Develop Reference

How can a widely used custom button track which class its onclick is called from?

In my application, I have a custom button that is used in many different custom views.
The behavior differs very slightly depending on which view the button was clicked in, I want to have one #OnClick implementation in my custom button class that takes care of every case in order to avoid having similar code in every custom view class.
Is there a way I can determine in the #OnClick block where the button was clicked from?
It looks something like
public class customButton extends appcompactimagebutton {
//stuff
#OnClick
public void onbuttonclick(){
//handles general behavior
//if (clicked from customViewA) {
//do A stuff
//}
}
}
and then I have customViewA that has a customButton within it, I'm not sure what to put in the if statement, if that's even a proper way to handle something like this

You can use the tag attribute. In your XML layouts, add a line
android:tag="viewname"
to the XML for the button (in code you can do .setTag("viewname"). You can then just modify your onClick to check the tag using this.getTag() and use that to identify where the click came from.

Adding functionality to onClick in Android

I want to run a function each time a button is pressed in my app. I know I can make a new button which extends Android's button and override onClick() but I have already made my entire app and want this new functionality as an afterthought. Can I somehow add this functionality without changing the class of all buttons in my app?
Lets say I want to add something like
runthisfunction();
before every onClick() code executes. There are many buttons in various activities and so they have their own onClick functions.
Is there a way that this function is run before each and every onClick() without the need to make a new class and changing all the existing buttons.

Add to your xml resource for whatever button/view you want to have an onClick listener:
android:onClick="fncClick"
For example:
<Button
android:id="#+id/btnClicker"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="fncClick" />
Then in the activity that utilizes that xml resource, include:
public void fncClick(View view) {
//TODO: Code here
}
This ONLY attaches an onClick listener for this specific button - not all buttons

Make Button in Android to repeat process inside activity until counter reaches certain number

I currently have Button in my main view which checks if users answer is correct.
Button CheckButton= (Button) this.findViewById(R.id.CheckButton);
CheckButton.setOnClickListener(new OnClickListener()
{
public void onClick(View v) {
// some action, setting text
}
});
If button is pressed once it checks if answer is correct, and if button is pressed second time I want it to repeat activity e.g. present user with another question.
OnClickListener is inside onCreate method and question is generated using switch and unique id (for game difficulty).
What would be the best way to set this repeat activity until it's been repeated 4 times. Thanks
switch (difficulty_level)
{
case DIFFICULTY_HARD:
// do this
case DIFFICULTY_EASY:
// do this
}

To me, this doesn't sound like logic belonging in the OnClickListener at all. The listener should simply register the click and then call a function in your activity "handleButtonClicked" that have access to fields that keep track of the number of clicks for the question, if the answer is correct and what the appropiate action is.
The fact that the OnClickListener is set in the onCreate only says that it is ready to be used after OnCreate. It doesn't require the OnCreate to be run again.

Instead of an anonymous inner implementation of OnClickListener, define it as a private class.
That way you can pass the parameter of how many iterations you want in its constructor / setter
Each time the application is launched, increase a counter; when such counter is bigger or equal than the said parameters, ignore the following clicks

You need a global state variable that you set when the click has occured twice, or you could just count and every even number you change the question by loading another activity.

Which is better in implementing click listener?

Which is a good practice in implementing click listener and why? Or is there a better way other than the two? Thanks.
First :
sampleButton.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
// do something
}
});
Second : implement OnClickListener then override onClick method?

The third option is to set the listener directly in your XML layout:
android:onClick="myClickHandler"
and then implement it in your Activity:
public void myClickHandler(View v){
// do something
}

You're technically doing the 2nd thing with the 1st one. The 1st case uses whats called an anonymous class which implements OnClickListener, but since is anonymous, doesn't have a class name and isn't editable from external classes. Explicitably implementing OnClickListener is useful if you expect to use the same onClick functionality in multiple different locations, or if the click code is long

The first approach is used when you want to perform the action only for a particular case, if many click events require the same action then use the second one.

Is it possible to chain event listeners in Android?

I have an activity which contains QuickContactBadges. I'm looking for a way to either chain event listeners on the QuickContactBadge, or to call the default listener from within an override.
Specifically, what I am looking to do is have the QuickContactBadge, when clicked to show the QuickContact card, and then to setResult and finish, to close my activity.
So either I want to add a second listener to the badge in addition to the default one, or implement something like the following:
bdg.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
QuickContactBadge bdg = (QuickContactBadge) view;
bdg.base.onClick(); // PSEUDO-CODE LINE
setResult(RESULT_CANCELED, null);
finish();
}
});
Are either of these methods possible, or is there some other way I should be doing this?

Well, the answer to what I was trying to do was not actually in an event listener at all.
The key to getting my activity to close when the QuickBadge is clicked was to add android:noHistory="true" to the activity definition in the application manifest file.
Though, it would still be interesting to know yes/no if there is a way to chain event listeners.