My app has been humming along nicely through various Android versions. I have users running it on Android 4.3, 5.0, 5.1 and 6.0 with no problems. However a user with a S7 Edge has just updated with Android 7.0 and the app is crashing when text is pasted into an EditText field (This is the first and only thing you do with this app - it starts you paste in text into a box and then the app parses the text).
I have looked at many threads on Null Pointer Exceptions and I have looked at the source for Editor.java but nothing is obvious. The stack trace below shows no problems with my code. Any ideas what they changed with 7.0 that could be causing this?
java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.widget.Editor$SelectionModifierCursorController.isDragAcceleratorActive()' on a null object reference
at android.widget.Editor.updateFloatingToolbarVisibility(Editor.java:1520)
at android.widget.Editor.onTouchEvent(Editor.java:1475)
at android.widget.TextView.onTouchEvent(TextView.java:10024)
at android.view.View.dispatchTouchEvent(View.java:10725)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2865)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2550)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2865)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2550)
at android.widget.ScrollView.dispatchTouchEvent(ScrollView.java:738)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2865)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2550)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2865)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2550)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2865)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2550)
at com.android.internal.policy.DecorView.superDispatchTouchEvent(DecorView.java:505)
at com.android.internal.policy.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1863)
at android.app.Activity.dispatchTouchEvent(Activity.java:3226)
at com.android.internal.policy.DecorView.dispatchTouchEvent(DecorView.java:467)
at android.view.View.dispatchPointerEvent(View.java:10954)
at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:5051)
at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4908)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4439)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4492)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4458)
at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4591)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4466)
at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4648)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4439)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4492)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4458)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4466)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4439)
at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:6936)
at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:6875)
at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:6836)
at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:7046)
at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185)
at android.view.InputEventReceiver.nativeConsumeBatchedInputEvents(Native Method)
at android.view.InputEventReceiver.consumeBatchedInputEvents(InputEventReceiver.java:176)
at android.view.ViewRootImpl.doConsumeBatchedInput(ViewRootImpl.java:7010)
at android.view.ViewRootImpl$ConsumeBatchedInputRunnable.run(ViewRootImpl.java:7073)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:927)
at android.view.Choreographer.doCallbacks(Choreographer.java:702)
at android.view.Choreographer.doFrame(Choreographer.java:632)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:913)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6688)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358)
I resolved it by removing
MyEditText.setMovementMethod(new ScrollingMovementMethod());
This is how you block the copy paste menu from appearing in any way, shape or form. This bug really drove me crazy, and as with any Samsung bug you know its in their code but you also know they won't fix it any time soon. Anyways, here's wonder wall...
Check if Android.Build.Model.toLowerCase().startsWith('sm-g930'). Do not match the whole string, the last letter is a minor version identifier. I stored this boolean in shouldBlockCopyPaste variable which comes up later.
If it matches you want to block the copy paste menu from showing. This is how you ACTUALLY DO IT!!!
Override these 2 functions, you'll notice my shouldBlockCopyPaste boolean, this is so other devices dont get blocked.
#Override
public ActionMode StartActionMode (ActionMode.Callback callback){
if (shouldBlockCopyPaste) {
return null;
} else {
return super.StartActionMode(callback);
}
}
#Override
public ActionMode StartActionMode (ActionMode.Callback callback, int type){
if (shouldBlockCopyPaste) {
return null;
} else {
return super.StartActionMode(callback, type);
}
}
I've seen this crash for a while in my app coming from Samsung devices. turned out that a long press on a TextView brought up the copy-paste menu on those devices and the user was even able to paste text over (although its not an EditText component). Ended up disabling all types of interactions in the XML of the culprit TextViews (most importantly longClickable) and the crash wen't away.
<TextView
...
android:longClickable="false"
android:clickable="false"
android:linksClickable="false" />
Related
When I create a new project, I get a strange behavior for unhandled exceptions. This is how I can reproduce the problem:
1) create a new Windows Forms Application (C#, .NET Framework 4, VS2010)
2) add the following code to the Form1_Load handler:
int vara = 5, varb = 0;
int varc = vara / varb;
int vard = 7;
I would expect that VS breaks and shows an unhandled exception message at the second line. However, what happens is that the third line is just skipped without any message and the application keeps running.
I don't have this problem with my existing C# projects. So I guess that my new projects are created with some strange default settings.
Does anyone have an idea what's wrong with my project???
I tried checking the boxes in Debug->Exceptions. But then executions breaks even if I handle the exception in a try-catch block; which is also not what I want. If I remember correctly, there was a column called "unhandled exceptions" or something like this in this dialog box, which would do excatly what I want. But in my projects there is only one column ("Thrown").
This is a nasty problem induced by the wow64 emulation layer that allows 32-bit code to run on the 64-bit version of Windows 7. It swallows exceptions in the code that runs in response to a notification generated by the 64-bit window manager, like the Load event. Preventing the debugger from seeing it and stepping in. This problem is hard to fix, the Windows and DevDiv groups at Microsoft are pointing fingers back and forth. DevDiv can't do anything about it, Windows thinks it is the correct and documented behavior, mysterious as that sounds.
It is certainly documented but just about nobody understands the consequences or thinks it is reasonable behavior. Especially not when the window procedure is hidden from view of course, like it is in any project that uses wrapper classes to hide the window plumbing. Like any Winforms, WPF or MFC app. Underlying issue is Microsoft could not figure out how to flow exceptions from 32-bit code back to the 64-bit code that triggered the notification back to 32-bit code that tries to handle or debug the exception.
It is only a problem with a debugger attached, your code will bomb as usual without one.
Project > Properties > Build tab > Platform target = AnyCPU and untick Prefer 32-bit. Your app will now run as a 64-bit process, eliminating the wow64 failure mode. Some consequences, it disables Edit + Continue for VS versions prior to VS2013 and might not always be possible when you have a dependency on 32-bit code.
Other possible workarounds:
Debug > Exceptions > tick the Thrown box for CLR exceptions to force the debugger to stop at the line of code that throws the exception.
Write try/catch in the Load event handler and failfast in the catch block.
Use Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException) in the Main() method so that the exception trap in the message loop isn't disabled in debug mode. This however makes all unhandled exceptions hard to debug, the ThreadException event is pretty useless.
Consider if your code really belongs in the Load event handler. It is very rare to need it, it is however very popular in VB.NET and a swan song because it is the default event and a double-click trivially adds the event handler. You only ever really need Load when you are interested in the actual window size after user preferences and autoscaling is applied. Everything else belongs in the constructor.
Update to Windows 8 or later, they have this wow64 problem solved.
In my experience, I only see this issue when I'm running with a debugger attached. The application behaves the same when run standalone: the exception is not swallowed.
With the introduction of KB976038, you can make this work as you'd expect again. I never installed the hotfix, so I'm assuming it came as part of Win7 SP1.
This was mentioned in this post:
The case of the disappearing OnLoad exception – user-mode callback exceptions in x64
Here's some code that will enable the hotfix:
public static class Kernel32
{
public const uint PROCESS_CALLBACK_FILTER_ENABLED = 0x1;
[DllImport("Kernel32.dll")]
public static extern bool SetProcessUserModeExceptionPolicy(UInt32 dwFlags);
[DllImport("Kernel32.dll")]
public static extern bool GetProcessUserModeExceptionPolicy(out UInt32 lpFlags);
public static void DisableUMCallbackFilter() {
uint flags;
GetProcessUserModeExceptionPolicy(out flags);
flags &= ~PROCESS_CALLBACK_FILTER_ENABLED;
SetProcessUserModeExceptionPolicy(flags);
}
}
Call it at the beginning of your application:
[STAThread]
static void Main()
{
Kernel32.DisableUMCallbackFilter();
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
I've confirmed (with the the simple example shown below) that this works, just as you'd expect.
protected override void OnLoad(EventArgs e) {
throw new Exception("BOOM"); // This will now get caught.
}
So, what I don't understand, is why it was previously impossible for the debugger to handle crossing kernel-mode stack frames, but with this hotfix, they somehow figured it out.
As Hans mentions, compile the application and run the exe without a debugger attached.
For me the problem was changing a Class property name that a BindingSource control was bound to. Running without the IDE I was able to see the error:
Cannot bind to the property or column SendWithoutProofReading on the
DataSource. Parameter name: dataMember
Fixing the BindingSource control to bind to the updated property name resolved the problem:
I'm using WPF and ran into this same problem. I had tried Hans 1-3 suggestions already, but didn't like them because studio wouldn't stop at where the error was (so I couldn't view my variables and see what was the problem).
So I tried Hans' 4th suggestion. I was suprised at how much of my code could be moved to the MainWindow constructor without any issue. Not sure why I got in the habit of putting so much logic in the Load event, but apparently much of it can be done in the ctor.
However, this had the same problem as 1-3. Errors that occur during the ctor for WPF get wrapped into a generic Xaml exception. (an inner exception has the real error, but again I wanted studio to just break at the actual trouble spot).
What ended up working for me was to create a thread, sleep 50ms, dispatch back to main thread and do what I need...
void Window_Loaded(object sender, RoutedEventArgs e)
{
new Thread(() =>
{
Thread.Sleep(50);
CrossThread(() => { OnWindowLoaded(); });
}).Start();
}
void CrossThread(Action a)
{
this.Dispatcher.BeginInvoke(a);
}
void OnWindowLoaded()
{
...do my thing...
This way studio would break right where an uncaught exception occurs.
A simple work-around could be if you can move your init code to another event like as Form_Shown which called later than Form_Load, and use a flag to run startup code at first form shown:
bool firstLoad = true; //flag to detect first form_shown
private void Form1_Load(object sender, EventArgs e)
{
//firstLoad = true;
//dowork(); //not execute initialization code here (postpone it to form_shown)
}
private void Form1_Shown(object sender, EventArgs e)
{
if (firstLoad) //simulate Form-Load
{
firstLoad = false;
dowork();
}
}
void dowork()
{
var f = File.OpenRead(#"D:\NoSuchFile756.123"); //this cause an exception!
}
When I create a new project, I get a strange behavior for unhandled exceptions. This is how I can reproduce the problem:
1) create a new Windows Forms Application (C#, .NET Framework 4, VS2010)
2) add the following code to the Form1_Load handler:
int vara = 5, varb = 0;
int varc = vara / varb;
int vard = 7;
I would expect that VS breaks and shows an unhandled exception message at the second line. However, what happens is that the third line is just skipped without any message and the application keeps running.
I don't have this problem with my existing C# projects. So I guess that my new projects are created with some strange default settings.
Does anyone have an idea what's wrong with my project???
I tried checking the boxes in Debug->Exceptions. But then executions breaks even if I handle the exception in a try-catch block; which is also not what I want. If I remember correctly, there was a column called "unhandled exceptions" or something like this in this dialog box, which would do excatly what I want. But in my projects there is only one column ("Thrown").
This is a nasty problem induced by the wow64 emulation layer that allows 32-bit code to run on the 64-bit version of Windows 7. It swallows exceptions in the code that runs in response to a notification generated by the 64-bit window manager, like the Load event. Preventing the debugger from seeing it and stepping in. This problem is hard to fix, the Windows and DevDiv groups at Microsoft are pointing fingers back and forth. DevDiv can't do anything about it, Windows thinks it is the correct and documented behavior, mysterious as that sounds.
It is certainly documented but just about nobody understands the consequences or thinks it is reasonable behavior. Especially not when the window procedure is hidden from view of course, like it is in any project that uses wrapper classes to hide the window plumbing. Like any Winforms, WPF or MFC app. Underlying issue is Microsoft could not figure out how to flow exceptions from 32-bit code back to the 64-bit code that triggered the notification back to 32-bit code that tries to handle or debug the exception.
It is only a problem with a debugger attached, your code will bomb as usual without one.
Project > Properties > Build tab > Platform target = AnyCPU and untick Prefer 32-bit. Your app will now run as a 64-bit process, eliminating the wow64 failure mode. Some consequences, it disables Edit + Continue for VS versions prior to VS2013 and might not always be possible when you have a dependency on 32-bit code.
Other possible workarounds:
Debug > Exceptions > tick the Thrown box for CLR exceptions to force the debugger to stop at the line of code that throws the exception.
Write try/catch in the Load event handler and failfast in the catch block.
Use Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException) in the Main() method so that the exception trap in the message loop isn't disabled in debug mode. This however makes all unhandled exceptions hard to debug, the ThreadException event is pretty useless.
Consider if your code really belongs in the Load event handler. It is very rare to need it, it is however very popular in VB.NET and a swan song because it is the default event and a double-click trivially adds the event handler. You only ever really need Load when you are interested in the actual window size after user preferences and autoscaling is applied. Everything else belongs in the constructor.
Update to Windows 8 or later, they have this wow64 problem solved.
In my experience, I only see this issue when I'm running with a debugger attached. The application behaves the same when run standalone: the exception is not swallowed.
With the introduction of KB976038, you can make this work as you'd expect again. I never installed the hotfix, so I'm assuming it came as part of Win7 SP1.
This was mentioned in this post:
The case of the disappearing OnLoad exception – user-mode callback exceptions in x64
Here's some code that will enable the hotfix:
public static class Kernel32
{
public const uint PROCESS_CALLBACK_FILTER_ENABLED = 0x1;
[DllImport("Kernel32.dll")]
public static extern bool SetProcessUserModeExceptionPolicy(UInt32 dwFlags);
[DllImport("Kernel32.dll")]
public static extern bool GetProcessUserModeExceptionPolicy(out UInt32 lpFlags);
public static void DisableUMCallbackFilter() {
uint flags;
GetProcessUserModeExceptionPolicy(out flags);
flags &= ~PROCESS_CALLBACK_FILTER_ENABLED;
SetProcessUserModeExceptionPolicy(flags);
}
}
Call it at the beginning of your application:
[STAThread]
static void Main()
{
Kernel32.DisableUMCallbackFilter();
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
I've confirmed (with the the simple example shown below) that this works, just as you'd expect.
protected override void OnLoad(EventArgs e) {
throw new Exception("BOOM"); // This will now get caught.
}
So, what I don't understand, is why it was previously impossible for the debugger to handle crossing kernel-mode stack frames, but with this hotfix, they somehow figured it out.
As Hans mentions, compile the application and run the exe without a debugger attached.
For me the problem was changing a Class property name that a BindingSource control was bound to. Running without the IDE I was able to see the error:
Cannot bind to the property or column SendWithoutProofReading on the
DataSource. Parameter name: dataMember
Fixing the BindingSource control to bind to the updated property name resolved the problem:
I'm using WPF and ran into this same problem. I had tried Hans 1-3 suggestions already, but didn't like them because studio wouldn't stop at where the error was (so I couldn't view my variables and see what was the problem).
So I tried Hans' 4th suggestion. I was suprised at how much of my code could be moved to the MainWindow constructor without any issue. Not sure why I got in the habit of putting so much logic in the Load event, but apparently much of it can be done in the ctor.
However, this had the same problem as 1-3. Errors that occur during the ctor for WPF get wrapped into a generic Xaml exception. (an inner exception has the real error, but again I wanted studio to just break at the actual trouble spot).
What ended up working for me was to create a thread, sleep 50ms, dispatch back to main thread and do what I need...
void Window_Loaded(object sender, RoutedEventArgs e)
{
new Thread(() =>
{
Thread.Sleep(50);
CrossThread(() => { OnWindowLoaded(); });
}).Start();
}
void CrossThread(Action a)
{
this.Dispatcher.BeginInvoke(a);
}
void OnWindowLoaded()
{
...do my thing...
This way studio would break right where an uncaught exception occurs.
A simple work-around could be if you can move your init code to another event like as Form_Shown which called later than Form_Load, and use a flag to run startup code at first form shown:
bool firstLoad = true; //flag to detect first form_shown
private void Form1_Load(object sender, EventArgs e)
{
//firstLoad = true;
//dowork(); //not execute initialization code here (postpone it to form_shown)
}
private void Form1_Shown(object sender, EventArgs e)
{
if (firstLoad) //simulate Form-Load
{
firstLoad = false;
dowork();
}
}
void dowork()
{
var f = File.OpenRead(#"D:\NoSuchFile756.123"); //this cause an exception!
}
I've been working on a BIG project (there's no point of showing any actual code anyway) and I've notice that the following message appears in the logs:
CoreText CopyFontsForRequest received mig IPC error (FFFFFFFFFFFFFECC) from font server
The error pops up as soon as a WebView has finished loading. And I kinda believe it's the culprit behind a tiny lag.
Why is that happening? What can I do to fix this?
P.S. Tried the suggested solution here to check whether it was something system-specific, but it didn't work.
More details:
The error appears when using the AMEditorAppearance.car NSAppearance file, from the Appearance Maker project. Disabling it (= not loading it all) makes the error go away.
I don't really care about the error message, other than that it creates some weird issues with fonts. E.g. NSAlert panels, with input fiels, show a noticeable flicker and the font/text seems rather messed up, in a way I'm not sure I can accurately describe. (I could post a video with that if that'd help)
This is probably related to system font conflicts and can easily be fixed:
Open Font book
Select all fonts
Go to the file menu and select "Validate fonts"
Resolve all font conflicts (by removing duplets).
Source: Andreas Wacker
Answer by #Abrax5 is excellent. I just wanted to add my experience with this problem and could not fit it into a comment:
As far as I can tell, this error is raised only on the first failed attempt to initialise an NSFont with a font name that is not available. NSFont initialisers are failable and will return nil in such a case at which time you have an opportunity to do something about it.
You can check whether a font by a given name is available using:
NSFontDescriptor(fontAttributes: [NSFontNameAttribute: "<font name>"]).matchingFontDescriptorWithMandatoryKeys([NSFontNameAttribute]) != nil
Unfortunately, this also raises the error! The following method does not, but is deprecated:
let fontDescr = NSFontDescriptor(fontAttributes: [NSFontNameAttribute: "<font name>"])
let isAvailable = NSFontManager.sharedFontManager().availableFontNamesMatchingFontDescriptor(fontDescr)?.count ?? 0 > 0
So the only way I found of checking the availability of a font of a given name without raising that error is as follows:
public extension NSFont {
private static let availableFonts = (NSFontManager.sharedFontManager().availableFonts as? [String]).map { Set($0) }
public class func available(fontName: String) -> Bool {
return NSFont.availableFonts?.contains(fontName) ?? false
}
}
For example:
NSFont.available("Georgia") //--> true
NSFont.available("WTF?") //--> false
(I'm probably overly cautious with that optional constant there and if you are so inclined you can convert the returned [AnyObject] using as! [String]...)
Note that for the sake of efficiency this will not update until the app is started again, i.e. any fonts installed during the app's run will not be matched. If this is an important issue for your particular app, just turn the constant into a computed property:
public extension NSFont {
private static var allAvailable: Set<String>? {
return (NSFontManager.sharedFontManager().availableFonts as? [String]).map { Set($0) }
}
private static let allAvailableAtStart = allAvailable
public class func available(fontName: String) -> Bool {
return NSFont.allAvailable?.contains(fontName) ?? false
}
public class func availableAtStart(fontName: String) -> Bool {
return NSFont.allAvailableAtStart?.contains(fontName) ?? false
}
}
On my machine available(:) takes 0.006s. Of course, availableAtStart(:) takes virtually no time on all but the first call...
This is caused by calling NSFont fontWithFamily: with a family name argument which is not available on the system from within Chromium's renderer process. When Chromium's sandbox is active this call triggers the CoreText error that you're observing.
It happens during matching CSS font family names against locally installed system fonts.
Probably you were working on a Chromium-derived project. More info can be found in Chromium Bug 452849.
The problem: I'm crashing when I want to render my incoming data which was retrieved asynchronously.
The app starts and displays some dialog boxes using XAML. Once the user fills in their data and clicks the login button, the XAML class has in instance of a worker class that does the HTTP stuff for me (asynchronously using IXMLHTTPRequest2). When the app has successfully logged in to the web server, my .then() block fires and I make a callback to my main xaml class to do some rendering of the assets.
I am always getting crashes in the delegate though (the main XAML class), which leads me to believe that I cannot use this approach (pure virtual class and callbacks) to update my UI. I think I am inadvertently trying to do something illegal from an incorrect thread which is a byproduct of the async calls.
Is there a better or different way that I should be notifying the main XAML class that it is time for it to update it's UI? I am coming from an iOS world where I could use NotificationCenter.
Now, I saw that Microsoft has it's own Delegate type of thing here: http://msdn.microsoft.com/en-us/library/windows/apps/hh755798.aspx
Do you think that if I used this approach instead of my own callbacks that it would no longer crash?
Let me know if you need more clarification or what not.
Here is the jist of the code:
public interface class ISmileServiceEvents
{
public: // required methods
virtual void UpdateUI(bool isValid) abstract;
};
// In main XAML.cpp which inherits from an ISmileServiceEvents
void buttonClick(...){
_myUser->LoginAndGetAssets(txtEmail->Text, txtPass->Password);
}
void UpdateUI(String^ data) // implements ISmileServiceEvents
{
// This is where I would render my assets if I could.
// Cannot legally do much here. Always crashes.
// Follow the rest of the code to get here.
}
// In MyUser.cpp
void LoginAndGetAssets(String^ email, String^ password){
Uri^ uri = ref new URI(MY_SERVER + "login.json");
String^ inJSON = "some json input data here"; // serialized email and password with other data
// make the HTTP request to login, then notify XAML that it has data to render.
_myService->HTTPPostAsync(uri, json).then([](String^ outputJson){
String^ assets = MyParser::Parse(outputJSON);
// The Login has returned and we have our json output data
if(_delegate)
{
_delegate->UpdateUI(assets);
}
});
}
// In MyService.cpp
task<String^> MyService::HTTPPostAsync(Uri^ uri, String^ json)
{
return _httpRequest.PostAsync(uri,
json->Data(),
_cancellationTokenSource.get_token()).then([this](task<std::wstring> response)
{
try
{
if(_httpRequest.GetStatusCode() != 200) SM_LOG_WARNING("Status code=", _httpRequest.GetStatusCode());
String^ j = ref new String(response.get().c_str());
return j;
}
catch (Exception^ ex) .......;
return ref new String(L"");
}, task_continuation_context::use_current());
}
Edit: BTW, the error I get when I go to update the UI is:
"An invalid parameter was passed to a function that considers invalid parameters fatal."
In this case I am just trying to execute in my callback is
txtBox->Text = data;
It appears you are updating the UI thread from the wrong context. You can use task_continuation_context::use_arbitrary() to allow you to update the UI. See the "Controlling the Execution Thread" example in this document (the discussion of marshaling is at the bottom).
So, it turns out that when you have a continuation, if you don't specify a context after the lambda function, that it defaults to use_arbitrary(). This is in contradiction to what I learned in an MS video.
However by adding use_currrent() to all of the .then blocks that have anything to do with the GUI, my error goes away and everything is able to render properly.
My GUI calls a service which generates some tasks and then calls to an HTTP class that does asynchronous stuff too. Way back in the HTTP classes I use use_arbitrary() so that it can run on secondary threads. This works fine. Just be sure to use use_current() on anything that has to do with the GUI.
Now that you have my answer, if you look at the original code you will see that it already contains use_current(). This is true, but I left out a wrapping function for simplicity of the example. That is where I needed to add use_current().
I'm currently developing a camera application for Android on which some problems have occurred. I need it to work on all Android devices and since all of these works in different ways specially with the camera hardware, I'm having a hard time finding a solution that works for every device.
My application main goal is to launch the camera on a button click, take a photo and upload it to a server. So I don't really need the functionality of saving the image on the device, but if that's needed for further image use I might as well allow it.
For example I'm testing my application on a Samsung Galaxy SII and a Motorola Pad. I got working code that launches the camera, which is by the way C# code since I'm using Monodroid:
Intent cameraIntent = new Intent(Android.Provider.MediaStore.ActionImageCapture);
StartActivityForResult(cameraIntent, PHOTO_CAPTURE);
And I fetch the result, similar to this guide I followed:
http://kevinpotgieter.wordpress.com/2011/03/30/null-intent-passed-back-on-samsung-galaxy-tab/
Why I followed this guide is because the activity returns null on my galaxy device (Another device oriented problem).
This code works fine on the Galaxy device. It takes a photo and saves the photo in the gallery from which i can upload to a server. By further research this is apparently galaxy standard behaviour, so this doesn't work on my Motorola pad. The camera works fine, but no image is saved to gallery.
So with this background my question is, am I on the right path here? Do I need to save the image to gallery in order for further use in my application? Is there any solution that works for every Android device, cause that's the solution i need.
Thanks for any feedback!
After reading the linked article, the approach taken in that article is geared toward the Galaxy line, since they appear to write to the gallery automatically.
This article discusses some other scenarios in detail:
Android ACTION_IMAGE_CAPTURE Intent
So, I don't necessarily think that following the linked article that you provided is the right path. Not all devices automatically write to the gallery as described in that article, afaik. The article I linked to points to the issues being related to security and suggests writing the image to a /sdcard/tmp folder for storing the original image. Going down a similar path would more than likely lead to code that is going to work reliably across many devices.
Here are some other links for reference:
Google discussion regarding this subject: http://code.google.com/p/android/issues/detail?id=1480
Project with potential a solution to the problem: https://github.com/johnyma22/classdroid
While that discussion/project are in Java/Android SDK, the same concepts should apply to Monodroid. I'd be happy to help you adapt the code to a working Mono for Android solution if you need help.
To long2know:
Yes the same concepts applies to Monodroid. I've already read the stack article you linked among with some other similar. However i don't like the approach in that particular post since it checks for bugs for some devices that are hardcoded into a collection. Meaning it might fail to detect bugs in future devices. Since i won't be doing maintenance on this application, i can't allow this. I found a solution elsewhere and adapted it to my case and i'll post it below if someone would need it. It works on both my devices, guessing it would work for the majority of other devices. Thanks for your post!
Solution that allows you to snap a picture and use, also with the option of using a image from gallery. Solution uses option menu for these purposes, just for testing. (Monodroid code).
Camera code is inspired by:
access to full resolution pictures from camera with MonoDroid
namespace StackOverFlow.UsingCameraWithMonodroid
{
[Activity(Label = "ImageActivity")]
public class ImageActivity
private readonly static int TakePicture = 1;
private readonly static int SelectPicture = 2;
private string imageUriString;
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
this.SetContentView(Resource.Layout.ImageActivity);
}
public override bool OnCreateOptionsMenu(IMenu menu)
{
MenuInflater flate = this.MenuInflater;
flate.Inflate(Resource.Menu.ImageMenues, menu);
return base.OnCreateOptionsMenu(menu);
}
public override bool OnOptionsItemSelected(IMenuItem item)
{
switch (item.ItemId)
{
case Resource.Id.UseExisting:
this.SelectImageFromStorage();
return true;
case Resource.Id.AddNew:
this.StartCamera();
return true;
default:
return base.OnOptionsItemSelected(item);
}
}
private Boolean isMounted
{
get
{
return Android.OS.Environment.ExternalStorageState.Equals(Android.OS.Environment.MediaMounted);
}
}
private void StartCamera()
{
var imageUri = ContentResolver.Insert(isMounted ? MediaStore.Images.Media.ExternalContentUri
: MediaStore.Images.Media.InternalContentUri, new ContentValues());
this.imageUriString = imageUri.ToString();
var cameraIntent = new Intent(MediaStore.ActionImageCapture);
cameraIntent.PutExtra(MediaStore.ExtraOutput, imageUri);
this.StartActivityForResult(cameraIntent, TakePicture);
}
private void SelectImageFromStorage()
{
Intent intent = new Intent();
intent.SetType("image/*");
intent.SetAction(Intent.ActionGetContent);
this.StartActivityForResult(Intent.CreateChooser(intent,
"Select Picture"), SelectPicture);
}
// Example code of using the result, in my case i want to upload in another activity
protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
// If a picture was taken
if (resultCode == Result.Ok && requestCode == TakePicture)
{
// For some devices data can become null when using the camera activity.
// For this reason we save pass the already saved imageUriString to the upload activity
// in order to adapt to every device. Instead we would want to use the data intent
// like in the SelectPicture option.
var uploadIntent = new Intent(this.BaseContext, typeof(UploadActivity));
uploadIntent.PutExtra("ImageUri", this.imageUriString);
this.StartActivity(uploadIntent);
}
// User has selected a image from storage
else if (requestCode == SelectPicture)
{
var uploadIntent = new Intent(this.BaseContext, typeof(UploadActivity));
uploadIntent.PutExtra("ImageUri", data.DataString);
this.StartActivity(uploadIntent);
}
}
}
}