Within Android, I'm trying to move a TextView from outside the parents bounds into view, but the contents never shows up, or remains clipped if it was partially within the bounds already.
Initial situation at start
Situation after animation
(Below this is another view, that was completely out of bounds and isn't drawn either)
I have 4 TextViews below each other in a custom Object extending RelativeLayout. Based on a percentage the top 2 should move outside it's bounds and the bottom 2 should move in (from the bottom).
I use the following code to update the properties of each TextView. In this class each variable **positionY* is filled with their initial position from the layout-xml. effect is percentage between 0 & 1. The animation works, but the views aren't drawn again.
public class ActionBarTitleView extends RelativeLayout {
public void updateTransition(float effect) {
float height = getHeight();
titleView1.setY(title1positionY - height*effect);
detailView1.setY(detail1positionY - height*effect);
titleView2.setY(title2positionY - height*effect);
detailView2.setY(detail2positionY - height*effect);
invalidate();
}
}
What I tried
After some researching I found a few hints what the issue might be, but so far none of the tried options had any effect. Below is a list of things I've found on SO and tried.
Calling invalidate() on the RelativeLayout - No effect.
Invalditing the TextViews - No effect.
clipChildren = false for the RelativeLayout - No effect.
setWillNotDraw = false for the RelativeLayout - No effect. (onDraw is being called)
I haven't tried to solve this with a ScrollView, but I don't want to really, cause that adds another layer in the hierachy for something pretty small.
I thought I understood the drawing logic, but perhaps I'm missing something, so I hope someone might be able to point me in the right direction.
What I ended up doing (September 3rd)
Since no real solution was offered, I tried again and came to the following "fix". I set both second labels to Visibility.GONE, but within the original bounds of the container view. Then when I start the animation, I set their correct values, then move them outside the bounds and finally setting Visiblity.VISIBLE. When the animation progresses the labels roll into view as supposed to. So a fix to the issue, but no real explanation why the TextViews aren't drawn again...
Related
I have a view in top of the screen which I want to always be displayed (In every device, even if keyboard is opened). The problem is that in the middle of the screen I have an EditText. In some devices, if the EditText gains focus, the keyboard opens and causes layout to move upward. I do not want to use AdjustResize which will cause background image to stretch. Is it possible to know if a layout was moved or not because of keyboard being opened? Also, how does this upward movement been calculated? I am thinking about reposition the view whenever is needed
-First attempt to solve the problem: I have tried Coordinator layout. I did not find a behavior to do what i want, so i tried to implement my own behavior. I added a space view in the bottom of the layout and whenever this view changed its position i tried to translate downward the top view. But even if layoutDependsOn() returns true the onDependentViewChanged() is not called in order to calculate the translation.
-Second attempt to solve the problem: I added again a space view in the bottom of the layout. Also, I Added an onGlobalLayoutListener in order to track if the keyboard was opened. If so, i tried to calculate space view's position and compare it with its previous position in order to move downward the top view.
-Third attempt was to use AdjustNothing and hand by myself the translations of the views that need to reposition theirselves on keyboard open. This was the only attempt that gave me some results, but seems buggy and in the future i am sure that will cause much more problems than it solves.
In addition, i found that x, y, translationX, translationY do not change in adjustPan. The only way to calculate the correct position is to use getLocationOnScreen(). But this is possible after the view was laid out. Can we calculate it before the view is laid out?
For future reference, in order to calculate the pixels of upward translation in AdjustPan mode you must do something like the following code. Basically, in AdjustPan we push as much as is needed the layout in order to make the focused EditText fully visible.
val rect = Rect()
constraintLayout.getWindowVisibleDisplayFrame(rect)
val editTextGlobalRect = Rect()
view.getGlobalVisibleRect(editTextGlobalRect)
//if it is true the editText will be hidden so the layout will be moved upwards due to adjust pan
val translation = if (editTextGlobalRect.bottom > visibleArea.bottom) {
//Calculate how much the layout is going to be pushed
editTextGlobalRect.bottom - visibleArea.bottom.toFloat()
} else {
0f
}
Also, if you want to calculate the new position of the view, in order to stick in the same screen position, you must do something like that:
val stationaryViewGlobalRect = Rect()
stationaryView.getGlobalVisibleRect(stationaryViewGlobalRect)
stationaryView.y = when {
translation <= stationaryViewGlobalRect.top -> {
//Stationary view is not hidden at all but it was moved upwards
stationaryViewGlobalRect.top - translation + resources.getDimension(R.dimen.stationary_view_margin_top)
}
translation <= stationaryViewGlobalRect.bottom -> {
//Stationary view is not fully hidden
translation + (stationaryViewGlobalRect.bottom - translation)
}
else -> translation + stationaryViewGlobalRect.top //Stationary view is fully hidden
}
my question is related to android feature to zoom the parent consisting of multiple child view's.
ZoomView->ParentView->[multiple childViews]
I am working on a Demo project to Zoom the child View and to pan infinitely.Zooming works perfectly as needed.
PROBLEM 1:
But if there is a EditText in the view and i try to zoom on that then below issues are faced by me.
on zooming in the text is blurred
pointing on a text is working fine but translating through the text is
translating very fast as its translation is multiplied by the
scalingFactor
Selecting the text is also having above issue.
Try running the the Demo to understand the issue if not clear from above
I have tried two approaches to Zoom the content of the View but both approaches gave the same issue.
Scaling canvas and transforming the MotionEvent by scaling the MotionEvent by Matrix.class of the Parent Class.
Setting ScaleX and ScaleY of the Parent containing the childViews
hierarchy of my demo project zooming the view(UML Diagram)
Basic problem is placing the cursor at the right position when the view is scaled to some value.
I have already referred to this thread
PROBLEM 2:
if i have a childView which is movable in the parent View then after zooming out if the childView is translated outside the bounds of parentView the events are ceased to capture and the child view becomes untouchable
i have tried using TouchDelegate but i don't know how to expand the parentView touch area .Code reference Thread
scale is 1 the area touch area is equal to screen for parentView and ZoomView
But when scale factor is not equal to one the touch area of parent is lesser(zoomIn) than the ZoomView as displayed
Yellow-parentView Touch Region
Cyan-ZoomView Touch Region
Green-ChildView Touch Region
ScreenShot here
Note:
This is my first Question on StackOverflow So please recommend if some edits are needed.
This the the closest i got to solve above problem's.
PROBLEM 1:
On zooming in the text is blurred
setLayerType(LAYER_TYPE_HARDWARE,null);
set layer type Hardware in the view which has text View. for me i
set it in green square view.
pointing on a text is working fine but translating through the text is translating very fast as its translation is multiplied by the scalingFactor
Selecting the text is also having above issue.
For above two:
This is a bug in android when you scale a view using the scaleX,scaleY api's the EditText get's event based on the current scale value of parent's.But issue is with the Cursor of editText.
The best solution we got is we wrote our own EditTextView (which extend's TextView).As we checked android framework source code we came to know that android use's PopUpWindow to display cursor on screen.
The source of issue is when we use scaleX and scaleY editText get's scaled even't as it's parent is scaled but as cursor is a PopUpWindow and not a child of EditText so event's are not scaled and above issue occur's
So wrote our own EditText if you see the source code EditText code is not very complex and can be written on our own.And to solve the scaling issue of Cursor, we added our own Cursor PopUpWindow and made it Scale aware.
NOTE:
(UPDATE)
Check at demo code here customEditText and CustomCursor.
Run the project set focus pink focus(BY Android) will come ,wait for few seconds then the black cursor will appear that is the custom cursor.
It is a very basic example and we need to add all other edit text Feature's on our own like multi-Select, popUpMenu etc.
PROBLEM 2: if i have a childView which is movable in the parent View then after zooming out if the childView is translated outside the bounds of parentView the events are ceased to capture and the child view becomes untouchable i have tried using TouchDelegate but i don't know how to expand the parentView touch area
This solution is specific to the given problem not a generic one
as there can be multiple solution's for this problem.
In this case 3 view's are there:
Yellow-parentView of green square View
Cyan-parent of yellow View
Green-ChildView non touchable outside parent
My Solution is that i used created a callback from green square view to Yellow parent view. Whenever the translation of green square view ended the callback is triggered and in yellow parent i used below code.
override fun eventEnded() {
setDelegate()
}
fun setDelegate() {
val rect = Rect()
val parent = (this.parent as View)
parent.getHitRect(rect)
val touchDelegate = TouchDelegate(rect, this)
if (View::class.java.isInstance(editorContainer.parent)) {
(editorContainer.parent as View).touchDelegate = touchDelegate
}
}
The above code translate to : when child view translation is ended check the bound's of parent and update the TouchDelegate accordingly.
As the problem i faced was when i scaled(Zoomed) the view then the View's delegate was not updated so for that also solution is same make a callback from zoomView (parent) to yellowView (childView) onScaleEnded call setDelegate().
When scale changes the hitArea also changes but as per delegate nothing is changed so we need to update the rect of TouchDelegate.
Please feel free to discuss in comment section. If someone has a better solution Really eager to know.As we tried many different solution's but nothing else worked.This is the best i found and i am using above code in production and haven't faced any issue till now.
The best approach for translating and scaling EditText is to use scaleX, scaleY, translateX, translateY on this particular EditText instead of parent layout canvas translation.
e.g. in kotlin
editText.scaleX = scaleFactor
editText.scaleY = scaleFactor
editText.translateX = offsetLeft
editText.translateŠ½ = offsetTop
By the way, it is possible to check if touch area and drawing area are the same in android studio using Tools -> Layout Inspector.
Background
To learn animations, I'm creating a Towers of Hanoi type of game. My main goal is to animate the movement of the block from one tower to another. I've got the following layout
|------RelativeLayout------|
|-Linear-|-Linear-|-Linear-|
|-Block1-|-----------------|
|-Block2-|-----------------|
|-Block3-|-----------------|
|--------------------------|
ID| Tower1 | Tower2 | Tower3 |
I've set the XML attribute android:clipChildren="false" on every ViewGroup.
For example, if I tried to animate the movement of Block1 from Tower1 to Tower2 using Block1.animate().setDuration(3000).translationX(1000). As the layout is right now, Block1 will animate within Tower1, but Block1 gets clipped the second it leaves Tower1.
I've played with changing the z-order by adding the blocks last in the XML file. It doesn't reliably work, though.
To ensure animations don't get clipped, I've decided to add a copy of the Block1 (named copyBlock) to the root RelativeLayout, position copyBlock on top of Block1, and animate it to the destination Tower2 (defined in coordinates)
To get the destination coordinates, I was planning on adding an invisible copyBlock to Tower2, then get the coordinates. This way, I can take advantage of the LinearLayout's layout functions to account for matters such as padding, gravity, etc. Otherwise, I'll have to get the position of Tower2, calculate the topmost block, adjust the coordinates of Block1 so that it'll be on top of the topmost block and centered.
But, I'm pretty sure this way is hacky, and there's a better way
Questions
How can I get the above destination coordinates without having to add an invisible view to the destination tower? Is there a way to ask for a "prelayout" without having to add View to the layout?
Do you have any explanations for why the animation gets clipped? Is there a better way to approach this rather than adding a new view to the root RelativeLayout ViewGroup?
Ok,
1- You can't overcome the clipping issue, because you are trying to move the child beyond the parent dimensions, unless you are moving within the same parent.
2- Use FrameLayout instead of RelativeLayout so you can control views margins correctly;
3- You can get the destination coordinates by knowing the height of the root layout and width, its seems the towers width are equal, so the (total width/3) will give the cell width then get the X coordinate, and the (total height - cell height ) will give the Y coordinate of the tower ( assuming you have the tower hight)
This question is very specific, What I am trying to do (with a list view) is described in great detail in the following article: http://www.pushing-pixels.org/2011/07/18/android-tips-and-tricks-synchronized-scrolling.html
Thanks #kaushal trivedi for the link
Details:
I have an android application I am working on that uses a list view with a custom adapter. The Listview Contains a Custom header of a non-fixed height. Also please note that the list items are also of variable height. My goal is to mimic the effect produced in the latest gmail app (as an example) where when you are viewing an email, and scroll past the header, it sticks to the top of the screen just under the action bar and the content continues to scroll under it. What I would like to do, is stick the bottom half of my header to the top of the screen.
My initial reasoning was to create an invisible view fixed in the desired location, and when the user scrolled to or past that location, make the view visible. The issue in this logic, is I need the exact pixel scroll height, which after many attempts I have determined very difficult to do. The exact issue I ran into is, it is not possible from what I can gather to retrieve the pixel level Y-scroll in an onScroll event, I have only been able to retrieve the value in the onScrollStateChanged event. Which as described above will not achieve the desired functionality.
Working with the onScroll event "int firstVisibleItem, int visibleItemCount, int totalItemCount" parameters is also not an option because of the fact that the content I want to "stick" is not the size of a list item, but a fraction of the size of the variable height header.
Is there a correct way to accomplish this effect? My current minSDK level is 10.
Update 10/10/13
I made some progress. The following code syncs the Y position floating view I have on the screen with the list view. b is the view I am setting just as an example.
NOTE: This is used in the onScroll event of the list view.
View c = view.getChildAt(0);
if (c != null) {
int currY = c.getTop();
int diffY = currY - lastY;
lastY = currY;
b.setTop(b.getTop() + diffY);
}
Now the issue is, the header of my List is a non fixed height as I said earlier. So I need to get the height of the header and apply an offset to "b" to place it at the bottom of the list header floating above the list.
This is the code I've tried so far.
header.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
The issue here us header.getMeasuredHeight(); always resolves to the same value no matter how tall the actual height is.
I understand I cannot get the height until after it is displayed. Is there a way I can get that value and set the offset after it is rendered?
Update 10/11/13
I Answered my last question as soon as I woke up this morning.
While the View.measure() code was returning a height. It appears to be the default height of the view, assuming there was no text (that would ultimately stretch the view). So I used the below event to listen for when the view is displayed, and then record its actual height (which works exactly as I had hoped :) )
ViewTreeObserver vto = header.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
b.setY(header.getMeasuredHeight() - 80); //80 is a temp offset
}
});
I have to go to work soon and being that I have still not fully achieved the desired effect, I will not mark this as answered yet. Hopefully I will be able to sit down and finish this in the next day or two. I am still open to suggestions on better ways of doing this.
Okay, so after a lot of time and research, I have found an answer to my question.
First off, Thank you #kaushal for this link: http://www.pushing-pixels.org/2011/07/18/android-tips-and-tricks-synchronized-scrolling.html
My solution ended up being somewhat complex. So instead of trying to describe it here, I made an example app and posted it here: https://github.com/gh123man/Partial-Header-ListView-Scroll-Sync
The specific file containing the code for the solution is here: https://github.com/gh123man/Partial-Header-ListView-Scroll-Sync/blob/master/src/com/example/partialheaderlistviewscrollsync/MainActivity.java
I am drawing a custom view in my application which basically takes arguments(XML) as the text to display and then keeps on rotating it infinitely.
While I was making this control I had a few doubts which I want to ask:
I have made 2 of my stylable attributes which I have declared in the attrs.xml file. These attributes are to set the width and the width of the circle used in my control. These values I would use in the ondraw method and the onmeasure method. I ran my program by declaring just these but there was an error which asked me to put android:width and android:height attributes. My question is why would I need those if I am already using my custom attributes to define the height and the width of my view
I am coding on a mac. Now when I was making my attrs.xml file, to get the autocomplete list which we usually get by ctrl+space was not showing up. Why is that. For e.g., i wanted to know what values can I give the format attribute of my custom attribute that like I am demostrating in the following:
<attr name ="somename" format="value I wanted to find out through autocomplete"> . Why is the autocomplete not popping up? It does pop up when I am making a.java file.
In my ondraw() method I wanted to draw a circle. Now for this I would require the co-ordinates of the center of the circle. So what I do is put 0, 0. But this is not correct. I want the circle to be at the center of the parent view it is in. So if my view is in a hierarchy I want it to respect that. I want to give the co-ordinates relative to the parent view. What is happeining right now is that it is being drawn at the top left corner of my screen. This is what I don't want. What do I do to achieve this?
why would I need those if I am already using my custom attributes to define the height and the width of my view?
This is because Android needs to know how and where to put your view in the layout. You can implement your view to make use of your custom height/width requirements by overriding View.onMeasure() to return your own size parameters. You can then just set android:layout_width="wrap_content" android:layout_height="wrap_content" in your layout file.
Why is the autocomplete not popping up? It does pop up when I am making a.java file.
Autocomplete and autodoc implementation for Android xml files is shaky at best, so it's not really surprising that it doesn't work. I'm not aware of a fix and AFAIK it's an IDE bug.
In my ondraw() method I wanted to draw
a circle. Now for this I would require
the co-ordinates of the center of the
circle. So what I do is put 0, 0. But
this is not correct. I want the circle
to be at the center of the parent view
it is in. So if my view is in a
hierarchy I want it to respect that. I
want to give the co-ordinates relative
to the parent view. What is happeining
right now is that it is being drawn at
the top left corner of my screen. This
is what I don't want. What do I do to
achieve this?
If you implemented onMeasure() correctly, the coordinates relative to parent should be taken care of already. To get the center of your view use the following code:
void onDraw(Canvas canvas)
{
int centerX = this.getWidth() / 2;
int centerY = this.getHeight()) / 2;
//..draw code here
}
Edit
Here's an example with source code that should help: http://mindtherobot.com/blog/272/android-custom-ui-making-a-vintage-thermometer/