Develop Reference

Android Studio: Can you display a view just for preview?

My app has a lot of views that are containers for fragments (which load an image and other views) and depend on an API to fetch images. To make the development of the design easier, I like to add a sample of that image in my xml. Right now, I'm adding a RelativeLayout with the FragmentContainer and a dummy ImageView using different visibility values for android:visibility and tools:visibility.
Is there a better way to show images just for preview purposes ? I'd like to have the preview Views not compiled in the release version.
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:visibility="gone"
tools:adjustViewBounds="true"
tools:src="#drawable/image"
tools:visibility="visible" />
<RelativeLayout
android:id="#+id/FragmentContainer"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</RelativeLayout>

If I understood your problem correctly, you could do something like this:
instead of using dummy views, use
<include tools:layout="#layout/layout_preview" layout="#layout/layout_actual"/>
where layout_preview.xml is whatever you want to use only in the preview, and layout_actual.xml is what will be used in the app
in case you wanted to only add a view in the preview, but have no view at all in the app, you can use a layout_actual.xml with an empty merge tag
<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android"/>
if you don't want to include useless layout, you might want to create the dummy ones only for debug build type, it will show an error in the layout because layout_dummy will be missing but since it's tools attribute you should be able to compile and run

Eclipse Content Assist Not Working Properly For Android Layout

Whenever I have Views inside a ViewGroup inside a android.support.v4.widget.DrawerLayout, Eclipse's autocomplete starts working weird. It doesn't display most of the properties
Example with DrawerLayout -> LinearLayout -> ImageView:
In the previous screenshot, you can see that I typed "android:scale..." and the IDE's intellisense isn't showing me the ImageView's android:scaleType
If I use Eclipse's Properties window for the ImageView, I can see that it is only displaying the basic properties for "View" (and not for ImageView...):
Now if the ImageView is not a descendant of the DrawerLayout and I put it somewhere else, the autocomplete works properly:
I've seen related questions such as:
Autocomplete does not work in XML files in particular hierarchy
Content Assist doesn't work in xml with support library
but they have been dead with no answers for quite a while...
Content assist doesn't work for Views (be it TextViews, EditText, Buttons...) that I add inside the DrawerLayout. It only suggests the 'basic' properties.
Does anybody know why this happens or how to fix this?
Sample layout:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical" >
<ImageView
android:id="#+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/some_image" />
</LinearLayout>
<RelativeLayout
android:id="#+id/drawer_view"
android:layout_width="240dp"
android:layout_height="match_parent"
android:layout_gravity="start" >
</RelativeLayout>
</android.support.v4.widget.DrawerLayout>

Just to give some closure to this 5 months-old question, I'll quote and link to Atul O Holic's answer. Thanks to Dileep Perla for pointing me there.
When using support package Widgets this is a common scenario (a weird
one too).
Here you using, android.support.v4.widget.DrawerLayout and hence the
issue. Happened with me a lot of time.
You can also try couple of options mentioned here.

I've found that using the tag can be handy in this case. Just put your layout that is inside the drawer in a separate layout file and then include it inside the drawer layout.

Setting Background For a Fragment?

I am using fragments in my application, and I have to change the Background for one of the fragments within FragmnetTabs. For this very reason I am setting the background in the layout of that fragmnet, which I can see in Graphical Layout of Eclipse is working fine. But when I run my application it shows me Fragments content with black background, instead of the image I set. I am setting it this way...
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#drawable/bg" >
<RelativeLayout/>
But this drwaable does not show up in the application. What could be the problem? Any help is appreciated. Thanks!
Edit:
If I try to set the background in the following way, it works fine.
android:background="#drawable:color/anycolor"
Why is it so that custom image is not getting shown up but android colour does?

You can try to do this in code. Call on your RelativeLayout
yourRelativeLayout.setBackground(getActivity().getResources().getDrawable(R.drawable.YourImage));

How do I add a tween animation to my custom view?

This is my first Android project, so bear with me. I created a custom view ("GameBoard" extends View) for drawing my game board and pieces by overriding the OnDraw. It all works fine. However, I'd like to add a tween-animated "You win" graphic at the end of the game. However, I can't figure out how to add an ImageView to my GameBoard view.
I read that I could use an XML file and add my custom view to it, but it didn't work. Here's my XML code:
<?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="#001133" >
<view Class = "com.myname.firstgame.GameBoard"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
</view>
</RelativeLayout>
I also tried it without the "view Class =" in the view tag. I also tried it without the ".GameBoard" in the view tag and specifying it in the "android:id=" tag. (All these attempts came from Google searches.)
If I can get it to work, I figure I can add an ImageView with my bitmap as the background, place it in the right spot, and animate it. I do a similar thing for my title screen and it works fine, but it uses an XML natively, without a custom view. (In hindsight, I'm wondering if I should have used XML rather than a custom view for the game board, but that's another matter.)
Can anyone help, please?

This seems to answer your question.
http://sankarganesh-info-exchange.blogspot.com/2011/04/performing-animation-in-android.html
just call the target.startAnimation() method when your user wins / loses / whatevers your game

Overlay view sometimes doesn't draw

I recently updated my phone to gingerbread and to my horror one of my apps stopped working!
The app consists of a SurfaceView and a layout (view) that shows up as an overlay over this SurfaceView.
THe xml looks like this:
<?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"
>
<com.mycompany.MySurfaceView
android:id="#+id/myview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
<include layout="#layout/settings"
android:layout_alignTop="#id/myview"
android:visibility="invisible"
android:id="#+id/settings"
/>
</RelativeLayout>
When the user press the menu button I use this code to show the view:
View settings = (View)findViewById(R.id.settings);
settings.setVisibility(View.VISIBLE);
This worked flawlessy on versions earlier than 2.3 but now the behaviour is very random.
Observations
Very rarely everything works.
Sometimes the view shows up after hiding / unhiding it.
Sometimes you can press the buttons on the view (even though it's invisible) this makes the view show up for the rest of the application lifetime.
The getVisibility method always report the correct value.
What I've tried
Rebuilding draw cache
Using BringToFront method
Post invalidate
Setting the initial value of the view to "visible", this makes everything work, but I really want it to be initially invisible!
If anyone wants to check the problem you can try it for yourself in my app (it's on market, search for "chainparticles").
Thanks!

Solved it by changing the views initial state to "gone". WTF?!