Develop Reference

Fill the screen with 2 RadioButtons?

How to fill a ConstraintLayout with two radioButtons inside of a RadioGroup? I can't find a way to do it. I post here two images, one is how I want to make it look, and the other is how it looks right now with my code.
This is how it looks right now
This is how I want
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/constraintLayout6">
<RadioGroup
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<RadioButton
android:id="#+id/radioButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#drawable/radio_selector"
android:button="#color/transparent"
android:elevation="4dp"
android:padding="16dp"
android:text="Paypal"
android:textAlignment="center" />
<RadioButton
android:id="#+id/radioButton2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#drawable/radio_selector"
android:button="#color/transparent"
android:elevation="4dp"
android:padding="16dp"
android:text="Contrarreembolso"
android:textAlignment="center" />
</RadioGroup>
</androidx.constraintlayout.widget.ConstraintLayout>

The best thing that I could do after reading some answers on StackOverflow and trying many things is to get to this point:
I have taken this layout:
<?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=".MainActivity">
<RadioGroup
android:layout_width="0dp"
android:layout_height="0dp"
android:orientation="vertical"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<RadioButton
android:id="#+id/radioButton"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_gravity="center"
android:background="#193312"
android:elevation="4dp"
android:text="Paypal"
android:textAlignment="center" />
<RadioButton
android:id="#+id/radioButton2"
android:layout_width="match_parent"
android:layout_height="0dp"
android:background="#122B33"
android:elevation="4dp"
android:gravity="center"
android:text="Contrarreembolso"
android:textAlignment="center" />
</RadioGroup>
</androidx.constraintlayout.widget.ConstraintLayout>
And used this code to get the height of the screen and put half of it on my views, inside your activity:
#Override
protected void onStart() {
super.onStart();
//Get the height is the screen
Display display = getWindowManager().getDefaultDisplay();
Point size = new Point();
display.getSize(size);
int height = size.y;
DisplayMetrics displayMetrics = new DisplayMetrics();
RadioButton radioButton1 = findViewById(R.id.radioButton);
RadioButton radioButton2 = findViewById(R.id.radioButton2);
//Give view half of the screen height
ViewGroup.LayoutParams params = radioButton1.getLayoutParams();
params.height = (height)/2;
ViewGroup.LayoutParams params2 = radioButton2.getLayoutParams();
params2.height = (height)/2;
}
Notice that this layout is not perfect looking, your radio buttons do spread across your device in height but they are not equal, the one thing left to do if you want your button to be equal in height is to calculate the action bar height and take it into account.

Relative Layout adding views programmatically one below other not aligning correctly

I am trying to add Text views programmatically to Relative layout parent one below other. However, the first view is not aligning correctly while the rest of the view got aligned correctly. See attached image.
My code:
private void setupQuestionChoices(int position) {
question.setText(questionList.get(position).question());
choicesTextViewsList.clear();
for (int i = 0; i < questionList.get(position).choices().size(); i++) {
TextView textView = new TextView(getActivity());
textView.setBackgroundResource(R.drawable.qa_button_background);
textView.setMinWidth(300);
textView.setGravity(Gravity.CENTER);
textView.setText(questionList.get(position).choices().get(i));
textView.setId(i);
RelativeLayout.LayoutParams layoutParams =
new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
if (i == 0) {
layoutParams.addRule(RelativeLayout.BELOW, question.getId());
} else {
layoutParams.addRule(RelativeLayout.BELOW, choicesTextViewsList.get(i - 1).getId());
}
layoutParams.addRule(RelativeLayout.CENTER_HORIZONTAL, RelativeLayout.TRUE);
layoutParams.setMargins(20, 20, 20, 20);
relativeLayout.addView(textView, layoutParams);
choicesTextViewsList.add(textView);
choicesTextViewsList.get(i).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
answerSelected = true;
}
});
}
}
Relative layout xml where I add my views to:
<?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"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true">
<RelativeLayout
android:id="#+id/relative_parent" //here is where I add views to
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/question"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="20dp"
android:layout_marginTop="40dp"
android:layout_marginEnd="20dp"
android:layout_marginBottom="10dp"
android:orientation="horizontal"
android:textColor="#color/colorPrimary"
android:textSize="30sp"
android:textStyle="bold" />
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_gravity="center"
android:layout_marginBottom="30dp"
android:gravity="center">
<androidx.appcompat.widget.AppCompatButton
android:id="#+id/button_back"
style="?android:attr/borderlessButtonStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_marginStart="30dp"
android:layout_marginTop="10dp"
android:layout_marginEnd="30dp"
android:background="#drawable/rectangle_border"
android:text="Back"
android:textColor="#android:color/darker_gray" />
<androidx.appcompat.widget.AppCompatButton
android:id="#+id/button_next"
style="?android:attr/borderlessButtonStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_alignParentEnd="true"
android:layout_marginStart="30dp"
android:layout_marginTop="10dp"
android:layout_marginEnd="30dp"
android:background="#drawable/rectangle_border"
android:text="Next"
android:textColor="#android:color/darker_gray" />
</RelativeLayout>
</RelativeLayout>
</ScrollView>
I read some posts related to this issue and followed the guidelines from them but that did not help.
How to lay out Views in RelativeLayout programmatically?
Create a new TextView programmatically then display it below another TextView

I was using the index of the for loop as id for the textViews which I changed to make Android generate Id for it as below and it is working fine now as expected.
I changed the line
textView.setId(i)
to
textView.setId(ViewGroup.generateViewId())
Thanks.

How do you place imageView on to of another imageView always in the same spot despite of the screen size or aspect ratio?

enter image description hereI am trying to create an app where a circle moves on top of random place on an ImageView. I have a placeholder TextView on the map which is supposed to tell the circle where to go. The problem occurs when I build the app to my phone and test it. The circle nor the placeholder textView is nowhere near the place where I wanted them to be. and the circle is not even on top of the textView. So here is the question: How can I keep the placeholder in the same spot on the map in every aspect ratio and screen size AND how can I move the circle on top of the placeholder?
I have been searching for an answer for almost two days now and I am starting to feel a little frustrated.
Here is my java code:
public class MainActivity extends AppCompatActivity {
Random random;
ImageView theMap;
ImageView pointerCircle;
int randomNum;
//PLACEHOLDERS
TextView place1;
TextView place2;
TextView place3;
TextView place4;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
theMap = (ImageView) findViewById(R.id.theMap);
pointer = (ImageView) findViewById(R.id.pointer);
//DEFINING THE PLACEHOLDERS
place1 = (TextView) findViewById(R.id.place1);
place2 = (TextView) findViewById(R.id.place2);
place3 = (TextView) findViewById(R.id.place3);
place4 = (TextView) findViewById(R.id.place4);
random = new Random();
}
public void findSpot(View view) {
randomNum = random.nextInt(4) + 1;
shuffle(randomNum);
}
public void shuffle(final int theNum) {
switch (theNum) {
case 1:
pointer.setY(place1.getY());
pointer.setX(place1.getX());
case 2:
pointer.setY(place2.getY());
pointer.setX(place2.getX());
case 3:
pointer.setY(place3.getY());
pointer.setX(place3.getX());
case 4:
pointer.setY(place4.getY());
pointer.setX(place4.getX());
}
}
}
And here is the XML:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
android:background="#android:color/black"
app:layout_constraintWidth_default="wrap"
app:layout_constraintHeight_default="wrap"
tools:context="com.example.aapotti.randomplaceonamap.MainActivity">
<Button
android:id="#+id/button"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:background="#drawable/button_border"
android:fontFamily="serif-monospace"
android:onClick="findSpot"
android:text="Find random spot!"
android:textAlignment="center"
android:textColor="#android:color/background_light"
android:textSize="20sp"
android:textStyle="bold"
android:visibility="visible"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
tools:layout_editor_absoluteY="493dp" />
<ImageView
android:id="#+id/pointer"
android:layout_width="100dp"
android:layout_height="100dp"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:layout_marginEnd="184dp"
android:layout_marginTop="204dp"
android:adjustViewBounds="true"
android:visibility="visible"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/pointer" />
<FrameLayout
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginBottom="8dp"
android:layout_marginTop="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<ImageView
android:id="#+id/theMap"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:adjustViewBounds="true"
android:visibility="visible"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintDimensionRatio="w,1:1"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/normalmap">
</ImageView>
<TextView
android:id="#+id/placeholder"
android:layout_width="15dp"
android:layout_height="15dp"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_marginStart="80dp"
android:layout_marginTop="90dp"
android:background="#android:color/white"
android:scaleType="centerCrop"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</FrameLayout>
</android.support.constraint.ConstraintLayout>

Make my custom view update text fields in editor

So im currently working on a custom card view and my goal is pretty easy. I want to update the textfield to the string I set in the custom card view xml.
But somehow I can't get it working after many hours of trying. Sometimes the editor won't load my xml with the custom card view... sometimes it gives me a extremely long error message... and sometimes it just stays black...
Therefore I have the following xml file :
<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:id="#+id/CallEntry_Holder"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:tag="0">
<com.test.larsmatthaus.projectnurser.customs.Custom_CardView
android:id="#+id/Call_Entry"
android:layout_width="match_parent"
android:layout_height="50dp"
app:cardBackgroundColor="#color/colorCardBackgroundR"
app:cardCornerRadius="5dp"
app:personName="test"
app:room="100"
app:ward="test"
tools:layout_editor_absoluteX="1024dp">
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="50dp">
<TextView
android:id="#+id/WardName"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginBottom="10dp"
android:layout_marginEnd="200dp"
android:layout_marginLeft="200dp"
android:layout_marginRight="200dp"
android:layout_marginStart="200dp"
android:layout_marginTop="10dp"
android:autoSizeTextType="uniform"
android:fontFamily="#font/comfortaa_light"
android:gravity="center"
android:text="Louisa Burgess"
android:textColor="#color/colorOverlayTC"
android:textSize="18sp"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageView
android:id="#+id/icon_2"
android:layout_width="31dp"
android:layout_height="0dp"
android:layout_marginBottom="8dp"
android:layout_marginLeft="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:adjustViewBounds="true"
android:scaleType="fitCenter"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toStartOf="#+id/icon_1"
app:layout_constraintHorizontal_bias="0.85"
app:layout_constraintStart_toEndOf="#+id/WardName"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/teddybear" />
<ImageView
android:id="#+id/icon_1"
android:layout_width="31dp"
android:layout_height="0dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:adjustViewBounds="true"
android:scaleType="fitCenter"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.95"
app:layout_constraintStart_toEndOf="#+id/WardName"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/bed" />
<TextView
android:id="#+id/RoomText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="8dp"
android:layout_marginStart="16dp"
android:layout_marginTop="8dp"
android:autoSizeTextType="uniform"
android:fontFamily="#font/comfortaa_light"
android:gravity="center"
android:text="105"
android:textColor="#color/colorOverlayTC"
android:textSize="24sp"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toStartOf="#+id/WardName"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/seperator_C"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:fontFamily="#font/comfortaa_light"
android:text="/"
android:textColor="#color/colorOverlayTC"
android:textSize="24sp"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="#+id/RoomText"
app:layout_constraintEnd_toStartOf="#+id/WardName"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toEndOf="#+id/RoomText"
app:layout_constraintTop_toTopOf="#+id/RoomText" />
<TextView
android:id="#+id/WardText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:fontFamily="#font/anaheim"
android:gravity="center"
android:text="Ward 2"
android:textColor="#color/colorOverlayTC"
android:textSize="18sp"
app:layout_constraintBottom_toBottomOf="#+id/seperator_C"
app:layout_constraintEnd_toStartOf="#+id/WardName"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toEndOf="#+id/seperator_C"
app:layout_constraintTop_toTopOf="#+id/seperator_C" />
</android.support.constraint.ConstraintLayout>
</com.test.larsmatthaus.projectnurser.customs.Custom_CardView>
It contains just one card view entry.
My custom card view class looks like this :
public class Custom_CardView{
public Context context;
public Map<Integer, Object> vars = new HashMap<Integer, Object>();
public Custom_CardView(#NonNull Context context, #Nullable AttributeSet attrs) {
super(context, attrs);
this.context = context;
setWillNotDraw(false);
View view = getRootView();
for(int index = 0; index<((ViewGroup)view).getChildCount(); ++index) {
View nextChild = ((ViewGroup)view).getChildAt(index);
vars.put(nextChild.getId(), nextChild);
}
Log.println(Log.DEBUG,"Custom_CardView","<Custom_CardView : Instantiated => ["+vars.size()+"] children>");
LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = inflater.inflate(R.layout.elements_call_entry, this, true);
TextView wardText = (TextView) findViewById(R.id.WardName);
wardText.setText("TEST");
}
protected void onDraw(Canvas canvas){
super.onDraw(canvas);
}
}
I want to update the TextView "wardName" to the attribute value i did set in the xml file...
But somehow the editor view crashes once I load it... Due to the Custom CardView Class... Theres no real error log...
The only one I received was this : Preview timed out while rendering the layout. This typically happens when there is an infinite loop or unbounded recursion in one of the custom views
What did I forgot ? What else could I try to modify the editors textview ?

Well it was pretty easy... just added a new layout activity which will inflate once the CardView is pressed. I just copy the CardView element and place it inside the inflated view => problem solved :)

ExpandableListView children width

I have an ExpandableListView in my app. I want to make the child layout a bit narrower than the group header and also keep it centered. Due to some visual effects i must set layout params from code however i can't seem to find the best solutions for this tried changing layout width from xml with no luck. Any advice will be helpful.
Thanks
adapter getChild() method:
#Override
public View getChildView(final int groupPosition, final int
childPosition,
boolean isLastChild, View convertView,
ViewGroup parent) {
final Item expandedListitem = (Item) getChild(groupPosition, childPosition);
Drawable drawable= ContextCompat.getDrawable(context,R.drawable.background_border);
GradientDrawable gradientDrawable= (GradientDrawable) drawable;
gradientDrawable.setStroke(5,expandedListitem.getColor());
if (Build.VERSION.SDK_INT >= 19) {
if (convertView == null) {
LayoutInflater layoutInflater = (LayoutInflater) this.context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = layoutInflater.inflate(R.layout.list_item, null);
}
if (!isLastChild) {
View divider = convertView.findViewById(R.id.linearfaq);
divider.setVisibility(View.INVISIBLE);
ViewGroup.LayoutParams params = convertView.getLayoutParams();
int width = (MainActivity.display.getWidth());
params.height = 110;
params.width=width-40;
params.addRule(RelativeLayout.CENTER_IN_PARENT);
params.addRule(RelativeLayout.CENTER_HORIZONTAL);
convertView.setLayoutParams(params);
View padder = convertView.findViewById(R.id.padder);
padder.setVisibility(View.INVISIBLE);
} else {
View divider = convertView.findViewById(R.id.linearfaq);
RelativeLayout.LayoutParams params = new
[![enter image description here][1]][1]RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT,
RelativeLayout.LayoutParams.WRAP_CONTENT);
int width = (MainActivity.display.getWidth());
params.height = 140;
params.width=width-40;
params.addRule(RelativeLayout.CENTER_IN_PARENT);
params.addRule(RelativeLayout.CENTER_HORIZONTAL);
convertView.setLayoutParams(params);
divider.setVisibility(View.VISIBLE);
View padder = convertView.findViewById(R.id.padder);
padder.setBackgroundColor(expandedListitem.getColor());
padder.setVisibility(View.VISIBLE);
}
}else{
if (convertView == null) {
LayoutInflater layoutInflater = (LayoutInflater) this.context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = layoutInflater.inflate(R.layout.list_item_low, null);
}
}
Item layout:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout android:layout_width="match_parent"
android:layout_height="wrap_content"
xmlns:android="http://schemas.android.com/apk/res/android"
android:background="#color/back" >
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
android:layout_centerHorizontal="true"
android:layout_centerInParent="true"
>
<CheckBox
android:layout_alignParentLeft="true"
android:layout_marginTop="2dp"
android:layout_marginEnd="8dp"
android:clickable="true"
android:focusableInTouchMode="false"
android:layout_marginRight="8dp"
android:layout_alignParentStart="true"
android:layout_width="wrap_content"
android:focusable="false"
android:layout_height="wrap_content"
android:id="#+id/checkbox"
/>
<TextView
android:inputType="text"
android:paddingRight="8dp"
android:layout_width="wrap_content"
android:focusable="false"
android:layout_marginTop="6dp"
android:textSize="16sp"
android:layout_height="wrap_content"
android:layout_toRightOf="#+id/checkbox"
android:layout_toEndOf="#+id/checkbox"
android:id="#+id/list_text"/>
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/del"
android:src="#android:drawable/ic_menu_delete"
android:layout_marginTop="3dp"
android:background="#null"
android:visibility="gone"
android:layout_marginRight="8dp"
android:layout_marginEnd="8dp"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"/>
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/checkbox"
android:layout_alignBottom="#+id/checkbox"
android:layout_centerHorizontal="true"
android:layout_marginTop="2dp"
android:orientation="horizontal"
android:id="#+id/relativeLayout">
<Button
android:id="#+id/plus"
android:layout_width="20dp"
android:layout_height="20dp"
android:layout_centerVertical="true"
android:background="#drawable/round_button"
android:clickable="true"
android:focusable="false"
android:text="+" />
<TextView
android:id="#+id/quantity"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:layout_marginLeft="8dp"
android:layout_marginStart="8dp"
android:layout_toEndOf="#+id/plus"
android:layout_toRightOf="#+id/plus" />
<Button
android:id="#+id/minus"
android:layout_width="20dp"
android:layout_height="20dp"
android:layout_centerVertical="true"
android:layout_marginLeft="8dp"
android:layout_marginStart="8dp"
android:layout_toEndOf="#+id/quantity"
android:layout_toRightOf="#+id/quantity"
android:background="#drawable/round_button"
android:clickable="true"
android:focusable="false"
android:text="-" />
</RelativeLayout>
<RelativeLayout
android:id="#+id/linearfaq"
android:layout_marginTop="35dp"
android:layout_width="match_parent"
android:layout_height="10dp"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:background="#color/back"
android:orientation="vertical" >
</RelativeLayout>
<RelativeLayout
android:id="#+id/padder"
android:layout_width="match_parent"
android:background="#color/blue"
android:visibility="gone"
android:layout_height="2dp"
android:layout_alignTop="#+id/linearfaq"
>
</RelativeLayout>
category layout:
<?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="horizontal"
android:background="#drawable/parent_border">
<TextView
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginLeft="30dp"
android:layout_marginStart="30dp"
android:focusable="false"
android:textSize="20sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/cat_text"/>

I'd put all Views in one single ConstraintLayout. By attaching the background to the parent left and right, the View is default centered. By adding margins left and right, you achieve the View being smaller.
Like in this example:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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="wrap_content">
<ImageView
android:id="#+id/imageView2"
android:layout_width="0dp"
android:layout_height="?attr/actionBarSize"
android:layout_marginBottom="8dp"
android:layout_marginEnd="16dp"
android:layout_marginStart="16dp"
android:layout_marginTop="8dp"
android:background="#android:color/darker_gray"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<CheckBox
android:id="#+id/checkBox"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:buttonTint="#android:color/background_light"
android:text="CheckBox"
android:textColor="#android:color/background_light"
app:layout_constraintBottom_toBottomOf="#+id/imageView2"
app:layout_constraintStart_toStartOf="#+id/imageView2"
app:layout_constraintTop_toTopOf="#+id/imageView2" />
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginStart="24dp"
android:layout_marginTop="8dp"
android:text="Stuff"
android:textColor="#android:color/background_light"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toEndOf="#+id/checkBox"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
which looks like this:
the
android:layout_width="0dp"
actually means the view will be stretched to match the constraints. A bit like "match_parent", but within the bounds you set via its constraints.
Play around with the ConstraintLayout a bit. Once you get the hang of it, you will not want to miss it anymore :)