add scheduleTransitionTo

constraintlayout/constraintlayout/src/main/java/androidx/constraintlayout/motion/widget/MotionLayout.java

@@ -1046,6 +1046,8 @@ public class MotionLayout extends ConstraintLayout implements
     private boolean mInLayout = false;
     private StateCache mStateCache;
     private Runnable mOnComplete = null;
+    private int[]mScheduledTransitionTo = null;
+    int mScheduledTransitions = 0;
 
     MotionController getMotionController(int mTouchAnchorId) {
         return mFrameArrayList.get(findViewById(mTouchAnchorId));
@@ -4002,6 +4004,11 @@ protected void fireTransitionCompleted() {
             mOnComplete.run();
         }
 
+        if (mScheduledTransitionTo != null && mScheduledTransitions > 0) {
+            transitionToState(mScheduledTransitionTo[0]);
+            System.arraycopy(mScheduledTransitionTo,1,mScheduledTransitionTo,0,mScheduledTransitionTo.length-1);
+            mScheduledTransitions--;
+        }
     }
 
     private void processTransitionCompleted() {
@@ -4205,6 +4212,25 @@ public void updateStateAnimate(int stateId, ConstraintSet set, int duration) {
         }
     }
 
+    /**
+     * on completing the current transition, transition to this state.
+     *
+     * @param id
+     */
+    public void scheduleTransitionTo(int id) {
+        if (getCurrentState() == -1) {
+            transitionToState(id);
+        } else {
+            if (mScheduledTransitionTo == null) {
+                mScheduledTransitionTo = new int[4];
+            } else if (mScheduledTransitionTo.length <= mScheduledTransitions) {
+                mScheduledTransitionTo =
+                        Arrays.copyOf(mScheduledTransitionTo, mScheduledTransitionTo.length * 2);
+            }
+            mScheduledTransitionTo[mScheduledTransitions++] = id;
+        }
+    }
+
     /**
      * Not sure we want this
      * @hide

projects/MotionLayoutVerification/app/src/main/java/android/support/constraint/app/VerificationActivity.java

@@ -85,10 +85,10 @@ public class VerificationActivity extends AppCompatActivity implements View.OnCl
     String s = AppCompatActivity.class.getName();
 
     private static boolean REVERSE = false;
+
 
     private final String RUN_FIRST = "verification_309";
     private final String LAYOUTS_MATCHES = "verification_\\d+";
-
     private static String SHOW_FIRST = "";
     MotionLayout mMotionLayout;
     private Flow mFlow;
@@ -541,14 +541,19 @@ public void addToFlow2(View view) {
      * @param view
      */
     public void twistViews(View view) {
-        rotate ++;
+        rotate++;
         int current = mMotionLayout.getCurrentState();
         ConstraintSet cset = mMotionLayout.cloneConstraintSet(current);
         int[] id = {R.id.button1, R.id.button2, R.id.button3, R.id.button4, R.id.button5, R.id.button6};
         for (int i : id) {
-            cset.setRotation(i, ((rotate &1)==0) ? 90 : 0);
+            cset.setRotation(i, ((rotate & 1) == 0) ? 90 : 0);
         }
+        int r = (rotate + 1);
+        String str = (((r & 1) == 0) ? "rot 90 " : "rot 0 ") +
+                (((r & 2) == 0) ? "then start" : "then end");
+        ((Button) view).setText(str);
         mMotionLayout.updateStateAnimate(current, cset, 200);
+        mMotionLayout.scheduleTransitionTo(((rotate & 2) == 0) ? R.id.start : R.id.end);
     }
 
     interface Test {

projects/MotionLayoutVerification/app/src/main/res/layout/verification_150.xml

@@ -23,6 +23,7 @@
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="2"
+        android:layout_marginTop="50dp"
         app:layout_constraintStart_toStartOf="@id/button1"
         app:layout_constraintTop_toBottomOf="@id/button1"  />
 
@@ -31,6 +32,7 @@
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="3"
+        android:layout_marginTop="50dp"
         app:layout_constraintStart_toStartOf="@id/button2"
         app:layout_constraintTop_toBottomOf="@id/button2"   />
 
@@ -39,6 +41,7 @@
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="4"
+        android:layout_marginTop="50dp"
         app:layout_constraintStart_toStartOf="@id/button3"
         app:layout_constraintTop_toBottomOf="@id/button3"  />
 
@@ -47,22 +50,22 @@
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="5"
-        app:layout_constraintStart_toStartOf="@id/button4"
+        app:layout_constraintStart_toEndOf="@id/button4"
         app:layout_constraintTop_toBottomOf="@id/button4"   />
 
     <Button
         android:id="@+id/button6"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="6"
-        app:layout_constraintStart_toStartOf="@id/button5"
+        app:layout_constraintStart_toEndOf="@id/button5"
         app:layout_constraintTop_toBottomOf="@id/button5"   />
 
     <Button
         android:id="@+id/button"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:text="animatedChange"
+        android:text="test updateStateAnimate and scheduleTransitionTo"
         android:onClick="twistViews"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintEnd_toEndOf="parent"