Develop Reference

How to center fit image in linear layout?

I have an xml screen with three children linear layouts in a parent linear layout of vertical orientation. First child contains an image view and when running the application I can not view any image. Why? is the image size too big?? If so.. how to scale it? However Image is view able in my design tab. of android stdudio. Below is my complete code for xml file.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/activity_sign_up"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.example.root.my_laoder.SignUp"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:adjustViewBounds="true"
android:scaleType="centerInside"
android:src="#drawable/ty"
/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:orientation="vertical"
android:paddingTop="50dp"
>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textEmailAddress"
/>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textPassword"
/>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="number"
/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:paddingTop="50dp"
>
<Button
android:text="Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0.5"/>
<Button
android:text="Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0.5"
/>
</LinearLayout>
</LinearLayout>

1. Add attribute android:gravity="center_horizontal" to LinearLayout, to show ImageView in center.
2. Update ImageView width to android:layout_width="wrap_content" and remove attribute android:layout_gravity="center".
3. Use android:scaleType="fitXY" instead of android:scaleType="centerInside"
Try this:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/activity_sign_up"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_horizontal">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:scaleType="fitXY"
android:src="#drawable/ty" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:orientation="vertical"
android:paddingTop="50dp">
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textEmailAddress" />
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textPassword" />
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="number" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:paddingTop="50dp">
<Button
android:text="Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0.5" />
<Button
android:text="Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0.5" />
</LinearLayout>
</LinearLayout>
OUTPUT:

what are the dimens values for these parameters?
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
and why you are using separate linearlayout for imageView even with parent layout as linear?
kindly remove that
have you checked the size of image you are using as a background in ImageView? if size is large than probably image is pushing your rest of your views out of the screen.try to give fixed width and height let's say 100dp for both and see if you are able to see anything.
If you wanna make imageView centre horizontally use in ImagView view
android:layout_gravity="center_horizontal"
above line of code will not work with separate linear layout for ImageView. If you are gonna use separate layout for ImageView anyway, use below line of code inside that linearlayout
android:gravity="center_horizontal"
Note: sorry I'm not able to leave a comment.

Try this for your ImageView:
<ImageView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:adjustViewBounds="true"
android:scaleType="centerInside"
android:src="#android:drawable/btn_minus" />

I think you missed scaleType of ImageView, Follow the steps to make your image center
1. Add attribute android:layout_gravity="center_horizontal" to show ImageView in center.
2. Set ImageView layout_width="match_parent" and
layout_height="#dimen/fixed_height"
==> height will be fixed but width will automatically adjust
according to device size
3. and set scaleType="fitEnd" or scaleType="fitCenter"
==> fitEnd is ( Scale the image from the end of the container ) and
possible to have space on top
if image is different each time.
==> fitCenter is (Scale the image from center) and possibility to
have space in top and bottom
Example:
<ImageView
android:id="#+id/cover_image"
android:layout_width="match_parent"
android:layout_height="#dimen/fixed_height"
android:layout_gravity="center_horizontal"
android:scaleType="fitEnd" />

Android design : a scrollview 3 button below

I'm trying to create a design (and i'm pretty bad at this -__- ) where I will have a scrollview and a set of 3 buttons, horizontally aligned ALWAYS at the bottom of the screen (I mean the scrollview should be ABOVE my layout with my button and may scroll, but the button have to ALWAYS be displayed/visible)
I have already tried several solution, the last one I used is this , but it doesn't succeeded :(
<?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"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<RelativeLayout
android:id="#+id/header"
android:layout_alignParentTop="true"
android:layout_width="match_parent"
android:layout_height="wrap_content">
</RelativeLayout>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/scroll"
android:layout_above="#+id/footer"
android:layout_below="#+id/header">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/imageView1"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Chargement en cours"
android:id="#+id/TNom"
android:layout_below="#+id/imageView1"
android:layout_centerHorizontal="true" />
</RelativeLayout>
</ScrollView>
<RelativeLayout
android:id="#+id/footer"
android:layout_width="match_parent"
android:layout_height="wrap_content">
android:layout_alignParentBottom="true">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="+"
android:id="#+id/Bplus"
android:onClick="onClickSuivant"
android:layout_toLeftOf="#+id/Begale"
android:layout_toStartOf="#+id/Begale" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="="
android:id="#+id/Begale"
android:onClick="onClickSuivant"
android:layout_centerHorizontal="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="-"
android:id="#+id/Bmoins"
android:onClick="onClickSuivant"
android:layout_toRightOf="#+id/Begale"
android:layout_toEndOf="#+id/Begale" />
</RelativeLayout>
NB : I have no need of the "header" part ... but the last code I found have it and it seems to be exactly I need.... seemed only -__- :(
And I have 2 questions on this design (while i'm asking, I ask everything :p )
1/ How may I force the size of the Image I will be downloading into ImageView1 to a "maximum" height (I mean my picture will be portrait OR landscape... let say 10*15 and 15*10 ... how may i forced them to be 10*6.666 instead of 15*10 <= It's an example... I don't know the image size I will have, but I know I want them at the same height every time, width may change according to the ratio)
2/why Lint is writing this part in red....
android:textAppearance="?android:attr/textAppearanceLarge"
Thx in advance to everyone who stops here and give me hints :)
(and sorry for my english)
EDIT : I have found some answer !! I used RELATIVELayout instead of LINEARLayout, which is recommended to do what I wanted ...
Si here is the "new" template (for reference if anyone is interested), where I still have problem
<?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:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
android:orientation="vertical">
<ScrollView
android:layout_width="match_parent"
android:id="#+id/scroll"
android:layout_height="0dp"
android:layout_weight="1">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<ImageView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/imageView1"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Chargement en cours"
android:id="#+id/TNom"
android:layout_below="#+id/imageView1"
android:layout_centerHorizontal="true" />
</LinearLayout>
</ScrollView>
<LinearLayout
android:id="#+id/footer"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:orientation="horizontal">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="+"
android:id="#+id/Bplus"
android:onClick="onClickSuivant"
android:layout_toLeftOf="#+id/Begale"
android:layout_toStartOf="#+id/Begale" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="="
android:id="#+id/Begale"
android:onClick="onClickSuivant"
android:layout_centerHorizontal="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="-"
android:id="#+id/Bmoins"
android:onClick="onClickSuivant"
android:layout_toRightOf="#+id/Begale"
android:layout_toEndOf="#+id/Begale" />
</LinearLayout>
With the previous design, button were well aligned and take all the screen (match_parent) ... with this one, they are located at the bottom left ... As android:layout_centerHorizontal="true" is made for RelativeLayout, problem come from this... how may i change it ?

Try using android:gravity="center" in your LinearLayout (which encapsulates the buttons) or android:layout_gravity="center" in Button elements. I believe the first option will be enough.
EDIT: regarding Lint warning message, I believe it's related to this line:
android:text="Chargement en cours"
It's discouraged to use hard-coded strings. Try replacing it by android:text="#string/my_string_id" and define such string in your strings.xml file.

Adding margins to listview

I am following a tutorial and I did not understand why exactly the margins that I applied to a list view contained within a relative layout does not affect the look when I test it on a device. However, if I put everything in a LinearLayout container it looks as it should. I don't understand why the layout does not work without this LinearLayout.
This is my code in layout for my listView:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#android:color/transparent">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="#dimen/inbox_horizontal_margin"
android:layout_marginRight="#dimen/inbox_horizontal_margin"
android:layout_marginTop="#dimen/inbox_vertical_margin"
android:background="#android:color/white">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/messageIcon"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/message_list_item_vertical_margin"
android:paddingBottom="#dimen/message_list_item_vertical_margin"
android:layout_alignParentStart="true"
android:contentDescription="#string/content_desc_message_icon"
android:src="#drawable/ic_action_picture"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="Medium Text"
android:id="#+id/senderLabel"
android:layout_centerVertical="true"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:layout_toRightOf="#+id/messageIcon"
android:layout_toEndOf="#+id/messageIcon"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceSmall"
android:text=" created at: 03.17.15"
android:id="#+id/createdAtLabel"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:layout_centerVertical="true"
android:layout_toRightOf="#+id/senderLabel"
android:layout_toEndOf="#+id/senderLabel"/>
</RelativeLayout>
</LinearLayout>
This is the result of the code:
this is the code without the LinearLayout:
<?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="wrap_content"
android:layout_marginLeft="#dimen/inbox_horizontal_margin"
android:layout_marginRight="#dimen/inbox_horizontal_margin"
android:layout_marginTop="#dimen/inbox_vertical_margin"
android:background="#android:color/white">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/messageIcon"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/message_list_item_vertical_margin"
android:paddingBottom="#dimen/message_list_item_vertical_margin"
android:layout_alignParentStart="true"
android:contentDescription="#string/content_desc_message_icon"
android:src="#drawable/ic_action_picture"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="Medium Text"
android:id="#+id/senderLabel"
android:layout_centerVertical="true"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:layout_toRightOf="#+id/messageIcon"
android:layout_toEndOf="#+id/messageIcon"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceSmall"
android:text=" created at: 03.17.15"
android:id="#+id/createdAtLabel"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:layout_centerVertical="true"
android:layout_toRightOf="#+id/senderLabel"
android:layout_toEndOf="#+id/senderLabel"/>
</RelativeLayout>
And this is the result of this layout:

Margin is outside a view , ListView uses AbsListView.LayoutParams by default, which doesn't include any margin support, just the height and width, thats why, it simply ignores the params value for margins. Try using padding for your relative layout instead

Make scrollview in layout (crash)

I'm trying to make a screen scrollable with scroll view but my application keeps crashing.
What I've done is to replace RelativeLayout by ScrollView, but it doesn't work.
I need your help with this. Here is the code of the screen:
<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"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="0dp"
android:background="#drawable/background01"
tools:context=".MainActivity"
android:id="#+id/relativeLayout">
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/id"
android:background="#drawable/lightcontainer"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:weightSum="1"
android:paddingLeft="20dp"
android:paddingRight="20dp"
android:layout_marginBottom="16dp">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/mainTitle1"
android:id="#+id/textView"
android:layout_gravity="center_horizontal"
android:layout_marginTop="20dp"
android:textSize="20sp"
android:textColor="#ffffff"
android:shadowColor="#000000"
android:shadowRadius="1.5"
android:shadowDx="2"
android:shadowDy="2"/>
</LinearLayout>

what you are trying to do is not an scrollable view it's just a relative layout. Try to put your code inside a ScrollView component, like this:
<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:fillViewport="true">
<!-- PUT YOUR CODE HERE -->
</ScrollView>
Make sure you close all tags correctly as well (your relative layout is not closed).
<RelativeLayout>
Content
</RelativeLayout> <-- This closing tag is always necessary

Button positioning using Layouts in Android

After many hours I can't fix button on the bottom of activity. Either is invisible or at the top. I tried also without relative layout, I tried adding another linear layout, but I still don't know how set this button.
<?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"
tools:context=".News" >
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<ImageView
android:id="#+id/imageView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:src="#drawable/news" />
<WebView
android:id="#+id/webView1"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<Button
android:id="#+id/newsbutton"
style="?android:attr/buttonStyleSmall"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:text="Chiudi" />
</LinearLayout>
</RelativeLayout>

<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"
android:orientation="vertical" >
<ImageView
android:id="#+id/imageView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:src="#drawable/news" />
<WebView
android:id="#+id/webView1"
android:layout_below="#id/imageView1"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<Button
android:id="#+id/newsbutton"
style="?android:attr/buttonStyleSmall"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:layout_alignParentBottom="true"
android:text="Chiudi" />
</RelativeLayout>

First, you have a warning in Legacy Android Layout Editor, that either RelativeLayout or LinearLayout is useless. That should be a hint for you. Pay attention to warnings, they're helpful in most of the times.
Indeed, you can get rid of LinearLayout.
So, the solution is:
Remove LinearLayout.
Add android:layout_below="#+id/imageView1" to the WebView.
Add android:layout_alignParentBottom="true" to the Button.
Add android:contentDescription to ImageView.
Use #string instead of hardcoded strings.
Optional steps are not bolded, they will remove warnings.
Whole working code, tested under Android 4.1.2:
<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"
android:orientation="vertical" >
<ImageView
android:id="#+id/imageView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:contentDescription="TODO: DESCRIPTION"
android:src="#drawable/ic_launcher" />
<WebView
android:id="#+id/webView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="#+id/imageView1" />
<Button
android:id="#+id/newsbutton"
style="?android:attr/buttonStyleSmall"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:layout_alignParentBottom="true"
android:text="Chiudi" />
</RelativeLayout>

copy paste the following in your button component ;)
android:layout_marginBottom="147dp"
android:layout_marginTop="50dp"
android:layout_marginleft="50dp"
android:layout_marginRight="47dp"
play only with the numbers and Im sure ull get the hang of it :)

Just add android:layout_below="#id/webView1" in your button.
If you would use LinearLayout, you could set the Widget that should fill the empty space like this: layout_height="0dp" and layout_weight="1". This should do the job too.