Develop Reference

What's happen about my ConstraintLayout why I am running?

everyone
I am a beginner. I tried to use ConstraintLayout with Android studio 3.1.1 and genymotion. when I run the project on genymotion emulator, It is different from what I have coded. Images FYI.

Each component needs to be constrained to be able to display correctly. I think you should do it. Because some TextView components seem to have no constraints

For Constrain Layout, You can to pull all point from the box of your TextView (for example)to top, bottom, left and right to remain it in the position. It could takes sometimes if have lots of button or textView or what so ever.
ConstrainLayout
sampleCode
<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">
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="Button"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.32" />
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="16dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="TextView"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
You have to pull the line from the dot of the box to everyside so it could stay at the position.
Since you are a beginner, I think You can consider LinearLayout.
As LinearLayout, it is align those textView and button or anything inside in arrangement. As long as You it in vertical or horizontal.
Example
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
....
//Edit your layout
</LinearLayout>
Another good layout for beginner is RelativeLayout
RelativeLayout you can drag and drop the textView or button or what so ever to the layout.
Example
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
....
//Edit your layout
</RelativeLayout>
U have to keep edit and arrange until the design is what you like.
However, I believe there is a lot of tutorial You can learn from Youtube. Check it Out.

moving items inside constraint layout cardview

This is my layout I am using for a activity.
<?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"
tools:context="com.example.phocast.AboutMeActivity">
<android.support.v7.widget.CardView
android:id="#+id/cv_abtme"
android:layout_width="369dp"
android:layout_height="260dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="101dp"
android:background="#color/colorPrimaryLight"
app:cardBackgroundColor="#color/bgcol_abtme"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.883">
<ImageView
android:id="#+id/imageView2"
android:layout_width="120sp"
android:layout_height="120sp"
app:srcCompat="#drawable/ic_face_black_24dp" />
<ImageView
android:id="#+id/iv1_abtme"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#id/tv_abtme"
app:srcCompat="#drawable/about_icon_facebook" />
<TextView
android:id="#+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:fontFamily="serif-monospace"
android:lineSpacingExtra="12sp"
android:text="#string/facebook_id"
android:textSize="18sp" />
<TextView
android:id="#+id/tv_abtme"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:fontFamily="cursive"
android:text="#string/user_name"
android:textAppearance="#style/TextAppearance.AppCompat.Large"
android:textSize="36sp" />
</android.support.v7.widget.CardView>
....
</android.support.constraint.ConstraintLayout>
The output looks like:
The problem is I can't move the items inside the cardview either programatically or using drag in design view of android studio.
Like, for say, I want to have
Imageview iv1_abtme(the facebook icon) below the tv_abtme
textview4 horizentally aligned to iv1_abtme
etc.
Can anyone kindly help me on what is going wrong here(why I cant simply drag items)

CardView is based on a FrameLayout and the documentation there clearly says:
Generally, FrameLayout should be used to hold a single child view, because it can be difficult to organize child views in a way that's scalable to different screen sizes without the children overlapping each other. You can, however, add multiple children to a FrameLayout and control their position within the FrameLayout by assigning gravity to each child, using the android:layout_gravity attribute.
So, to solve your problem, your CardView needs to have a single child that is a view group for your views, such as LinearLayout, RelativeLayout, or ConstraintLayout.

Android - center text in OpenSansBTextView

I'm designing my constraint layout using XML.
I have an OpenSansBTextView and I need my text to be centered in it. It's centered horizontally, and not centered vertically. I don't know why. Here is my xml file. Can you see my mistake?
<android.support.constraint.ConstraintLayout
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:background="#color/colorAccent"
android:id="#+id/dashboard">
<com.doyousonder.android.utils.RochesterTextView
android:id="#+id/YourActivity"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
android:layout_marginStart="25dp"
app:layout_constraintVertical_bias="0.34"
android:text="#string/YourActivity"
android:textColor="#color/colorPrimaryMoreDark"
android:textSize="23sp" />
<com.doyousonder.android.utils.OpenSansRTextView
android:id="#+id/YouVoted"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/YourActivity"
android:layout_marginTop="15dp"
android:layout_marginStart="20dp"
android:text="#string/YouVoted"
android:textColor="#color/colorPrimaryMoreDark"
android:textSize="15sp" />
<com.doyousonder.android.utils.OpenSansSBTextView
android:id="#+id/VoteCount"
android:layout_width="29dp"
android:layout_height="35dp"
app:layout_constraintStart_toEndOf="#+id/YouVoted"
app:layout_constraintTop_toTopOf="#+id/YouVoted"
app:layout_constraintBottom_toBottomOf="#+id/YouVoted"
android:layout_marginStart="5dp"
android:background="#drawable/more_curved_edge_button_button_primarycolor_background"
android:gravity="center"
android:text="1"
android:textAlignment="center"
android:textSize="25sp" />

You haven't provided much code to work with, i.e what is the youVoted variable. I'm assuming youvoted is your parent layout
I think you're issue comes with how you set up your constraints. Try these instead
...other layout info
app:layout_constraintBottom_toBottomOf="#+id/YouVoted"
app:layout_constraintStart_toStartOf="#+id/YouVoted"
app:layout_constraintTop_toTopOf="#+id/YouVoted"
app:layout_constraintEnd_toEndOf="#+id/YouVoted"/>
Explanation
I believe the mistake is you made is stating your textview should start at the end of your youvoted layout instead of saying it should start at the start of the youvoted layout.
change app:layout_constraintStart_toEndOf="#+id/YouVoted" to app:layout_constraintStart_toStartOf="#+id/YouVoted"
also add an end constraint.
app:layout_constraintEnd_toEndOf="#+id/YouVoted"

Nested Constraint Layout not showing if using Match_Constraints

I'm trying to create a nested ConstraintLayout in Android.
The objective is to have an Image to the left, and another constraint layout to the right, inside a constraint layout, as the following image:
It correctly shows on the preview, but inside the application, it bugs and doesn't show at all
Layout File:
<?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:id="#+id/box_npcs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<ImageView
android:id="#+id/npcImage"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_marginLeft="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
app:layout_constraintBottom_toBottomOf="#+id/layoutInformation"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toTopOf="#+id/layoutInformation"
app:srcCompat="#color/colorBlueishGreen" />
<android.support.constraint.ConstraintLayout
android:id="#+id/layoutInformation"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="4dp"
android:maxWidth="250dp"
app:layout_constraintHorizontal_bias="0.021"
app:layout_constraintLeft_toRightOf="#+id/npcImage"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent">
<TextView
android:id="#+id/top_priority"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:ellipsize="start"
android:text="DummyTextIsDummy"
android:textAppearance="#style/TextAppearance.AppCompat.Body1"
android:textColor="#color/common_google_signin_btn_text_light_default"
android:textSize="24sp"
android:textStyle="bold"
android:typeface="normal"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:ignore="HardcodedText" />
</android.support.constraint.ConstraintLayout>
</android.support.constraint.ConstraintLayout>
The layout is being added to another ConstraintLayout using the code
parent.addChild(inflater.inflate(R.layout.box_npc);
How should I fix this? And even, what is the issue?

The situation faced was that OP was trying to add the created ConstraintLayout to another ConstraintLayout programatically. That was being made using
inflater.inflate(R.layout.box, null)
It was an incorrect approach, as this ignores the layout parameters from the box. What was made to fix it was
inflater.inflate(R.layout.box, PARENT_LAYOUT/* One that box was being added to*/)
This fixes some issues due to the fact that the layout parameters were now being respected by the parent layout.
More information: Understaing Android's Layout Inflater.inflate()

For child views of each inner ConstraintLayout, use the id of parent layout instead of "parent".
For example instead of:
app:layout_constraintTop_toTopOf="parent"
Use
app:layout_constraintTop_toTopOf="#+id/parent_id"

Evenly spacing views using ConstraintLayout

A common use for LinearLayout is to evenly space (weight) views, for example:
How do you implement evenly spaced views like this using the new ConstraintLayout?
ConstraintLayout links for reference: blog post, I/O session video

There are two ways to accomplish this using ConstraintLayout: Chains and Guidelines. To use Chains, make sure you are using ConstraintLayout Beta 3 or newer and if you want to use the visual layout editor in Android Studio, make sure you are using Android Studio 2.3 Beta 1 or newer.
Method 1 - Using Chains
Open the layout editor and add your widgets as normal, adding parent constraints as needed. In this case, I have added two buttons with constraints to the bottom of the parent and side of the parent (left side for Save button and right side for Share button):
Note that in this state, if I flip to landscape view, the views do not fill the parent but are anchored to the corners:
Highlight both views, either by Ctrl/Cmd clicking or by dragging a box around the views:
Then right-click on the views and choose "Center Horizontally":
This sets up a bi-directional connection between the views (which is how a Chain is defined). By default the chain style is "spread", which is applied even when no XML attribute is included. Sticking with this chain style but setting the width of our views to 0dp lets the views fill the available space, spreading evenly across the parent:
This is more noticeable in landscape view:
If you prefer to skip the layout editor, the resulting XML will look like:
<android.support.constraint.ConstraintLayout
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">
<Button
android:id="#+id/button_save"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="#string/button_save_text"
android:layout_marginStart="8dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="4dp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintRight_toLeftOf="#+id/button_share"
app:layout_constraintHorizontal_chainStyle="spread" />
<Button
android:id="#+id/button_share"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="#string/button_share_text"
android:layout_marginStart="4dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp"
app:layout_constraintLeft_toRightOf="#+id/button_save"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintBottom_toBottomOf="parent" />
</android.support.constraint.ConstraintLayout>
Details:
setting the width of each item to 0dp or MATCH_CONSTRAINT lets the views fill the parent (optional)
the views must be linked together bidirectionally (right of save button links to share button, left of share button links to save button), this will happen automatically via the layout editor when choosing "Center Horizontally"
the first view in the chain can specify the chain style via layout_constraintHorizontal_chainStyle, see the documentation for various chain styles, if the chain style is omitted, the default is "spread"
the weighting of the chain can be adjusted via layout_constraintHorizontal_weight
this example is for a horizontal chain, there are corresponding attributes for vertical chains
Method 2 - Using a Guideline
Open your layout in the editor and click the guideline button:
Then select "Add Vertical Guideline":
A new guideline will appear, that by default, will likely be anchored to the left in relative values (denoted by left-facing arrow):
Click the left-facing arrow to switch it to a percentage value, then drag the guideline to the 50% mark:
The guideline can now be used as an anchor for other views. In my example, I attached the right of the save button and the left of the share button to the guideline:
If you want the views to fill up the available space then the constraint should be set to "Any Size" (the squiggly lines running horizontally):
(This is the same as setting the layout_width to 0dp).
A guideline can also be created in XML quite easily rather than using the layout editor:
<android.support.constraint.Guideline
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/guideline"
android:orientation="vertical"
app:layout_constraintGuide_percent="0.5" />

To create 2 views in same line, equal width, just need to define
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<Button
android:id="#+id/button1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="Button 1"
app:layout_constraintEnd_toStartOf="#+id/button2"
app:layout_constraintStart_toStartOf="parent" />
<Button
android:id="#+id/button2"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="Button 2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#+id/button1" />
</android.support.constraint.ConstraintLayout>
Note
width = 0dp (MATCH_CONSTRAINT)
Constraint of button1 and button2 must like above
Result
MORE
If you want View1 bigger than View2 you can use weight or percent.
Example, View1 width = 2 *View2 width use weight
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
>
<Button
android:id="#+id/button3"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="Button 3"
app:layout_constraintEnd_toStartOf="#+id/button4"
app:layout_constraintHorizontal_weight="2"
app:layout_constraintStart_toStartOf="parent"
/>
<Button
android:id="#+id/button4"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="Button 4"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_weight="1"
app:layout_constraintStart_toEndOf="#+id/button3"
/>
</android.support.constraint.ConstraintLayout>
Result
Example, View1 width = 2 *View2 width use percent
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
>
<Button
android:id="#+id/button5"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="Button 5"
app:layout_constraintEnd_toStartOf="#+id/button6"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintWidth_percent="0.667"
/>
<Button
android:id="#+id/button6"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="Button 6"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#+id/button5"
app:layout_constraintWidth_percent="0.333"
/>
</android.support.constraint.ConstraintLayout>
Result

Well if it helps someone
the key is here app:layout_constraintHorizontal_weight="1" and
the best thing about constraint layout is that it supports circular dependency and here this is what I have done using exactly that.
For first child
app:layout_constraintEnd_toStartOf="#+id/textInputSecondChild"
For second child
app:layout_constraintLeft_toRightOf="#+id/textInputFirstChild"
here is the complete demo
<android.support.design.widget.TextInputLayout
android:id="#+id/textInputParent"
android:layout_width="0dp"
android:layout_height="wrap_content"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent">
<EditText
android:id="#+id/editTextParent"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="#string/state" />
</android.support.design.widget.TextInputLayout>
<android.support.design.widget.TextInputLayout
android:id="#+id/textInputFirstChild"
android:layout_width="0dp"
android:layout_height="wrap_content"
app:layout_constraintEnd_toStartOf="#+id/textInputSecondChild"
app:layout_constraintHorizontal_weight="1"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textInputParent">
<EditText
android:id="#+id/editTextChildOne"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="#string/pin_code" />
</android.support.design.widget.TextInputLayout>
<android.support.design.widget.TextInputLayout
android:id="#+id/textInputSecondChild"
android:layout_width="0dp"
android:layout_height="wrap_content"
app:layout_constraintHorizontal_weight="1"
app:layout_constraintLeft_toRightOf="#+id/textInputFirstChild"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textInputParent">
<EditText
android:id="#+id/editTextChildSecond"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="#string/country" />
</android.support.design.widget.TextInputLayout>

You shoul read about weighted chains. An example of code is here.
<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"
>
<TextView
android:id="#+id/figure_1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
app:layout_constraintEnd_toStartOf="#id/figure_2"
app:layout_constraintHorizontal_weight="1"
app:layout_constraintStart_toStartOf="parent"
tools:text="1"
/>
<TextView
android:id="#+id/figure_2"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
app:layout_constraintEnd_toStartOf="#id/figure_3"
app:layout_constraintHorizontal_weight="1"
app:layout_constraintStart_toEndOf="#id/figure_1"
tools:text="2"
/>
<TextView
android:id="#+id/figure_3"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
app:layout_constraintEnd_toStartOf="#id/figure_4"
app:layout_constraintHorizontal_weight="1"
app:layout_constraintStart_toEndOf="#id/figure_2"
tools:text="3"
/>
<TextView
android:id="#+id/figure_4"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_weight="1"
app:layout_constraintStart_toEndOf="#id/figure_3"
tools:text="4"
/>
</android.support.constraint.ConstraintLayout>
So, set android:layout_width="0dp", app:layout_constraintHorizontal_weight="1" and link every view with neighbours like:
app:layout_constraintStart_toEndOf="#id/figure_2"
app:layout_constraintEnd_toStartOf="#id/figure_4"

Once you have your chained items, you can still use weights on them like relative layout to keep them evenly spaced. The example below shows how to keep them evenly spaced with different size textViews.
<TextView1
app:layout_constraintHorizontal_weight="1" />
<TextView2
app:layout_constraintHorizontal_weight="1" />
<TextView3
app:layout_constraintHorizontal_weight="1" />
<TextView4
app:layout_constraintHorizontal_weight="1" />