How to make custom completion Handler with Objective-C - ios

Question

I've looked through various documents, but don't know how to apply the completion handler in the following cases.
//example function.
//default textView height 100.0f
-(void)getHeightResult{
[self initHeight];
NSLog(#"%#", [self setTextManager]);
}
-(NSString *)setTextManager{
if(self.textView.frame.size.heigh != 100){
return #"new Height";
} else{
return #"Default Height;
}
}
-(void)initHeight{
int result;
for(int i = 0 ; i <= 20: i ++){
result = result + i;
}
//result = 210
self.textView.frame.size.height = result;
}
When executing the above functions, getHeightResult always outputs 'Default Height'.
How can I apply a Completion Handler to get it returned as the value calculated in initHeight from a source like this?
We ask for answers to help you understand the Completion Handler, not for asking the actual source.

Answer 1

Code for completionHandler,
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
[self getSize:^(bool status) {
if (status == true) {
// perofm your operioan
NSLog(#"Done");
}
}];
}
typedef void (^CompletionBlock)(_Bool status);
-(void)getSize:(CompletionBlock)block{
__block int count = 0;
[self initWidth:^(bool status) {
count++;
if (count == 2) {
block(true);
}
}];
[self initHeight:^(bool status) {
count++;
if (count == 2) {
block(true);
}
}];
}
-(void)initHeight:(CompletionBlock)block{
int result;
for(int i = 0 ; i <= 100; i ++) {
result = result + i;
}
block(true);
}
-(void)initWidth:(CompletionBlock)block{
int result;
for(int i = 0 ; i <= 20; i ++){
result = result + i;
}
block(true);
}