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" />

Horizontaly center a LinearLayout

I have the following LinearLayout:
<?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="fill_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/about_vertical_margin"
tools:context=".MainActivity">
<LinearLayout
android:id="#+id/dev_buy_layout"
android:layout_width="wrap_content"
android:layout_height="#dimen/dev_by_layout_height"
android:orientation="horizontal"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:gravity="center_horizontal"
android:layout_gravity="center_horizontal">
<TextView
android:id="#+id/dev_buy_text"
android:text="#string/dev_buy_text"
android:layout_width="#dimen/dev_by_width"
android:layout_height="wrap_content"
android:layout_marginEnd="#dimen/activity_horizontal_margin"
android:layout_marginRight="#dimen/activity_horizontal_margin" />
<TextView
android:id="#+id/dev_by_value"
android:text="#string/dev_by_value"
android:layout_width="120dp"
android:layout_height="wrap_content" />
</LinearLayout>
</RelativeLayout>
But it will not center itself, even after looking around for answers, they were of no use so far.
How may I do it?

android:layout_centerHorizontal="true"
This will work fine for you as parent layout is RelativeLayout
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_gravity="center_horizontal"
And Remove These Lines :)

It should work with centerInParent property, as the main parent is a RelativeLayout.
Just do the following:
android:layout_centerInParent="true"

There are two ways you can do it.
First of all remove following lines from LinearLayout
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_gravity="center_horizontal"
First would be add below line inside LinearLayout
android:layout_centerHorizontal="true"
else
Second would be write below line inside RelativeLayout
android:gravity="center_horizontal"

Android: Custom Expandeble List and TextView issue

I faced with one issue when I tried to create my custom Expandable List View.
I can't make text ("9.2") on the center of the cell.
incorrect image
But on the prevew mode it looks fine.
correct image
Here my xml file:
<?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:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:background="#android:color/background_dark">
<LinearLayout
android:id="#+id/titles"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingLeft="#dimen/space_between_elements"
android:orientation="vertical"
android:layout_toRightOf="#+id/image"
android:layout_toLeftOf="#+id/rate">
<TextView
android:id="#+id/bigTitle"
style="#style/PrimaryFont"
android:text="A big title"/>
<TextView
android:id="#+id/littleTitle"
style="#style/SecondaryFont"
android:layout_marginTop="#dimen/space_between_elements"
android:text="A little title" />
</LinearLayout>
<TextView
android:id="#+id/rate"
style="#style/RatingFont"
android:text="9.2"
android:layout_alignParentTop="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_alignBottom="#+id/titles" />
<ImageView
android:id="#+id/image"
android:layout_width="#dimen/touchable_ui_components"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:src="#drawable/abc_ic_cab_done_holo_dark"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_alignBottom="#id/titles" />
</RelativeLayout>
I think the main issue due to +id/image becasue without +id/titles it also looks incorrectly.

Try this for the TextView with id rate.
android:layout_centerVertical="true"
Remove
android:layout_alignParentTop="true"
Be careful with the padding, it might move the drawable region not be in the center. (see http://developer.android.com/reference/android/view/View.html ->Size, padding and margins)
Also these two:
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
have similar effects, use only one. I prefer Right
(see http://developer.android.com/reference/android/widget/RelativeLayout.html#ALIGN_PARENT_END)

Android: 2 relative layout divided in half screen

I tried many times to draw 2 Relative layout aligned horizontally and divided in half screen.
I design the image with paint to explain a bit better what i mean.
Any suggestion?

Another way to accomplish the same task without needing to use a LinearLayout is to put a center-aligned "shim" in the middle of the parent layout, then align other elements to it. If you set the half-width element's width to match_parent, but align both their left and right sides, they'll end up shrinking themselves to fit.
<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: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.EqualWidthExample" >
<!-- An invisible view aligned to the center of the parent. Allows other
views to be arranged on either side -->
<View
android:id="#+id/centerShim"
android:layout_height="match_parent"
android:layout_width="0dp"
android:visibility="invisible"
android:layout_centerHorizontal="true"/>
<!--Set width to match_parent sets maximum width. alignParentLeft aligns
the left edge of this view with the left edge of its parent. toLeftOf
sets the right edge of this view to align with the left edge of the
given view. The result of all three settings is that this view will
always take up exactly half of the width of its parent, however wide
that may be. -->
<Button
android:id="#+id/btLeft"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_toLeftOf="#+id/centerShim"
android:text="Left Button" />
<!--Same deal, but on the right -->
<Button
android:id="#+id/btRight"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_toRightOf="#+id/centerShim"
android:layout_below="#+id/tvLeft"
android:text="Right Button" />
</RelativeLayout>

You can put these 2 RelativeLayouts inside a LinearLayout with horizontal orientation, then use the weight for both RelativeLayouts. This will divide the LinearLayout in 2 equal parts.
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
android:baselineAligned="false">
<RelativeLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1">
</RelativeLayout>
<RelativeLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1">
</RelativeLayout>
</LinearLayout>

now you can do it easily using PercentRelativeLayout
<android.support.percent.PercentRelativeLayout
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:padding="16dp"
tools:context=".MainActivity">
<Button
android:id="#+id/button"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:text="Button"
app:layout_widthPercent="50%"/>
<Button
android:id="#+id/button2"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_toRightOf="#id/button"
android:text="Button 2"
app:layout_widthPercent="50%"/>
</android.support.percent.PercentRelativeLayout>
don't forget to add the gradle dependency
dependencies {
compile 'com.android.support:percent:25.3.1'
}
code in github
Update
PercentRelativeLayout is Deprecated since API level 26.0.0

You could use an non-recommended structure with nested wieghts
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:baselineAligned="false"
android:weightSum="5">
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
android:layout_gravity="center">
<TextView
android:id="#+id/TopTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Top Text View"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="5dp"/>
</RelativeLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal"
android:weightSum="2"
android:layout_weight="4">
<RelativeLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin">
<TextView
android:id="#+id/LeftTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Left Text View"
android:layout_centerHorizontal="true"
android:layout_marginTop="30dp"/>
</RelativeLayout>
<RelativeLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin">
<TextView
android:id="#+id/RightTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Right Text View"
android:layout_centerHorizontal="true"
android:layout_marginTop="30dp"/>
</RelativeLayout>
</LinearLayout>
</LinearLayout>

I see 4 relativelayouts in your drawing...?
If you mean the two in the middle put them into one LinearLayout (horizontal orientation), let all of them have a width of match_parent and give both relative layouts a weight of 1

How to remove margins around ButtonBar without removing them from the rest of an Activity?

Suppose I have a layout that looks something like this:
<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:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin" >
<TextView
android:id="#+id/greeting"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello, world!" />
<LinearLayout
android:id="#+id/actions"
style="?android:attr/buttonBarStyle"
android:background="#dddddd"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true" >
<Button
android:id="#+id/button1"
style="?android:attr/buttonBarButtonStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0.5"
android:text="Button1" />
<Button
android:id="#+id/button2"
style="?android:attr/buttonBarButtonStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0.5"
android:text="Button2" />
</LinearLayout>
</RelativeLayout>
Rendered in Eclipse, I get the following:
Notice that there is a margin around the ButtonBar. Is there any way to remove this without affecting the rest of the Activity? If I modify the android:padding* attributes, then the "Hello, world!" will run up against the left side of the Activity.

Move the android:padding* to the greeting element, removing it from the parent layout. Then that item alone with have padding while the button bar will not.
If you need to add additional items later on (rather than just the single TextView), you would want to wrap them in a new layout and put the padding on that layout.

set the android:padding for each of the layout you created...
the child placed within parent layout will have the padding set for them...you can use layout_margin instead...