Develop Reference

Recyclerview cannot be scrolled?

I have this screen.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="5dp">
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<android.support.v7.widget.RecyclerView
android:id="#+id/my_recycler_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:scrollbars="vertical"/>
</RelativeLayout>
<Button
android:id="#+id/btn_sync"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:onClick="DoUpload"
android:text="Sync with server"
/>
</LinearLayout>
It looks like this (which is OK):
So I add more datas, now it looks like this:
The RecyclerView cannot be scrolled, and the button is hidden. How to fix this?

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="5dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
android:id="#+id/my_recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical"
android:layout_weight="1"/>
<Button
android:id="#+id/btn_sync"
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_gravity="center_horizontal"
android:onClick="DoUpload"
android:text="Sync with server"/>
</LinearLayout >
</LinearLayout>
just copy this code and use it will be working fine

I have edited the code for you this will solve the problem and button will be at the end of RecyclerView
<?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"
android:padding="5dp">
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="#+id/my_recycler_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:scrollbars="vertical" />
<Button
android:id="#+id/btn_sync"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/my_recycler_view"
android:layout_gravity="center_horizontal"
android:onClick="DoUpload"
android:text="Sync with server" />
</RelativeLayout>
</LinearLayout>

Try this,
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="5dp">
<RelativeLayout
android:layout_above="#id/btn_sync"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.RecyclerView
android:id="#+id/my_recycler_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:scrollbars="vertical"/>
</RelativeLayout>
<Button
android:id="#+id/btn_sync"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:onClick="DoUpload"
android:text="Sync with server"
android:layout_alignParentBottom="true"
/>
</RelativeLayout>

Try using constraint layout like below
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:padding="5dp">
<android.support.v7.widget.RecyclerView
android:id="#+id/my_recycler_view"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toTopOf="#id/btn_sync"
android:scrollbars="vertical" />
<Button
android:id="#+id/btn_sync"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
android:onClick="DoUpload"
android:text="Sync with server" />
</android.support.constraint.ConstraintLayout>
This layout should keep the button from hiding and recyclerview will scroll when more data items are added.

used nestedScrollView
<?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">
<android.support.v4.widget.NestedScrollView
android:id="#+id/nestedScrollView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:overScrollMode="never">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
</LinearLayout>

How do I get an imageView and textview to both fill the layout when setting bitmap programmatically?

What I want is for qrcodetext to fit and display all the text in qrcode_layout and have qrimageView to fill the rest of qrcode_layout? But my layout below has the entire qrimageView cover qrcode_layout. I tried a bunch of other variations but without success.
Here is what it looks like.
Here is what I want it to look like.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_height="match_parent"
android:layout_width="match_parent"
android:orientation="vertical"
android:id="#+id/qrcodelayout">
<LinearLayout
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:orientation="vertical">
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/qrimageView"
android:layout_gravity="center_horizontal"
android:layout_marginTop="8dp" />
</LinearLayout>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/qrcodetext"
android:gravity="center"
android:layout_gravity="center_horizontal"
android:layout_marginTop="4dp" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</LinearLayout>
</RelativeLayout>

Use following code. Align your textview to bottom and then align your Qrcode Image above text:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/qrcodetext"
android:gravity="center"
android:layout_alignParentBottom="true"
android:layout_marginTop="4dp" />
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/qrimageView"
android:layout_gravity="center_horizontal"
android:layout_above="#id/qrcodetext"
android:layout_alignParentTop="true"
android:layout_marginTop="8dp" />
</RelativeLayout>

I think what i have understand you want is below: Plz check and tell me:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_height="match_parent"
android:layout_width="match_parent"
android:orientation="vertical"
android:id="#+id/qrcodelayout">
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:id="#+id/qrcodetext"
android:gravity="center"
android:layout_weight="1"
android:layout_gravity="center_horizontal"
android:layout_marginTop="4dp" />
<LinearLayout
android:layout_height="match_parent"
android:layout_width="match_parent"
android:orientation="vertical"
android:layout_weight="1">
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/qrimageView"
android:layout_gravity="center_horizontal"
android:layout_marginTop="8dp" />
</LinearLayout>
</LinearLayout>
<!--<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</LinearLayout>-->
</RelativeLayout>

Linear Layout does not fill the whole screen

Why the linear layout does not fill the whole screen?
As you can see I am using match parent in the linear layout.
If I delete the Scrollbar nothing changes. The button is not at the bottom of the screen.
main_activity.xml:
<?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:id="#+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/black"
tools:context="com.sarahp.demo.MainActivity">
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout ----------> HERE
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:id="#+id/textview_demo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginBottom="32dp"
android:layout_marginTop="32dp"
android:text="#string/demo"
android:textSize="42dp"/>
<RelativeLayout
android:id="#+id/fragment_container_a"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
<RelativeLayout
android:id="#+id/fragment_container_b"
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_alignParentBottom="true"
android:background="#color/transparent"/>
</LinearLayout>
</ScrollView>
</RelativeLayout>
F A is the fragment part.

Give android:fillViewport="true" to your ScrollView.
Your xml will looks like below. Main_Activity.xml
<?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">
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="40dp"
android:text="Test Demo"
android:textStyle="bold"
android:gravity="center"/>
<RelativeLayout
android:id="#+id/fragment1"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="0.5"
android:background="#drawable/border_image">
<TextView
android:layout_width="match_parent"
android:layout_height="100dp"
android:gravity="center"
android:text="Test text Fragement1" />
</RelativeLayout>
<RelativeLayout
android:id="#+id/fragment2"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="0.5"
>
<TextView
android:layout_width="match_parent"
android:layout_height="100dp"
android:gravity="center"
android:text="Test text Fragement2" />
</RelativeLayout>
</LinearLayout>
</ScrollView>
</RelativeLayout>

Remove the relative layout
<ScrollView
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:id="#+id/textview_demo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginBottom="32dp"
android:layout_marginTop="32dp"
android:text="#string/demo"
android:textSize="42dp"/>
<RelativeLayout
android:id="#+id/fragment_container_a"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
<RelativeLayout
android:id="#+id/fragment_container_b"
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_alignParentBottom="true"
android:background="#color/transparent"/>
</LinearLayout>
</ScrollView>

RecycleView cells fill the screen

I'm following a tutorial on android programming and have run into trouble with recycleviews. The cells of the view each seem to fill a full screen of space rather than a just the information in the cell. Shown here:
activity_fragment.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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:fitsSystemWindows="true"
tools:context="com.example.moore.criminalintent.CrimeActivity">
<include layout="#layout/content_fragment" />
</android.support.design.widget.CoordinatorLayout>
content_fragment.xml
<?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"
tools:context="com.example.moore.criminalintent.CrimeActivity"
tools:showIn="#layout/activity_fragment">
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/fragment_container"
android:layout_width="wrap_content"
android:layout_height="wrap_content"></FrameLayout>
</RelativeLayout>
fragment_crime.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="#string/Crime_title_label"
style="?android:listSeparatorTextViewStyle"/>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/crime_title"
android:hint="#string/crime_title_hint"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="#string/crime_detail_label"
style="?android:listSeparatorTextViewStyle"/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/crime_date"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"/>
<CheckBox
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/crime_solved"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
android:text="#string/crime_solved_label"/>
</LinearLayout>
fragment_crime_list.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.RecyclerView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/crime_recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
list_item_crime.xml
<?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:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/list_item_crime_solved_check_box"
android:layout_alignParentRight="true"
android:padding="4dp"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/list_item_crime_title_text_view"
android:layout_toLeftOf="#id/list_item_crime_solved_check_box"
android:textStyle="bold"
android:padding="4dp"
tools:text="Crime Title"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/list_item_crime_date_text_view"
android:layout_toLeftOf="#id/list_item_crime_solved_check_box"
android:layout_below="#id/list_item_crime_title_text_view"
android:padding="4dp"
tools:text="Crime Date"/>
</RelativeLayout>
I can post more code if its needed. Any help with how to fix this would be greatly appreciated.

Try this:
list_item_crime.xml
<?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:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/list_item_crime_solved_check_box"
android:layout_alignParentRight="true"
android:padding="4dp"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/list_item_crime_title_text_view"
android:layout_toLeftOf="#id/list_item_crime_solved_check_box"
android:textStyle="bold"
android:padding="4dp"
tools:text="Crime Title"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/list_item_crime_date_text_view"
android:layout_toLeftOf="#id/list_item_crime_solved_check_box"
android:layout_below="#id/list_item_crime_title_text_view"
android:padding="4dp"
tools:text="Crime Date"/>
</RelativeLayout>

How to fix parsing XML: unbound prefix in android

I am getting an XML:Unbound prefix error in android i tried a lot but it was still occurring please make it solve as soon as possible..........................................................................................................................................................................................................................................................................................................
<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">
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Click" />
<pl.pawelkleczkowski.customgauge.CustomGauge
android:id="#+id/gauge3"
android:layout_width="200dp"
android:layout_height="200dp"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:paddingBottom="10dp"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:paddingTop="10dp"
app:endValue="100"
app:pointEndColor="#color/Green"
app:pointStartColor="#color/Red"
app:startAngel="180"
app:startValue="0"
app:strokeCap="BUTT"
app:strokeColor="#color/Gray"
app:strokeWidth="20dp"
app:sweepAngel="180" />
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/gauge3"
android:layout_centerHorizontal="true"
android:layout_marginBottom="52dp"
android:text="0"
android:textSize="30dp"
android:textStyle="bold" />
</RelativeLayout>

Change
<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">
to
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:gauge="http://schemas.android.com/apk/res-auto"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent" >

Change
<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">
to
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">