As I work on developing an Android app using HTML5/JavaScript, I've encountered some limitations. One challenge I face is calling a function implemented in Java code from within JavaScript, specifically to create a particular type of dialog. While the process seems straightforward, there are nuances involved:
public class MyClass () {
// other stuff
public void createMyDialog (/* arguments */) {
DialogBuilder builder = ...
builder.setItems(myItems, new DialogInterface.OnClickListener () {
@Override
public void OnClick (DialogInterface dialog, int which) {
droidGap.loadUrl(/* what now? */);
}
});
}
}
To expose this class to JavaScript, the following steps can be followed:
MyClass myClass = new MyClass();
appView.addJavascriptInterface(myClass, "myClass");
Although this setup allows for access to window.myClass.createMyDialog() from JavaScript, I desire to include a callback function that would receive the which variable as an argument. This requires modifying the method signature to:
public void createMyDialog (final String callback)
and invoking it with something like
window.myClass.createMyDialog(
function (which) {
alert(which);
}
);
I have managed to make this work by passing the function as a string and then executing
appView.loadUrl("javascript:(" + callback + ")(" + which + ");");createMyDialog from JavaScript within a class context, such as:
function myJSClass () {
this.myVar = -1;
this.myFunc = function () {
window.myClass.createMyDialog(
function (which) {
this.myVar = which;
}
);
}
}
var myObj = new myJSClass();
myObj.myFunc();
The issue arises when trying to reference this, which ends up pointing to window instead of the intended class instance due to the call originating from Java. Various solutions like storing var _this = this or utilizing bind have not proven effective in preserving the correct context.
I am aware that frameworks like PhoneGap offer functionalities similar to what I'm attempting with navigator.notification.confirm. So, what would be the recommended approach in this scenario?
Your insights are greatly appreciated!