怎么对包含自定义对象的NSMutableArray排序

Compare method

Either you implement a compare-method for your object:

- (NSComparisonResult)compare:(Person *)otherObject {
return [self.birthDate compare:otherObject.birthDate];
}

NSArray *sortedArray;
sortedArray = [drinkDetails sortedArrayUsingSelector:@selector(compare:)];

NSSortDescriptor (better)

or usually even better:

NSSortDescriptor *sortDescriptor;
sortDescriptor = [[[NSSortDescriptor alloc] initWithKey:@"birthDate"
ascending:YES] autorelease];
NSArray *sortDescriptors = [NSArray arrayWithObject:sortDescriptor];
NSArray *sortedArray;
sortedArray = [drinkDetails sortedArrayUsingDescriptors:sortDescriptors];

You can easily sort by multiple keys by adding more than one to the array. Using custom comparator-methods is possible as well. Have a look at thedocumentation.

Blocks (shiny!)

There's also the possibility of sorting with a block since Mac OS X 10.6 and iOS 4:

NSArray *sortedArray;
sortedArray = [drinkDetails sortedArrayUsingComparator:^NSComparisonResult(id a, id b) {
NSDate *first = [(Person*)a birthDate];
NSDate *second = [(Person*)b birthDate];
return [first compare:second];
}];

For this particular example I'm assuming that the objects in your array have a 'position' method, which returns an

NSInteger

.

NSArray *arrayToSort = where ever you get the array from... ;NSComparisonResult (^sortBlock)(id, id) = ^(id obj1, id obj2) {if ([obj1 position] > [obj2 position]) {return (NSComparisonResult)NSOrderedDescending;}if ([obj1 position] < [obj2 position]) {return (NSComparisonResult)NSOrderedAscending;}return (NSComparisonResult)NSOrderedSame;};NSArray *sorted = [arrayToSort sortedArrayUsingComparator:sortBlock];

Note: the "sorted" array will be autoreleased.[/code]

If this 'position' is in NSDictory.

NSComparisonResult (^sortBlock)(id, id) = ^(id obj1, id obj2) {            NSInteger p1= [((NSString*) [obj1 objectForKey:@"position"]) integerValue];            NSInteger p2= [((NSString*) [obj2 objectForKey:@"position"]) integerValue];            if (p1 > p2) {                return (NSComparisonResult)NSOrderedDescending;            }            if (p1 < p2) {                return (NSComparisonResult)NSOrderedAscending;            }            return (NSComparisonResult)NSOrderedSame;        };