Develop Reference

Android Right and Left Swipe Gestures handling

so I tried Zala's code for handling the gestures from this question android how to handle right to left swipe gestures, it works but the problem is my component is inside a scrollview so the gestures sometimes are detected sometimes not, I tried few different codes to solve this scrollview issue still the same behavior.
Anyone could help please !

scrollView.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:{
downX = event.getX();}
case MotionEvent.ACTION_UP:{
upX = event.getX();
float deltaX = downX - upX;
if(Math.abs(deltaX)>0){
if(deltaX>=0){
swipeToRight();
return true;
}else{
swipeToLeft();
return true;
}
}
}
}
return false;
}
});

Android: How to make a CustomListView which is in a Fragment in a SlidingDrawer scroll- and clickable?

I would like to set up following layout with working scroll and click events:
My CustomSlidingDrawer.xml:
<com.project.util.CustomSliderDrawer
android:id="#+id/slidingDrawerHotelList"
android:layout_width="0dp"
android:layout_height="match_parent"
android:allowSingleTap="false"
android:content="#+id/content"
android:handle="#+id/handle"
android:orientation="horizontal" >
<RelativeLayout
android:id="#+id/handle"
android:layout_width="0dp"
android:layout_height="match_parent" >
<RelativeLayout
android:id="#+id/content"
android:layout_width="0dp"
android:layout_height="0dp" >
</RelativeLayout>
</RelativeLayout>
</com.project.util.CustomSliderDrawer>
The width of the elements are set during runtime.
Here I have to mention, that my real content is in the handle of the Drawer, and the content is only a dummy. I'm doing that in this way, because I was not able to hide the handle. Or make it invisible. So, if I want to swipe in I touch the handle (my content) and pull. In the SlidingDrawer, the handle is a placeholder for a fragment which contains a CustomListView.
What now works: I can scroll the SlidingDrawer.
What behavior I would like to gain:
On the SlidingDrawer the MotionEvents are detected in X-Axis direction (Vertical swipe). If a MotionEvent in Y-Axis direction is detected, then the Events shoud go to my CustomListView. Even the onClicks should pass through to the ListView.
What I've tried: I read a lot: here, this page and this one
Then I tried to put all the navigation control in the main activity, what makes really sense in my eyes:
MainActivity:
slidingDrawer.setOnTouchListener(new OnTouchListener() {
int downX, downY;
#Override
public boolean onTouch(View v, MotionEvent event) {
int action = event.getAction();
switch (action) {
case MotionEvent.ACTION_DOWN:
downX = (int) event.getX();
downY = (int) event.getY();
break;
case MotionEvent.ACTION_MOVE:
int deltaX = downX - (int) event.getX();
int deltaY = downY - (int) event.getY();
if (Math.abs(deltaX) > Math.abs(deltaY)) {
Log.i(TAG, "scrollX direction");
isVerticalSwipe = true;
} else {
Log.i(TAG, "scrollY direction");
isVerticalSwipe = false;
}
break;
case MotionEvent.ACTION_UP:
break;
}
return false;
}
});
But when I try here to return "isVerticalSwipe" as local, the SlidingDrawer works not properly anymore. :-(
The 2nd try was to intercept the touch events in the custom sliding drawer:
CustomSlidingDrawer:
#Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
Log.i(TAG, "onInterceptTouchEvent ACTION_DOWN");
xDistance = yDistance = 0f;
downX = (int) ev.getX();
downY = (int) ev.getY();
break;
case MotionEvent.ACTION_MOVE:
Log.i(TAG, "onInterceptTouchEvent ACTION_MOVE");
final int curX = (int) ev.getX();
final int curY = (int) ev.getY();
xDistance += Math.abs(curX - downX);
yDistance += Math.abs(curY - downY);
downX = curX;
downY = curY;
if (xDistance > yDistance)
return false;
}
return super.onInterceptTouchEvent(ev);
}
Here happens only the DOWN event and the MOVE event is never reached.
I also made some trys with "dispatchTouchEvent" but I got no success.
I know, that the events will pass through the "layer" of my views - from top to bottom.
So it would be perfect to know, how I can implement the construct from the first link above in my CustomSlidingDrawer (= top view) and when a vertical swipe is detected keep and handle it and if it's a horizontal swipe, then please send it to the CustomListView and perform there the events.
Any help, thoughts, ideas or code snippets are appreciated. :)
Thank you!
[EDIT]
I've made some progress. I get now my events from the SlidingDrawer down to my ListView. I can scroll and click in the list - that works fine. But unfortunately, my SlidingDrawer shows no reaction anymore. These lines are in my custom SlidingDrawer:
#Override
public boolean onInterceptTouchEvent(MotionEvent event) {
gestureDetector = new GestureDetector(new MyGestureDetector());
if (gestureDetector.onTouchEvent(event)) {
return true;
} else if (event.getAction() == MotionEvent.ACTION_UP
|| event.getAction() == MotionEvent.ACTION_CANCEL) {
return false;
} else {
Log.i(TAG, "gestureDetector returned false");
return false;
}
}
class MyGestureDetector extends SimpleOnGestureListener {
#Override
public boolean onDown(MotionEvent e) {
Log.i(TAG, "onDown");
downX = (int) e.getX();
downY = (int) e.getY();
return false;
}
#Override
public boolean onScroll(MotionEvent e1, MotionEvent e2,
float distanceX, float distanceY) {
float deltaX = downX - e2.getX();
float deltaY = downY - e2.getY();
if (Math.abs(deltaX) > Math.abs(deltaY)) {
Log.i(TAG, "scrollX direction");
return true;
} else {
Log.i(TAG, "scrollY direction");
return false;
}
}
}
I don't really understand why it's not working, if there is a swipe in x-direction, then my Drawer should handle the gesture, bc I return true. Instead every event is forwarded to the ListView.
I tried to run "dispatchTouchEvent" before the "onInterceptTouchEvent" but I had no success. Maybe there is a better solution instead of using a SlidingDrawer for moving views by finger?

Okay, after a lot of tears, sweat and blood I finally found a solution which works for me: I don't take a SlidingDrawer anymore and move my layout via changing the LayoutParams.
Over the "dispatchTouchEvent" I get access to my list.
#Override
public boolean dispatchTouchEvent(MotionEvent ev) {
if (mGestureDetector.onTouchEvent(ev)) {
return true;
}
if (ev.getAction() == MotionEvent.ACTION_UP) {
Log.i(TAG, "ACTION_UP");
Log.i(TAG, "getLeft: " + getLeft());
if (getLeft() < 280) {
// run ani to left
} else {
// run ani to right
}
}
return super.dispatchTouchEvent(ev);
}
And in my GestureDetector I handle in the overridden onScroll-function the layout translation. If someone has need for the detector don't hesitate to ask, I'll share.

Correctly detecting a swipe on a GridView placed inside a ViewPager in Android

I have a ViewPager which uses GridViews for pages. I would like the ViewPager to switch pages when I swipe across the screen.
The problem is that swipes are not detected when they are made across the GridView. Outside of the GridView, the swipes work correctly; it seems that the GridView is trapping all touch events without passing it to ViewPager first.
While fiddling with the source code, I did this to a custom class extended from GridView:
#Override
public boolean onTouchEvent(MotionEvent event) {
return pager.onInterceptTouchEvent(event);
}
-- where pager refers to the ViewPager class. With this, ViewPager will correctly detect swipes and move pages accordingly, but it doesn't allow GridView to accept any events, so I can't click on the items.
What I would like to be able to do is correctly detect swipes in ViewPager and item clicks on GridView.

I had trouble with colig's implementation, but I was able to get it to work by subclassing ViewPager and overriding the onInterceptTouchEvent() method. I only checked for swipes in the X direction to allow for vertical scrolling if necessary.
private static final int minSwipeDistance = 30;
private float mTouchX;
#Override
public boolean onInterceptTouchEvent(MotionEvent event) {
boolean response = super.onInterceptTouchEvent(event);
float x = event.getX();
switch (event.getActionMasked()) {
case MotionEvent.ACTION_DOWN:
mTouchX = x;
break;
case MotionEvent.ACTION_MOVE:
float dX = Math.abs(x - mTouchX);
if (dX > minSwipeDistance)
return true;
break;
}
return response;
}

Alix is on the right track. I managed to come up with this simple-looking fix. I'm not entirely sure of how it works, but it does! And for future reference, it works for other kinds of views too -- TableLayout, for example -- not just GridView.
#Override
public boolean onInterceptTouchEvent(MotionEvent event) {
x = event.getX();
y = event.getY();
switch (event.getActionMasked()) {
case MotionEvent.ACTION_DOWN: {
downX = x;
downY = y;
return super.onInterceptTouchEvent(event);
}
case MotionEvent.ACTION_MOVE: {
deltaX = Math.abs(downX - x);
deltaY = Math.abs(downY - y);
return super.onTouchEvent(event);
}
case MotionEvent.ACTION_UP: {
if (deltaX > 4 && deltaY > 4) {
super.onTouchEvent(event);
}
}
}
return super.onInterceptTouchEvent(event);
}

You can override onInterceptTouchEvent for dispatch evenement where you want

Viewflipper with Scrollviews and a nav bar

I have a viewflipper which includes a number of layouts. Each layout has a scrollview as the root.
Below the viewflipper I have a horizontal scrollview which contains textviews which acts as a navigation bar.
My original issue was that the fling stopped working as soon as I added a scrollview but I added the following code:
#Override
public boolean dispatchTouchEvent(MotionEvent ev){
super.dispatchTouchEvent(ev);
return gestureDetector.onTouchEvent(ev);
}
And the scrolling now works along with the fling.
The only issue I have now though is that the HSV nav bar now acts a little strange. Sometimes when I try to slide it across, to select new contents, the HSV springs back to where it was. Other times the HSV thinks I want to fling and moves to the next contents. This is of course dependant of the speed I try to scroll it.
I want the nav bar to work independently of the flipper.
I'm trying to understand the code to fix it myself but not getting anywhere.
I have the following in my onCreate:
gestureDetector = new GestureDetector(new MyGestureDetector());
gestureListener = new View.OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
if (gestureDetector.onTouchEvent(event)) {
return true;
}
return false;
}};
I have the MyGestureDetector class:
class MyGestureDetector extends SimpleOnGestureListener {
#Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
try {
if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH)
return false;
// right to left swipe
if(e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
flipper.setInAnimation(flip_in_from_right);
flipper.setOutAnimation(flip_out_to_left);
flipper.showNext();
} else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
flipper.setInAnimation(flip_in_from_left);
flipper.setOutAnimation(flip_out_to_right);
flipper.showPrevious();
}
} catch (Exception e) {
// nothing
}
And then the override:
#Override
public boolean dispatchTouchEvent(MotionEvent ev){
super.dispatchTouchEvent(ev);
return gestureDetector.onTouchEvent(ev);
}
Can anyone shed any light on this?

Where exactly is your HSV? Is it pinned to the bottom of the screen? If so, here's what I would do. Within your onFling event, check the Y position of the fling and make sure it's not within your HSV. If it is, then return false and you should be good to go.

Android ListView tolerance

I have list items that have a HorizontalScrollView in each of them. Hence, I should be able to swipe up and down the list and also swipe through the list item horizontally. (e.g. Pulse News App).
What I'm encountering is that, whenever I scroll the HorizontalScrollView, the ListView also gets scrolled by tiny bit but giving out annoying disturbances in terms of User Experience.
So, I was actually thinking to subclass ListView and implement my own ListView widget. However, I don't know which method to override so that I could increase X tolerance and stop the listview from giving these unwanted flickering.

gestureDetector = new GestureDetector(new YScrollDetector());
public boolean onInterceptTouchEvent(MotionEvent ev) {
//Call super first because it does some hidden motion event handling
boolean result = super.onInterceptTouchEvent(ev);
//Now see if we are scrolling vertically with the custom gesture detector
if (gestureDetector.onTouchEvent(ev)) {
return result;
}
//If not scrolling vertically (more y than x), don't hijack the event.
else {
return false;
}
}
// Return false if we're scrolling in the x direction
class YScrollDetector extends SimpleOnGestureListener {
#Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
try {
if (Math.abs(distanceY) > Math.abs(distanceX)) {
return true;
} else {
return false;
}
} catch (Exception e) {
// nothing
}
return false;
}
}
This is will help you, you have to override these in the custom list view you create,i used this to eliminate the problem in my application. Hope this helps.