Develop Reference

Android ListView width keeps changing

Firstly, I am new to android so if I have missed something basic I apologise.
I have a page which has two ListViews side by side, both with varying amounts of content. I also have a TextView above the ListViews and another TextView below the listviews. These text view boxes change based on items selected in either of the two ListViews.
These two ListViews sit side by side, taking up half of the screen each, while a Textview sits directly above and directly below, both centred to the page. An image is shown below.
This is the page looking normal on load.
The problem is when I select an item from either list. I have a feeling I am missing some XML properties, but I am not sure which properties or if this is even the case. When an item is selected, let's say from the ListView on the right, the TextView at the bottom is updated with text taken from an array. The ListView also decides to change the width and I am not sure why this is.... I don't want the ListView to change width. I want it to remain taking up half of the page and half of the page only.
This is the page after an item from the right ListView has been selected.
I would also like to keep things in RelativeLayout. I also believe it is only an XML issue and not to do with the adapter or any other code so I will not include that for now. I can include it if required.
Any help would be great. Thanks in advance.
content_titles.xml my activity xml file
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".TitlesActivity">
<ListView
android:id="#+id/unlocked_titles_list"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:longClickable="true"
android:layout_below="#+id/current_title"
android:layout_alignEnd="#+id/requirements"
android:layout_marginEnd="26dp"
android:layout_above="#+id/requirements">
</ListView>
<TextView
android:id="#+id/current_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="65dp"
android:text="Current Title: Novice"
android:textSize="24sp"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"/>
<ListView
android:id="#+id/locked_titles_list"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_alignStart="#+id/requirements"
android:layout_marginStart="28dp"
android:layout_above="#+id/requirements"
android:layout_below="#+id/current_title"/>
<TextView
android:id="#+id/requirements"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="34dp"
android:text="temp"
android:textAlignment="center"
android:textSize="24sp"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"/>
</RelativeLayout>
activity_listview.xml used as the individual rows of the ListViews
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/label"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="10dip"
android:textSize="16dip"
android:textStyle="bold" >
</TextView>

The problems with layout could be caused by ScrollView to be the wrapper
I stumbled upon some note in http://developer.android.com/reference/android/widget/ExpandableListView.html
"...Note: You cannot use the value wrap_content for the android:layout_height attribute of a ExpandableListView in XML if the parent's size is also not strictly specified (for example, if the parent were ScrollView you could not specify wrap_content since it also can be any length. However, you can use wrap_content if the ExpandableListView parent has a specific size, such as 100 pixels."
I removed wrapping ScrollView and linear layout started working properly. Now its only to understand how to wrap the stuff to ScrollView. God help me
But anyway this is really weird behavior. I think that fill_parent is not really correct wording. When using heirarchyviewer tool I always see WRAP_CONTENT and MATCH_PARENT values for layout_width and leayout_height. So probably fill_parent is actually means match_parent which puts me in cognitive dissonance.

You have your layout_width properties set to wrap_content. This means that they could change as the data changes. I would recommend putting your ListViews in a LinearLayout with orientation:horizontal and set the amount of space that each element takes up with layout_weight. Here is a relevant SO question What does android:layout_weight mean?

Inserting many views into one layout without them overflowing to the end of the screen

I'm looking for a way that I can dynamically add views into a layout (currently a LinearLayout) and that they won't overflow into the end of the screen and be hidden.
I can't use ScrollViews since it has to look like one sentence (It's a "fill the blanks" question).
I'm just looking for an idea on how to do this, not the code itself.
Thanks in advance, Shay.

If you are using linear layout than use linear layout with weights:
For example:
You have a LinearLayout with vertical orientation and you have 2 ImageViews inside it and you want these ImageViews always to take equal space.
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:weightSum="2"
android:orientation="vertical"
android:layout_gravity="center">
You can set the layout_weight of each ImageView to 1 and the weightSum in LinearLayout to 2 to achieve this.
<ImageView
android:layout_height="wrap_content"
android:layout_weight="1"
android:layout_height="0dp"/>
This will work correctly for any device without overflow into the end of the screen and be hidden

Have elements equally span entire width / height of their RelativeLayout

I have, say three buttons i would like to list below one another in a layout. Depending on the device, screen size, pixel density, orientation and so on, i would like the buttons to span the entire height of their parent layout. The buttons each have a fixed height (dp), so the spanning is more likely concerning the space between the buttons.
I saw several questions on various forums regarding how a LinearLayout is supposedly a fix for this problem, by nesting a layout for each element, having the layout span. I would very much like to avoid nesting layouts, and I'm using a RelativeLayout as of now, so if there is any way to go about it with this type of layout it will be of great help! :)
Additionally, I would like the top and bottom button to "touch" the parent layout border at the top and bottom, and the last (or rest) button to fill out the rest of the vertical space equally.
Thank you in advance.

I'm not entirely sure what you wish to achieve, but you should be able to do this using a LinearLayout & weights (so you don't have to nest multiple layouts).
If you want the 3 buttons to take up the entire parent of the screen just add a weight to each for example:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:id="#+id/button_one"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"/>
<Button
android:id="#+id/button_two"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"/>
<Button
android:id="#+id/button_three"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"/>
</LinearLayout>

Try to set to topButton a field in XML:
android:layout_alignTop="true";
Try to set to middleButton a field in XML:
android:layout_centerVertical="true";
Try to set to bottomButton a field in XML:
android:layout_alignBottom="true";

Android Linear Layout gives me headache

I've got the following xml file:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/linearLayout1"
android:background="#android:color/transparent"
android:layout_marginTop="0px"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:weightSum="1"
android:orientation="horizontal">
<Button android:id="#+id/info" android:text="Info" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="bottom"></Button>
<Button android:id="#+id/town" android:text="Town" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="bottom"></Button>
<Button android:id="#+id/unit" android:text="Unit" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="bottom"></Button>
<Button android:layout_height="wrap_content" android:text="EndTurn" android:id="#+id/endturn" android:layout_width="wrap_content" android:layout_gravity="bottom"></Button>
</LinearLayout>
which provides the following result: http://i42.tinypic.com/otdkb4.png
Now I've got some questions about this:
The top and bottom padding, how to get rid of it?
I tried RelativeLayout, multiple layouts within each other, padding, margin, changing height nothing seem to affect it in any way.
Is there a way to get the layout transparent? android:background seems to be the wrong one.
Between the third and the fifth button is a bit more space (where the fourth button should be). I catch it the in the program and set it to invisible.
unitButton.setVisibility(INVISIBLE);
unitButton.setWidth(0);
Now the space between the two buttons is more than double of the normal range (between 1 and 2) Any idea on this? - Altough this is a minor problem
Thanks in advance.

1: Is the layout presented in a Dialog? If so, that'll give you some headaches. To get more control you should either create your own custom Dialog extension (as some dialog layout values are hardcoded), or display your layout in another way (a new activity on top, or using a framelayout perhaps)?
2: To get a layout transparent, simply don't give it a background-attribute. (Though, if you really are using a dialog, the dialog box is not transparent, and it is that which you see. You can also set it to be transparent by setting background to "#00000000" (which is what you do).
3: A View with visibility as "invisible" is still measured, that means both its width/height as well as its margins and padding is displayed as empty space in your layout. Setting the visibility to "gone" instead will not measure it, and you won't need the setWidth(0) either. (You can still display it later by setting it back to "visible")
Edit: removing the unused "weightSum" attribute might also be a good idea, as the view is now expecting its children to have a total weight of something other than 0.

How to create layout like this?

I have a horizontal LinearLayout, inside which I have 2 TextViews. Let's say that the LinearLayout's width is 320px. If the TextViews don't fit into the LinearLayout (they are together wider than 320px), I want to somehow achieve this:
The second TextView is fully displayed and is at the right edge of the LinearLayout
The first TextView is only shown partially, only first x characters are visible
What I mean:
[TextView1|TextView2_________________________] // this is normal
[VeryVeryL...|VeryVeryLongTextView2] // VeryVeryLongTextView1 is not fully visible

To get the effect you're requesting in the comments above, you could modify Mayra's solution to something like:
<LinearLayout ...>
<TextView android:layout_width="wrap_content"
android:maxWidth="20dp"
android:layout_height="wrap_content"/>
<TextView android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"/>
I think that will work. Weirdly, the maxWidth param is only present on a couple view classes, but TextView luckily is one of them. You'd think it'd be useful in more cases, so I'm not sure why it's not just available in the default view params.

Specify a specific width for your first textView (i.e, 20dp... note, it is better to use dp than hard coded pixels, to deal with multiple resolutions of devices), give your 2nd TextView a weight of 1. This tells it to take up the remaining space. For example:
<LinearLayout ...>
<TextView android:layout_width="20dp"
android:layout_height="wrap_content"/>
<TextView android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"/>
</LinearLayout>