Develop Reference

HorizontalScrollView onTouch

I Am using Horizontal Scroll View and its work fine , i have 2 web view inside my horizontal Scroll View , my problem is that when u scroll down or up in the web view sometime it go left or right to the other web view because of the Horizontal Scroll View , i use this code
HorizontalScrollView hv = (HorizontalScrollView)findViewById(R.id.horizontalScrollView2);
webView22.setOnTouchListener(new View.OnTouchListener() {
private String TAG;
public boolean onTouch(View v, MotionEvent event) {
Log.v(TAG,"PARENT TOUCH");
findViewById(R.id.webView22).getParent().requestDisallowInterceptTouchEvent(false);
return false;
}
});
webView22.setOnTouchListener(new View.OnTouchListener() {
private String TAG;
public boolean onTouch(View v, MotionEvent event)
{
Log.v(TAG,"CHILD TOUCH");
// Disallow the touch request for parent scroll on touch of child view
findViewById(R.id.webView23).getParent().requestDisallowInterceptTouchEvent(true);
return false;
}
});
when i use the TAG i got error say The field FragmentActivity.TAG is not visible
but when i add the private String TAG; it go , anyway i am not sure if it is correct ,
How ever after i test it the webView22 is good and great but if i want to go right and left using the Horizontal it will not be work ,
i tried to change the CHILD TOUCH to BUTTON_BACK but still the same . i feel that tag not doing anything it just go to
findViewById(R.id.webView22).getParent().requestDisallowInterceptTouchEvent(false);
return false;
i hope some one can help

Actually, the case here is that both the horizontal scroll view and the web view consume the scroll event. Now it will be hard for the Android OS to decide onto which listener should this scroll event go to.
An option to this will be using Slide animations instead of a horizontal scroll view.
fragmentTransaction.setCustomAnimations(R.anim.slide_bottom_in,
R.anim.slide_bottom_out,R.anim.slide_bottom_in,
R.anim.slide_bottom_out);
But these will again need to be triggered with some event. like button click.
Or you can go for the view pager implementation.

i had the same issue, there are some ways, but many of them require changing the layout, wrong data is send to the child of HorizontalScrollView mostly in the cases where there are children inside the child of HorizontalScrollView.
So i did things like this, instead of:
val childA = horizontalScrollView.getChild(0)
childA.setOnTouchListener(this)
do
horizontalScrollView.setOnTouchListener(this)
This way you have to calculate the clicks, and calls, but it works better than before to me, the scroll was slow and glitchy before.
var touchHistory=0
var lastTouchX=0f
override fun onTouch(v: View?, event: MotionEvent?): Boolean {
if (event == null || v == null) return false
when {
event.action == MotionEvent.ACTION_DOWN -> {
touchHistory=0
lastTouchX=event.x
// Screen1=0-480 / Screen2=0-2304 / ScrollPos=0-2304
// Sample: 240 480 - 576 2304 = 240+576 = result
val child = (v as HorizontalScrollView).getChildAt(0)
val sXCurrent = event.x.toDouble()
val sXMax = v.width.toDouble()
val s2XCurrent = scrollX
val s2XMax = child.width
val clickPos = s2XCurrent+sXCurrent
val result = clickPos/s2XMax
// Do something
}
event.action == MotionEvent.ACTION_UP -> {
if(touchHistory==0){
//Click performed, do something
}
//if touchHistory > 0 is currently scrolling and click is omitted
lastTouchX=event.x
touchHistory=0
}
event.action == MotionEvent.ACTION_MOVE -> {
if(event.x!=lastTouchX)touchHistory++ //Check wether is clicking or scrolling
lastTouchX=event.x
}
}
return false
}

Android view handle scroll gestures but ignore touch up

I have a use case where there are two views on screen one of which is partially covering another. The one that is above needs to handle scroll events and ignore touch up. The partially obscured view should handle touch up events, including those that happen in the area of overlap that are ignored by the obscuring view.
a simplified example layout is below.
the closest i've come uses GestureDetectorCompat on the top view returning true in onDown (otherwise i don't get any further events,) true in onScroll, and false in onSingleTapUp. i have tried several things in the view behind all with the same results: i get taps on the un-obscured section, but the top view eats all of the motion events for the obscured portion.

What you want to do is not as straightforward as you would probably like because of how Android handles touch event flow. So let me set the stage with a little context first:
The reason this is a tricky proposition is because Android defines a gesture as all the events between an ACTION_DOWN and the corresponding ACTION_UP. ACTION_DOWN is the only point at which the framework is searching for a touch target (which is why you have to return true for that event to see any others). Once a suitable target has been found, ALL the remaining events in that gesture will be delivered directly to that view and nobody else.
This means that if you want a single event to go to a different destination, you will have to capture and redirect it yourself. All touch events flow from parent views to child views in one long chain. Parent views control when and how touch events move from one child to the next, including modifying the coordinates of the MotionEvent so the match the local bounds of each child view. Because of this, the most effective place to manipulate touch events is in a custom ViewGroup parent implementation.
The following example comes with a big bag of assumptions. Basically, I'm assuming that both views are nothing more than a dumb View with no internal wishes to handle touch (which is probably wrong). Applying this code to other, more complex, child views may requires some rework...but this should get you started.
The best place to force touch redirection is in a common parent of the two views, since it is the origin of the touch for both (as described above).
public class TouchUpRedirectLayout extends FrameLayout implements View.OnTouchListener {
private int mTargetViewId;
private View mTargetView;
private boolean mTargetTouchActive;
private GestureDetector mGestureDetector;
public TouchUpRedirectLayout(Context context) {
super(context);
init(context);
}
public TouchUpRedirectLayout(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
public TouchUpRedirectLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init(context);
}
private void init(Context context) {
mGestureDetector = new GestureDetector(context, mGestureListener);
}
public void setTargetViewId(int resId) {
mTargetViewId = resId;
updateTargetView();
}
#Override
protected void onFinishInflate() {
super.onFinishInflate();
//Find the target view, if set, once inflated
updateTargetView();
}
//Set the target view to handle gestures
private void updateTargetView() {
if (mTargetViewId > 0) {
mTargetView = findViewById(mTargetViewId);
if (mTargetView != null) {
mTargetView.setOnTouchListener(this);
}
}
}
private Rect mHitRect = new Rect();
#Override
public boolean onInterceptTouchEvent(MotionEvent event) {
switch (event.getActionMasked()) {
case MotionEvent.ACTION_UP:
if (mTargetTouchActive) {
mTargetTouchActive = false;
//Validate the up
int index = indexOfChild(mTargetView) - 1;
if (index < 0) {
return false;
}
for (int i=index; i >= 0; i--) {
final View child = getChildAt(i);
child.getHitRect(mHitRect);
if (mHitRect.contains((int) event.getX(), (int) event.getY())) {
//Dispatch and mark handled
return child.dispatchTouchEvent(event);
}
}
//Steal this event
return true;
}
//Allow default processing
return false;
default:
//Allow default processing
return false;
}
}
//Receive touch events from the target (scroll handling) view
#Override
public boolean onTouch(View v, MotionEvent event) {
mTargetTouchActive = true;
return mGestureDetector.onTouchEvent(event);
}
//Handle gesture events in target view
private GestureDetector.SimpleOnGestureListener mGestureListener = new GestureDetector.SimpleOnGestureListener() {
#Override
public boolean onDown(MotionEvent e) {
Log.d("TAG", "onDown");
return true;
}
#Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
Log.d("TAG", "Scrolling...");
return true;
}
};
}
This example layout (I subclassed FrameLayout, but you could choose whichever layout you are using currently as the parent of the two views) tracks a single "target" view for the purposes of notifying the "down" and "scroll" gestures. It also notifies us when a gesture is in play that will include an ACTION_UP event that we need to capture and forward to another obscured view.
When an up event occurs, we use the intercept functionality of ViewGroup to direct that event away from the original "target" view, and dispatch it to the next available child view whose bounds fit the event. You could just as easily hard-code the second "obscured" view here as well, but I've written it to dispatch to any and all possible children underneath...similar to the way ViewGroup handles touch delegation to children in the first place.
Here is an example layout:
<com.example.touchoverlaptest.app.TouchUpRedirectLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/view_root"
android:layout_width="match_parent"
android:layout_height="400dp"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context="com.example.touchoverlaptest.app.MainActivity">
<View
android:id="#+id/view_obscured"
android:layout_width="match_parent"
android:layout_height="250dp"
android:background="#7A00" />
<View
android:id="#+id/view_overlap"
android:layout_width="match_parent"
android:layout_height="250dp"
android:layout_gravity="bottom"
android:background="#70A0" />
</com.example.touchoverlaptest.app.TouchUpRedirectLayout>
...and Activity with the view in action:
public class MainActivity extends Activity implements View.OnTouchListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TouchUpRedirectLayout layout = (TouchUpRedirectLayout) findViewById(R.id.view_root);
layout.setTargetViewId(R.id.view_overlap);
layout.findViewById(R.id.view_obscured).setOnTouchListener(this);
}
#Override
public boolean onTouch(View v, MotionEvent event) {
Log.i("TAG", "Obscured touch "+event.getActionMasked());
return true;
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
The target view will fire all the gesture callbacks, and the obscured view will receive the up events. The OnTouchListener in the activity is simply to validate that the events are delivered.
If you would like more detail about custom touch handling in Android, here is a video link to a presentation I did recently on the topic.

OnTouch method consumes click event and prevents execution in parent

I'm having a FrameLayout that has an extended ImageView (github) as a child. When I set an onClick()-Event to the FrameLayout it won't be triggered. The reason appears to be the onTouch() method's return value.
If I set the ACTION_DOWN's return value to false the event is passed along properly - but then the Multitouch functionalities break. Also running performClick() in the ACTION_UP event comes to nothing.
How to handle those events correctly?

Currently I solved the issue by manually passing the click event to the view's parents:
new GestureDetector( context, new GestureDetector.SimpleOnGestureListener()
{
#Override
public boolean onSingleTapConfirmed( MotionEvent event )
{
View view = MultitouchImageView.this;
if( !performClick() )
{
while( view.getParent() instanceof View )
{
view = (View) view.getParent();
if( view.performClick() )
{
return true;
}
}
return false;
}
return true;
}
...
}
Doing the same thing for an occuring LongPress event. It works the way I need it but I don't like the solution..

Try setting the parent FrameLayout to receive touches before the ImageView child.
You can do this by adding
android:descendantFocusability="beforeDescendants"
to the xml of the parent.
e.g.
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:descendantFocusability="beforeDescendants">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</FrameLayout>

Is it possible to pass an onTouchEvent to multiple views in Android?

I have read a few questions regarding this topic on SO but haven't really found a solid answer to it.
I have a framelayout that I stack multiple custom views on, however the onTouch event only works with the top view. (the custom views are all the same view with the same onTouch event, just multiple of them)
FrameLayout
customView[2] <--- this is the last view added and the only one that receives the event
customView[1]
customView[0]
I'm testing it on Android 2.2 and am wondering if there is any way for the other views below to know where the touch happened?
EDIT (Adding some code)
I'm adding some code to hopefully help explain where I'm running into issues. At first I just automatically had the onTouchEvent return true. This made it so that the last view (in my case customerView[2]) would be the only one generating a value.
However, once I added the method to set the onTouchEvent to return true or false, now the only view returning a generated value is customView[0].
I hope this clears up what I am asking. I'm rather new to this and I appreciate you taking the time to explain it (and of course I appreciate your patience).
Also, I realize that my TextView's don't update with the value on each touchEvent, I'm working on fixing that.
My Activity:
public class MyActivity extend Activity {
CustomView[] customView;
TextView[] textView;
int numViews 3;
//FrameLayout and Params created
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
for(int i = 0; i < numViews; i++) {
customView[i] = new CustomView(this, i);
//Allows the onTouch to be handled by all Views - View[0] is the bottom view
if(i == 0) {
customView[i].setTouchBool(true); //set view's onTouch to return true
} else {
customView[i].setTouchBool(false); //set view's onTouch to return false
}
//Set TextView to display the number generated by the CustomView
textView[i].setText(Double.toString(customView[i].getGeneratedNumber()));
//Add views to main layout
frame.addView(textView[i]);
frame.addView(customView[i]);
}
}
}
My View:
public class CustomView extends View {
boolean onTouchHandler = true;
int xVal = 0, yVal = 0;
int index;
double generatedNum = 0;
public CustomView(Context context) {
this(context, 0);
this.index = 0;
}
public CustomView(Context context, int index) {
super(context);
this.index = index;
}
#Override
public boolean onTouchEvent(MotionEvent ev) {
final int action = ev.getAction();
switch(action) {
case MotionEvent.ACTION_DOWN: {
//do logic
}
case MotionEvent.ACTION_MOVE: {
//do logic
}
case MotionEvent.ACTION_UP: {
xVal = (int) ev.getX();
yVal = (int) ev.getY();
generateNumber(xVal, yVal, index);
break;
}
}
return onTouchHandler;
}
private void generateNumber(int x, int y, int index) {
if(index == 0) {
generatedNum = (x / 2) * (y / 2) + 64;
} else {
generatedNum = (x / 2) * (y / 2) + (index * 128);
}
}
public double getGeneratedNumber() {
return generatedNum;
}
public boolean setTouchBool(boolean b) {
this.onTouchHandler = b;
}
}

Android will cascade down the views calling onTouchEvent on each one until it receives a true from one of them. If you want a touch event to be handled by all of them, then return false until it reaches the last one.
EDIT:
Ok. If I understand correctly, you have a single top view containing a bunch of child views one layer deep. My original answer was assuming that you had three custom views that were on top of each other in the ViewGroup's hierarchy (View3 is a child of View2. View2 is a child of View1. View1 is a child of ParentView). You want the user's touch event on the parent view to get sent to all of it's children.
If that's the case, AFAIK, there is no view in Android's API that allows that. So, you'll have to make a custom view that does it.
OK, I haven't tested this, so please tell me if it works and if it's what you're trying. Create a custom class that extends whatever object frame is, then override the onTouch method like so.
#Override
public boolean onTouchEvent(MotionEvent ev) {
for(int i = 0; i < this.getChildCount(); i++){
this.getChildAt(i).dispatchTouchEvent(ev);
}
return true;
}
Now, keep the same logic that your custom views have, except they should all return false because your parent view will not receive the onTouch event unless they do as stated in my previous answer
note: with this implementation, the child view that the user actually touches will fire twice because the logic will go
fire child touch event -> return false -> fire parent touch event -> fire child touch event again

I know this question is very old, but I had the same problem and solved it by creating my own Layout to determine which child is actually touched.
I therefore iterate over the children of my custom layout and check if the user actually clicked on the view. The collision detection is handled in the custom view's onTouch() method. (Collision detection is done by intersecting a Region() with the event's x,y coordinates. For me this was convennient because I drew the custom view with a Path())
Here is a kotlin code snippet from my custom layout for better understanding:
class CustomLayout(context: Context, attrs: AttributeSet) :
RelativeLayout(context, attrs){
override fun dispatchTouchEvent(ev: MotionEvent): Boolean {
if(ev.action != MotionEvent.ACTION_UP){
return true
}
//Iterate over child view and search for the right child that should handle this touch event
for (i in childCount - 1 downTo 0) {
val child = getChildAt(i)
if (!viewTouched(child, ev)) {
continue
}
//Do something
Timber.d("Touched view: ${child.id}")
}
return true
}
private fun viewTouched(child: View, ev: MotionEvent) : Boolean {
child as OnTouchListener
//onTouch() does the collision detection
return child.onTouch(child, ev)
}

Disable the touch events for all the views

What's the best way to disable the touch events for all the views?

Here is a function for disabling all child views of some view group:
/**
* Enables/Disables all child views in a view group.
*
* #param viewGroup the view group
* #param enabled <code>true</code> to enable, <code>false</code> to disable
* the views.
*/
public static void enableDisableViewGroup(ViewGroup viewGroup, boolean enabled) {
int childCount = viewGroup.getChildCount();
for (int i = 0; i < childCount; i++) {
View view = viewGroup.getChildAt(i);
view.setEnabled(enabled);
if (view instanceof ViewGroup) {
enableDisableViewGroup((ViewGroup) view, enabled);
}
}
}

Override the dispatchTouchEvent method of the activity and like this:
#Override
public boolean dispatchTouchEvent(MotionEvent ev){
return true;//consume
}
If you return true all touch events are disabled.
Return false to let them work normally

You could try:
your_view.setEnabled(false);
Which should disable the touch events.
alternatively you can try (thanks to Ercan):
#Override
public boolean dispatchTouchEvent(MotionEvent ev){
return true;//consume
}
or
public boolean dispatchTouchEvent(MotionEvent ev) {
if(!onInterceptTouchEvent()){
for(View child : children){
if(child.dispatchTouchEvent(ev))
return true;
}
}
return super.dispatchTouchEvent(ev);
}

This piece of code will basically propagate this event to the parent view, allowing the touch event, if and only if the inProgress variable is set to false.
private boolean inProgress = false;
#Override
public boolean dispatchTouchEvent(MotionEvent ev) {
if (!inProgress)
return super.dispatchTouchEvent(ev);
return true;
}

Use this. returning true will indicate that the listener has consumed the event and android doesn't need to do anything.
view.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
return true;
}
});

The easiest way to do this is
private fun setInteractionDisabled(disabled : Boolean) {
if (disabled) {
window.setFlags(WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE, WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE)
} else {
window.clearFlags(WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE)
}
}

What about covering a transparent view over all of your views and capturing all touch event?

getWindow().setFlags(WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE,
WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE);

In Kotlin:
fun View.setEnabledRecursively(enabled: Boolean) {
isEnabled = enabled
if (this is ViewGroup)
(0 until childCount).map(::getChildAt).forEach { it.setEnabledRecursively(enabled) }
}
// usage
import setEnabledRecursively
myView.setEnabledRecursively(false)

I made this method, which works perfect for me. It disables all touch events for selected view.
public static void disableView(View v) {
v.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
return true;
}
});
if (v instanceof ViewGroup) {
ViewGroup vg = (ViewGroup) v;
for (int i = 0; i < vg.getChildCount(); i++) {
View child = vg.getChildAt(i);
disableView(child);
}
}
}

It may not be possible for the whole application. You will have to override onTouchEvent() for each view and ignore the user inputs.

Per your comment:
i just want to be able to disable the views of the current activity at some point
you seem to want to disable all touch for the current activity regardless of the view touched.
Returning true from an override of Activity.dispatchTouchEvent(MotionEvent) at the appropriate times will consume the touch and effectively accomplish this. This method is the very first in a chain of touch method calls.

In case you want to disable all the views in a specific layout, one solution is adding a cover ( a front view that fills up the whole layout ) to consume all the touch events, so that no events would be dispatched to other views in that layout.
Specifically, you first need to add a view to the layout in xml file ( note that it should be placed after all the other views ), like
<FrameLayout>
... // other views
<View
android:id="#+id/vCover"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</FrameLayout>
then, remember to set click listener to that view in your code so that it will consume touch events, like
override fun onCreate(savedInstanceState: Bundle?) {
viewBinding.vCover.setOnClickListener {}
}
That's all you need.
At the point you want to enable all the view, just gone the cover.

This worked for me, I created an empty method and called it doNothing.
public void doNothing(View view)
{
}
Then called this method from onClick event on all the objects I wanted to disable touch event. android:onClick="doNothing"
When the click or touch event is fired nothing is processed.

One more easier way could be disabling it through layout (i.e. .xml) file:
Just add
android:shouldDisableView="True"
for the view you want disable touch events.