c# - Xamarin Android KitKat Object reference not set to an instance of an object -

i've installed xamarin in vs2017 (15.3).

following https://developer.xamarin.com/guides/android/platform_features/introduction_to_kitkat/ , https://developer.xamarin.com/guides/android/getting_started/hello,android/hello,android_quickstart/

the project file has application android compile version set android 4.4 (kit kat). android manifest min , target version both set android 4.4 (api level 19 - kit kat)

for debugger have selected

5" kitkat (4.4) xxhdpi phone (android 4.4 - api 19). 

(7" tablet did not work).

when build/rebuild get:

1>------ rebuild started: project: phoneword, configuration: debug cpu ------ 1>    processing: obj\debug\res\layout\main.xml 1>    processing: obj\debug\res\values\strings.xml 1>  phoneword -> e:\source\workspaces\phoneword\phoneword\bin\debug\phoneword.dll 1>    processing: obj\debug\res\layout\main.xml 1>    processing: obj\debug\res\values\strings.xml 1>    processing: obj\debug\res\layout\main.xml 1>    processing: obj\debug\res\values\strings.xml ========== rebuild all: 1 succeeded, 0 failed, 0 skipped ========== 

when try debug get: "there deployment errors. continue?"

1>------ build started: project: phoneword, configuration: debug cpu ------

1>  phoneword -> e:\source\workspaces\phoneword\phoneword\bin\debug\phoneword.dll 2>starting deploy 5" kitkat (4.4) xxhdpi phone ... 2>starting emulator 5" kitkat (4.4) xxhdpi phone ... 2>an error occured. see full exception on logs more details. 2>object reference not set instance of object. ========== build: 1 succeeded, 0 failed, 0 up-to-date, 0 skipped ========== ========== deploy: 0 succeeded, 1 failed, 0 skipped ========== 

error list:

ide0006 error encountered while loading project. project features, such full solution analysis failed project , projects depend on it, have been disabled. 

in log (help > xamarin > open logs) see:

 system.nullreferenceexception: object reference not set instance of object.  @ microsoft.visualstudio.shell.threadhelper.get_joinabletaskcontext()  @ microsoft.visualstudio.emulator.utilities.vstelemetryhelper.logevent(iserviceprovider serviceprovider, string eventpath, idictionary`2 properties)  @ microsoft.visualstudio.emulator.logging.vsemulatortelemetrylogger.logevent(string eventname, idictionary`2 properties)  @ microsoft.visualstudio.emulator.logging.devicetelemetrylogger.logevent(string eventname, idictionary`2 properties)  @ microsoft.visualstudio.emulator.emulatorservice.<>c__displayclass3_0.<startasync>b__0()  @ system.threading.tasks.task`1.innerinvoke()  @ system.threading.tasks.task.execute()  --- end of stack trace previous location exception thrown ---  @ system.runtime.compilerservices.taskawaiter.throwfornonsuccess(task task)  @ system.runtime.compilerservices.taskawaiter.handlenonsuccessanddebuggernotification(task task)  @ xamarin.visualstudio.android.devices.microsoftandroiddeviceprovider.<>c__displayclass18_0.<<startemulator>b__0>d.movenext() in c:\d\lanes\4985\306f76ac\source\xamarinvs\src\core\visualstudio.android\devices\microsoftandroiddeviceprovider.cs:line 114  --- end of stack trace previous location exception thrown ---  @ system.runtime.compilerservices.taskawaiter.throwfornonsuccess(task task)  @ system.runtime.compilerservices.taskawaiter.handlenonsuccessanddebuggernotification(task task)  @ microsoft.visualstudio.threading.joinabletask.completeoncurrentthread()  @ microsoft.visualstudio.threading.joinabletask`1.completeoncurrentthread()  @ microsoft.visualstudio.threading.joinabletaskfactory.run[t](func`1 asyncmethod, joinabletaskcreationoptions creationoptions)  @ merq.asyncmanager.run[t](func`1 asyncmethod) in c:\projects\merq\src\async\merq.async.core\merq.async.core.portable\asyncmanager.cs:line 64  @ xamarin.visualstudio.android.devices.microsoftandroiddeviceprovider.startemulator(iandroidvirtualdevice virtualdevice, iprogressreport progress, cancellationtoken cancellationtoken) in c:\d\lanes\4985\306f76ac\source\xamarinvs\src\core\visualstudio.android\devices\microsoftandroiddeviceprovider.cs:line 114  @ xamarin.visualstudio.android.commandhandlers.startupvirtualdevicecommandhandler.startup(imonoandroiddevice device, iprogressreport progress, iandroidvirtualdeviceprovider virtualdeviceprovider, cancellationtoken cancellationtoken) in c:\d\lanes\4985\306f76ac\source\xamarinvs\src\core\visualstudio.android\commandhandlers\startupvirtualdevicecommandhandler.cs:line 75  @ xamarin.visualstudio.android.commandhandlers.startupvirtualdevicecommandhandler.execute(startupvirtualdevicecommand command, iprogressreport progress, cancellationtoken cancellationtoken) in c:\d\lanes\4985\306f76ac\source\xamarinvs\src\core\visualstudio.android\commandhandlers\startupvirtualdevicecommandhandler.cs:line 48  @ xamarin.visualstudio.commands.commandhandlerbase`2.execute(tcommand command, cancellationtoken cancellationtoken) in c:\d\lanes\4985\306f76ac\source\xamarinvs\src\core\visualstudio\commands\commandhandlerbase.cs:line 151  @ xamarin.visualstudio.commands.commandhandlerbase`2.<>c__displayclass1_0.<executeasync>b__0() in c:\d\lanes\4985\306f76ac\source\xamarinvs\src\core\visualstudio\commands\commandhandlerbase.cs:line 117  @ system.threading.tasks.task`1.innerinvoke()  @ system.threading.tasks.task.execute() --- end of stack trace previous location exception thrown ---    @ system.runtime.compilerservices.taskawaiter.throwfornonsuccess(task task)  @ system.runtime.compilerservices.taskawaiter.handlenonsuccessanddebuggernotification(task task)  @ xamarin.visualstudio.android.commandhandlers.deploycommandhandler.<>c__displayclass19_0.<<startupvirtualdeviceanddeploy>b__0>d.movenext() in c:\d\lanes\4985\306f76ac\source\xamarinvs\src\core\visualstudio.android\commandhandlers\deploycommandhandler.cs:line 240 

when opening main.axml get:

mono.android.designerexception: java.lang.illegalstateexception @ mono.android.designerexception.fromthrowable(designerexception.java:46) @ mono.android.designersession.checkrenderresultforerror(designersession.java:187) @ mono.android.designersession.load(designersession.java:239) @ mono.android.designersession.processmessage(designersession.java:704) @ mono.android.messagelistener.executemessage(messagelistener.java:88) @ mono.android.messagelistener$runner.run(messagelistener.java:44) @ java.lang.thread.run(thread.java:748) caused by: java.lang.illegalstateexception: main looper has been prepared. @ android.os.looper.preparemainlooper(looper.java:104) @ com.android.layoutlib.bridge.bridge.preparethread(bridge.java:544) @ com.android.layoutlib.bridge.bridge.createsession(bridge.java:426) @ com.android.ide.common.rendering.layoutlibrary.createsession(layoutlibrary.java:368) @ mono.android.designersession.load(designersession.java:233) ... 4 more 

any suggestions? android sdk manager have installed android sdk build-tools 19.1 , android 4.4.2 (api 19).

(19.1 because 19.0.3 / 19.0.2 / 19.0.1 / 19 obsolete).

any suggestions on how working?

(needed write app on samsung sm-t560 android 4.4.4)

think fixed - launch "visual studio emulator android" manually start menu/app list, launch 1 you're after manually within vs emulator tool, fires , initialises it. next time tried within vs worked ok. can use emulator ui download other profiles , api levels well, these show in vs2017 start/debug dropdown options.