Develop Reference

Display image to take 80% of screen

Using XML with relative layout as root layout , is there way that I can tell the image view to use 80% of screen and center it in the middle.
If I use wrap content or numeric dp then the image might be too small on big screens or too big for small screens. I want it to be 80‰ no matter what the screen looks like?
Please let me know how you would approach this thanks

You use PercentRelativeLayout, import this
dependencies {
...
compile 'com.android.support:percent:23.3.0'
...
}
In XML, you use <android.support.percent.PercentRelativeLayout> instead <RelativeLayout>, it will support below code for those child
app:layout_heightPercent="80%"
app:layout_widthPercent="80%"
With android:layout_width/height, you can use "wrap_content", or without using, no problem.

Well ,you can't do this on XML cause these mathematical operations can't be done there. You can just use MATCH_PARENT in the XML.
And then programmatically get the particular Views MeasuredWidth() and then set the width to be 80% of that.
Much easier and cleaner this way.

You can use PercentRelativeLayout
<android.support.percent.PercentRelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
app:layout_widthPercent="80%"
app:layout_heightPercent="80%"
android:layout_centerInParent="true"/>
</android.support.percent.PercentFrameLayout>

You can create using weight in linear layout like following
<?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"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="8"
android:orientation="horizontal">
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1" />
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="8">
<ImageButton
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1" />
</LinearLayout>
</RelativeLayout>

Android: Layout looks different on different devices

Hi I have an activity with an imageview and a row with buttons at the bottom.The buttons are added to the iconView layout programmatically.When I test my app on my HTC one the buttons are displayed correct.
Once I run it on a device with a smaller screen it is cropped i.e. only the top of the buttons is displayed.
How can I make my code device independent?
<?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:background="#000000"
android:orientation="horizontal" >
<LinearLayout
android:id="#+id/mainView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/background2"
android:orientation="vertical" >
<ImageView
android:id="#+id/imageView"
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="0.95"
android:orientation="vertical"
android:paddingLeft="4dp"
android:paddingTop="4dp"
android:paddingRight="4dp"
android:paddingBottom="4dp"
android:src="#android:drawable/ic_menu_camera" />
<LinearLayout
android:id="#+id/iconView"
android:layout_weight="0.05"
android:layout_width="match_parent"
android:layout_height="60dp"
android:orientation="horizontal" >
</LinearLayout>
</LinearLayout>
</LinearLayout>
Thanks in advance.

Try this layout:
<?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:background="#000000" >
<RelativeLayout
android:id="#+id/mainView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/background2" >
<ImageView
android:id="#+id/imageView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="4dp"
android:layout_above="#+id/iconView"
android:src="#android:drawable/ic_menu_camera" />
<LinearLayout
android:id="#+id/iconView"
android:layout_width="match_parent"
android:layout_height="60dp"
android:layout_alignParentBottom="true"
android:orientation="horizontal" />
</RelativeLayout>
</LinearLayout>

Try this
make the first view with android:layout_weight="1"
and the with a static height without the layout_weight, this should solve it

Unfortunately the solutions did not work. Eventually I changed my code and add the buttons in the xml, not programmatically. This works fine. I don't know why...

When adding button either programmatically or in XML layout, try to use LinearLayout as the parent for button and leverage the "weightsum" property of that LinearLayout.
When you're going to share the real state of screen's width or height equally between a number of views such as buttons or textview or ..., you can set "layout_weight" property on those controls. Notice that, this is only possible when using LinearLayouts.
What happens at the end is that the linearlayout's real estate is calculated and allocated according to each child's element's "layout_weight" value.
The example below shows how to put two buttons beside each other and make them fill the screen's width equally :
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:weightSum="2"
>
<Button
android:id="#+id/btn_left"
android:layout_width="0dp" // width is calculated by weight
android:layout_height= "wrap_content"
android:layout_weight="1" />
<Button
android:id="#+id/btn_right"
android:layout_width="0dp" // width is calculated by weight
android:layout_height= "wrap_content"
android:layout_weight="1" />
<LinearLayout/>

Nested Layouts inside Linear Layout (vertical) - Ensuring the last nested layout displays its contents

I have a linear-layout (vertically-oriented) that contains two nested linear layouts inside of it.
The first linear-layout has a background image that is applied dynamically based on the context o the particular activity. The image pretty much takes up the whole size of the screen
The second linear-layout contains two checkboxes (horizontally-oriented) that should be displayed at the bottom of the activity.
My question is, how can I ensure that the second linear-layout displays at the bottom of the screen and just shows the minimal amount it needs to, allowing the first linear-layout to display as much as its background image as possible? Currently it's being pushed off the screen by the first LL's bg image.
Thank you.

Using Weight you can do what you want:
<?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" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
android:background="#FF0000"
android:layout_weight="1"
>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:background="#00FF00"
android:layout_weight="1"
>
<CheckBox
android:id="#+id/checkBox1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="CheckBox" />
<CheckBox
android:id="#+id/checkBox2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="CheckBox" />
</LinearLayout>
</LinearLayout>

You can use RelativeLayout as the outer layout instead of LinearLayout
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/mainLayout"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout
android:id="#+id/bottomLayout"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
...
</LinearLayout>
<LinearLayout
android:id="#+id/topLayout"
android:layout_above="#id/bottomLayout"
android:layout_centerHorizontal="true"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
...
</LinearLayout>
</RelativeLayout>

<LinearLayout
... >
<LinearLayout
...
android:layout_height="0dp"
android:layout_weight="1"
>
...
</LinearLayout>
<LinearLayout
...
android:layout_height="wrap_content"
>
...
</LinearLayout>
</LinearLayout>
Notice on the weighted layout, the height is set to "0dp". With only one weighted, the weighted one will stretch to fit the rest of the available area.

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

ANDROID Background for LinearLayouts

i used nested LinearLayouts for the purpose of putting the EditTexts and Buttons in the center of the screen like this:
I want to change the background of this. So I inserted another LinearLayout on the top of everything else. But its not working. All I can see is black which indicates that I have covered the Editext and Buttons.
I think have to arrange the layouts properly.
any suggestions on how i may put a background(i.e. color, as of now)?
I am posting my xml.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:background="#+id/OceanBlue">
<LinearLayout
android:orientation="vertical"
android:layout_width="wrap_content">
<LinearLayout
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="right" >
<EditText
android:id="#+id/et_username"
android:layout_width="170px"
android:layout_height="wrap_content"/>
</LinearLayout>
<LinearLayout
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<EditText
android:id="#+id/et_password"
android:password="true"
android:layout_width="170px"
android:layout_height="wrap_content"/>
</LinearLayout>
<LinearLayout
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<Button
android:id="#+id/button_ok"
android:text="Login"
android:layout_width="86px"
android:layout_height="wrap_content">
</Button>
<Button
android:id="#+id/button_cancel"
android:text="Cancel">
</Button>
</LinearLayout>
</LinearLayout>

I dont know how you are getting this without specifying any layout_height or layout_width
Use
android:layout_width="fill_parent"
android:layout_height="fill_parent"
in your main parent linear layout.I think it will solve your issue.

Are you able to see the layout, thats unexpected? You did not specify the height or width for parent layout so i think that is the problem.
In case of having these kinds of designs its better to use relative layout which provides main features to deign the layout as our wish