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How to properly terminate an activity from a custom view class?

Similar to this post. Have a custom view (extends EditText) which must have the ability to call the finish() method of the parent activity if the user presses the END key.
How can I access the activity object of the host activity in order to call its finish() method from within the custom view class?
public class SuppressInputEditText extends androidx.appcompat.widget.AppCompatEditText {
public SuppressInputEditText(Context context) {
super(context);
}
public SuppressInputEditText(Context context, AttributeSet attrs) {
super(context, attrs);
}
public SuppressInputEditText(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#Override
public boolean onKeyPreIme(int keyCode, KeyEvent event) {
return true;
}
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
return true;
}
#Override
public boolean onKeyUp(int keyCode, KeyEvent event) {
switch (keyCode){
case 6: //end key
//todo: call finish() method of parent activity.
break;
}
return true;
}
}
I can use the getContext() method of my class, available because it inherits from view, to get a context, but I don't know how to use that to access the finish() method. Any help or pointers would be greatly appreciated.
UPDATE:
Looking for a solution that can keep the class independent. Thanks!

if you know the host i.e the activity where it's custom view is showing then you can do something like this.
(getContext() as? MainActivity)?.finish()
java
((MainActivity)getContext()).finish()
place this under try and catch
Edit: Create an interface which your Host activity implements and pass this as a listener yo your custom view then whenever needed to call this.
for ex.
interface CustomInputEditListener{
public void onFinish();
}
in your Host activity implement this.
MainActivity extends AppCompatActivity() implements CustomInputEditListener{
//call this from onCreate()
public void setHostListener(){
suppressInputEditText.setHostEditListener(this);
}
#Override public void onFinish(){
finish() ;
}
}
in your SuppressInputEditText class create a method like this.
public void setHostEditListener(CustomInputEditListener listener){
this.hostListener = listener;
}
and whenever you need to call finish just call
hostListener.onFinish();

Cast context to Activity then call finish like below
Kotlin
(context as? Activity)?.finish()
Java
((Activity) context).finish()

Android - How to call method in custom View from Main Activity?

I have created a custom View that will display a circle (the idea is that the user will be able to interact with this "ball" in various ways)
From my main activity class, I want to adjust some of the "ball's" properties, in this case change its color.
My problem is that nothing happens (no errors either, the app runs but doesn't do what I want) when I try to call the various methods from my MainActivity class, but if I do it from CircleView class, it works (for example changing the color upon touch)
Here is my custom View class (CircleView.java):
public class CircleView extends View {
private int circleColor = Color.GREEN;
private Paint paint;
public CircleView(Context context) {
super(context);
init(context, null);
}
#Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_SCROLL:
this.circleColor = setRandomColor();
invalidate();
break;
case MotionEvent.ACTION_DOWN:
this.circleColor = setRandomColor();
invalidate();
break;
}
return super.onTouchEvent(event);
}
public CircleView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context, attrs);
}
private void init(Context context, AttributeSet attrs) {
paint = new Paint();
paint.setAntiAlias(true);
}
public void setCircleColor(int circleColor) {
this.circleColor = circleColor;
invalidate();
}
public int setRandomColor() {
Random random = new Random();
int randomColor = Color.argb(255, random.nextInt(), random.nextInt(), random.nextInt());
return randomColor;
}
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
//...
//someXvalue, someYvalue, someRadius are being set here
//...
paint.setColor(circleColor);
canvas.drawCircle(someXvalue, someYvalue, someRadius, paint);
}
}
And here is my MainActivity.java class:
public class MainActivity extends Activity implements
GestureDetector.OnGestureListener {
private GestureDetectorCompat mDetector;
CircleView circle;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mDetector = new GestureDetectorCompat(this, this);
circle = new CircleView(this);
}
#Override
public boolean onTouchEvent(MotionEvent event) {
this.mDetector.onTouchEvent(event);
return super.onTouchEvent(event);
}
#Override
public boolean onDown(MotionEvent event) {
return true;
}
#Override
public boolean onSingleTapConfirmed(MotionEvent event) {
circle.setCircleColor(circle.setRandomColor(0));
circle.invalidate();
return true;
}
}
I am new to Android development, and Java as well. I realize it could be something with the Context, which is something I have not fully understood yet. Could also be something with the TouchEvents. I am sure that someone out there can see my mistake. Any help is appreciated.

your circle view is not a part of activity's layout , it's just a object in memory which has no link to your activity screen so solutions
1.) Either set circle as Activity's view
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mDetector = new GestureDetectorCompat(this, this);
circle = new CircleView(this);
setContentView(circle);
}
2.) you can create your <yourpackagename.CircleView ...attributes .../> tag in your activity_main.xml and then use findViewById to initialize it in your activity.

1)If all you want to do with gestures is on tap, just implement an onClickListener on your View instead.
2)You aren't actually using the GestureDetector anywhere. The way it works is you set an onTouchListener for the view you want to get gestures on, and send the events to the gesture detector. You aren't ever sending data for any view to the detector, so it will never do anything.
3)Not a bug just an oddness- why circle.setColor(circle.setRandomColor())? I would expect a function named setXXX to actually set XXX, rather than having to do it yourself later. Not following that convention will work, but make debugging and maintenance hard.
Edit: Also what #Pavneet_Singh said- your circle isn't in your layout anywhere, so it won't be on screen.

GestureOverlayView: changing gesture color while swiping

I have only a simple MyGestureOverlayView extends GestureOverlayView in my layout; I want that when the user swipes and the GestureOverlayView recognizes the gesture, it doesn't change color. I want that the color will change only when I call overlay.setGestureColor(int color), but in fact this method changes the color that will have the next gesture when recognized by the super class, not while the user is swiping.
So my question is: how can I change the color of the gesture while the user is performing the gesture?
public class MyGestureOverlayView extends GestureOverlayView implements
GestureOverlayView.OnGesturePerformedListener,
GestureOverlayView.OnGestureListener {
private static final String TAG = MyGestureOverlayView.class.getName();
private GiocoActivity mContext;
private boolean mRecognized;
private GestureLibrary gestures;
public MyGestureOverlayView(Context context, AttributeSet attrs) {
super(context, attrs);
if (context instanceof GiocoActivity)
mContext = (GiocoActivity) context;
gestures = GestureLibraries.fromRawResource(mContext, R.raw.gesture);
if (!gestures.load())
mContext.finish();
addOnGesturePerformedListener(this);
addOnGestureListener(this);
}
#Override
public void onGesturePerformed(GestureOverlayView overlay, Gesture gesture) {
ArrayList<Prediction> predictions = gestures.recognize(gesture);
Log.d(TAG, "Gesture riconosciuta!");
// Sorry for my English :)
if (predictions.size() > 0 && predictions.get(0).score > 3.0) {
overlay.setGestureColor(Color.GREEN);
// The color doesn't change here, but it will change in the next gesture
String action = predictions.get(0).name;
mRecognized = true;
Toast.makeText(mContext, action, Toast.LENGTH_SHORT).show();
}
else {
overlay.setGestureColor(Color.RED);
// The color doesn't change here, but it will change in the next gesture
mRecognized = false;
}
Log.d(TAG, "Fine riconoscimento Gesture; esito: "+ mRecognized);
}
#Override
public void onGestureStarted(GestureOverlayView overlay, MotionEvent event) {
Log.d(TAG, "Gesture iniziata!");
}
#Override
public void onGesture(GestureOverlayView overlay, MotionEvent event) {
Log.d(TAG, "Gesture in corso!");
if (mRecognized) // Always false for the first gesture
overlay.setGestureColor(Color.GREEN); // Same as before
else
overlay.setGestureColor(Color.RED); // Same as before
}
#Override
public void onGestureEnded(GestureOverlayView overlay, MotionEvent event) {
Log.d(TAG, "Gesture finita!");
}
#Override
public void onGestureCancelled(GestureOverlayView overlay, MotionEvent event) {
Log.d(TAG, "Gesture cancellata!");
}
}
Besides, the callback method onGesturePerformed is called after onGestureEnded, so the boolean mRecognized in onGesture() is always false whem I perform a gesture for the first time and when it'll be recognized from the super class it'll be displayed red in any case (both recognized or not by my onGesturePerformedListener).
Sorry if I was complicate, this is my first question, and I found only one question similar to this, but it has no answers.
Thanks for your time.

Android adding onClick on soft keyboard on activity

I am trying to add an onClick on the soft keyboard for an activity. The reason why is that i want to check if the user is currently active. So what i have done is that if the user clicks on the app i will reset a inactivity timer. The problem is that when a user interacts with the soft keyboard it doesn't call the function onUserInteraction() which is a function I override in the activity. So i need help to find a way to keep track if the soft keyboard has been clicked for every textfield etc I have in the activity. (I know that i can insert a onclick listerner on every EditText field but i rather not do that, because if I would use many EditText fields it would not be so nice)

So this is what i ended up with. I was hoping for something else, but this solves the problem. Thanks for the help!
public class ActivityEditText extends android.support.v7.widget.AppCompatEditText {
private TextWatcher tw;
public ActivityEditText(Context c)
{
super(c);
this.setOurTCL();
}
public ActivityEditText(Context context, AttributeSet attrs) {
super(context, attrs);
this.setOurTCL();
}
public ActivityEditText(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
this.setOurTCL();
}
private void setOurTCL()
{
this.tw = new TextWatcher() {
#Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
InactivityManager.resetTime();
}
#Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
}
#Override
public void afterTextChanged(Editable s) {
}
};
this.addTextChangedListener(this.tw);
}
#Override
public void removeTextChangedListener(TextWatcher watcher) {
if(!watcher.equals(this.tw))
super.removeTextChangedListener(watcher);
}
}

To handle an individual key press, implement onKeyDown() or onKeyUp() as appropriate. Usually, you should use onKeyUp() if you want to be sure that you receive only one event. If the user presses and holds the button, then onKeyDown() is called multiple times.

Create a class some thing like UserInteractionEditText and extend EditText and set the onclick lisetener in that class use that class in all the XML layouts as you use EditText you can do some thing like this:
public class UserInteractionEditText extends EditText implements View.OnClickListener {
public UserInteractionEditText(Context context) {
super(context);
}
public UserInteractionEditText(Context context, AttributeSet attrs) {
super(context, attrs);
}
public UserInteractionEditText(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#Override
public void onClick(View v) {
//TODO:: Handle user Click Events
}
}

You can use onUserInteraction() function of activity. You need to override this function in your activity.
This function get calls when you perform any kind of interaction with your activity.
#Override
public void onUserInteraction() {
super.onUserInteraction();
// Your code goes here
}
You can refer this example and also this answer, refer the docs here
Hope this helps.

Countdown on Button - Android

I want to implement a button that counts down when pressed. The idea is to allow the user to cancel the activation of the button. Once pressed, I would like for the button to change to red and read "CANCEL (3)" and countdown to "CANCEL (0)" and if it is pressed again, the countdown will stop and nothing will happen. If it is not canceled, the app will go to the next screen after time expires. Is there a way to update a button's text each second (for the countdown) and change its functionality?
Thanks

You can use postDelayed on a Handler to invoke your method later on the UI thread so that you can update the UI.
There's actually a very nice article about how this is done on Android already: http://developer.android.com/resources/articles/timed-ui-updates.html
You can get a Handler either by creating one in code running on the UI thread, or by calling getHandler() on a view (e.g. your button itself).
I'd provide an example, but the article linked already does so with great detail and clarity, so I'll defer to it.
Edit: here's a rough overview of how this will look. I don't have the Android SDK installed right now, so I can't verify that this works.
public class CountdownButton extends Button {
private boolean isCounting = false;
private int count;
private final Runnable countdownRunnable = new Runnable() {
#Override
public void run() {
setText(Integer.toString(count));
if (count > 0) {
count--;
getHandler().postDelayed(countdownRunnable, 1000);
} else {
// count reached zero
isCounting = false;
setText("boom");
}
}
}
private final View.OnClickListener onClickListener = new View.OnClickListener() {
#Override
public void onClick(View view) {
if (isCounting) {
// stop counting
isCounting = false;
getHandler().removeCallbacks(countdownRunnable);
setText("cancelled");
} else {
// start counting
isCounting = true;
count = 10;
countdownRunnable.run();
}
}
}
public CountdownButton(Context context) {
super(context);
setOnClickListener(onClickListener);
}
public CountdownButton(Context context, AttributeSet attrs) {
super(context, attrs);
setOnClickListener(onClickListener);
}
public CountdownButton(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
setOnClickListener(onClickListener);
}
}
The timing may not be perfect (especially if there's a lot of other CPU work going on), but it should be good enough for your purposes.