Develop Reference

Android: Why subtitle in ListView not grey?

I use latest Android Studio and SDK. In preview & real device i see this:
My code:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.myappname.view.AboutActivity">
<ListView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/listViewAbout" />
</RelativeLayout>
How i make subtitle text color is gray? Like this:

I'm going out on a limb and assume that you're using the row layout simple_list_item_2.xml (based on the screenshot) which gives you two rows. The problem, if you may call it that, is that depending on the SDK version, the styling for this layout has changed.
On SDK 23, it looks like this:
However, on say SDK 19, it looks like this:
Why?
To understand this we first need to take a look at the xml that generates the rows from simple_list_item_2.xml, you'll see it's a pretty simple layout that uses the now deprecated view TwoLineListItem but that's just a plus on why to use your custom layout.
<TwoLineListItem xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minHeight="?attr/listPreferredItemHeight"
android:mode="twoLine"
android:paddingStart="?attr/listPreferredItemPaddingStart"
android:paddingEnd="?attr/listPreferredItemPaddingEnd">
<TextView android:id="#id/text1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:textAppearance="?attr/textAppearanceListItem" />
<TextView android:id="#id/text2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="#id/text1"
android:layout_alignStart="#id/text1"
android:textAppearance="?attr/textAppearanceListItemSecondary" />
</TwoLineListItem>
The reason is because of the way the style textAppearanceListItemSecondary is resolved in each SDK version. The style is what gives the text the size, the color, etc. The evolution of the interface in Android has given birth to a huge ecosystem of themes and relying on the default styling will result in inconsistencies like the one you stumbled upon.
What to do about it?
You should use your own layout for this to allow for uniform styling across versions. To do so, please refer to any of the multiple questions covering this matter. But in short it just means creating a layout file, call it for example custom_row.xml and having the layout look exactly as you please. This also gives you total control over placement of the items, extra Views that you may need, and overhead in terms of coding is minimal compared to the SimpleAdapter or ArrayAdapter that perhaps you were using.
Note
You should consider moving your code towards RecyclerView instead of ListView if you haven't already.

You can set Textview property
android:textColor="#color/grey"
in you Adapter layout to change colour of your sub item
Hope this will help

How to set default text in TextView to see it in the layout preview while binding?

So I would like to see my layout preview with the fields filled with something like default placeholders but if I use bindings the settext attribute is already used and the fields are showing empty since there is no info from the models yet.
<TextView
android:id="#+id/tv_user_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_margin="5dp"
android:gravity="center"
**android:text="#{showBlueportSpotViewModel.name}"**
android:textAllCaps="true"
android:textSize="20sp"
android:textStyle="bold"/>
I tried this:
android:text="#{showBlueportSpotViewModel.name ?? #string/blueport_placeholder_name}"
but I still see the view empty.
Do you guys any workaround? I guess once a workaround is found, it can be used to ImageView and src for example and etc..
Thank you!

You can use the tools attribute to define properties that will appear in the layout preview but will not appear when you run the app.
Add the following to your root view:
xmlns:tools="http://schemas.android.com/tools"
Then use the tools attribute to define text that will only appear in the layout preview:
tools:text="placeholder text"
The tools attribute is very useful when mocking up views in the editor. All of the tools attributes are stripped when the app is packaged. More information here: http://tools.android.com/tech-docs/tools-attributes

I found a workaround
I added
xmlns:bind="http://schemas.android.com/apk/res/android"
to the layout
and just having duplicated declarations in the view like:
android:text="#string/blueport_placeholder_name"
bind:text="#{showBlueportSpotViewModel.name}"
or
android:src="#{showBlueportSpotViewModel.blueportImageDrawable}"
bind:src="#drawable/android_menu_header"
I don't really know if this has secondary wrong consequences so I won't accept this answer until somebody can comment and say if it is okay.. Thanks!

Re-creating Google+ app's UI

I'm fairly new to Android development and planning to build a simple news reader app to further familiarize myself to the platform.
The problem is; I want each of the news-item to look like Google+'s post item below:
Well, basically a big headline picture with a title and some description underneath.
I tried to re-create it using a Button (because the whole thing needs to be clickable by the user) while setting a drawable at the top of the text. It worked quite nicely.. until I decided to add more drawables to it:
Here's my XML code (although I doubt anyone would need it):
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<Button
android:id="#+id/button1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:drawableLeft="#drawable/ic_launcher"
android:drawablePadding="8dp"
android:drawableTop="#drawable/temp_jakarta"
android:text="Button" />
</RelativeLayout>
Can you tell me why is this happening or maybe, suggest me another way to accomplish this?
Thanks in advance!
p.s., I'm pretty sorry about the link; as a new user, SO didn't allow me to post images just yet. :(

Put everything inside a RelativeLayout and place one relative to others (event on top, this doesn't matter at all) using the layout_below/above/left_of/right_of/... etc.
See http://developer.android.com/guide/topics/ui/layout/relative.html for usage, http://developer.android.com/reference/android/widget/RelativeLayout.html for a complete reference of the RelativeLayout class and "Android Layout Tricks" series in the Developer Blog for some tips_
http://android-developers.blogspot.com.es/2009/02/android-layout-tricks-1.html
http://android-developers.blogspot.com.es/2009/02/android-layout-tricks-2-reusing-layouts.html
http://android-developers.blogspot.com.es/2009/03/android-layout-tricks-3-optimize-with.html

iOS to Android: How to display a TextView

I have a background in iPhone development, which may be a cause of some of my confusion with Android, which I am very new at developing.
My question is this: How to I create two TextViews, and specify their exact location on screen? For example, on the iPhone, I would create a UILabel, generate a rectangular frame that specified the label's size and position, and then set this rectangle to the frame property of the UILabel.
If you can help me understand the similarities with Objective C and iOS' UILabel, that would be most helpful.

On Android, we don't use absolute screen positions. This is highly discouraged. It's pretty understandable that you think this way if you are coming from iOS. But you need to revise your habits.
Instead of absolute positions, we use layouts, such as LinearLayout, RelativeLayout or FrameLayout. All of these allow you to arrange your views dynamically. And in many cases, it will automagically adapt to the screen size, which vary a lot from device to device.
Actually, there's nothing exotic about dynamic layouts. Many major UI toolkits, such as GTK, or Qt, work similarly. Pixel position are a bad idea in my opinion, except maybe in the Apple world, where the OS and the hardware are tightly coupled, but this is an exception actually.
So, in your case, all that you need is to put your text views into the appropriate layout. Please read the documentation and tutorials about the different types of layouts mentioned above to decide which one is best. The question is how you want your views to be placed relatively to each other.

Create a basic Android project in eclipse. You will be having a main.xml layout file in your project. You can open it in Eclipse using Ctrl+Shift+r and keying in main.xml
copy paste this in your xml after clearing its content.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:id="#+id/textView1"
android:layout_width="fill_parent"
android:text="TextView One"
android:layout_height="fill_parent"
android:layout_weight="1"></TextView>
<TextView
android:id="#+id/textView2"
android:layout_width="fill_parent"
android:text="TextView Two"
android:layout_height="fill_parent"
android:layout_weight="1"></TextView>
</LinearLayout>

Non-urgent Android layout id attribute quirk

I'm working on a couple of apps at the moment while I try to learn my way around the Android SDK. I had a bit of trouble recently with my layouts where I was defining, for example, an EditText element as such...
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<EditText
android:id="#+id/price_per_pack"
android:layout_width="100dip"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toLeftOf="#id/price_per_pack"
android:layout_alignParentLeft="true"
android:textSize="12pt"
android:text="Price Per Pack"/>
</LinearLayout>
The application was compiling correctly, however when I attempted to start the activity which utilizes this layout nothing would happen. Through a process of elimination I identified the id attribute as the troublesome one and while playing about I discovered that changing
android:id="#+id/price_per_pack"
to
android:id="#+android:id/price_per_pack"
solved my problem and the application behaved as expected. My initial attempt at declaring the id attribute was based upon examples in the SDK documentation so I'm wondering if somebody could explain to me why I needed to make the above change to get it working?
I'm sure that it won't make any difference but I'm developing using the android-mode.el emacs plugin and have a completely up-to-date copy of the SDK.
Thanks in advance.

From Android Documentation:
With the android package namespace in place, we're now referencing an ID from the android.R resources class, rather than the local resources class.
It looks like you might have some syntax errors in your code posted.