Develop Reference

Setting maximum height on RecyclerView

I have a dialog fragment that contains linear layout that involves a titleText above a RecyclerView, and at the very bottom, there's a button below the recyclerView.
Since a recyclerView expands or collapses based on the number of items the adapter sets, the button sometimes gets truncated and no longer appears to be on screen, since the recyclerView just covers the entire screen.
My question is, is there a way to set the maximum height of the recyclerView without ever hiding the button underneath. I also don't want to just give the view a random height just in case the recyclerView contains no items, and it would just be a blank section.
Please let me know if you've ever run into this issue, and how you resolved this. Thanks!

UPDATED
You can achieve this easily using layout weights. Here's an example:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:text="Title"
android:textSize="21sp"/>
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingBottom="30dp">
</android.support.v7.widget.RecyclerView>
</LinearLayout>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:text="Submit"/>
</FrameLayout>
The Title and RecyclerView will wrap content according to contents and button will always take up bottom place.

I suggest using RelativeLayout as it handles the positioning of views for cases like yours, so that you can actually focus on main design.
<?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">
<TextView
android:id="#+id/title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:text="Some title" />
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="#+id/title"
android:layout_above="#+id/button"/>
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:gravity="center"/>
</RelativeLayout>
Above XML code is the skeleton code for what you need. you can add margins and dimensions to control the spacing. But in any case (until you provide negative margins) your views will never overlap each other.
Main trick of using RelativeLayout is the ability to use XML tags like
android:layout_below or android:layout_above or android:layout_start
or android:layout_end which perfectly aligns your view the way you
want.

Android not able to scroll up

I have a login layout with two EditText and a Button. When I'm typing some text in EditText, as the keyboard open it overlap the some of my layout. I try to scroll up but not able to scroll up layout to be visible. Ｉ'm using Relative Layout to create it. How to solve it?
Thank you.

Place your EditTexts and Button inside a ScrollView. Whatever is inside ScrollView can be scrolled. So your problem will be solved.
Note that ScrollView can host only one child. So you have to place all your Views inside a ViewGroup like LinearLayout or RelativeLayout
Although Julia Zhao's answer is correct, it uses RelativeLayout. If you use RelativeLayout you have to do more work to make your Views appear one below the other. So I suggest you to use LinearLayout with android:orientation="vertical" inside it. It will automatically place one View below the other without any extra effort. So you won't issues like one View overlapping on other.
<?xml version="1.0" encoding="utf-8"?>
<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical">
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="UserName"/>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:hint="Password"/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:text="Login"/>
</LinearLayout>
</ScrollView>

Try nesting everything in a ScrollView, hope this helps.
<?xml version="1.0" encoding="utf-8"?>
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:id="#id/RLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#000000"
xmlns:android="http://schemas.android.com/apk/res/android"
>
// Your code
</RelativeLayout>
</ScrollView>

Android scrollview eating up added layouts

I have a layout something like this:
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginBottom="10dp"
android:background="#ff303f"
android:id="#+id/layout">
<ImageView
android:id="#+id/picture"
android:layout_width="300dp"
android:layout_height="300dp"
android:layout_centerInParent="true"/>
<Button
android:id="#+id/cancel"
android:layout_width="45dp"
android:layout_height="45dp"
android:layout_alignRight="#id/picture"
android:background="#drawable/cross_out"/>
</RelativeLayout>
I inflate it using the usual layout inflator service, set up some functionality to the button and an image to the imageview (all images are of same size and aspect ratio).
After that, I add this view to my fragment's layout which is nothing but a ScrollView which is a parent, it has a child linear layout that I call 'map' and simply add it to the map.
Expected : The added layouts should get added properly and I can scroll through it. Actual : If more than 2 are added, the first one gets eaten up. I can see it half or sometimes it is completely eaten up. :\
Any idea whats going on here? Thanks a lot for your time.
EDIT: Here's the layout file I add the inflated layout into:
<?xml version="1.0" encoding="utf-8"?>
<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/scrollView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#f6ff45">
<LinearLayout
android:id="#+id/map"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#43ff44"
android:orientation="vertical"
android:layout_margin="10dp"
android:layout_gravity="center"
android:layout_marginTop="15dp">
</LinearLayout>
</ScrollView>
I also forgot to mention that after adding 3 or more of these layouts, I realized there's unnecessary empty space in the end. :\

try to define scrollView from Java code like
//Initialize the TextView for vertical scrolling
output = (TextView) findViewById(R.id.textView);
output.setMovementMethod(new ScrollingMovementMethod());

Center ListView horizontally

As easy as it seems to be, as stubbornly this ListView won't center itself (or it's content within - doesn't matter to me).
This is activity layout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
tools:context="com.drobiazko.den.mobineon.MainActivity"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:gravity="center_horizontal"
android:background="#drawable/bg">
<RelativeLayout android:id="#+id/clock_container"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<!--<RelativeLayout android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#android:color/holo_blue_dark">-->
<com.drobiazko.den.mobineon.ListViewRowsHeight
android:id="#+id/listview"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:overScrollMode="never"
android:scrollbars="none"
android:divider="#null"
android:listSelector="#android:color/transparent"
android:persistentDrawingCache="scrolling|animation"
android:background="#android:color/holo_green_dark" />
<!--</RelativeLayout>-->
</LinearLayout>
This is ListView's item layout:
<?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">
<ImageView android:id="#+id/btn_icon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
style="#style/custom_btn_icon" />
<TextView android:id="#+id/btn_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
style="#style/custom_btn_name" />
<TextView android:id="#+id/btn_count"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
style="#style/custom_btn_count" />
</RelativeLayout>
I've tried everything (including simplifying layout to max), but it still won't go.
Funny that the first relative layout clock_container - centers like a charm, due to parent LinearLayout's android:gravity="center_horizontal". Why won't ListView?
Added later:
Inspired by FOliveira's answer, I've done some investigation and found that:
everything works fine, parent LinearLayout has android:gravity="center_horizontal" and centers his children respectfully. The reason for ListView's children are left-aligned is that ListView takes all possible width despite his android:layout_width="wrap_content" attribute.
Anyone knows why is that?

First of all , i would remove the first linear layout and stay only with the relative layout as the parent.
After having the relative layout as the main parent , set the CENTER_IN_PARENT attribute to true.
The mistake you are making is that you are setting the gravity of Linear Layout child to center horizontal, which is correct, but the only children being affected by this option is the Relative layout itself.

screen with top banner, webview and bottom banner

I'm trying to create a very simple android screen with the following content: top banner, webview and bottom banner. for some reason, i can't do it. my xml look like:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout android:id="#+id/FrameLayout02"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:orientation="vertical"
android:fitsSystemWindows="true" android:isScrollContainer="false">
<ImageView android:layout_width="wrap_content" android:layout_above="#+id/Web"
android:layout_height="fill_parent" android:layout_gravity="top"
android:src="#drawable/logo"></ImageView>
<WebView android:layout_gravity="center" android:id="#+id/Web"
android:layout_height="fill_parent" android:layout_width="fill_parent"></WebView>
<ImageView android:layout_width="wrap_content" android:layout_below="#+id/Web"
android:layout_height="fill_parent" android:layout_gravity="bottom"
android:src="#drawable/logo"></ImageView>
</LinearLayout>
what is wrong?
Thanks,
Daniel

Short answer all is wrong. Your code is a mess.
Long answer. You are trying to have an ImageView above a WebView and at the bottom another ImageView. I'm not exactly sure what of the mistakes broke it but that's also not important. Take a look at my example 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">
<ImageView android:id="#+id/topimage"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:src="#drawable/icon"/>
<ImageView android:id="#+id/bottomimage"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:src="#drawable/icon"/>
<WebView android:id="#+id/web"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_below="#id/topimage"
android:layout_above="#id/bottomimage"/>
</RelativeLayout>
Now what my XML does is simple. It uses a RelativeLayout as a container to allow a more flexible child alignment. The ImageView called topimage will adjust its height to its content and fill the parent in width. It is aligned to its parents top. The second ImageView is similar with the only exception that it is pinned to its parents bottom. The WebView is aligned in between both ImageViews. It adjust it's height to the 'ImageView`s heights.
Try to always keep some kind of structure in your XML and also Java code so you and also others can throw a look at it without starting to cry.