Develop Reference

How to get a whole screen in an activity to scroll when a scrollable recyclerView imakes up only half of the phone screen

I want my whole screen to scroll but only my recycler will scroll at the moment. This occurs despite all elements being placed in a linear layout inside a Scroll View.
Any ideas where the error is? Here's the relevant code.
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
tools:context=".NoodleDetailActivity">
<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">
<ImageView
android:id="#+id/noodleImage"
android:layout_width="match_parent"
android:layout_height="200dp"
android:adjustViewBounds="false"
android:scaleType="centerCrop"
app:srcCompat="#mipmap/ic_launcher" />
<TextView
android:id="#+id/description"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#drawable/border_bottom"
android:fontFamily="sans-serif-smallcaps"
android:hapticFeedbackEnabled="false"
android:padding="30dp"
android:text="TextView"
android:textSize="18sp" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/extras_recycler"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="0dp"
android:background="#F2F2F2"
android:padding="0dp" />
</LinearLayout>
</ScrollView>
</androidx.constraintlayout.widget.ConstraintLayout>
This is what it looks visually.
demo appearance

Found out: it seems best practice is to set the recyclerView to be the whole layout and make it contain multiple view types.
I won't be using a nested scroll view.

GridView item height is mismatched with other

I am using a grid view. It shows issue in some devices. One item of the grid view looks shorter in height than others.
It looks like this in some devices, and in some its fine.
Layout :
<?xml version="1.0" encoding="utf-8"?>
<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"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:layout_width="match_parent"
android:background="#android:color/white"
android:layout_height="match_parent">
</RelativeLayout>
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true">
<LinearLayout android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.admin.fueloneApp.MainDriver"
tools:showIn="#layout/app_bar_main"
android:weightSum="8">
<TextView
android:id="#+id/main_welcome"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="#dimen/dimen_20dp"
android:text="#string/welcome"
android:textColor="#color/colorPrimary"
android:textStyle="bold" />
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/gridviewMain"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginBottom="#dimen/dimen_40dp"
android:layout_marginLeft="#dimen/dimen_40dp"
android:layout_marginRight="#dimen/dimen_40dp"
android:columnWidth="80dp"
android:horizontalSpacing="#dimen/dimen_10dp"
android:numColumns="2"
android:stretchMode="columnWidth"
android:verticalSpacing="10dp"></GridView>
</LinearLayout>
</ScrollView>
<TextView
android:id="#+id/textView20"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_centerInParent="false"
android:text="For Any Queries Related To Mobile App Click On Service Request"
android:textAlignment="center" />
</RelativeLayout>
Item layout
EDIT : Added item layout of the grid view.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/single_grid"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/colorPrimary1"
android:orientation="vertical">
<ImageView
android:id="#+id/gris_img"
android:layout_gravity="center"
android:layout_width="80dp"
android:scaleType="fitXY"
android:layout_height="100dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/grid_cat"
android:textSize="15sp"
android:textColor="#color/divider_color"
android:gravity="center"/>
</LinearLayout>
How can I manage the height of each item? What is the solution for this? Please help. thank you...

Gridview is having a tendency to adjust the height of all element with the tallest element in all. Hence this behaviour you are seeing.You can use StaggeredGridView.

i think your grid layout cell height is wrap_content. this problem same occur with me . change your layout height wrap_content to match_parent.
android:layout_height="match_parent"
for better solution please update your grid view item layout cell here.

Add Textview property :
android:maxLines="1"
android:singleLine="true"
if text not visible single line, you need change textview to autosizing-textview
enter link description here

How to implement this type of GridView in Android?

I implemented a GridView like below:
But when I rotate the phone this is what happens:
I want the images stay the way they are in Portrait mode. I don't want spacing between views.
Grid view:
<FrameLayout 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="#f0f0f0"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context=".MainActivity"
tools:showIn="#layout/activity_main">
<GridView
android:id="#+id/gridView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:clickable="true"
android:columnWidth="170dp"
android:drawSelectorOnTop="true"
android:focusable="true"
android:gravity="center"
android:numColumns="auto_fit"
android:stretchMode="columnWidth" />
</FrameLayout>
Grid Item:
<?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="wrap_content"
android:background="#color/blue"
android:orientation="vertical">
<ImageView
android:id="#+id/image"
android:layout_width="match_parent"
android:layout_height="200dp" />
</LinearLayout>
Here I'm re-sizing image in the adapter like below:
holder = new ViewHolder();
holder.image = (ImageView) row.findViewById(R.id.image);
ImageItem item = data.get(position);
holder.image.setImageBitmap(Bitmap.createScaledBitmap(item.getImage(), 180, 200, true));
I also want the images to re-size properly without any blurring, etc.

You have given android:columnWidth="170dp" and in griditem.xml you have given fixed height,That why this thing is happening.

use following example for auto adjustment of gridview
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<GridView
android:id="#+id/gridview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:verticalSpacing="0dp"
android:horizontalSpacing="0dp"
android:stretchMode="columnWidth"
android:numColumns="auto_fit"/>
</FrameLayout>

why cannot i see a textView above another view in relative layout?

I have this 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"
android:orientation="vertical"
android:paddingLeft="8dp"
android:paddingRight="8dp" >
<TextView
android:id="#+id/errorMsg"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_above="#+id/pointsText"
android:visibility="gone"/>
<TextView
android:id="#+id/pointsText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_above="#+id/offers_list"
android:text="you have 100 points"
android:visibility="visible"/>
<ListView
android:id="#+id/offers_list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:drawSelectorOnTop="false"
android:dividerHeight="0dp"
android:divider="#00000000"/>
</RelativeLayout>
Yet I cannot see pointsText in my eclipse graphical previewer.
What am I missing?

You have
android:layout_above="#+id/offers_list"
for your TextView but you don't have any positioning for your ListView. Since RelativeLayouts place their children at the top-left by default, your ListView would be at the top and there would be nowhere above it to place your TextView.
Try removing that property from your TextView and add
android:layout_below="#id/pointsText"
on your ListView.
I just tested this and it does work. I can see the pointsText TextView above the list. So, you will want to do something different with your error TextView or you will quite possibly have the same issue with that when you want to change its visibility.
A bit off-topic
RelativeLayout doesn't have an orientation property so that doesn't do you any good but doesn't do you any real harm either.

When you use relative layouts, layout elements lay upon each other. To prevent that you should place element Relatively to other layouts. make your code 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"
android:paddingLeft="8dp"
android:paddingRight="8dp" >
<TextView
android:id="#+id/errorMsg"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_above="#+id/pointsText"
android:visibility="gone"/>
<TextView
android:id="#+id/pointsText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_above="#+id/offers_list"
android:text="you have 100 points"
android:visibility="visible"
android:layout_below="#+id/errorMsg"/>
<ListView
android:id="#+id/offers_list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:drawSelectorOnTop="false"
android:dividerHeight="0dp"
android:divider="#00000000"
android:layout_below="#+id/pointsText"/>
</RelativeLayout>
Now you will be able to see your all layouts

try 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:paddingLeft="8dp"
android:paddingRight="8dp" >
<LinearLayout
android:id="#+id/linearLayout1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<TextView
android:id="#+id/errorMsg"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:visibility="gone"/>
<TextView
android:id="#+id/pointsText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="you have 100 points"
android:visibility="visible"/>
</LinearLayout>
<ListView
android:id="#+id/offers_list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="#id/linearLayout1"
android:divider="#00000000"
android:dividerHeight="0dp"
android:drawSelectorOnTop="false" />
</RelativeLayout>

If this is a fragment inside an activity, you may want to check the nesting of say, the AppBarLayout and the layout into which you add the fragment

Fragment application, how to add a footer?

I'm working on an Android application with 4 tabs.
Here is my activity_main.xml
<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent">
</android.support.v4.view.ViewPager>
And here is one of my tab (they are all the same for the moment)
<?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"
android:background="#ff8400" >
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:text="Top Screen"
android:textSize="20dp"
android:layout_centerInParent="true"/>
</RelativeLayout>
How could I add a footer that would be visible on each tab?
It's to add a player that stays visible while scrolling the tab.

You're going to need to make a change to your main activity layout. You can do it with a LinearLayout or RelativeLayout. Because a LinearLayout is less expensive I will show you that here.
<?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.view.ViewPager
android:id="#+id/pager"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_weight="1"/>
<View
android:id="#+id/music_player"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
The view could been anything, I would recommend using a framelayout there and putting in a fragment if it is going to be as complicated as a music player. How this works is you set the height of the musicplayer (wrap_content) and you tell the pager to take up the rest of the space with layout_height="0dp" and layout_weight="1".
If you want to do a RelativeLayout then the musicplayer would alignParentBottom="true" and the pager would have layout_above="#+id/music_player with either layout_height="matchparent" or alignParentTop="true".