Develop Reference

Customize fastScrollOverlay?

I'm trying to customize the letter popup that appears during scroll. I was able to change it's colors and the position from my styles, but I need to make the text and the whole element bigger as well as move it closer to the vertical center of the screen. Is any of these things possible? How can I do them?
This is my current code from my style.xml file:
<item name="android:fastScrollOverlayPosition">floating</item>
<item name="android:fastScrollTextColor">#000000</item>
<item name="android:fastScrollPreviewBackgroundLeft">#drawable/square</item>
<item name="android:fastScrollPreviewBackgroundRight">#drawable/square</item>

I don't have any info about further customization of the default overlay.
There's a more flexible alternative, though. You could add a TextView to your layout which only appears when the user is scrolling, and show the letter returned from your SectionIndexer's getPositionForSection method. You could then style this view exactly to your liking, and center it in a full-screen RelativeLayout.

LinearLayout with style and without orientation issue?

I have style for LinearLayout:
<style name="clickable_zone">
<item name="android:layout_height">match_parent</item>
<item name="android:layout_width">match_parent</item>
<item name="android:id">#+id/click_zone</item>
<item name="android:background">#drawable/simple_button_holo</item>
<item name="android:orientation">horizontal</item>
</style>
I use this style at different layouts as:
<LinearLayout
style="#style/clickable_zone" />
But in this case I get warning about orientation issue. Of course, I can disable this warning. But, can I resolve my problem, without disabling the warning?
UPD1. Issue message:
Checks that LinearLayouts with multiple children set the orientation
The default orientation of a LinearLayout is horizontal. It's pretty easy to believe that the layout is vertical, add multiple children to it, and wonder why only the first child is visible (when the subsequent children are off screen to the right). This lint rule helps pinpoint this issue by warning whenever a LinearLayout is used with an implicit orientation and multiple children.
It also checks for empty LinearLayouts without an orientation attribute that also defines an id attribute. This catches the scenarios where children will be added to the LinearLayout dynamically.

Customizing Android ScrollView's Vertical Scrollbar

I need to customize ScrollView so it will look like in the picture:
I already successfully customized the Thumb and the Track, but I don't know how to add Arrows like in the picture I provided.
Here is the style I'm using:
<!-- Scrollbar -->
<style name="scroll_view">
<item name="android:scrollbarAlwaysDrawVerticalTrack">true</item>
<item name="android:scrollbars">vertical</item>
<item name="android:fadeScrollbars">false</item>
<item name="android:scrollbarThumbVertical">#drawable/sb_thumb</item>
<item name="android:scrollbarTrackVertical">#drawable/sb_track_vertical_bg</item>
</style>
The Arrows should be a part of the ScrollView style to avoid extra spacing and also they need to be simple, non clickable and e.t.c.

If you want to add buttons for up and down, you can place two buttons above and below of Scrollview.And programatically scroll the scroll bar on button click.
For that purpose, you can use following code,
scrollview.scrollTo(5, 10);

Android TextView hidden when setting to single line scroll horizontal and center horizontal

I am trying to make a TextView to a fixed size, center the containing text, show the text in a single line and if the text is larger than the TextView, let the user scroll the TextView horizontal.
I almost managed to achieve this by setting this style for my TextView:
<style name="custom_text">
<item name="android:layout_gravity">center_vertical</item>
<item name="android:gravity">center_horizontal</item>
<item name="android:maxLines">1</item>
<item name="android:scrollHorizontally">true</item>
</style>
The scroll works exactly how I want, the only bad thing is that the TextView is invisible when the screen shows up. To make the TextView visible it seems that I have to scroll the TextView in any direction. I tried to scroll the TextView from code in hope that the TextView will show up but no success.
How I can solve this?
Thank you!

Button scales to background image instead of content

What I need to do is have the background image just fill up the natural size of the button, as when no background is specified and the default grey background image is shown. But instead, my button scales up to the size of the background image rather than the text.
There was a previous question, but nobody had a solution.
The button:
<Button
android:id="#+id/morebtn"
style="#style/CustomButton"
android:text="More" />
I have this custom button style (greybutton is a 9-patch):
<resources>
<style name="CustomButton" parent="#android:style/TextAppearance">
<item name="android:textColor">#FFFFFF</item>
<item name="android:layout_marginLeft">10dip</item>
<item name="android:layout_marginRight">10dip</item>
<item name="android:layout_marginBottom">10dip</item>
<item name="android:layout_width">wrap_content</item>
<item name="android:layout_height">wrap_content</item>
<item name="android:layout_centerInParent">true</item>
<item name="android:background">#drawable/greybutton</item>
<item name="android:textSize">20sp</item>
</style>
</resources>
Right now it fills up the screen widthwise, despite being told to wrap_content. When I remove android:background from the Button style, the button shrinks down to wrap the text as expected.
Does anyone see why my background image isn't behaving like the default Button background?

Why don't you use ImageButton instead:
<ImageButton android:src="#drawable/greybutton"
android:scaleType="fitCenter" android:layout_width="wrap_content"
android:layout_height="wrap_content" />
then you can adjust the scaling with the scaleType attribute.
The only downside is you can't set any text.

Damnit. I had an hdpi drawable that hadn't been converted to 9patch, and for some reason that was getting applied instead of the one in the mdpi drawables folder even on my mdpi screen. The background scaling actually does work as expected after all. Sorry!
(So if you're browsing this question with a similar problem, check your drawables folder to make sure you're drawing what you think you are. Also: may wish to be sure the content boundaries in your nine-patch are of the appropriate size. Note that they aren't the same as the stretchable boundaries.)

You could try hard coding the height and width of the buttons using dip. That will be an issue if you need the Text on the buttons to change but it should work to restrain the button from expanding to the size of the image. Of course a large image will make the button larger.. the width / height is wrap_content, and the image is clearly part of the content... try hardcoding width / height parameters.

Add these two items to your CustomButton style
<item name="android:minWidth">0dp</item>
<item name="android:minHeight">0dp</item>