问题
Here's an answer for a similar question in Objective C but I'm not sure what's the right way to translate it to MonoTouch.
Basically, I want to be able to catch JavaScript errors and know at least filename and line number—unfortunately, window.onerror doesn't give this crucial information.
In particular, I'm not sure if I should expose a native library or if I can write this in pure MonoTouch.
回答1:
I adopted Pablo's UIWebView+Debug category inspired by Robert Sanders and Kresimir Prcela's answers.
Note that his code also includes a private API call you can use to enable remote web inspector.
(For some reason this thing doesn't work for me though.)
Update: here's how to debug UIWebView in Mountain Lion—you need to download an older version of Chromium.
Remember to only use private API while debugging—if you submit an app and forget to remove these calls, Apple will reject your app. For this reason both Xcode and MonoDevelop code use DEBUG conditions.
Here is the complete source code I'm using:
Xcode project
UIWebView+Debug.h
//
// WebView+Debug.h
// VOL
//
// Created by Pablo Guillen Schlippe on 26.07.11.
// Copyright 2011 Medienhaus.
//
/*
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
associated documentation files (the "Software"), to deal in the Software without restriction,
including without limitation the rights to use, copy, modify, merge, publish, distribute,
sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or
substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
// This little drop in category is based on the following StackOverflow article:
// https://stackoverflow.com/questions/193119/
#ifdef DEBUG
// Use this to toggle logging
#define kDidParseSource 0
#define kFailedToParseSource 1
#define kExceptionWasRaised 1
#define kDidEnterCallFrame 0
#define kWillExecuteStatement 0
#define kWillLeaveCallFrame 0
void enableRemoteWebInspector(void);
#endif
UIWebView+Debug.m
//
// WebView+Debug.m
// VOL
//
// Created by Pablo Guillen Schlippe on 26.07.11.
// Copyright 2011 Medienhaus. All rights reserved.
//
#ifdef DEBUG
#import <objc/runtime.h>
#import "UIWebView+Debug.h"
@class WebView;
@class WebFrame;
@class WebScriptCallFrame;
#pragma mark -
static NSString* getAddress() {
id myhost =[NSClassFromString(@"NSHost") performSelector:@selector(currentHost)];
if (myhost) {
for (NSString* address in [myhost performSelector:@selector(addresses)]) {
if ([address rangeOfString:@"::"].location == NSNotFound) {
return address;
}
}
}
return @"127.0.0.1";
}
void enableRemoteWebInspector() {
[NSClassFromString(@"WebView") performSelector:@selector(_enableRemoteInspector)];
NSLog(@"Point your browser at http://%@:9999", getAddress());
}
#pragma mark -
@interface ScriptDebuggerDelegate : NSObject
-(id)functionNameForFrame:(WebScriptCallFrame*)frame;
-(id)callerForFrame:(WebScriptCallFrame*)frame;
-(id)exceptionForFrame:(WebScriptCallFrame*)frame;
@end
#pragma mark -
@implementation ScriptDebuggerDelegate
// We only have access to the public methods declared in the header / class
// The private methods can also be accessed but raise a warning.
// Use runtime selectors to suppress warnings
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Warc-performSelector-leaks"
-(id)functionNameForFrame:(WebScriptCallFrame*)frame {
SEL functionNameSelector = @selector(functionName);
return [(id)frame performSelector:functionNameSelector];
}
-(id)callerForFrame:(WebScriptCallFrame*)frame {
SEL callerSelector = @selector(caller);
return [(id)frame performSelector:callerSelector];
}
-(id)exceptionForFrame:(WebScriptCallFrame*)frame {
SEL exceptionSelector = @selector(exception);
return [(id)frame performSelector:exceptionSelector];
}
#pragma clang diagnostic pop
- (void)webView:(WebView *)webView didParseSource:(NSString *)source
baseLineNumber:(unsigned)lineNumber
fromURL:(NSURL *)url
sourceId:(int)sid
forWebFrame:(WebFrame *)webFrame {
if (kDidParseSource)
NSLog(@"ScriptDebugger called didParseSource: \nsourceId=%d, \nurl=%@", sid, url);
}
// some source failed to parse
- (void)webView:(WebView *)webView failedToParseSource:(NSString *)source
baseLineNumber:(unsigned)lineNumber
fromURL:(NSURL *)url
withError:(NSError *)error
forWebFrame:(WebFrame *)webFrame {
if (kFailedToParseSource)
NSLog(@"ScriptDebugger called failedToParseSource:\
\nurl=%@ \nline=%d \nerror=%@ \nsource=%@",
url, lineNumber, error, source);
}
- (void)webView:(WebView *)webView exceptionWasRaised:(WebScriptCallFrame *)frame
sourceId:(int)sid
line:(int)lineno
forWebFrame:(WebFrame *)webFrame {
if (kExceptionWasRaised)
NSLog(@"ScriptDebugger exception:\
\nsourceId=%d \nline=%d \nfunction=%@, \ncaller=%@, \nexception=%@",
sid,
lineno,
[self functionNameForFrame:frame],
[self callerForFrame:frame],
[self exceptionForFrame:frame]);
}
// just entered a stack frame (i.e. called a function, or started global scope)
- (void)webView:(WebView *)webView didEnterCallFrame:(WebScriptCallFrame *)frame
sourceId:(int)sid
line:(int)lineno
forWebFrame:(WebFrame *)webFrame {
if (kDidEnterCallFrame)
NSLog(@"ScriptDebugger didEnterCallFrame:\
\nsourceId=%d \nline=%d \nfunction=%@, \ncaller=%@, \nexception=%@",
sid,
lineno,
[self functionNameForFrame:frame],
[self callerForFrame:frame],
[self exceptionForFrame:frame]);
}
// about to execute some code
- (void)webView:(WebView *)webView willExecuteStatement:(WebScriptCallFrame *)frame
sourceId:(int)sid
line:(int)lineno
forWebFrame:(WebFrame *)webFrame {
if (kWillExecuteStatement)
NSLog(@"ScriptDebugger willExecuteStatement:\
\nsourceId=%d \nline=%d \nfunction=%@, \ncaller=%@, \nexception=%@",
sid,
lineno,
[self functionNameForFrame:frame],
[self callerForFrame:frame],
[self exceptionForFrame:frame]);
}
// about to leave a stack frame (i.e. return from a function)
- (void)webView:(WebView *)webView willLeaveCallFrame:(WebScriptCallFrame *)frame
sourceId:(int)sid
line:(int)lineno
forWebFrame:(WebFrame *)webFrame {
if (kWillLeaveCallFrame)
NSLog(@"ScriptDebugger willLeaveCallFrame:\
\nsourceId=%d \nline=%d \nfunction=%@, \ncaller=%@, \nexception=%@",
sid,
lineno,
[self functionNameForFrame:frame],
[self callerForFrame:frame],
[self exceptionForFrame:frame]);
}
@end
#pragma mark -
@interface UIWebView ()
-(id)setScriptDebugDelegate:(id)delegate;
@end
#pragma mark -
@implementation UIWebView (Debug)
- (void)webView:(id)sender didClearWindowObject:(id)windowObject
forFrame:(WebFrame*)frame {
ScriptDebuggerDelegate* delegate = [[ScriptDebuggerDelegate alloc] init];
objc_setAssociatedObject(sender, @"ScriptDebuggerDelegate", delegate, OBJC_ASSOCIATION_RETAIN);
[sender setScriptDebugDelegate:delegate];
}
@end
#endif
MonoTouch project
AppDelegate.cs
[Register ("AppDelegate")]
public partial class AppDelegate : UIApplicationDelegate
{
[Conditional("DEBUG")]
[DllImport ("__Internal", EntryPoint = "enableWebInspector")]
public extern static void EnableRemoteWebInspector ();
public override bool FinishedLaunching (UIApplication application, NSDictionary launchOptions)
{
// It will tell you the port in the console,
// More info here: http://antony_perkov.blogspot.com/2012/03/debugging-uiwebview-content-in.html
EnableRemoteWebInspector();
return true;
}
}
Because I couldn't get LinkWith attribute to work properly, I put this in project properties:
iPhone Build Project Options
Simulator
-gcc_flags "-L${ProjectDir}/Native -lNativeLib-arm7 -force_load ${ProjectDir}/Native/libNativeLib-arm7.a"
Device
-gcc_flags "-L${ProjectDir}/Native -lNativeLib-i386 -force_load ${ProjectDir}/Native/libNativeLib-i386.a"
Custom Commands > Before Build
Command
Simulator
sh ${SolutionDir}/NativeLib/compile-arm "${ProjectConfigName}"
Device
sh ${SolutionDir}/NativeLib/compile-arm "${ProjectConfigName}"
Working directory
${SolutionDir}/NativeLib
Finally, these are the build scripts:
compile-i386
xcodebuild -project NativeLib.xcodeproj -target NativeLib -sdk iphonesimulator -configuration $1 clean build
cp build/$1-iphonesimulator/libNativeLib.a ../ProjectName/Native/libNativeLib-i386.a
compile-arm
xcodebuild -project NativeLib.xcodeproj -target NativeLib -sdk iphoneos -arch armv6 -configuration $1 clean build
cp build/$1-iphoneos/libNativeLib.a ../ProjectName/Native/libNativeLib-arm6.a
xcodebuild -project NativeLib.xcodeproj -target NativeLib -sdk iphoneos -arch armv7 -configuration $1 clean build
cp build/$1-iphoneos/libNativeLib.a ../ProjectName/Native/libNativeLib-arm7.a
I realize this may not be the best way to do this, but it works just fine.
Feel free to post a simpler solution if you know one.
来源：https://stackoverflow.com/questions/11527181/how-do-i-catch-uiwebview-errors-in-monotouch