I would like to define the z order of the views of a RelativeLayout in Android.
I know one way of doing this is calling bringToFront.
Is there are better way of doing this? It would be great if I could define the z order in the layout xml.
The easiest way is simply to pay attention to the order in which the Views are added to your XML file. Lower down in the file means higher up in the Z-axis.
Edit:
This is documented here and here on the Android developer site. (Thanks #flightplanner)
If you want to do this in code
you can do
View.bringToFront();
see docs
Please note, buttons and other elements in API 21 and greater have a high elevation, and therefore ignore the xml order of elements regardless of parent layout. Took me a while to figure that one out.
In Android starting from API level 21, items in the layout file get their Z order both from how they are ordered within the file, as described in correct answer, and from their elevation, a higher elevation value means the item gets a higher Z order.
This can sometimes cause problems, especially with buttons that often appear on top of items that according to the order of the XML should be below them in Z order. To fix this just set the android:elevation of the the items in your layout XML to match the Z order you want to achieve.
I you set an elevation of an element in the layout it will start to cast a shadow. If you don't want this effect you can remove the shadow with code like so:
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
myView.setOutlineProvider(null);
}
I haven't found any way to remove the shadow of a elevated view through the layout xml.
I encountered the same issues: In a relative layout parentView, I have 2 children childView1 and childView2. At first, I put childView1 above childView2 and I want childView1 to be on top of childView2. Changing the order of children views did not solve the problem for me. What worked for me is to set android:clipChildren="false" on parentView and in the code I set:
childView1.bringToFront();
parentView.invalidate();
Please note that you can use view.setZ(float) starting from API level 21. Here you can find more info.
Thought I'd add an answer since the introduction of the
android:translationZ
XML field changed things a tad. The other answers that suggest running
childView1.bringToFront();
parentView.invalidate();
are totally spot on EXCEPT for that this code will NOT bring childView1 in front of any view with a hardcoded android:translationZ in the XML file. I was having problems with this, and once I removed this field from the other views, bringToFront() worked just fine.
API 21 has view.setElevation(float) build-in
Use ViewCompat.setElevation(view, float); for backward compatibility
More methods ViewCompat.setZ(v, pixels) and ViewCompat.setTranslationZ(v, pixels)
Another way collect buttons or view array and use addView to add to RelativeLayout
childView.bringToFront() didn't work for me, so I set the Z translation of the least recently added item (the one that was overlaying all other children) to a negative value like so:
lastView.setTranslationZ(-10);
see https://developer.android.com/reference/android/view/View.html#setTranslationZ(float) for more
Or put the overlapping button or views inside a FrameLayout. Then, the RelativeLayout in the xml file will respect the order of child layouts as they added.
You can use custom RelativeLayout with redefined
protected int getChildDrawingOrder (int childCount, int i)
Be aware - this method takes param i as "which view should I draw i'th".
This is how ViewPager works. It sets custom drawing order in conjuction with PageTransformer.
Check if you have any elevation on one of the Views in XML. If so, add elevation to the other item or remove the elevation to solve the issue. From there, it's the order of the views that dictates what comes above the other.
You can use below code sample also for achieving the same
ViewCompat.setElevation(sourceView, ViewCompat.getElevation(mCardView)+1);
This is backward compatible.
Here mCardView is a view which should be below sourceView.
Related
I've got a problem and have no idea how to fix it. I'm using a ConstraintLayout in android
I want to set my TextView to wrap_content programmatically but respect my constraints.
Now the issue is that if i set my constriantWidth to WRAP_CONTENT it does not respect the constraints it's given to it.
I've found that there is a solution in xml in it here:
Wrap_content view inside a ConstraintLayout stretches outside the screen
but in this issue no where is it described how to set the property of constrainedwidth to true programmaticly.
I've tried a few things but have not found a solution to my problem:
set.constrainWidth(textView.getId(),ConstraintSet.WRAP_CONTENT)
just wraps the content without keeping in my constriants that i've set.
I've also tried to set the constraintedWidth with the ConstraintLayout.Params but nothing happend.
And i have no clue if en how i can set constrainedWidth in my ConstraintSet.
and
set.constrainWidth(textView.getId(),ConstraintSet.MATCH_CONSTRAINT_WRAP)
Just makes my text a thin line of my text and doesn't show my text anymore.
If someone could help i would be very great full.
PS. Sorry for my english not a native speaker.
Use constrainDefaultWidth:
set.constrainDefaultHeight(textView.getId(), ConstraintSet.MATCH_CONSTRAINT_WRAP);
I need to use following otherwise my custom widget was overlapped by a Toolbar:
android:layout_marginTop="?android:attr/actionBarSize"
But I want to have additional margin, say 10dp. I cannot do something like:
android:layout_marginTop="?android:attr/actionBarSize + 10dp"
because + is not allowed character there. Is there any other way except coding a rule programmatically?
You could wrap your ViewGroup into another one just to add the 10dp margin. Not optimal but that would work.
Layout XML files do not support expressions. So You can't Perform exepression on it. You can perform in XSLT.
There is one trick describe below.
margin + padding as describe in this Answer.
Source : How do I apply mathematical operations to Android dimensions?
Why new created constraintLayout does not have android:id="#+id/constraint_layout_file_name"?
After creating new constraintLayout we suppose to go to Design view and start creating our layout. But when we do so and we add to our layout for example a TextView, place it where we like and provide constraints so it stays like this after pushing layout on a device it will not stay where we want it to be. It will appear on left top corner on a device because constraints we provided have error
The id "constraintLayout" is not defined anywhere.
What we have to do is to manually add android:id="#+id/constraint_layout_file_name" and edit all constraints. Example:
wrong constraint:
app:layout_constraintLeft_toLeftOf="#+id/constraintLayout"
corect one:
app:layout_constraintLeft_toLeftOf="#+id/constraint_layout_file_name"
Reason why I do ask is that it took me too much time to figure out what I'm doing wrong and I think I'm not the only one.
i had the same problem.
and when i turned on the Autoconnect (on the top | left side) it fixed it by changing it
from:
app:layout_constraintLeft_toLeftOf="#+id/constraintLayout"
to:
app:layout_constraintLeft_toLeftOf="parent"
first,compile 'com.android.support.constraint:constraint-layout:1.0.0-beta4';
second,sync your project!
I'm creating my own personalized ListView by extending the ListView itself. This particular ListView shouldn't have scrollbars.
How can I disable the XML android:scrollbars attribute for my custom ListView?
I can't find a way to disable them programmatically. What am I missing?
The answer from dzeikei's will disable the scrollbars programmatically and ignore any value from android:scrollbars but what I'm really asking on 1. is how to make android:scrollbars an invalid attribute for my custom component.
Updated
OK as Richardo found out, seems like my original answer is the reverse way since the scrollbar is displayed internally :)
The correct way will be to call
super.setHorizontalScrollBarEnabled(false) and super.setVerticalScrollBarEnabled(false) in the constructor and override setHorizontalScrollBarEnabled() and setVerticalScrollBarEnabled() do nothing :D
Override isHorizontalScrollBarEnabled() and
isVerticalScrollBarEnabled() in your subclass to return false.
you could also override setHorizontalScrollBarEnabled() and
setVerticalScrollBarEnabled() for good measure.
Try keeping #null for android:scrollbars. Am not sure. But, I usually use #null when i want to remove anything from XML attributes.
I have been working in android for past few months. The problem for me is now related to Z index value. I am having a layout with a textview,edittext and imageview.
Suppose i have a xml file something like this..
<Layout1>
<edittext><zindex>3</zindex></edittext>
<textview><zindex>2</zindex></textview>
<imageview><zindex>1</zindex></imageview>
</Layout1>
So my question is that am reading this xml file by DOM parser and i want to set the z index value for all these by the values defined in the xml. Now is there any function or property that i can use to do it.
I have learnt about coding it with xml, but that will make it hardcoded. I want a dynamic display so how do i adjust layout with the zindex values.... HELP PLZ
there is no Z-index in android layouts. You'll need to use FrameLayout or RelativeLayout if you need to place elements on top of each other in reverse order.
see Placing/Overlapping(z-index) a view above another view in android
You can use view.setZ(float) starting from API level 21. Here you can find more info.