Develop Reference

Cannot add weight param to fragment in android studio?

I am trying to add weight param to fragment xml in android studio so that my two fragements can take half screen each but adding weight have no effect on the layout. what interesting is i still can add weight to normal activity views here is the screen shot
Here is my layout file
<?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"
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="io.designcoder.vivz.lifecycle.xml.ActivityFragmentXml">
<fragment
android:id="#+id/fragment_xml_a"
class="io.designcoder.vivz.lifecycle.xml.FragmentXmlA"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
tools:layout="#layout/fragment_xml_a"
/>
<fragment
android:id="#+id/fragment_xml_b"
class="io.designcoder.vivz.lifecycle.xml.FragmentXmlB"
android:layout_width="match_parent"
android:layout_below="#id/fragment_xml_a"
android:layout_height="wrap_content"
tools:layout="#layout/fragment_xml_b"
/>
</RelativeLayout>

remember that: weight param can only work in linearlayout. if you want to let the two fragments share the screen in horizontal, make the orientation of linearlayout horizontal and make the width of each fragment "0dp" or "wrap_content" so that you can weight them. The same way in vertical. You can look my codes below for example.
the weight example
<?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: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="horizontal"
tools:context="com.example.dysaniazzz.testdemo.MainActivity">
//the background only to distinguish the fragment
<fragment
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:background="#android:color/holo_red_light" />
<fragment
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:background="#android:color/holo_green_light" />
</LinearLayout>

You try using code below:
<?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:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="cungxunu.cunghoangdao.cheng.myapplication.MainActivity">
<fragment
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="0dp"/>
<fragment
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="0dp"/>
</LinearLayout>

You should not use Relative layout as weight would not work there.
So User Linear layout for that.
<?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:layout_width="match_parent"
android:layout_height="match_parent"
android:weightSum="2"
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="io.designcoder.vivz.lifecycle.xml.ActivityFragmentXml">
<fragment
android:id="#+id/fragment_xml_a"
class="io.designcoder.vivz.lifecycle.xml.FragmentXmlA"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
tools:layout="#layout/fragment_xml_a"
/>
<fragment
android:id="#+id/fragment_xml_b"
class="io.designcoder.vivz.lifecycle.xml.FragmentXmlB"
android:layout_width="match_parent"
android:layout_below="#id/fragment_xml_a"
android:layout_height="0dp"
tools:layout="#layout/fragment_xml_b"
/>
</LinearLayout>

Android studio layout background error

<?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"
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="#drawable/background"
tools:context="com.example.black.myfirstproject.MainActivity">
<EditText
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="#+id/editText"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
</RelativeLayout>
android:background="#drawable/background"
i wanted background in MainActivity so added background and clicked "Run"
-> app is down
why my app is down?
// before added background.png in res ->drawable folder

You should use an ImageView - Caution: there are serious memory implications if large images aren't loaded correctly.
You should also read: Displaying Bitmaps Effectively
<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.black.myfirstproject.MainActivity">
<EditText
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="#+id/editText"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:src="#drawable/background"/>
</RelativeLayout>
Also refer to:
android:scaleType=""
for options on positioning the image and specifying how it is displayed within the ImageView.

RelativeLayout: how to delete border around second layout?

I have an xml file which contains two RelativeLayouts. The trouble is that the second Relativelayout does not go up to the display limit. It looks like a border around the layout.
How can I display the second layer also on the border of the display?
<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:background="#color/colorAccent"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context="newservice"
tools:showIn="#layout/activity_newservice">
<RelativeLayout
android:id="#+id/test"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/colorPrimaryDark"
android:layout_alignBottom="#+id/viewmap"
android:layout_centerHorizontal="true">
</RelativeLayout>
</RelativeLayout>

Remove this line on the top layout:
android:paddingTop="#dimen/activity_vertical_margin"
You are putting a padding on the top, so the second layout will not fill the first like you want.
Regards!

Remove your
android:paddingXXX from parent RelatvieLayout
that is making issue

<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:background="#color/colorAccent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context="newservice"
tools:showIn="#layout/activity_newservice">
<RelativeLayout
android:id="#+id/test"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/colorPrimaryDark"
android:layout_alignBottom="#+id/viewmap"
android:layout_centerHorizontal="true">
</RelativeLayout>
</RelativeLayout>
Try this

Textview not skipping to next line android

I am a complete beginner in android programming, and I am working with TextViews. I want two TextViews with one on top and one on bottom. But it doesn't work, and I am not sure why. Here is the xml
<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="match_parent" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin" tools:context=".MainActivity">
<TextView
android:text="#string/hello_world"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<TextView
android:text="#string/hello_world"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
So I have the first TextView as fill_parent for width to skip a line, but instead it just takes it out. I can't add a picture as a I just made this account for this question, but it just displays the first TextView and not the next. What is the mistake I made?

In a LinearLayout, you need to set the orientation.
android:orientation="vertical"

Use this code, here orientation was missing in your code
<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="match_parent" 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:orientation="vertical"
tools:context=".MainActivity">
<TextView
android:text="#string/hello_world"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<TextView
android:text="#string/hello_world"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>

Background image at the right bottom corner?

I have the following simple layout:
<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=".MainActivity" >
<TextView
android:id="#+id/textview_app_description"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/app_description" />
</RelativeLayout>
How could I add there background image at the right bottom corner (it should be semi-transparent, since may be behind the text - I've tried to use ImageView, but it doesn't work with such scenario)?

Would this work?
<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=".MainActivity" >
<ImageView
android:id="#+id/xxx"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignParentBottom="true"
android:alpha="0.4"
android:src="#drawable/xxx"/>
<TextView
android:id="#+id/textview_app_description"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/app_description" />
</RelativeLayout>

You can use an XML Bitmap drawable as a background. Say the image (with desired transparency) is stored in bg.png. If you just use it as the background, it will stretch to fill the view; however, you can define an XML bitmap drawable with a gravity attribute. Let's put it in /res/drawable/bottom_right_bg.xml:
<?xml version="1.0" encoding="utf-8"?>
<bitmap
xmlns:android="http://schemas.android.com/apk/res/android"
android:src="#drawable/bg"
android:gravity="bottom|right" />
Then you can add an android:background attribute to the 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:background="#drawable/bottom_right_bg"
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=".MainActivity" >
<TextView
android:id="#+id/textview_app_description"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/app_description" />
</RelativeLayout>