Upgrade to Pro — share decks privately, control downloads, hide ads and more …

ConstraintLayout, Inside and Out

Dave Smith
September 29, 2016

ConstraintLayout, Inside and Out

Overview of the ConstraintLayout API and the basic mechanics of how it resolves constraints into view parameters.

Dave Smith

September 29, 2016
Tweet

More Decks by Dave Smith

Other Decks in Programming

Transcript

  1. <android.support.constraint.ConstraintLayout
 ... >
 
 <Button
 android:id="@+id/button_cancel"
 ...
 android:layout_marginBottom="16dp"
 android:layout_marginStart="16dp"
 app:layout_constraintBottom_toBottomOf="parent"


    app:layout_constraintStart_toStartOf="parent"/>
 
 <Button
 android:id="@+id/button_next"
 ...
 android:layout_marginBottom="16dp"
 android:layout_marginStart="16dp"
 app:layout_constraintBottom_toBottomOf="parent"
 app:layout_constraintStart_toEndOf="@+id/button_cancel"/>
 
 
 </android.support.constraint.ConstraintLayout>
  2. <android.support.constraint.ConstraintLayout
 ... >
 
 <Button
 android:id="@+id/button"
 ...
 app:layout_constraintTop_toTopOf="parent"
 app:layout_constraintBottom_toBottomOf="parent"
 app:layout_constraintStart_toStartOf="parent"


    app:layout_constraintEnd_toEndOf="parent"
 app:layout_constraintHorizontal_bias="0.25"
 app:layout_constraintVertical_bias="0.25"/>
 
 </android.support.constraint.ConstraintLayout>
  3. <android.support.constraint.ConstraintLayout
 ... >
 
 <android.support.constraint.Guideline
 android:id="@+id/guideline"
 ...
 android:orientation="vertical"
 app:layout_constraintGuide_percent="0.25"/>
 


    <Button
 android:id="@+id/button_cancel"
 ...
 app:layout_constraintBottom_toBottomOf="parent"
 app:layout_constraintLeft_toLeftOf="@+id/guideline"
 app:layout_constraintTop_toTopOf="parent"
 app:layout_constraintVertical_bias="0.25"/>
 
 <Button
 android:id="@+id/button_next"
 ...
 app:layout_constraintBottom_toBottomOf="parent"
 app:layout_constraintLeft_toLeftOf="@+id/guideline"
 app:layout_constraintTop_toTopOf="parent"
 app:layout_constraintVertical_bias="0.75"/>
 
 </android.support.constraint.ConstraintLayout>
  4. <android.support.constraint.ConstraintLayout
 ... >
 
 <ImageView
 android:layout_width="0dp"
 android:layout_height="wrap_content"
 app:layout_constraintDimensionRatio="16:9"
 app:layout_constraintTop_toTopOf="parent"
 app:layout_constraintLeft_toLeftOf="parent"


    app:layout_constraintRight_toRightOf="parent"/>
 
 <ImageView
 android:layout_width="0dp"
 android:layout_height="wrap_content"
 app:layout_constraintDimensionRatio="4:3"
 app:layout_constraintBottom_toBottomOf="parent"
 app:layout_constraintLeft_toLeftOf="parent"
 app:layout_constraintRight_toRightOf="parent"/>
 
 </android.support.constraint.ConstraintLayout>
  5. <android.support.constraint.ConstraintLayout
 ... >
 
 <ImageView
 android:id="@+id/image_banner"
 android:layout_width="0dp"
 android:layout_height="0dp"
 app:layout_constraintDimensionRatio="H,16:9"
 app:layout_constraintLeft_toLeftOf="parent"


    app:layout_constraintRight_toRightOf="parent"
 app:layout_constraintTop_toTopOf="parent"/>
 
 <ImageView android:id="@+id/image_portrait"
 android:layout_width="0dp"
 android:layout_height="0dp"
 app:layout_constraintDimensionRatio="H,16:9"
 app:layout_constraintBottom_toBottomOf="parent"
 app:layout_constraintLeft_toLeftOf="parent"
 app:layout_constraintTop_toBottomOf="@+id/image_banner"/>
 
 </android.support.constraint.ConstraintLayout>
  6. <android.support.constraint.ConstraintLayout
 ... >
 
 <Button
 android:id="@+id/button_first"
 ...
 app:layout_constraintBottom_toTopOf="@+id/button_second"
 app:layout_constraintTop_toTopOf="parent"
 app:layout_constraintVertical_weight="1.0"

    />
 
 <Button
 android:id="@+id/button_second"
 ...
 app:layout_constraintBottom_toTopOf="@+id/button_third"
 app:layout_constraintTop_toTopOf="@+id/button_first"
 app:layout_constraintVertical_weight="1.0" />
 
 <Button
 android:id="@+id/button_third"
 ...
 app:layout_constraintBottom_toBottomOf="parent"
 app:layout_constraintTop_toBottomOf="@+id/button_second"
 app:layout_constraintVertical_weight="1.0" />
 
 </android.support.constraint.ConstraintLayout>
  7. ConstraintSet set = new ConstraintSet(); // Manual connect
 set.connect(startId, ConstraintSet.LEFT,

    endId, ConstraintSet.LEFT, margin);
 set.connect(...);
 set.connect(...); 
 // From XML layout
 set.clone(context, R.layout.layout_transition_1);
 // From current state
 set.clone(constraintLayout); // Animate to a new set
 ConstraintLayout mConstraintLayout = ...;
 private void transitionTo(ConstraintSet constraintSet) {
 TransitionManager.beginDelayedTransition(mConstraintLayout);
 constraintSet.applyTo(mConstraintLayout);
 }
  8. LP = x RP = LP + wP TP =

    y BP = TP + hP R = L + w L ≥ LP + mL R ≤ RP - mR L + R = LP + RP + mL – mR B = T + h T ≥ TP + mT B ≤ BP - mB T + B = TP + BP + mT – mB Parent Constraints Horizontal Constraints Vertical Constraints