I want to create an Android Application that use scrollView, but i don't want to scroll it with drag on the screen, but i want to scroll it with a button. my first question is how to disable all of touch on the scrollView, so it won't scroll when user touch on it?
and the second how to scrool with a button? for the second question, i try to use scrollTo() method. so this is my code on the button
public void UpCLick(View view){
currentY=currentY - 1;
vertScroll.scrollTo(currentX,currentY);
}
public void DownCLick(View view){
currentY=currentY + 1;
vertScroll.scrollTo(currentX,currentY);
}
but it always get stopped. FYI currentX, and currentY is an Integer variable.
extend ScrollView and override onTouchEvent() in ScrollView. don't call super method in it.
#Override
public boolean onTouchEvent(MotionEvent event) {
// super.onTouchEvent(event); // don't do this
return true;
}
and use ScrollView.scrollBy(int,int) method for scrolling.
Related
I have a RecyclerView (with LinearLayoutManager) and a custom RecyclerView.ItemDecoration for it.
Let's say, I want to have buttons in the decoration view (for some reason..).
I inflate the layout with button, it draws properly. But I can't make the button clickable. If I press on it, nothing happening(it stays the same, no pressing effect) and onClick event is not firing.
The structure of ItemDecoration layout is
<LinearLayout>
<TextView/>
<Button/>
</LinearLayout>
And I'm trying to set listener in ViewHolder of the decoration
class ItemDecorationHolder extends RecyclerView.ViewHolder {
public TextView header;
public Button button;
public HeaderHolder(View itemView) {
super(itemView);
header = (TextView)itemView.findViewById(R.id.header);
button = (Button)itemView.findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
//.. Show toast, etc.
}
});
}
}
And i'm drawing the decoration in onDrawOver method. (actually, I'm modifying this codebase: https://github.com/edubarr/header-decor )
Any ideas? Is it doable?
Thanks!
While the real header is scroll off the screen, the visible one is drawing on canvas directly ,not like a normal interactive widget.
You have these options
Override RecyclerView.onInterceptTouchEvent(), though with some invasiveness so I prefer the next one.
Make use of RecyclerView.addOnItemTouchListener(), remember the motion event argument has been translated into RecyclerView's coordinate system.
Use a real header view, but that will go a little far I think.
If you take option 1/2, Button.setPressed(true) and redraw the header will have a visual press effect.
In addition to what Neil said,
the answer here might help.
Passing MotionEvents from RecyclerView.OnItemTouchListener to GestureDetectorCompat
And then you just need to calculate the height of the header and see if the click falls onto that header view and handle the event yourself.
private class RecyclerViewOnGestureListener extends GestureDetector.SimpleOnGestureListener {
#Override
public boolean onSingleTapConfirmed(MotionEvent e) {
float touchY = e.getY();
ALLog.i(this, "Recyclerview single tap confirmed y: " + touchY);
//mGroupHeaderHeight is the height of the header which is used to determine whether the click is inside of the view, hopefully it's a fixed size it would make things easier here
if(touchY < mGroupHeaderHeight) {
int itemAdapterPosition = mRecyclerView.getLayoutManager().getPosition(mRecyclerView.findChildViewUnder(0, mGroupHeaderHeight));
//Do stuff here no you have the position of the item that's been clicked
return true;
}
return super.onSingleTapConfirmed(e);
}
#Override
public boolean onDown(MotionEvent e) {
float touchY = e.getY();
if(touchY < mGroupHeaderHeight) {
return true;
}
return super.onDown(e);
}
#Override
public boolean onSingleTapUp(MotionEvent e) {
float touchY = e.getY();
if(touchY < mGroupHeaderHeight) {
return true;
}
return super.onSingleTapUp(e);
}
}
As Neil is pointing out, things are getting more complicated than that. However by definition you can't.
So, why not including good libraries that do that and more?
I propose my hard work for clickable sticky header in my FlexibleAdapter project, which uses a real view (not decorators) to handle click events on headers when sticky.
There's also a working demo and a Wiki page on that part (and not only).
I have an Activity with a ViewPager with 3 dynamically created Fragments. Each page has numerous Buttons and ImageButtons that activate on their own onTouch..MotionEvent.ACTION_DOWN.
The problem I'm having is that these buttons activate accidentally when am trying to swipe the ViewPager.
Can anyone recommend a way to keep this from happening?
Thanks
Josh
Instead of using onTouch..MotionEvent.ACTION_DOWN.
on the ImageButton I will make them implement;
.OnItemClickListener() /This ensures that only when clicked they will call the desired functionality, I suggest you to check it out this way and let me know.
Hope it helps, more info at; The Documentation for OnItemClickListener
I think that the flow you are following is not really good, the button also has the business code to handle the ACTION_DOWN touch event and the parent (ViewPager) always need handle touch event to detect the scroll events, so button will handle the ACTION_DOWN touch event first and then pass the touch to ViewPager.
You can move the business code into the OnClickListener of Button or another way you should let the button intercept the touch event and don't pass it to ViewPager (Parent View).
This can be easy to handle by customize the Viewpager class and add a variable in the custom ViewPager like this :
private boolean mTouchEnable = true;
#Override
public boolean onTouchEvent(MotionEvent arg0) {
if (!mTouchEnable) {
return false;
}
return super.onTouchEvent(arg0);
}
The button will need a reference to the viewPager and set the mTouchEnable = false in ACTION_DOWN and true in ACTION_UP
I did a viewpager of buttons and I was able to replicate the issue.
I solved to this way:
My buttons have a listener OnClickListener
optionButton.setOnClickListener(this);
public void onClick(View v) {
// your code here
}
Then I add this button to my customPagerAdapter
In your customViewPager you have to override the onInterceptTouchEvent method like this:
#Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
super.onInterceptTouchEvent(ev);
if (ev.getAction() == MotionEvent.ACTION_MOVE) {
return true;
}
else{
return false;
}
}
This code will intercept the MotionEvent.ACTION_MOVE in child views (return true) and won't intercept MotionEvent.ACTION_DOWN neither onClick event in the child views.
The question explains everything I want.
HorizontalScrollView seems to be the only widget for which setOnClickListener() does'nt trigger.
NOTE: I can't use onTouch event because on every touch it is triggered 4-5 times.
I also can't use onTouch on its parent view because parent view has many buttons with different functionality.
The following description is not important:
But still, these are the existing links I've searched(none helped):
horizontalscrollview onclicklistener doesn't get called
How to implement on click listener for horizontalscrollview
Click event of HorizontalScrollView
Android click event of items in HorizontalScrollView not respond after scroll
These are the links which I posted(none got answered completely):
Insert views in HorizontalScrollView programatically
One of the ImageButton not clicking & make HorizontalScrollView clickable
I asked multiple questions in these links, 1 of which was "onClickListener for HorizontalScrollView". That part of my question was never answered.
Hence an all exclusive question.
I came up with two ways of doing it.
The simpler (but less ideal) one:
HorizontalScrollView scrollView = (HorizontalScrollView) findViewById(R.id.scrollView);
scrollView.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_UP) {
// Do stuff
}
return false;
}
});
This will get called only once when you click, drag or whatever you do with your finger. However, it will also react to all kinds of gestures, so if you want to detect only tap/click events, you need to further investigate the "event" object and filter out events you don't need. This may be more work than you would like, so you should better use a GestureDetector to do it for you.
This leads to method 2:
HorizontalScrollView scrollView = (HorizontalScrollView) findViewById(R.id.scrollView);
final GestureDetector detector = new GestureDetector(this, new OnGestureListener() {
#Override
public boolean onSingleTapUp(MotionEvent e) {
// Do stuff.
return false;
}
// Note that there are more methods which will appear here
// (which you probably don't need).
});
scrollView.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
detector.onTouchEvent(event);
return false;
}
});
Well it happened to me now and I came here for solution, but in my case it was just easier to listen to onClick to its child view instead...
I have a scrollView with lot of elements
ScrollView scroller = (ScrollView)findViewById(R.id.scrollView);
I need to attach an onClickListener to the scrollview so I do
scroller.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// This is all you need to do to 3D flip
AnimationFactory.flipTransition(viewAnimator, FlipDirection.LEFT_RIGHT);
}
});
But this is not getting triggered when I touch. Any Ideas?
The best solution seem to put LinearLayout into ScrollView and set the setOnClickListener on it.
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/myLayout"
android:clickable="true"
android:orientation="vertical">
<!-- content here -->
</LinearLayout>
</ScrollView>
in the Activity :
LinearLayout lin = (LinearLayout) fragment.rootView.findViewById(R.id.myLayout);
lin.setOnTouchListener(new setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
// Whatever
}
});
You need to set the setOnClickListener directly on the ScrollView's child.
Since a ScrollView can have only one child, you can simply use this approach:
ScrollView scrollView = //...
View.OnClickListener mOnClickListener = new View.OnClickListener() {
#Override
public void onClick(View view) {
// ...
}
//Set the onClickListener directly on the ScrollView's child
scrollView.getChildAt(0).setOnClickListener(mOnClickListener);
It is because the child of the ScrollView is getting the touch event of the user and not the ScrollView. You must set android:clickable="false" attribute to each and every child of the ScrollView for the onClickListener to work on ScrollView.
Or else the alternate could be to set the onClickListener on each of the ScrollView's children and handle it.
UPDATE 22/12/2020
sadly this also triggers after each scroll event.
This the actually the answer to the question without any odd cases by using View.OnTouchListener instead of View.OnClickListener on the ScrollView and detecting the MotionEvent.ACTION_UP where the finger is left off the screen.
To make sure that it's not a scroll, then save previous touched screen x, y values of the MotionEvent.ACTION_DOWN and compare it to those of MotionEvent.ACTION_UP. If they are not equal then certainly the user is moving their finger (i.e. scrolling) before they left it off the screen.
int mXOld, mYOld; // field values to save the tap down on the ScrollView
scrollView.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
int x = (int) event.getX();
int y = (int) event.getY();
if (event.getAction() == MotionEvent.ACTION_DOWN) {
mXOld = x;
mYOld = y;
} else if (event.getAction() == MotionEvent.ACTION_UP) {
if (x == mXOld || y == mYOld) { // detecting it's not a horizontal/vertical scrolling in ScrollView
// HERE add the code you need when the ScrollView is clicked
Toast.makeText(MainActivity.this, "Click", Toast.LENGTH_SHORT).show();
return false;
}
}
return false;
}
});
Original Answer: Odd case that is different than the question
My problem was somehow different, so I wanted to share it..
I have a ScrollView that I have to use match_parent in its width & height; and I have an internal TextView that is centered in the ScrollView.
The text of the TextView can be long so it occupies the full height of the ScrollView, and sometimes it can be short, so there will be blank areas on the top and bottom., So setting the OnClickListener on the TextView didn't help me whenever the text is short as I want the blank areas detects the click event as well; and also the OnClickListener on the ScrollView doesn't work..
So, I solved this by setting OnTouchListener on the ScrollView and put code into MotionEvent.ACTION_UP So it can kind of simulating complete tap by lefting off the finger off the screen.
private View.OnTouchListener mScrollViewTouchListener = new View.OnTouchListener() {
#SuppressLint("ClickableViewAccessibility")
#Override
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_UP) {
// DO Something HERE...
}
return false;
}
};
As #Zain pointed out, sometimes it is necessary to capture OnClicks for the whole area of the Scrollview, while the childs may be smaller or invisible.
To circumvent scrolling detected as an onClick, we used a GestureDetector:
final protected GestureDetector gestureDetector = new GestureDetector(getActivity(),
new GestureDetector.SimpleOnGestureListener() {
#Override
public boolean onSingleTapUp(MotionEvent e) {
return true;
}
});
in onCreateView
scrollView.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
if(gestureDetector.onTouchEvent(event)){
[do stuff]
}
return false;
}
});
I think you can custom a ScrollView, override the dispatchTouchEvent method, add add the custom onClick callback.
I have a Linear Layout that has a Button and a TextView on it. I have written a OnTouchEvent for the activity. The code works fine if I touch on the screen, but if I touch the button the code does not work. What is the possible solution for this?
public boolean onTouchEvent(MotionEvent event) {
int eventaction=event.getAction();
switch(eventaction)
{
case MotionEvent.ACTION_MOVE:
reg.setText("hey");
break;
}
return true;
}
The problem is the order of operations for how Android handles touch events. Each touch event follows the pattern of (simplified example):
Activity.dispatchTouchEvent()
ViewGroup.dispatchTouchEvent()
View.dispatchTouchEvent()
View.onTouchEvent()
ViewGroup.onTouchEvent()
Activity.onTouchEvent()
But events only follow the chain until they are consumed (meaning somebody returns true from onTouchEvent() or a listener). In the case where you just touch somewhere on the screen, nobody is interested in the event, so it flows all the way down to your code. However, in the case of a button (or other clickable View) it consumes the touch event because it is interested in it, so the flow stops at Line 4.
If you want to monitor all touches that go into your Activity, you need to override dispatchTouchEvent() since that what always gets called first, onTouchEvent() for an Activity gets called last, and only if nobody else captured the event. Be careful to not consume events here, though, or the child views will never get them and your buttons won't be clickable.
public boolean dispatchTouchEvent(MotionEvent event) {
int eventaction=event.getAction();
switch(eventaction) {
case MotionEvent.ACTION_MOVE:
reg.setText("hey");
break;
default:
break;
}
return super.dispatchTouchEvent(event);
}
Another option would be to put your touch handling code into a custom ViewGroup (like LinearLayout) and use its onInterceptTouchEvent() method to allow the parent view to steal away and handle touch events when necessary. Be careful though, as this interaction is one that cannot be undone until a new touch event begins (once you steal one event, you steal them all).
HTH
Let me add one more comment to this excellent post by #Devunwired.
If you've also set an onTouchListener on your View, then its onTouch() method will be called AFTER the dispatch methods, but BEFORE any onTouchEvent() method, i.e. in between no.3 and no.4 on #Devunwired's answer.
Try to set the descendantFocusability attribute of your layout to blocksDescendants
Activity::onTouchEvent will be called only when non of the views in the Activity WIndow consumes/handles the event. If you touch the Button, the Button will consume the events, so the Activity won't be able to handle it.
Check out following articles for more about Android Touch Event handling pipeline.
http://pierrchen.blogspot.jp/2014/03/pipeline-of-android-touch-event-handling.html
you can also try onUserInteraction():
#Override
public void onUserInteraction(){
//your code here
super.onUserInteraction();
}
works well for me!
RecyclerView list_view = findViewById(R.id.list_view);
list_view.addOnItemTouchListener(new RecyclerView.SimpleOnItemTouchListener(){
#Override
public boolean onInterceptTouchEvent(#NonNull RecyclerView rv, #NonNull MotionEvent e) {
View child = rv.findChildViewUnder(e.getX(), e.getY());
Log.i("Hello", "World");
return false;
}
});
use public boolean dispatchTouchEvent(MotionEvent event) instead on onTouchEvent()