NSMutablearray将对象从索引移动到索引

Question

我有一个带有可重复行的UItableview,数据在NSarray中.那么当调用适当的tableview委托时,如何在NSMutablearray中移动对象？

问这个的另一种方法是如何重新排序NSMutableArray？

Answer 1

id object = [[[self.array objectAtIndex:index] retain] autorelease];
[self.array removeObjectAtIndex:index];
[self.array insertObject:object atIndex:newIndex];

就这样.处理保留计数很重要,因为数组可能是唯一引用该对象的数组.

Answer 2

ARC兼容类别:

NSMutableArray里+ Convenience.h

@interface NSMutableArray (Convenience)

- (void)moveObjectAtIndex:(NSUInteger)fromIndex toIndex:(NSUInteger)toIndex;

@end

NSMutableArray里+ Convenience.m

@implementation NSMutableArray (Convenience)

- (void)moveObjectAtIndex:(NSUInteger)fromIndex toIndex:(NSUInteger)toIndex
{
    // Optional toIndex adjustment if you think toIndex refers to the position in the array before the move (as per Richard's comment)
    if (fromIndex < toIndex) {
        toIndex--; // Optional 
    }

    id object = [self objectAtIndex:fromIndex];
    [self removeObjectAtIndex:fromIndex];
    [self insertObject:object atIndex:toIndex];
}

@end

用法:

[mutableArray moveObjectAtIndex:2 toIndex:5];

Answer 3

使用Swift,Array它就像这样简单:

斯威夫特3

extension Array {
    mutating func move(at oldIndex: Int, to newIndex: Int) {
        self.insert(self.remove(at: oldIndex), at: newIndex)
    }
}

斯威夫特2

extension Array {
    mutating func moveItem(fromIndex oldIndex: Index, toIndex newIndex: Index) {
        insert(removeAtIndex(oldIndex), atIndex: newIndex)
    }
}