I am using ListView to implement a timeline. I enabled FastScroll and used SectionIndexer so that user could drag the scrollbar and see the section text displayed.
The problem is all these are built-in UI. The textview that displays the section text is too small for me, I am trying to display 05pm and it's too long for the textview(or other UI?).
Any easier way to resolve this? For instance, a method I can set the font size of the section text or the textview layout?
Thanks!
Looking through the source code for AbsListView, you can find the class that handles the fast scrolling mechanism which ends up being FastScroller. FastScroller actually draws the image drawable and text on the canvas that was provided to the AbsListView like so...
canvas.drawText(mSectionText, (int) (rectF.left + rectF.right) / 2 - hOff, (int) (rectF.bottom + rectF.top) / 2 + mOverlaySize / 4 - descent - vOff, paint);
The code above actually draws the text on top of the bottom image drawable so it does not respect the bounds of the bottom drawable, which is why the text is actually overflowing and not being cut off. As to why this is designed this way? My guess is that the intention of the index feature was to be mainly used for single characters such as A, B, C, etc... and therefore the fast scroll index feature was designed to fit that.
So, to give a definite answer to your question, there's really no way to change the text size or change how the text is being drawn unless you modify AbsListView and FastScroller to suit your need.
Related
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.
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 have a ListView with an adapter attached. The data behind it is a couple of articles. The articles have a title and a subtitle, the length of both varies.
Sometimes the text of either one is so long that the TextView doesn't fit the View created by the adapter which has a fixed height.
Is there a possibility to find out if both TextViews are completely visible within the View?
I know I would have to wait for the layout to be drawn, would do it with getViewTreeObserver().addOnGlobalLayoutListener(...)
It seems like you can only completely fit two lines per title and subtitle. If I were you, I'd measure the length of the text with the paint that's used to draw it and see if it's less than (width of line) * (number of lines).
For example, consider the following:
boolean doesTitleFitBounds = titleTextView.getPaint().measureText(titleText) < (TITLE_LINE_WIDTH * TITLE_NUM_ROWS);
where TITLE_LINE_WIDTH is the available width for your text in pixels (accounting for paddings/margins etc) and TITLE_NUM_ROWS is the number of rows you have per title.
Similarly, you can do a check for the subtitle to see if it fits its own bounds.
I have built a ListView and my items - at least in part - contain titles of various (text) lengths.
In order to enable the user to read as much of the title as possible, I'm trying to change my adapter to auto-pick a feasible font size for my texts.
So I'm working with the TextView's paint object to measure the text in a basline font size (14dp) and try to compare against the available space. If the text is too big, I reduce the font size to 12dp (later I might think about reducing it even further).
// Note: vh.filmTitleTextView is my TextView, filmText contains the title I want to display
filmTitleTextView.setTextSize(TypedValue.COMPLEX_UNIT_DIP, 14);
float textWidth = vh.filmTitleTextView.getPaint().measureText(filmText);
if (textWidth > vh.filmTitleTextView.getWidth())
vh.filmTitleTextView.setTextSize(TypedValue.COMPLEX_UNIT_DIP, 12);
The issue is that on first run, vh.filmTitleTextView.getWidth() always returns zero. I guess this is because the layout has not been rendered before and the size is not yet known.
I can't just go with the full size of the ListView because the textView doesn't have the same width (despite the fact that it is set to layout_width="fill_parent") - there are some elements around it.
Any ideas?
Had a similar problem that was my bane for a long time - this might help ya: Auto Scale TextView Text to Fit within Bounds
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/