我可以自动创建UIImageView实例吗？

Question

Now I create is as follow (my file.h):

UIImageView *pic1, *pic2, *pic3, *pic4, *pic5, *pic6, *pic7, *pic8, *pic9, *pic10;

Then in my (file.m):

UIImageView *pic1 = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@”picName.png”]];

UIImageView *pic2 = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@”picName.png”]];
……

UIImageView *pic10 = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@”picName.png”]];

I need many instances of UIImageView (number triggered by other factors) of only one in this case picture.

Is there any way to create multiple instances of UIImageView automatically in my file.m, somehow as follow?:

for (int x; (x=10); x++)
{
    UIImageView * pic[x] = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"myPic.png"]];
}

This example doesn't work but I'd like to show what I want to program.

Answer 1

Of course you can - that is what the arrays are for:

NSMutableArray *pics = [NSMutableArray array];
for (int i = 0 ; i != 10 ; i++) {
    [pics addObject:[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"myPic.png"]]];
}

In case the name of the picture depends on the index, use NSString 's stringWithFormat to produce the name of the picture - for example, you can do it like this:

NSMutableArray *pics = [NSMutableArray array];
for (int i = 0 ; i != 10 ; i++) {
    NSString *imgName = [NSString stringWithFormat:@"myPic%d.png"];
    [pics addObject:[[UIImageView alloc] initWithImage:[UIImage imageNamed:imgName]]];
}

Answer 2

If the names of images follow a standard pattern you can just loop over the required amount and build the image name dynamically using the index.

If the names of the images do not follow a standard patten you can chuck them in an array and loop over them

NSArray *imageNames = @[
  @"alarm.jpg",
  @"bell.jpg",
  @"car.jpg"
];

NSMutableArray *imageViews = [[NSMutableArray alloc] init];

for (NSString *imageName in imageNames) {
  [imagesViews addObject:({
    [[UIImageView alloc] initWithImage:[UIImage imageNamed:imageName]];
  })];
}

---

Completely optional - further reading

You could write yourself a simple category that abstracts this looping and collecting the results into a new array. This would allow you to simply write

NSArray *imageNames = @[
  @"alarm.jpg",
  @"bell.jpg",
  @"car.jpg"
];

NSArray *imageViews = [imageNames pas_arrayByMappingWithBlock:^(id obj){
  return [[UIImageView alloc] initWithImage:[UIImage imageNamed:imageName]];
}];

The category to do that would look something like this:

@interface NSArray (PASAdditions)

- (NSArray *)pas_arrayByMappingWithBlock:(id (^)(id obj))block

@end

@implementation NSArray (PASAdditions)

- (NSArray *)pas_arrayByMappingWithBlock:(id (^)(id obj))block
{
  NSMutableArray *result = [[NSMutableArray alloc] init];

  for (id obj in self) {
    [result addObject:block(obj)];
  }

  return [result copy];
}

@end