Develop Reference

NestedScrollView scrolls on top when content changes

I have a fragment_layout.xml with two buttons (filter_1_btn, filter_2_btn) that perform filtering to the items of a RecyclerView. The problem is that when I scroll a bit (because the TextView above the buttons contains multiple lines of text) and then apply the filtering, then the NestedScrollView scrolls on top of the screen. Is there a way to stay at the same scrolled height after the filtering?
fragment_layout
<?xml version="1.0" encoding="utf-8"?>
<androidx.core.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/nested_scrollView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:descendantFocusability="blocksDescendants"
android:focusable="true"
android:focusableInTouchMode="true"
android:orientation="vertical">
<TextView
android:id="#+id/description_tv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="36dp"
android:text="Very long random text..." />
<Button
android:id="#+id/filter_1_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Filter 1"/>
<Button
android:id="#+id/filter_2_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Filter 2"/>
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="24dp" />
</LinearLayout>
</androidx.core.widget.NestedScrollView>

This is happening because the recyclerView's container is set to wrap_content , so when the height get smaller than the NestedScrollView, it gets scrolled to top.
you can fix it by providing a height larger than NestedScrollView :
So add minHeight :
<?xml version="1.0" encoding="utf-8"?>
<androidx.core.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/nested_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:descendantFocusability="blocksDescendants"
android:focusable="true"
android:focusableInTouchMode="true"
android:orientation="vertical">
<TextView
android:id="#+id/description_tv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="36dp"
android:text="Very long random text..." />
<Button
android:id="#+id/filter_1_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Filter 1" />
<Button
android:id="#+id/filter_2_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Filter 2" />
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minHeight="1000dp">
<!-- Add min height to support scrolling-->
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="24dp" />
</FrameLayout>
</LinearLayout>
</androidx.core.widget.NestedScrollView>

ImageView not showing in linear layout that is inside a scrollview

I am trying to have two scrollable items inside my scrollview so I put a linear layout into the scroll view and inside the linear layout I put an imageview and a textview. The textview shows up but the imageview does not. What is the issue here?
<?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:orientation="vertical"
android:paddingStart="#dimen/layout_padding"
android:paddingEnd="#dimen/layout_padding"
tools:context=".MainActivity">
<TextView
android:id="#+id/name_text"
style="#style/NameStyle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="#string/name"
android:textAlignment="center" />
<ImageView
android:id="#+id/star_image"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:contentDescription="#string/yellow_star"
app:srcCompat="#android:drawable/btn_star_big_on" />
<ScrollView
android:id="#+id/bio_scroll"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<ImageView
android:id="#+id/profile_picture"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="#dimen/layout_margin"
android:contentDescription="#string/profile_picture"
tools:srcCompat="#mipmap/image" />
<TextView
android:id="#+id/bio_text"
style="#style/NameStyle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:lineSpacingMultiplier="1.2"
android:text="#string/bio" />
</LinearLayout>
</ScrollView>
</LinearLayout>

Solved: I was missing this line: app:srcCompat="#mipmap/image"
I feel dumb

ScrollView with LinearLayout child does not wrap_content correctly

So, I have the following .xml:
<?xml version="1.0" encoding="utf-8"?>
<ScrollView 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"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context="com.scopesystems.cityalert.ui.Despre"
tools:showIn="#layout/app_bar_despre"
android:background="#drawable/toolbar_incercare">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:id="#+id/linear_parent">
<RelativeLayout
android:layout_width="0dip"
android:layout_height="wrap_content"
android:layout_weight="0.1" />
<RelativeLayout
android:layout_width="0dip"
android:layout_height="wrap_content"
android:layout_weight="2.8" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<!--General-->
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
style="#style/sectionHeader"
android:text="#string/general"
/>
<ListView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/despre_general"/>
<!--Evaluti-ne-->
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
style="#style/sectionHeader"
android:text="#string/evaluatine"
/>
<!--Confidentialitate si licente-->
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
style="#style/sectionHeader"
android:text="#string/confidentialitate"
/>
<ListView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/despre_politici"/>
</LinearLayout>
</RelativeLayout>
<RelativeLayout
android:layout_width="0dip"
android:layout_height="wrap_content"
android:layout_weight="0.1" />
</LinearLayout>
</ScrollView>
The issue is that the last ListView is on only 1 row, and it has to be scrolled to display all the items in the list. I tried to add to the linear_parent a height of match_parent but it wont let me, it says that I should use instead wrapcontent. How can i change the layout to display the items on all the screen, not just half?

In this case, On the ScrollView use android:fillViewport="true" and for child of ScrollView android:height="wrap_content".

Center-align horizontally UI items

I'm attempting to create my first Android app and I'd like to horizontally align the items on screen and in rows.
I've tried setting the layout_gravity to center_horizontal as shown below however that doesn't appear to do anything. What am I missing?
Code:
<?xml version="1.0" encoding="utf-8"?>
<android.support.wear.widget.BoxInsetLayout 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="#dimen/box_inset_layout_padding"
tools:deviceIds="wear">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="#dimen/inner_frame_layout_padding"
app:boxedEdges="all"
android:minWidth="25px"
android:minHeight="25px">
<GridLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:rowCount="8"
android:layout_gravity="center_horizontal"
android:columnCount="1"
android:orientation="horizontal">
<TextView
android:id="#+id/text"
android:visibility="visible"
android:textSize="9dp"
android:layout_row="1"/>
<TextView
android:id="#+id/text2"
android:visibility="visible"
android:text="#string/hello_world"
android:textAlignment="center"
android:textSize="9dp"
android:layout_row="2"/>
<TextView
android:id="#+id/serviceScore"
android:layout_row="4"
android:visibility="visible"
android:textAlignment="center"
android:textSize="50dp"/>
</GridLayout>
</FrameLayout>
</android.support.wear.widget.BoxInsetLayout>
UI:

Greet by Nice! Just add Gravity of layout center instead of center_horizontal of GridLayout.
android:layout_gravity="center"

How do you position views and other UI items in a fragment layout?

I have a message interface consisting of a listview, an edit text box and a button found in a tutorial online. In my implementation of the xml it lays out perfectly with the listview above the text box and button. However, when I try to implement the layout using two fragments (1) for an audio player at the top of the screen and (2) below that for the messaging, I cannot force the text box and button to display below the list view.
How can I do that below are the XMLs.
(1) Works as expected:
<?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=".MainActivity"
>
<ListView
android:id ="#+id/message_list"
android:layout_weight="100"
android:layout_width="match_parent"
android:layout_height="0dp"
android:divider="#null"
/>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<EditText
android:id="#+id/new_message"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="100"
android:inputType="text">
<requestFocus />
</EditText>
<Button
android:id="#+id/send_message"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#color/colorPrimary"
android:text="#string/send_message"
android:textColor="#android:color/white" />
</LinearLayout>
</LinearLayout>
(2) Positions the text and button at the top of or near the top of the list view:
<?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">
<ListView
android:id="#+id/message_list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:divider="#null" />
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<EditText
android:id="#+id/new_message"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="100"
android:inputType="text"
android:labelFor="#id/new_message" />
<Button
android:id="#+id/send_message"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#color/colorPrimary"
android:text="#string/send_message"
android:textColor="#android:color/white" />
</LinearLayout>
</RelativeLayout>
Changing (2) to linear layout has not fixed my issue.

This somehow fixed my problem although it seemed not to have worked before.
<?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="com.example.app.MessageFragment">
<ListView
android:id ="#+id/message_list"
android:layout_weight="100"
android:layout_width="match_parent"
android:layout_height="0dp"
android:divider="#null"
/>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<EditText
android:id="#+id/new_message"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="100"
android:inputType="text"
android:labelFor="#id/new_message" />
<Button
android:id="#+id/send_message"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#color/colorPrimary"
android:text="#string/send_message"
android:textColor="#android:color/white" />
</LinearLayout>
</LinearLayout>

Your second layout has no constraints. You should make sure that your LinearLayout is aligned bottom and the listview is above the LinearLayout. It should be something like this :
<?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">
<ListView
android:id="#+id/message_list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="#+id/llText"
android:divider="#null" />
<LinearLayout
android:id="#+id/llText"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_alignParentBottom="true"
android:layout_height="wrap_content">
<EditText
android:id="#+id/new_message"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="100"
android:inputType="text"
android:labelFor="#id/new_message" />
<Button
android:id="#+id/send_message"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#color/colorPrimary"
android:text="Hello"
android:textColor="#android:color/white" />
</LinearLayout>
</RelativeLayout>