Develop Reference

view not snapped to top on LinearLayout

I have a LinearLayout and its XML is:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
android:layout_gravity="center"
android:orientation="horizontal"
tools:context=".MainActivity">
<Button
android:id="#+id/button3"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Button" />
<Button
android:id="#+id/button2"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="3"
android:text="Button" />
<Button
android:id="#+id/button"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="2"
android:text="Button" />
</LinearLayout>
and it is the result is:
as you can see the top left button has a little margin from top but as the code shows there are no margins.
why is this happening?
also there is a weird solution which is if you set gravity:top to all buttons you will get the expected result. but why is it even needed because linearlayout(horiz) should start adding items from top left to top right.

I was referring some documents and SO threads to look for the solution as the question seemed very intresting to me.
Finally I have found out the reason.
A horizontal LinearLayout aligns the baselines of all its child controls by default. So the first line of text in your multi-line button is vertically aligned with the single line of text in the other buttons.
To disable this behaviour, set android:baselineAligned="false" on the LinearLayout.
All credit goes to #Karu for this answer : https://stackoverflow.com/a/8290258/4211264

This is due to text wrapping in first button. Other two buttons take too match space on screen. And first button try's to stay on screen by self wrapping. I don't know what is your task. If you want to keep buttons in one line try to use layout_weight = 1 on all buttons.

This is because you have given different weights to every button. You need to give equal weight to every button. Replace your layout file code with this.
<LinearLayout 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"
android:layout_gravity="center"
android:orientation="horizontal"
tools:context=".MainActivity">
<Button
android:id="#+id/button3"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Button" />
<Button
android:id="#+id/button2"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Button" />
<Button
android:id="#+id/button"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Button" />

ScrollView does not expand

I have nine ImageView(s) inside scrollview and each one has a LinearLayout below it with "gone" visibility. when one of the image clicked the linearlayout below it set to visible.
I added scrollToTop() function to scroll image view to the top to be able to see the list but the last one (image #9) does not response to scroll and stay at the bottom. the list is get visible but I have to scroll manually.
<ScrollView android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
.
.
.
<ImageView android:id="#+id/iv_img1"
android:layout_width="match_parent"
android:layout_height="100dp"/>
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:visibility="gone">
<TextView android:text="1" style="#style/tv_number" />
<TextView android:text="1" style="#style/tv_number" />
<TextView android:text="1" style="#style/tv_number" />
</LinearLayout>
.
.
.
</LinearLayout>
</ScrollView>
the Java Functions:
scrollToTop(containerList.getTop(), 0);

The first internal LinearLayout should be layout_height wrap_content

Flat buttons, listview android

I have a hard time pointing out what UI elements are used here? Is it buttons or listviews?

This view is not seems as a list view. They are either Buttons or ImageButtons fitted in some layout.

If you want to make this in a ListView, you are gonna have a hard time. The best would be to make it in a GridLayout, if you are not that confident in working with that then the easiest solution would be a LinearLayout in the root with vertical orientation, and then add a LinearLayout with horizontal orientation where the childs have `weight="1"
Something like this (Just for the first two buttons):
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginTop="20dp">
<FrameLayout
android:layout_width="0dp"
android:layout_height="50dp"
android:layout_weight="1"
android:clickable="true"
android:layout_marginRight="10dp"
android:onClick="onChildOneClick">
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="Button 1"
android:background="android:color/green" />
</FrameLayout>
<FrameLayout
android:layout_width="0dp"
android:layout_height="50dp"
android:layout_weight="1"
android:clickable="true"
android:layout_marginLeft="10dp"
android:onClick="onChildTwoClick" />
</LinearLayout>
</LinearLayout>
Inside your framelayout you can put a ImageView + TextView to make it look like the sketch

Layout issue: dialog containing ExpandableListView

Here follows the code for my dialog.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:orientation="vertical" >
<CheckBox
android:id="#+id/source_select_public"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="#string/source_select_public" />
<ExpandableListView
android:id="#+id/source_select_list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:groupIndicator="#android:color/transparent" />
<LinearLayout
android:id="#+id/source_select_commands"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="3dp"
android:orientation="horizontal" >
<Button
android:id="#+id/source_select_cancel"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="#android:string/cancel" />
<Button
android:id="#+id/source_select_ok"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="#android:string/ok" />
</LinearLayout>
</LinearLayout>
When the ExpandableListView is open, it is automatically scrollable; however, the two buttons below it disappear. I have tried enclosing the whole layout within a ScrollView, but then the scrollable behavior of the ExpandableListView is broken (i.e. it gets too small to be actually touched). What I would like to achieve is a dialog that can take up all the screen while allowing the ExpandableListView to be the only scrollable component. Can someone help me with this, please?

Old question, but this can be achieved using a relative layout as the root layout instead of a linear layout

Android ScrollView and buttons at bottom of the screen

I want to implement this: A ScrollView that contains many elements (ImageViews, TextViews, EditTexts etc) and then after the ScrollView some buttons (which are custom ImageViews) that appear always exactly at the bottom of the screen.
If I use the android:fillViewport="true" attribute, then if the elements of the ScrollView are too big to fit in the screen size the buttons get invisible . If I use the android:Weight=1 attribute then the ScrollView gets only 50% of the Screen when the screen is big and it can fit (I want the buttons to take a small percentage, about 10%). If I set the android:Weight to bigger values then the buttons appear very small.
Please help! Maybe it is something simple that I overlooked but I’ve been banging my head for hours!

Just created and tested it. Looks like you want.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:id="#+id/buttons"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:gravity="center"
android:layout_alignParentBottom="true">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Custom Button1"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Custom Button2"/>
</LinearLayout>
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="#id/buttons">
<!--Scrollable content here-->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:text="test text"
android:textSize="40dp"/>
</LinearLayout>
</ScrollView>
</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ScrollView
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello World"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hallo Welt"
/>
</LinearLayout>
</ScrollView>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="0">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Go next page"
android:layout_alignParentRight="true" />
</RelativeLayout>
</LinearLayout>

This worked for me. Give the scroll view a weight of 1. Put all the other widgets following the scroll view in a layout. The scroll view will grow enough to not block the rest.
Widgets in scroll view and rest at bottom

scrollview cannot fit the screen because you put it on a linear layout, so linear layout fit in the screen,
just try to make scrollview as root elemen on xml layout
<?xml version="1.0" encoding="utf-8"?>
<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/scrollView1"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<LinearLayout
android:id="#+id/linearLayout1"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<!-- Here you can put some XML stuff and BOOM! your screen fit to scrollview -->
</LinearLayout>
</ScrollView>

If you do not want to use RelativeLayout, it is better to use LinearLayout. This method is better in my opinion.
Just set the layout_weight to one