I implemented my gesture listener according to this topic: ListView Horizontal Fling Gesture
however, I can see that list scrolling is slower, sometimes (when you scroll very slowly) it blocks too.
I think the problem is in the listener: it takes time to compute values and so get the actual "left to right" fling I'm searching for...isn't there a more efficient way?
edit
Problem is here:
#Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
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) {
System.out.println("right to left");
animatedStartActivity(0);
// right to left swipe
} else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
System.out.println("left to right");
animatedStartActivity(1);
}
return false;
}
evaluation of this method takes time
edit2:
I guess problem is because listview already has its own gesture listener and attaching mine overrides it. It is a problem because listview gesture listener takes in account speed and acceleration too, to give a nice moving effect. My listener is pretty raw, so list scrolling is not smooth anymore..
Even if my onFLing method always returns false (so it does not consume the event) list scrolling is affected...
edit3:
Ok maybe I found the solution but I need your help!
I can set the onTouchListener on the container layout, problem is that listview actually overrides parent's onTouch so I need to reverse the situation: onTouchEvent on listview has to be intercepted by the parent, so that returning false it is brougth to listview
SOLVED!!!
Problem was that ListView's onTouchEvent performed some other operations! So I extended ListView:
public class FlingListView extends ListView{
private GestureDetector detector; //this is my detector
public void setDetector(GestureDetector detector){
this.detector = detector;
}
public FlingListView(Context context) {
super(context);
// TODO Auto-generated constructor stub
}
public FlingListView(Context context,AttributeSet set) {
super(context,set);
// TODO Auto-generated constructor stub
}
public FlingListView(Context context,AttributeSet set, int a) {
super(context,set,a);
// TODO Auto-generated constructor stub
}
//here I do the magic
#Override
public boolean onTouchEvent(MotionEvent ev) {
// TODO Auto-generated method stub
super.onTouchEvent(ev); //I always do the list on touch event
return(detector.onTouchEvent(ev)); //..but I return the detector!
}
}
I don't know if this is the best solution but still...it works!
Related
What I'm trying to do is change the font size and foreground/background color of a webview.
I have done this using the following method (placed inside the activity):
private void updateFont(int fontSize, String fontColor) {
if (fontSize != 0) {
contentWebview.getSettings().setDefaultFontSize(fontSize);
}
if (!fontColor.equals("")) {
contentWebview.loadUrl(fontColor);
}
}
Now this is working fine. However I added something to my contentWebview (which is a custom webview I created) - below is some snippet of the custom webview:
public class ContentWebview extends WebView {
public ContentWebview(Context context) {
super(context);
}
public ContentWebview(Context context, AttributeSet attrs) {
super(context, attrs);
loadWebview();
gestureDetector = new GestureDetector(new MyGestureDetector());
gestureListener = new OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
return gestureDetector.onTouchEvent(event);
}
};
setOnTouchListener(gestureListener);
}
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) {
int currentPosition = getScrollX()/displayWidth +1;
scrollTo(currentPosition*displayWidth, 0);
} else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
int currentPosition = getScrollX()/displayWidth;
scrollTo(currentPosition*displayWidth, 0);
}
} catch (Exception e) {
// nothing
}
return true;
}
}
public boolean onTouchEvent(MotionEvent ev) {
if(ev.getAction()==MotionEvent.ACTION_UP) {
int currentPosition = getScrollX()/displayWidth;
if(getScrollX()%displayWidth>displayWidth/2) {
currentPosition++;
} else {
// do nothing
}
scrollTo(currentPosition*displayWidth, 0);
}
return super.onTouchEvent(ev);
}
Basically I've created a custom WebView that snaps to a fixed calculated position when it is scrolled or flinged. Now this is where the problem arises - once I scrolled this particular webview, the previous method (updateFont) doesn't work anymore - the webview doesn't change font size or color.
I have also narrowed down the problem to this particular line:
setOnTouchListener(gestureListener);
If I comment out this line, the updateFont method works again even after I scrolled the webview, but the snap-to-page on fling functionality of my webview is also gone.
What am I missing here?
Update: Problem only occurs in froyo devices. 2.3 and above doesn't seem to have the problem
There's a few issues with the WebView and GestureDetectors - try always returning false in your onFling(..) method instead of true - using a gesture detector in the fashion you do is known to block pretty basic stuff (such as even updating the currently displayed page).
after some tinkering with the project, I found out that the property changes loaded in the custom webview is interpreted after some time. The delay is caused by an onNewPictureListener triggering an endless call to a javascript command, which gets interpreted by the webview first, before executing other stuff. Removing this fixed the problem.
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
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.
I have a ViewFlipper which holds a single ImageView. i want to be able to swipe to change the image / view, and click the image to play a sound.
I have a GestureDetector which is handling OnFling to change the view. I tried to put an onClickListener to the imageview, which worked but stopped the OnFling working.
Lastly, I added an onSingleTapConfirmed to my GestureDetector. This worked, however it registers a click anywhere in the Activity not just the ImageView.
Can anyone suggest how to narrow down the onSingleTapConfirmed to just work on the Imageview?
Here's my code so far:
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) {
Log.v("Swipe", "Right to Left");
viewFlipper.setInAnimation(slideLeftIn);
viewFlipper.setOutAnimation(slideLeftOut);
viewFlipper.addView(nextImage(true));
viewFlipper.showNext();
} else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
Log.v("Swipe", "Left to Right");
viewFlipper.setInAnimation(slideRightIn);
viewFlipper.setOutAnimation(slideRightOut);
viewFlipper.addView(nextImage(false));
viewFlipper.showNext();
}
} catch (Exception e) {
// nothing
}
return false;
}
#Override
public boolean onSingleTapConfirmed(MotionEvent e)
{
// TODO Auto-generated method stub
Log.v("SingleTap", "OnSingleTapConfirmed Run");
return super.onSingleTapConfirmed(e);
}
}
private View nextImage(boolean righttoleft) {
ImageView imgv1 = new ImageView(this);
if(righttoleft == true)
{
Uri image = Uri.parse("android.resource://com.owentech.brainybaby/drawable/" + variables.letters[variables.currentpos]);
imgv1.setImageURI(image);
imgv1.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
return imgv1;
}
I had encountered this problem in the past.
Maybe you can try to implement single tap by setting an OnTouchListener to ViewFlipper, thus, the ViewFlipper will be the only touch event receiver. Then write the playing sound code in onTouch function. Finally, set onTouch function's return value to false for the sake of keeping the onFling working.
viewFlipper.setOnTouchListener(new OnTouchListener()
{
#Override
public boolean onTouch(View view, MotionEvent e) {
// TODO Auto-generated method stub
switch(e.getActionMasked())
{
case MotionEvent.ACTION_DOWN:
//put the playing sound code here.
break;
}
return false; //means that the listener dosen't consume the event
}
}
);
It's just a simple solution to solve this problem. If you want to achieve more complicated function such as avoiding sound playing when finger is swiping on the screen to change the view, you have to take more effort to distinguish gestures, e.g. calculate the time between ACTION_DOWN event and ACTION_UP event and play the sound if it's less than 300ms.
I hope this will be helpful to you. :)
I'm trying to implement a view that has both a longClickListener and a gesture dectector. Basically, I need a button to show a view when the user long clicks on the first view, and then I want to dectect a fling motion up. I would like to make it so that the user does not have to lift their finger at all, and hit both the longclick, and the fling motion.
Here is my code for the longClickListener:
flipCard.setOnLongClickListener(new View.OnLongClickListener() {
public boolean onLongClick(View view) {
answerRight.setVisibility(View.VISIBLE);
answerRight.startAnimation(AnimationUtils.loadAnimation(view.getContext(), R.anim.grow_from_middle));
answerWrong.setVisibility(View.VISIBLE);
answerWrong.startAnimation(AnimationUtils.loadAnimation(view.getContext(), R.anim.grow_from_middle));
return false;
}
});
Here is the code for my gesture dector:
gestureDetectorScore = new GestureDetector(new ScoreGestureDetector());
gestureListenerScore = new View.OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
if (gestureDetectorScore.onTouchEvent(event)) {
return true;
}
return false;
}
};
private class ScoreGestureDetector extends SimpleOnGestureListener {
private static final int SWIPE_MIN_DISTANCE = 5;
private static final int SWIPE_THRESHOLD_VELOCITY = 2;
#Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
try {
//if (Math.abs(e1.getX() - e2.getX()) > SWIPE_MAX_OFF_PATH)
//return false;
// right to left swipe
//if(e1.getY() - e2.getY() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
if(e1.getY() - e2.getY() > SWIPE_MIN_DISTANCE){
Toast.makeText(AndroidOrientationSensor.this, "Up Swipe", Toast.LENGTH_SHORT).show();
}
//else if (e2.getY() - e1.getY() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
else if (e2.getY() - e1.getY() > SWIPE_MIN_DISTANCE){
Toast.makeText(AndroidOrientationSensor.this, "Down Swipe", Toast.LENGTH_SHORT).show();
}
} catch (Exception e) {
// nothing
}
return false;
}
#Override
public boolean onDown(MotionEvent e1){
Toast.makeText(AndroidOrientationSensor.this, "Up Swipe", Toast.LENGTH_SHORT).show();
return true;
}
}
Finally, I am setting the gesture dectector to the the "flipCard" view like this:
flipCard.setOnTouchListener(gestureListenerScore);
Any help would be greatly appreciated.
I think the problem you're going to have is if the touch event is consumed by the button, then the second view won't receive it.
Even if it did, the fling I imagine will only get called when the user performs a fling from start to finish.
The only thing I can think of doing (despite it being very horrible / hacky) is to try and inset a fake up touch event. This might then allow the user to perform the fling, but this isn't particularly stable either.
Better way to handle it would be to have a view group consume the touch events, pass the touch events to a gesture detector to detect a long click, then set a flag within the view groups touch listener to indicate a fling is expected, then manually detect when prev y and current y go beyond a threshold. This will give you some idea of velocity but probably no where near as meaningful as the velocity provided in the onFling callback method.
What I ended up doing to solve this problem is placing a gestureDectector on the view and overriding the onDown method. This allowed me to simulate a click event. I was unable to get both a long click and a swipe event, but for my purposes the click event triggers during the swipe which seems to work well enough. Thanks to GauntFace for the inspiration.
The GestureListener also has a onLongPress event.