what's the difference of setVisibility(View.INVISIBLE); setVisibility(0); - android

I met a strange issue, when i set a textview visibility as
text.setVisibility(0); I cannot hide this textview. But after i update the code to text.setVisibility(View.INVISIBLE), the textview is hidden...
I have no idea, why this happened....

You got misconcept I think,
0 stands for VISIBLE..You can check here Developer Doc
0 is for VISIBLE
4 is for INVISIBLE
8 is for GONE
So nothing going wrong in your case,Its working properly as per you passed the parameter.

That's because 0 means VISIBLE. INVISIBLE is 4. These are constant values defined in View:
View.VISIBLE
View.INVISIBLE
View.GONE

Simple because INVISIBLE has the value 4.
So,Try this code text.setVisibility(4);
Will work.

The int is the problem
DOC OFFICIAL
android:visibility
Controls the initial visibility of the view.
Must be one of the following constant values.
Constant Value Description
visible 0 Visible on screen; the default value.
invisible 1 Not displayed, but taken into account during layout
gone 2 Completely hidden, as if the view had not been added.
This corresponds to the global attribute resource symbol visibility.
Related Methods
setVisibility(int)

Related

How do i make the constraintlayout wrap my textview programmatically

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);

Character spacing for "1" in a textview

I'm using a Digital-7 Typeface for a pair of TextViews. The problem with the TextViews is that whenever I use the character "1" in it, the characters left of the "1" get pushed back and they lose their proper spacing. As seen here:
You can see the 9's are properly in place while the 1's get squished together. Is there any piece of code that can help me fix this or do I need a better Typeface?
As what Der Golem said, switching to a monospace Typeface fixed my issue.
Please try this property in XML, Hope it will work.
android:textScaleX="1.2"
Must be a floating point value, such as "1.2". You can change the value depending on your requirement.

How to change the below target in run time in android?

For example, I have a imageView 1 , imageView 2 and imageView3
In the XML I use a relative layout to group them
eg.
imageView1:
below of 2
imageView3:
visiblity: gone
after certain action (in run time)
eg.
imageView1:
below of 3
imageView3:
visiblity: visible
I think something similiar, but can not find the correct syntax
imageView1.setLayoutParams(new LayoutParams(Below));
Thanks for helping
What's your API level? If, by chance, you are using a min SDK of 17, you can just use removeRule(int verb) to remove the below of 2 and then add below of 3.
Otherwise, what I do is I keep two instances of RelativeLayout.LayoutParams for a given view. Try something like this:
belowTwoParams.addRule(RelativeLayout.BELOW, 2.getId());
belowThreeParams.addRule(RelativeLayout.BELOW, 3.getId());
Where belowTwoParams and belowThreeParams are both instances of RelativeLayout.LayoutParams. Keep in mind that your "2" and "3" views need to have valid IDs, set either in the XML or programatically before adding these rules.
Afterwards, you just call imageView1.setLayoutParams(belowTwoParams //or belowThreeParams accordingly);

Increase height of TextView on runtime

I have a TextView and I want to increase its height on runtime.
I have used android:layout_height="wrap_content" but it did not gave me the desired result.
I'm using a Relative Layout.
i get text through edittext and i want to set it on textview.
when i do this it shows only one line, and when i click on edittext it get expanded and full message is shown.
Add in Oncreate method of your
Activity class,
((TextView)
findViewById(R.id.YOURTEXTVIEWIDHERE)).setHeight(IntegerValuePixels);
hard to tell without more details - but do you really need to change it on runtime? because obviously you're not happy with the height at startup.
have you thought about using android:layout_height="fill_parent", eventually in combination with the android:minHeight attribute of other components?

Defining Z order of views of RelativeLayout in Android

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.

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