我的浏览器在搭建好基本UI后运行还算正常。但添加了自动旋转代码后，开始报错。即使关闭Xcode，在模拟器上独立运行app，也只能坚持不到一分钟就闪退。
错误代码：
***Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '<ViewController: 0x7f877a71a1a0>: An -observeValueForKeyPath:ofObject:change:context: message was received but not handled.
Key path: estimatedProgress
Observed object: <WKWebView: 0x7f877a5c41c0; frame = (0 0; 667 375); gestureRecognizers = <NSArray: 0x7f877a5e1e30>; layer = <CALayer: 0x7f877a5c3b70>>
Change: {
kind = 1;
new = "0.6176357155547082";
}
Context: 0x0'
***First throw call stack:
(
0 CoreFoundation 0x000000010b7a4c65 __exceptionPreprocess + 165
1 libobjc.A.dylib 0x000000010b43dbb7 objc_exception_throw + 45
2 CoreFoundation 0x000000010b7a4b9d +[NSException raise:format:] + 205
3 Foundation 0x000000010b06acaf -[NSObject(NSKeyValueObserving)observeValueForKeyPath:ofObject:change:context:] + 73
4 NewBrowserProject 0x000000010aefa246 -[ViewController observeValueForKeyPath:ofObject:change:context:] + 1030
5 Foundation 0x000000010af9ad96 NSKeyValueNotifyObserver + 356
6 Foundation 0x000000010af99fbd NSKeyValueDidChange + 466
7 Foundation 0x000000010af9e6df -[NSObject(NSKeyValueObserverNotification) didChangeValueForKey:] + 118
8 WebKit 0x000000010d2c47d1 _ZN6WebKit13PageLoadState13commitChangesEv + 1133
9 WebKit 0x000000010d227dc6 _ZN6WebKit12WebPageProxy17didChangeProgressEd + 74
10 WebKit 0x000000010d23a96c _ZN6WebKit12WebPageProxy17didReceiveMessageEPN3IPC10ConnectionERNS1_14MessageDecoderE + 2976
11 WebKit 0x000000010d12df58 _ZN3IPC18MessageReceiverMap15dispatchMessageEPNS_10ConnectionERNS_14MessageDecoderE + 120
12 WebKit 0x000000010d26cd9c _ZN6WebKit15WebProcessProxy17didReceiveMessageEPN3IPC10ConnectionERNS1_14MessageDecoderE + 24
13 WebKit 0x000000010d0b5baa _ZN3IPC10Connection15dispatchMessageENSt3__110unique_ptrINS_14MessageDecoderENS1_14default_deleteIS3_EEEE + 94
14 WebKit 0x000000010d0b85c4 _ZN3IPC10Connection18dispatchOneMessageEv + 110
15 JavaScriptCore 0x00000001153c1436 _ZN3WTF7RunLoop11performWorkEv + 454
16 JavaScriptCore 0x00000001153c1cea _ZN3WTF7RunLoop11performWorkEPv + 26
17 CoreFoundation 0x000000010b6d8431 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
18 CoreFoundation 0x000000010b6ce2fd __CFRunLoopDoSources0 + 269
19 CoreFoundation 0x000000010b6cd934 __CFRunLoopRun + 868
20 CoreFoundation 0x000000010b6cd366 CFRunLoopRunSpecific + 470
21 GraphicsServices 0x0000000110264a3e GSEventRunModal + 161
22 UIKit 0x000000010bddf8c0 UIApplicationMain + 1282
23 NewBrowserProject 0x000000010af00aaf main + 111
24 libdyld.dylib 0x000000010e5fb145 start + 1
25 ??? 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)
看来是上一篇提到的添加进度条的代码出现了问题。
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
if ([keyPath isEqualToString:@"estimatedProgress"] && object == self.webView) {
[self.loadingProgress setAlpha:1.0f];
[self.loadingProgress setProgress:self.webView.estimatedProgress animated:YES];
if(self.webView.estimatedProgress >= 1.0f) {
[UIView animateWithDuration:0.3
delay:0.3
options:UIViewAnimationOptionCurveEaseOut
animations:^ {
[self.loadingProgress setAlpha:0.0f];
}
completion:^(BOOL finished) {
[self.loadingProgress setProgress:0.0f animated:NO];
}
];
}
}else {
[super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
}
}
这段代码在WKWebView的estimatedProgress属性发生变化时，显示UIProgressView控件，并当estimatedProgress属性为1时消失。
我的代码问题在于：设备每次旋转后，app都会移除WKWebView控件，并重新添加新的WKWebView控件。其estimatedProgress属性出现了从1到0的情况，对于这个观察事件来讲却无法作出反应，因为我将UIProgressView控件添加到了WKWebView控件上，随之移除并重新生成。
解决办法是，不再对WKWebView做 移除并重新生成 的老办法，而是直接设置setAutoresizingMask:属性。