataItemURLKey];
         [self.documentURLs addObject:url];
         [(NSMutableArray *)_documentFilenames addObject:[url lastPathComponent]];
     }

     [self.tableView reloadData];
 }

 - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
     return ;
 }

 - (NSInteger)tableView:(UITableView *)tableView
  numberOfRowsInSection:(NSInteger)section {
     return [self.documentFilenames count];
 }

 - (UITableViewCell *)tableView:(UITableView *)tableView
          cellForRowAtIndexPath:(NSIndexPath *)indexPath {
     UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"FileCell"];

     NSString * path = self.documentFilenames[indexPath.row];
     cell.textLabel.text = path.lastPathComponent.stringByDeletingPathExtension;
     return cell;
 }

 - (IBAction)chooseColor:(id)sender {
     NSInteger selectedColorIndex = [(UISegmentedControl *)sender selectedSegmentIndex];
     [self setTintColorForIndex:selectedColorIndex];

 //    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
 //    [prefs setInteger:selectedColorIndex forKey:@"selectedColorIndex"];
 //    [prefs synchronize];

     NSUbiquitousKeyValueStore * prefs = [NSUbiquitousKeyValueStore defaultStore];
     [prefs setLongLong:selectedColorIndex forKey:@"selectedColorIndex"];
 }

 - (void)setTintColorForIndex:(NSInteger)selectedColorIndex {
     UIColor *tint = nil;
     switch (selectedColorIndex) {
         case :
             tint = [UIColor redColor];
             break;
         case :
             tint = [UIColor colorWithRed: green:0.6 blue: alpha:];
             break;
         case :
             tint = [UIColor blueColor];
             break;
         default:
             break;
     }
     [UIApplication sharedApplication].keyWindow.tintColor = tint;
 }

 - (void)viewDidAppear:(BOOL)animated {
     [super viewDidAppear:animated];

 //    NSUserDefaults * prefs = [NSUserDefaults standardUserDefaults];
 //    NSInteger selectedColorIndex = [prefs integerForKey:@"selectedColorIndex"];

     NSUbiquitousKeyValueStore * prefs = [NSUbiquitousKeyValueStore defaultStore];
     NSInteger selectedColorIndex = (int)[prefs longLongForKey:@"selectedColorIndex"];

     [self setTintColorForIndex:selectedColorIndex];
     [self.colorControl setSelectedSegmentIndex:selectedColorIndex];
 }

 - (void)viewDidLoad
 {
     [super viewDidLoad];

     UIBarButtonItem * addButton = [[UIBarButtonItem alloc]
                                   initWithBarButtonSystemItem:UIBarButtonSystemItemAdd
                                   target:self
                                   action:@selector(insertNewObject)];
     self.navigationItem.rightBarButtonItem = addButton;
     [self reloadFiles];
 }

 - (void)insertNewObject {
     // get the name
     UIAlertView *alert =
     [[UIAlertView alloc] initWithTitle:@"Filename"
                                message:@"Enter a name for your new TinyPix document."
                               delegate:self
                      cancelButtonTitle:@"Cancel"
                      otherButtonTitles:@"Create", nil];
     alert.alertViewStyle = UIAlertViewStylePlainTextInput;
     [alert show];
 }

 - (void)alertView:(UIAlertView *)alertView
 didDismissWithButtonIndex:(NSInteger)buttonIndex {
     if (buttonIndex == ) {
         NSString *filename = [NSString stringWithFormat:@"%@.tinypix",
                               [alertView textFieldAtIndex:].text];
         NSURL *saveUrl = [self urlForFilename:filename];
         self.chosenDocument = [[BIDTinyPixDocument alloc] initWithFileURL:saveUrl];
         [self.chosenDocument saveToURL:saveUrl
                       forSaveOperation:UIDocumentSaveForCreating
                      completionHandler:^(BOOL success) {
                          if (success) {
                              NSLog(@"save OK");
                              [self reloadFiles];
                              [self performSegueWithIdentifier:@"masterToDetail"
                                                        sender:self];
                          } else {
                              NSLog(@"failed to save!");
                          }
                      }];
     }
 }

 - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
     if (sender == self) {
         // if sender == self, a new document has just been created,
         // and chosenDocument is already set.

         UIViewController * destination = segue.destinationViewController;
         if ([destination respondsToSelector:@selector(setDetailItem:)]) {
             [destination setValue:self.chosenDocument forKey:@"detailItem"];
         }
     } else {
         // find the chosen document from the tableview
         NSIndexPath * indexPath = [self.tableView indexPathForSelectedRow];
         NSString * filename = self.documentFilenames[indexPath.row];
         NSURL * docUrl = [self urlForFilename:filename];
         self.chosenDocument = [[BIDTinyPixDocument alloc] initWithFileURL:docUrl];
         [self.chosenDocument openWithCompletionHandler:^(BOOL success) {
             if (success) {
                 NSLog(@"load OK");
                 UIViewController *destination = segue.destinationViewController;
                 if ([destination respondsToSelector:@selector(setDetailItem:)]) {
                     [destination setValue:self.chosenDocument forKey:@"detailItem"];
                 }
             } else {
                 NSLog(@"failed to load!");
             }
         }];
     }
 }

3、创建BIDTinyPixView视图类，用于显示用户可编辑的网格。

 #import <UIKit/UIKit.h>
 @class BIDTinyPixDocument;

 @interface BIDTinyPixView : UIView
 @property (strong, nonatomic) BIDTinyPixDocument * document;
 @end

 #import "BIDTinyPixView.h"
 #import "BIDTinyPixDocument.h"

 typedef struct {
     NSUInteger row;
     NSUInteger column;
 } GridIndex;

 @interface BIDTinyPixView ()

 @property (assign, nonatomic) CGSize blockSize;
 @property (assign, nonatomic) CGSize gapSize;
 @property (assign, nonatomic) GridIndex selectedBlockIndex;

 @end

 @implementation BIDTinyPixView

 - (id)initWithFrame:(CGRect)frame
 {
     self = [super initWithFrame:frame];
     if (self) {
         // Initialization code
         [self commonInit];
     }
     return self;
 }

 - (id)initWithCoder:(NSCoder *)aDecoder {
     self = [super initWithCoder:aDecoder];
     if (self) {
         [self commonInit];
     }
     return self;
 }

 - (void)commonInit{
     _blockSize = CGSizeMake(, );
     _gapSize = CGSizeMake(, );
     _selectedBlockIndex.row = NSNotFound;
     _selectedBlockIndex.column = NSNotFound;
 }

 // Only override drawRect: if you perform custom drawing.
 // An empty implementation adversely affects performance during animation.
 - (void)drawRect:(CGRect)rect
 {
     // Drawing code
     if (!_document) return;

     for (NSUInteger row = ; row < ; row++) {
         for (NSUInteger column = ; column < ; column++) {
             [self drawBlockAtRow:row column:column];
         }
     }
 }

 - (void)drawBlockAtRow:(NSUInteger)row column:(NSUInteger)column {
     CGFloat startX = (_blockSize.width + _gapSize.width) * ( - column) + ;
     CGFloat startY = (_blockSize.height + _gapSize.height) * row + ;
     CGRect blockFrame = CGRectMake(startX, startY, _blockSize.width, _blockSize.height);
     UIColor *color = [_document stateAtRow:row column:column] ?
         [UIColor blackColor] : [UIColor whiteColor];
     [color setFill];
     [self.tintColor setStroke];
     UIBezierPath *path = [UIBezierPath bezierPathWithRect:blockFrame];
     [path fill];
     [path stroke];
 }

 - (GridIndex)touchedGridIndexFromTouches:(NSSet *)touches {
     GridIndex result;
     UITouch *touch = [touches anyObject];
     CGPoint location = [touch locationInView:self];
     result.column =  - (location.x * 8.0 / self.bounds.size.width);
     result.row = location.y * 8.0 / self.bounds.size.height;
     return result;
 }

 - (void)toggleSelectedBlock {
     [_document toggleStateAtRow:_selectedBlockIndex.row
                          column:_selectedBlockIndex.column];
     [[_document.undoManager prepareWithInvocationTarget:_document]
      toggleStateAtRow:_selectedBlockIndex.row column:_selectedBlockIndex.column];
     [self setNeedsDisplay];
 }

 - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
     self.selectedBlockIndex = [self touchedGridIndexFromTouches:touches];
     [self toggleSelectedBlock];
 }

 - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
     GridIndex touched = [self touchedGridIndexFromTouches:touches];
     if (touched.row != _selectedBlockIndex.row
         || touched.column != _selectedBlockIndex.column) {
         _selectedBlockIndex = touched;
         [self toggleSelectedBlock];
     }
 }

4、添加BIDDetailViewController内容

 @interface BIDDetailViewController : UIViewController

 @property (strong, nonatomic) id detailItem;

 @end

 #import "BIDDetailViewController.h"
 #import "BIDTinyPixView.h"

 @interface BIDDetailViewController ()
 @property (weak, nonatomic) IBOutlet BIDTinyPixView *pixView;
 - (void)configureView;
 @end

 @implementation BIDDetailViewController

 #pragma mark - Managing the detail item

 - (void)setDetailItem:(id)newDetailItem
 {
     if (_detailItem != newDetailItem) {
         _detailItem = newDetailItem;

         // Update the view.
         [self configureView];
     }
 }

 - (void)configureView
 {
     // Update the user interface for the detail item.

     if (self.detailItem) {
         self.pixView.document = self.detailItem;
         [self.pixView setNeedsDisplay];
     }
 }

 - (void)viewDidLoad
 {
     [super viewDidLoad];
     // Do any additional setup after loading the view, typically from a nib.
     [self configureView];
 }
 //当用户按下返回按钮回到主列表时，文档实例将在没有进行任何保存操作的情况下被销毁，所以添加如下方法。
　　//一旦用户离开详情页面，就关闭文档，关闭文档会导致该文档被自动保存，保存工作发生在后台线程中。
 - (void)viewWillDisappear:(BOOL)animated
 {
     [super viewWillDisappear:animated];
     UIDocument * doc = self.detailItem;
     [doc closeWithCompletionHandler:nil];
 }

5、添加iCloud支持

创建授权文件

6、如何查询

@property (strong, nonatomic) NSMetadataQuery * query;
@property (strong, nonatomic) NSMutableArray * documentURLs;

- (void)reloadFiles {
    NSFileManager * fileManager = [NSFileManager defaultManager];
    // passing nil is OK here, matches first entitlement
    NSURL * cloudURL = [fileManager URLForUbiquityContainerIdentifier:nil];
    NSLog(@"got cloudURL %@", cloudURL);  // returns nil in simulator

    self.query = [[NSMetadataQuery alloc] init];
    _query.predicate = [NSPredicate predicateWithFormat:@"%K like '*.tinypix'",
                        NSMetadataItemFSNameKey];
    _query.searchScopes = [NSArray arrayWithObject:
                           NSMetadataQueryUbiquitousDocumentsScope];
    [[NSNotificationCenter defaultCenter]
     addObserver:self
     selector:@selector(updateUbiquitousDocuments:)
     name:NSMetadataQueryDidFinishGatheringNotification
     object:nil];
    [[NSNotificationCenter defaultCenter]
     addObserver:self
     selector:@selector(updateUbiquitousDocuments:)
     name:NSMetadataQueryDidUpdateNotification
     object:nil];
    [_query startQuery];
}

//实现查询完成时的那些通知
//查询的结果包含在一个NSMetadataItem对象的列表，从中我们可以获取文件URL和创建日期等数据项，我们根据创建日期来排列这些项，然后获取所有的URL以供之后使用。
- (void)updateUbiquitousDocuments:(NSNotification *)notification {
    self.documentURLs = [NSMutableArray array];
    self.documentFilenames = [NSMutableArray array];

    NSLog(@"updateUbiquitousDocuments, results = %@", self.query.results);
    NSArray *results = [self.query.results sortedArrayUsingComparator:
                        ^NSComparisonResult(id obj1, id obj2) {
                            NSMetadataItem *item1 = obj1;
                            NSMetadataItem *item2 = obj2;
                            return [[item2 valueForAttribute:NSMetadataItemFSCreationDateKey] compare:
                                    [item1 valueForAttribute:NSMetadataItemFSCreationDateKey]];
                        }];

    for (NSMetadataItem *item in results) {
        NSURL *url = [item valueForAttribute:NSMetadataItemURLKey];
        [self.documentURLs addObject:url];
        [(NSMutableArray *)_documentFilenames addObject:[url lastPathComponent]];
    }

    [self.tableView reloadData];
}

7、保存到哪里

 - (NSURL *)urlForFilename:(NSString *)filename
 {
     // be sure to insert "Documents" into the path
     NSURL * baseURL = [[NSFileManager defaultManager]
                       URLForUbiquityContainerIdentifier:nil];
     NSURL * pathURL = [baseURL URLByAppendingPathComponent:@"Documents"];
     NSURL * destinationURL = [pathURL URLByAppendingPathComponent:filename];
     return destinationURL;
 }

8、将首选项保存到iCloud

 - (IBAction)chooseColor:(id)sender {
     NSInteger selectedColorIndex = [(UISegmentedControl *)sender selectedSegmentIndex];
     [self setTintColorForIndex:selectedColorIndex];

 //    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
 //    [prefs setInteger:selectedColorIndex forKey:@"selectedColorIndex"];
 //    [prefs synchronize];

     NSUbiquitousKeyValueStore * prefs = [NSUbiquitousKeyValueStore defaultStore];
     [prefs setLongLong:selectedColorIndex forKey:@"selectedColorIndex"];
 }

 - (void)viewDidAppear:(BOOL)animated {
     [super viewDidAppear:animated];

 //    NSUserDefaults * prefs = [NSUserDefaults standardUserDefaults];
 //    NSInteger selectedColorIndex = [prefs integerForKey:@"selectedColorIndex"];

     NSUbiquitousKeyValueStore * prefs = [NSUbiquitousKeyValueStore defaultStore];
     NSInteger selectedColorIndex = (int)[prefs longLongForKey:@"selectedColorIndex"];

     [self setTintColorForIndex:selectedColorIndex];
     [self.colorControl setSelectedSegmentIndex:selectedColorIndex];
 }