While similar questions have been asked in the past they don't seem to really have been answered which might be due to confusion as to what's being asked.
Put simply, I'd like to detect which view is being entered as your finger slides over the screen. The best example of this in action is the soft keyboard on any android phone. When you press any key it shows up as a popup to tell you what letter is under your finger. If you now move your finger over the keyboard in a single gesture the various letters pop up as you move over the various letters of the alphabet.
What listeners are used for this type of behaviour. I've tried OnTouchListeners but they seem to be only when you 'touch' the button as opposed to 'finger past' them
Button button = (Button)findViewById(R.id.button);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {doStuff();}
});
button.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
doStuff();
return false;
}
});
OnFocusChangeListener don't help either.
create a Layout
add Views to your Layout
set the setOnTouchListener to your Layout
override the onTouch method with the following:
public boolean onTouch(View v, MotionEvent event)
{
LinearLayout layout = (LinearLayout)v;
for(int i =0; i< layout.getChildCount(); i++)
{
View view = layout.getChildAt(i);
Rect outRect = new Rect(view.getLeft(), view.getTop(), view.getRight(), view.getBottom());
if(outRect.contains((int)event.getX(), (int)event.getY()))
{
// over a View
}
}
}
EDIT:
I saw keyboard. I guess, it just one view and coordinates of every letter is known. So you can easily compute which letter the user slides through
AND NOW THE ANSWER:
I'm not sure, but probably this code helps your.
It's so far away, I wrote it for me. But the idea is following.
If I remember right, there is no gesturedetector for views, but you can combine touchlistener of the view with geturelistener of your activity.
Once you've touched your view, you have
private GestureDetector mGestureDetector;
// x and y coordinates within our view
private static float sideIndexX;
private static float sideIndexY;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
...
mGestureDetector = new GestureDetector(this, new SideIndexGestureListener());
}
class MyGestureListener extends
GestureDetector.SimpleOnGestureListener
{
#Override
public boolean onScroll(MotionEvent e1, MotionEvent e2,
float distanceX, float distanceY)
{
// we know already coordinates of first touch
// we know as well a scroll distance
sideIndexX = sideIndexX - distanceX;
sideIndexY = sideIndexY - distanceY;
// when the user scrolls within our side index
// we can show for every position in it a proper
// item in the country list
if (sideIndexX >= 0 && sideIndexY >= 0)
{
doStuff();
}
return super.onScroll(e1, e2, distanceX, distanceY);
}
}
button.setOnTouchListener(new OnTouchListener()
{
#Override
public boolean onTouch(View v, MotionEvent event)
{
// now you know coordinates of touch
// store them
sideIndexX = event.getX();
sideIndexY = event.getY();
doStuff();
return false;
}
});
You may want to try GestureDetector.
http://android-developers.blogspot.com/2010/06/making-sense-of-multitouch.html
it's geared to multitouch, but this is a good start toward understanding android touch/gestures, next stop, api docs/samples
The simple answer is you can't - not like the iPhone when in accessibility mode.
Until Ice Cream Sandwich that is. It now has the iPhone-like capability of being able to identify elements under your finger without having to lift it.
It's fairly straight forward to handle this manually.
Using your parent layout as the onTouchListener (in the following example, I extend a RelativeLayout), you can check for collisions between a MotionEvent and the child Views using simple co-ordinate comparison logic:
/** Returns the View colliding with the TouchEvent. */
private final View getCollisionWith(final MotionEvent pMotionEvent) {
// Declare the LocationBuffer.
final int[] lLocationBuffer = new int[2];
// Iterate the children.
for(int i = 0; i < this.getChildCount(); i++) { /** TODO: Order. */
// Fetch the child View.
final View lView = this.getChildAt(i);
// Fetch the View's location.
lView.getLocationOnScreen(lLocationBuffer);
// Is the View colliding?
if(pMotionEvent.getRawX() > lLocationBuffer[0] && pMotionEvent.getRawX() < lLocationBuffer[0] + lView.getWidth() && pMotionEvent.getRawY() > lLocationBuffer[1] && pMotionEvent.getRawY() < lLocationBuffer[1] + lView.getHeight()) {
// Return the colliding View.
return lView;
}
}
// We couldn't find a colliding View.
return null;
}
Calls to getCollisionWith will return View references that may be manipulated arbitrarily.
Related
I'd like to respond to horizontal "fling" gestures on individual cells in a vertically scrolling ListView. Currently I've accomplished this by using a GestureDetector for each cell view in the list.
I'm noticing, though, that it's much harder to actually get a horizontal "fling" to register with one of the cell views than if they were just stuck in a non-scrolling linear layout.
For instance, if I tap down inside a cell then drag my finger "up and to the right" fairly quickly this is recognized as a fling in the non-scrolling case, but isn't recognized in the scrolling case.
I've experimented with sub-classing ListView and overriding onInterceptTouchEvent, then I can't seem to get it right. What I would like to have happen is for gestures that will eventually be recognized as "flings" on a child view to be ignored by the scroll view. I would want to limit these based on the "angle" of the gesture, i.e. the ratio of the Y distance to the X distance. If that ratio is sufficiently high then its a "vertical" fling and the ListView should handle it. If that ratio is sufficiently low then it's a "horizontal" fling and the ListView should ignore it and allow a child view to handle it.
Can anyone provide some perspective on how this might be accomplished? I'm assuming I'll going to have to do something clever in the onInterceptTouchEvent method of the ListView sub-class.
try this:
final ListView v = new ListView(this);
ArrayAdapter<String> a = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1);
a.add("one");
a.add("two");
a.add("three");
a.add("four");
v.setAdapter(a);
OnGestureListener ogl = new SimpleOnGestureListener() {
#Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
if (Math.abs(velocityX) > Math.abs(velocityY)) {
Log.d(TAG, "onFling " + v.pointToPosition((int) e1.getX(), (int) e1.getY()));
return true;
}
return false;
}
};
final GestureDetector detector = new GestureDetector(ogl);
OnTouchListener otl = new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
return detector.onTouchEvent(event);
}
};
v.setOnTouchListener(otl);
OnItemClickListener oicl = new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Log.d(TAG, "onItemClick " + position);
}
};
v.setOnItemClickListener(oicl);
setContentView(v);
i'm using a SemiClosedSlidingDrawer (http://pastebin.com/FtVyrcEb) and i've added on content part some buttons on the top of slider which are always visibles.
The problems is that they are clickable (or click event is dispatched) only when slider is fully opened... When slider is "semi-opened" click event not seems dispached to button... I have inspected with debugger into onInterceptTouchEvent() and in both cases (opened/semi-collapsed) the following code
#Override
public boolean onInterceptTouchEvent(MotionEvent event) {
if (mLocked) {
return false;
}
final int action = event.getAction();
float x = event.getX();
float y = event.getY();
final Rect frame = mFrame;
final View handle = mHandle;
handle.getHitRect(frame);
//FOLLOWING THE CRITICAL CODE
if (!mTracking && !frame.contains((int) x, (int) y)) {
return false;
}
return false but only when slider is opened event was dispached...
It checks if a (x,y) relative to the click are contained in a rectangle created starting from the HandleButton view of sliding drawer...
final Rect frame = mFrame;
final View handle = mHandle;
handle.getHitRect(frame);
and this is obviously false because i'm clicking on a button contained inside the content part of slidingdrawer and that's ok...
As i said above the problem is that in semi-collapsed state, buttons contained in content part are not receiving the event...
Have you any idea how can i solve this issue?
Can be some state of slidingdrawer that avoid to click childs when collapsed?
Thanks in advance...
Right, I think I've figured out a way to do this.
First you need to modify onInterceptTouchEvent() to return true whenever the user presses the visible content during the semi-opened state. So, for instance, if your SemiClosedSlidingDrawer view is located at the very bottom of the screen, you can use a simple detection algorithm, like this:
public boolean onInterceptTouchEvent(MotionEvent event) {
...
handle.getHitRect(frame);
// NEW: Check if the user pressed on the "semi-open" content (below the handle):
if(!mTracking && (y >= frame.bottom) && action == MotionEvent.ACTION_DOWN) {
return true;
}
if (!mTracking && !frame.contains((int) x, (int) y)) {
...
}
Now the touch events during the user's interaction with the semi-opened content will be dispatched to onTouchEvent(). Now we just need to intercept these events and "manually" redirect them to the right view (note that we also need to offset the coordinates for the child view):
public boolean onTouchEvent(MotionEvent event) {
...
if (mTracking) {
...
}
else
{
// NEW: Dispatch events to the "semi-open" view:
final Rect frame = mFrame;
final View handle = mHandle;
handle.getHitRect(frame);
float x = event.getX();
float y = event.getY() - frame.bottom;
MotionEvent newEvent = MotionEvent.obtain(event);
newEvent.setLocation(x, y);
return mContent.dispatchTouchEvent(newEvent);
}
return mTracking || mAnimating || super.onTouchEvent(event);
}
It's a bit of a messy implementation, but I think the basic concept is right. Let me know how it works for you!
I am a newbie in Andoird.
In my case, I have a scenario that when click certain part of an image it will trigger onclick events. I tried to detecte the position when the onTouch is fired, it works, but I think it's not a standard implementation, so what is the best practice for such case?
thanks.
here is codes like:
imgView.setOnTouchListener((OnTouchListener) new OnTouchListener(){
public boolean onTouch(View v, MotionEvent event) {
if(isIn(event.getX(), event.getY(), 124,3,221,36)){
ShowMemberInfo(R.string.app_m01);
} else if(isIn(event.getX(), event.getY(), 8,155,72,181)){
..
}
return true;
}
private boolean isIn(float x, float y, int fx, int fy, int tx, int ty) {
return x<tx && x > fx && y<ty && y>fy;
}
Try to use ImageButton
Simply implement onClickListener() for your ImageView.
Easiest way to implement onClick event is to include android:onClickMe="methodName" inside your <ImageView> in XML layout and define that method inside your activity file.
For example:
public void methodName(View v)
{
....
....
// do whatever you want for click even ton imageview
}
If you want to detect the position where user touched(Relative to the ImageView user touched), you can get the touch point from MotionEvent object.
Try to register a touch event listener for the ImageView and get the touched point position from MotionEvent object's getX() and getY() methods when touch event is triggered. And then define a rectangular area and using contains() to check whether the touch point is inside the area or not.
ImageView img = new ImageView(this);
img.setOnTouchListener(new OnTouchListener(){
#Override
public boolean onTouch(View v, MotionEvent event) {
Log.w("Hit test", "is hit? "+isIn(event.getX(),event.getY(),0,0,120,120));
return false;
}
});
private boolean isIn(float x, float y, int fx, int fy, int tx, int ty){
return new Rect(fx,fy,tx,ty).contains((int)x,(int)y);
}
Hope this will be helpful to you. :)
I am using view pager to swipe between the views in Android.
Now I need to capture tap event for each of the views. when I override the touch listener to capture the tap event, the swipe action doesn't happen and the screen remains in the first page itself. How do I add touch listener to view pager?
Code:
viewPager.setOnTouchListener(new OnTouchListener(){
#Override
public boolean onTouch(View v, MotionEvent event)
{
mDetector.onTouchEvent(event);
return true;
}});
For the above code I am able to capture tap event, but the swipe action becomes Impossible.
Here i leave you a snippet from my code to detect a "click" on the OnTouchListener, i hope it helps
mImagePager.setOnTouchListener(new OnTouchListener() {
private float pointX;
private float pointY;
private int tolerance = 50;
#Override
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction()){
case MotionEvent.ACTION_MOVE:
return false; //This is important, if you return TRUE the action of swipe will not take place.
case MotionEvent.ACTION_DOWN:
pointX = event.getX();
pointY = event.getY();
break;
case MotionEvent.ACTION_UP:
boolean sameX = pointX + tolerance > event.getX() && pointX - tolerance < event.getX();
boolean sameY = pointY + tolerance > event.getY() && pointY - tolerance < event.getY();
if(sameX && sameY){
//The user "clicked" certain point in the screen or just returned to the same position an raised the finger
}
}
return false;
}
});
We can use Gestures (Link1, Link2):
public boolean onTouchEvent (MotionEvent ev)
Hope this helps!
Nancy, you don't need to manually override the Page swipes or the touch events. Just add the pages to the ViewPager and the ViewPager will automatically take care of swiping.
You do, however, have to attach touch listeners to the object in each page. So if Page 1 has a Linear Layout with many buttons and you need to find out when those buttons are clicked, you need to attach OnClickListeners for each of those buttons.
Do let me know your use case so we can better understand, why you need to find out when a page has been clicked!
Just to add to Jorge's great answer, you may just use distance instead of sameX and sameY, which is a bit more elegant. Sample:
// Ignore events that are swipes rather then touches
float distX = event.getX() - pointX;
float distY = event.getY() - pointX;
double dist = Math.sqrt(distX * distX + distY * distY);
if (dist > tolerance) {
return false;
}
Put the click event on the item view of the viewpager inside the viewPagerAdapter in the method instantiateItem like -
#Override
public Object instantiateItem(ViewGroup container, final int position) {
// Declare Variables
ImageView jive_image;
inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View itemView = inflater.inflate(R.layout.list_item_viewpager, container,
false);
itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
onBackPressed();
}
});
// Add viewpager_item.xml to ViewPager
((ViewPager) container).addView(itemView);
return itemView;
}
I'm having a problem implementing a long press within my custom view, based on a HorizontalScrollView.
The HorizontalScrollView has a child LinearLayout, which in turn has a child View. The View draws bitmaps to the canvas via OnDraw().
I'd like to allow the HorizontalScrollView to scroll normally, either fast or slow. But, if the user holds their finger (even if scrolling) on one of the images, it would immediately cancel the scrolling and allow the user to perform a function with the selected image. (In this particular case, they'd be moving the image around the screen, but it could really be any number of functions.)
I've tried many combinations of handling the events (true, false, super) within each layer (HorizontalScrollView and View) but none seem to work 100%. Some combinations get there most of the way, some others part of the way, but they always seem to be missing one feature or another (scroll, hit test, etc.).
The closest I've gotten is to return false within the HorizontalScrollView's onInterceptTouchEvent() and true within the View's onTouch() event. This allows the scroll and also registers the hit test on the image. But, it immediately passes control back to the onTouch() event of the HorizontalScrollView. That makes it impossible to check if the image has been pressed for a number of seconds (long press).
If I return true within the View's onTouch() event, the hit test registers, and I'm able to check if the user has long pressed the image within ACTION_MOVE. But, then the HorizontalScrollView doesn't scroll.
Am I missing something completely obvious, or have I simply chosen two views that don't play well together? Any insight is appreciated.
right,
dont know if you have sorted this or not, I have mashed some bits together that I think do what you ask, if not then hey ho.
I have an activity that loads in the horizontal scroller, this might not be the best way but it works for me:
HolderActivity class (the one that loads in the HorizontalScrollView class) I have:
int selectedItem;
public boolean onLongClick(View v, int position) {
selectedItem = position;
openContextMenu(v);
return true;
}
public boolean onItemClick(int position) {)//do what you want here on click (press)
#Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
String[] menuItems = {"Menu item 1 text", "Cancel"};
for (int i = 0; i<menuItems.length; i++) {
menu.add(Menu.NONE, i, i, menuItemsRemove[i]);
}
menu.setHeaderTitle("My menu title");
}
in your HorizontalScrollView class's constructor pass I pass through a context in there like so:
public MyScroller(Context context) {
super(context);
this.context = context;
}
I have a method for creating the items from an ArrayList called setFeatureItems like so:
public void setFeatureItems(ArrayList<MyListEntity> items){}
Within this method I add a GestureDetector passing the context to it to each item like so:
mGestureDetector = new GestureDetector(context, new MyGestureDetector());
And the MyGestureDetector nested class which has the reference to the all important parentActivity is like this:
class MyGestureDetector extends SimpleOnGestureListener {
#Override
public void onLongPress(MotionEvent arg0) {
parentActivity.onLongClick(MyScroller.this, mActiveFeature);
};
#Override
public boolean onSingleTapUp(MotionEvent arg0) {
parentActivity.onItemClick(mActiveFeature);
return true;
};
#Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
try {
//right to left
if(e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
int featureWidth = getMeasuredWidth();
mActiveFeature = (mActiveFeature < (mItems.size() - 1))? mActiveFeature + 1:mItems.size() -1;
smoothScrollTo(mActiveFeature*featureWidth, 0);
return true;
}
//left to right
else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
int featureWidth = getMeasuredWidth();
mActiveFeature = (mActiveFeature > 0)? mActiveFeature - 1:0;
smoothScrollTo(mActiveFeature*featureWidth, 0);
return true;
}
} catch (Exception e) {
Log.e("Fling", "There was an error processing the Fling event:" + e.getMessage());
}
return false;
}
}
I have cut this from an existing proj so there might be remnants where I have not made it generic enough, I hope this makes sense or helps, let me know If i can add any more detail