在NSMutableArray中移动多个对象

Question

假设我有这样一个NSMutableArray：

对象0对象1对象2对象3对象4

并将对象0和对象1移到对象4后面：

对象2对象3对象4对象0对象1

我有这段相当长的代码来实现多个对象的重新排序，但我想知道是否有一种更简单、更优雅的方法：

    int from = 0;
    int to = 5;
    int lastIndexOfObjectsToBeMoved = 1;    
    NSMutableArray *objectsToBeMoved = [[NSMutableArray alloc] init];
    for (int i = from; i < lastIndexOfObjectsToBeMoved; i++) {
        object *o = [self.objects objectAtIndex:i];
        [objectsToBeMoved addObject:o];
    }

    NSUInteger length = lastIndexOfObjectsToBeMoved-from;
    NSRange indicesToBeDeleted = NSMakeRange(from, length);
    [self.objects removeObjectsInRange:indicesToBeDeleted];


    NSIndexSet *targetIndices = [NSIndexSet indexSetWithIndexesInRange:NSMakeRange(to, length)];
    [self.objects insertObjects:objectsToBeMoved atIndexes:targetIndices];

编辑:对不起，我应该澄清，我并不总是把对象移到最末尾，但我也希望能够将对象2和3移动到索引0。

Answer 1

创建要移到后面的索引的NSRange。用subarrayWithRange获取这些对象，用removeObjectsInRange:删除它们，并通过调用addObjectsFromArray:将它们添加回末尾。这是一种更简洁的写作方式。

Answer 2

rowIndexes是一个带有您喜欢移动的对象的NSIndexSet

行是索引目标。

NSArray *objectsToMove = [your_array objectsAtIndexes: rowIndexes];

// If any of the removed objects come before the row
// we want to decrement the row appropriately
row -= [rowIndexes countOfIndexesInRange: (NSRange){0, row}];

[your_array removeObjectsAtIndexes:rowIndexes];
[your_array replaceObjectsInRange: (NSRange){row, 0}
       withObjectsFromArray: objectsToMove];

我希望这对你有帮助