How change this from UIWebView to WKWebView? - objective-c

Question

I have tried with the 3 or 4 posts about this here but none use file path and I cannot get this working with WKWebView, it works with UIWebView, please can someone help me.
Yes, I am very new to this, I tried all day before posting here tonight, so easy to understand instructions would be great. Thanks.
.h file:
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController
#property (weak, nonatomic) IBOutlet UIWebView *contentWebView;
#end
.m file:
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController
#synthesize contentWebView;
- (void)viewDidLoad {
[super viewDidLoad];
NSString *filePath = [[NSBundle mainBundle]pathForResource:#"LockBackground" ofType:#"html"];
NSURL * fileURL = [NSURL fileURLWithPath:filePath isDirectory:NO];
NSURLRequest * myNSURLRequest = [[NSURLRequest alloc]initWithURL:fileURL];
[contentWebView loadRequest:myNSURLRequest];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end

Answer 1

Simply changing
#property (weak, nonatomic) IBOutlet UIWebView *contentWebView;
to
#property (weak, nonatomic) IBOutlet WKWebView *contentWebView;
should work.
If you intend to provide support for both iOS 7 and iOS 8, you'll have to declare two variables and add the following verification:
if ([WKWebView class]) {
// do new webview stuff
}
else {
// do old webview stuff
}