How to handle uncaughtErrorEvent & Exception to write a log in NativeScript? - nativescript

Question

var application = require("application");
application.on(application.uncaughtErrorEvent, function (args) {
if (args.android) {
// For Android applications, args.android is an NativeScriptError.
console.log("NativeScriptError: " + args.android);
} else if (args.ios) {
// For iOS applications, args.ios is NativeScriptError.
console.log("NativeScriptError: " + args.ios);
}
});
I tried above example in {N}#2.0.1 but it does not work for me.
Can you explain more detail?

Answer 1

Answered in NativeScript github repository enter link description here as follows:
application.uncaughtErrorEvent will trigger whenever your app is crashing and the cause is not handled.
For example:
if you try to initialize an android button with null context like this in your main-page.js it will throw an error
in main-page.js
var btn = new android.widget.Button(null);
What you can do to catch this error is to use uncaughtErrorEvent
in app.js
"use strict";
var application = require("application");
application.on(application.uncaughtErrorEvent, function (args) {
if (args.android) {
// For Android applications, args.android is an NativeScriptError.
console.log(" *** NativeScriptError *** : " + args.android);
console.log(" *** StackTrace *** : " + args.android.stackTrace);
console.log(" *** nativeException *** : " + args.android.nativeException);
}
else if (args.ios) {
// For iOS applications, args.ios is NativeScriptError.
console.log("NativeScriptError: " + args.ios);
}
});
application.start({ moduleName: "main-page" });
From the log you can see the following information:
NativeScriptError : Error: The application crashed because of an uncaught exception.
from the stackTrace you can see the cause of this error :
Attempt to invoke virtual method 'android.content.res.Resources
android.content.Context.getResources()' on null reference object
You also have a pointer where the error has occured:
Frame: function:'navigatingTo', `file:'/data/data/org.nativescript.cameraUpload/files/app/main-page.js',
line: 11, column: 15`