Develop Reference

ViewPager preview layout in Android Studio

Is it possible to show a preview layout for ViewPager in AndroidStudio like in ListView/RecyclerView/etc.?

Short answer: No.
I think you're talking about ViewPager from ViewPager 2. My answer will be assuming ViewPager 2. Pls update the question to clarify that.
- Workaround: a hidden include
<include
android:visibility="gone"
tools:visibility="visible"
layout="#layout/item_that_shows_inside_viewholder"/>
And I agree that's a very poor way to do it.
If in constraint layout you can loosely match the same constraints to make this show on top. And yes, you will inflate this in production code so you may incurr in performance slow down depending on what you have there.
It's very unfortunate that tools:layout doesn't exist or work properly (yes, I got inconsistent results while trying it).
- 2nd less worst way is using isInEditMode on code on the parent class
something in the fashion of
class CustomView ....
init {
// inflate layout that contains ViewPager
if ( isInEditMode() ) {
//do something that replaces ViewPager with its inflated view holder
}
}
which has served me well when I can use that. However that's unsuitable for most places.
- If at least ViewPager were not final we could extend and do some tricks there using isInEditMode like above.
- You can make a custom class wrapper with internal field ViewPager
One way that does certainly work is making your custom class extend FrameLayout and having an internal view that is your actual ViewPager. But then you have to re-implement and delegate all its methods, which is a big pain. Maybe kotlin has a way to do that, but so far I don't know how. Or maybe using reflection or kotlin poet could be a way to do that. It's too risky for my taste.
- If we could make a databinding adapter to do the isInEditMode like above it would work. But databinding adapters don't run in preview.
- I tend to think these tools attributes get processed by Android Studio, so it would take probably an android studio plugin to work around it.
This is the current full list of tools attributes: https://developer.android.com/studio/write/tool-attributes.html#toolslistitem_toolslistheader_toolslistfooter
It may be useful reading this Android XML Is there a way to use the tool namespace with custom attributes?
where a library to read custom attributes with tools gets mentioned. There may be an alternative with this library, but I have never used it and not sure how it works:
https://github.com/giljulio/sneakpeek
I'd love to be proved wrong, but in my opinion all of the options are dead ends or too much effort.

In Andriod studio some views are shown in run time but not in compile time. Think about Frame Layout as a container for fragment transaction. We may place any kind of views on that container in run time. So, it's not possible to show a view while coding. The viewpager is playing same kind of role here. So, we can't show a view there before running and actually placing a fragment/other view there.
I hope you are clear now. :)

This is possible, when putting the ViewPager into it's own XML layout resource.
Alike this one can show the desired Fragment instead of the ViewPager:
<fragment
android:id="#+id/fragment_viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout="#layout/fragment_viewpager"
tools:layout="#layout/fragment_preview" />
This also provides the XML preview for the navigation graph design view.
tools:layout only works with fragment, but not with include.

i think it's not...some of the layouts have no preview while coding or designing ...like TabLayout

Although I don't think there is such a functionality out of the box, I used the following workaround to achieve design time preview for the ViewPager:
Add an <include> with the view that you will use in your ViewPager as a layout,just after the ViewPager itself
Set tools:visibility="visible" and android:visibility="gone" to this <include> view so that it will be visible at design time but not at runtime. Also set tools:visibility="gone" to the ViewPager so that it will be invisible at design time.
The idea is to hide ViewPager at design time and show its contents instead while doing the opposite at runtime. This should work for other controls as well.
To show an example:
<androidx.viewpager.widget.ViewPager
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintTop_toBottomOf="#id/tabl1"
tools:visibility="gone">
</androidx.viewpager.widget.ViewPager>
<include
layout="#layout/fragment_example1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:visibility="gone"
tools:visibility="visible"
app:layout_constraintTop_toBottomOf="#id/tabl1" />
I hope this helps you

Displaying a TextView immediately after another

I am a first time developer for Android, so you can say I've been learning as I was developing. For most of my code that doesn't have to do with the XML layout, I had no problem patching my rookie mistakes. With that said, my rookie mistakes has caught up to me in regards to two TextViews when I initially designed them with the GUI interface designer (my major rookie mistake).
My display_city tv and display_today_date tv seem to have a symbiotic relationship with each other. Removal of either one would crash the app. They seem so dependent on each other that changing each other's positioning is impossible (at least from the myriad of things I have tried such as setting layout margins).
<TextView
android:id="#+id/display_city"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="20dip"
android:layout_above="#+id/display_today_date"
android:layout_below="#+id/get_data"
android:layout_centerHorizontal="true"
android:gravity="center_horizontal" />
<TextView
android:id="#+id/display_today_date"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_below="#+id/display_pollen_type"/>
My question is - how do I simply position display_today_date immediately after my display_city? When I first started this Android app, I relied a lot on the GUI builder. That was my first rookie mistake, which resulted in this symbiotic relationship I explained.
Currently this is what my app looks like:
I have tried changing display_today_date's layout to android:layout_below="#+id/display_city. This results in a crash. I checked logcat, but it did not give me relevant information to the reason of the crash within the XML file.
P.S. get_data is my TextEdit box.

You already have the city to show above the date with the line android:layout_above="#+id/display_today_date". You can't have 2 views in a relative layout each reference the other, or it won't be able to figure out what to do. If you don't want to put the city above the date, delete that line then add the code to place it where you want.

You could use a LinearLayout with the orientation set to horizontal. That way there is no reference to another view. So if you delete one the other one won't cause the app to crash.

Creating such a Button with Android? (Inspired by iOS)

On an iOS App I saw such a Button:
The same I would like to do in Android, how could I achieve this?
What I tried is the following code:
<Button
android:id="#+id/widget41"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="5dp"
android:layout_marginRight="5dp"
android:text="Email1 testmail#gmail.com"
android:textStyle="bold" />
Looks something like that:
Well just a normal (ugly looking) Button. I have no idea, how I could style it like in iOS. Any suggestions or links would be appreciated!

The best solution would be to create your own custom view that behaves like the iOS counterpart (though, as other users have mentioned, Android does have it's own design guidelines, and the view that you are seeing is an iOS implementation that is designed for that platform).
If you look at the iOS image above (a copy of yours with some parts highlighted), I have split it up into sections.
You could use an Android ViewGroup like a LinearLayout to create the overall image, and give the LinearLayout a border or background (which can be a bitmap image of a rounded rectangle for example (See Android Nine Patch for an example of how to make this fit multiple screens).
Firstly, for the mail icon you would need a LeftAligned ImageView
with appropriate dimensions.
Next up we have a Bold TextView containing the text "Email1".
This is followed by another TextView which is blue and uses the
elipsize property (as defined in an Android XML layout) to create
"..." at the end once the text has reached the max width it can
consume. (Use android:ellipsize="end" in the XML)
Finally we have an indicator image, which again can be an ImageView
sized appropriately.
You could also achieve this with a RelativeLayout, which would allow you to RightAlign the indicator image, LeftAlign the mail icon, and allow the text to fill the space in between that it can get hold of.
Example of Nine Patch use for the background here

That is UITableView in iOS(just like ListView in android). It depends on the list item design you do it. There is no such Button Control in Android.

You should design your own button to looks like iOS one.
Android has it own design guidelines:
http://developer.android.com/design/patterns/pure-android.html

Well, as others have clearly mentioned there is no default Button in Android like this, and for your info neither is in iOS. Its all about the design. Anything is possible, in the end it all comes to how far are you willing to go to achieve it.
Below is a simple code, that will be close to your design.
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:layout_margin="5dp"
android:background="#drawable/text_background"
android:drawableLeft="#drawable/envelope"
android:drawablePadding="10dp"
android:drawableRight="#drawable/right_arrow"
android:ellipsize="end"
android:gravity="center_vertical"
android:text="#string/email" />
There can be other ways also, like that whole view could be a ViewGroup, either a LinearLayout or a RelativeLayout and there could be multiple TextViews and ImageViews inside that.

Here is a tutorial for creating stylized android buttons. You can round the corners and change the background colors to look like the buttons in ios.
Here is a similar question.
Hope this helps.

How to keep background image size when software keyboard show

When the software keyboard shows, it resizes my layout and thus squeezes the background image together. My question is basically a duplicate of this question, which is explained in a very good way:
Software keyboard resizes background image on Android
However, that question was closed when they found a hack to solve it. I cannot use this hack. My entire layout is inside a ScrollView, and I need to be able to use this scrollview properly at all times. By using android:windowSoftInputMode="stateVisible|adjustPan" the user will not be able to scroll down and see the bottom of the screen while the keyboard is showing, since the layout will partly exist behind the keyboard. Thus the solution is unacceptable to me. Are there any better solutions out there?
Cheers,

I actually ran into a similar problem not too long ago. I stumbled upon the correct answer with a bit of work, though.
In your android manifest for this project, attached to the specific activity that you are using, use the line android:windowSoftInputMode="adjustPan|stateVisible" in the activity tag.
adjustPan basically means that your activity will not resize itself to fit the soft keyboard, and stateVisible means that the soft keyboard will show when requested (this can be stateAlwaysVisible, etc if necessary)
source :
Android Dev for Activity tags

After days of hardcore hacking I finally managed to construct a solution so advanced it might actually hurt to read it. I place an ImageView with the background behind the scrollview, and set scaleType="matrix" so it does not shrink when the keyboard is shown.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#color/black"
>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:src="#drawable/mah_kewl_background"
android:scaleType="matrix"
/>
<ScrollView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:fillViewport="true"
>
<RelativeLayout
android:id="#+id/smsLayout"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="PLUNX"
/>
</RelativeLayout>
</ScrollView>
</RelativeLayout>

You can use the windowBackground property, which makes the drawable fit the whole screen.
To do that you need to:
1- Create a style:
<style name="Background" parent="#android:style/Theme.NoTitleBar">
<item name="android:windowBackground">#drawable/you_bg_drawable</item>
</style>
2- Set your activity style in the AndroidManifest.xml
<activity
android:name=".ui.your_activity"
android:theme="#style/Background"/>

I was googling for a solution to this exact problem when I came across this, and after doing some research I found a solution I think is slightly better. Instead of hacking with a ImageView you can use this from your activity:
getWindow().setBackgroundDrawableResource(R.drawable.bg_my_background);
Hope it helps anyone else searching for a solution for this.

I can't comment on your answer but I'd like to add something.
I understand your dilemma and why the solution you linked to isn't a complete solution for your situation (since you can't scroll to the bottom of the view). I have a similar situation with a large scrollable EditText box. When the soft keyboard pops up I don't like my background getting squished.
I have tried your solution and while at first glance it appears to work, there are some situations where it might not be ideal:
If you allow your app the have a landscape mode, the background will not resize/stretch
If you run your app on a device with a larger screen or dpi, your background may not fill the screen
Basically it seems that when you set the scaleType to matrix you're telling Android to draw the background 1:1 and not to scale. So what's happening when you open the soft keyboard using your solution is, your scrollView and imageView are all getting resized as usual, but the image src you set remains 1:1 thus continues showing the same area.
So if for example your background image was set to a specific size (e.g. 480 x 800) and it perfectly fills your Nexus One, the moment you rotate to landscape you will have a black area along the right.
This is moot, of course, if your background is simply a repeating pattern, in which case you can make it extremely large and hopefully compensate for various screens (maybe even tablets).
Or you can also supply different backgrounds for different screen sizes/densities/orientations, but this still doesn't account for scaling.
In a vain effort to try and solve this, I stumbled upon a View attribute called android:isScrollContainer. This attribute tells certain views whether or not they are allowed to resize upon display of the soft keyboard. This is also mentioned by someone in your linked solution. I have tried setting this (to false) on the ViewGroup containing my background, but any child element that scrolls seems override it causing the squishing again.
As of right now I don't think there is a complete solution for our situation. Your's definitely works in some instances and I thank you for the effort. Hopefully Google will offer a solution in the future, but I don't think they would consider this a problem/priority.

Maybe there's another (really simple!) solution:
In styles.xml:
create a new style like this:
<style name="Yourstyle" parent="AppBaseTheme">
<item name="android:windowBackground">#drawable/mybackground</item>
</style>
AppBaseTheme is your normally used theme for your app.
Then you add in Manifest.xml:
<activity
android:name="com.your.app.name.Activity"
android:theme="#style/Yourstyle">
</activity>
So you have the same style but with a background.
Important: don't set any backgrounds in your normal .xml file!
It's my first post and I hope it helps and sorry for my English.

in Androidmanifest in activity tag use:
<activity ... android:windowSoftInputMode="adjustPan" ></activity>
check Android Developer reference

How about a solution where the 'background' is a Layout. Can we inflate a layout, make it the entire window size, then insert it as a window background?

After a lot of time searching...
Put android:windowSoftInputMode="adjustPan|stateVisible" in each Activitys

Design view problem in xml file : Android

When I run my application, buttons are not displaying(A little part is displaying, that makes feel that something is there), although I scroll down.
How to solve my problem. Is there any way to set size of textboxes (Where size depends on screen size).

Pankaj did you checked the orientation of the root LinearLayout tag ??
All you need to do is change root LinearLayout's orientation to vertical & you will see every button in your layout
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
& please read more about layouts before implementing them.

As #100rabh already said you should really start reading about Android layouts.
Some very good articles by Romain Guy are here and of course on his blog.
There is also a very good series of articles on Mobiletuts+ called Android User Interface Design by Lauren Darcey and Shane Conder.
You should really check that out and then redesign your layout.

As you're using linear layouts, you can use android:layout_weight. If you search, you'll find many examples.