Added an animation when changing steps for the progress bar stepper type.

Piotr Zawadzki · zawadz88 · commit ebe865c92f87 · 2017-03-10T14:30:00.000+01:00
diff --git a/material-stepper/src/main/java/com/stepstone/stepper/StepperLayout.java b/material-stepper/src/main/java/com/stepstone/stepper/StepperLayout.java
@@ -681,7 +681,7 @@ private void onNext() {
     }
 
     private void invalidateCurrentPosition() {
-        mStepperType.onStepSelected(mCurrentStepPosition);
+        mStepperType.onStepSelected(mCurrentStepPosition, false);
     }
 
     private boolean verifyCurrentStep(Step step) {
@@ -714,13 +714,13 @@ private void onComplete() {
         mListener.onCompleted(mCompleteNavigationButton);
     }
 
-    private void onUpdate(int newStepPosition, boolean animateButtons) {
+    private void onUpdate(int newStepPosition, boolean userTriggeredChange) {
         mPager.setCurrentItem(newStepPosition);
         final boolean isLast = isLastPosition(newStepPosition);
         final boolean isFirst = newStepPosition == 0;
-        AnimationUtil.fadeViewVisibility(mNextNavigationButton, isLast ? View.GONE : View.VISIBLE, animateButtons);
-        AnimationUtil.fadeViewVisibility(mCompleteNavigationButton, !isLast ? View.GONE : View.VISIBLE, animateButtons);
-        AnimationUtil.fadeViewVisibility(mBackNavigationButton, isFirst && !mShowBackButtonOnFirstStep ? View.GONE : View.VISIBLE, animateButtons);
+        AnimationUtil.fadeViewVisibility(mNextNavigationButton, isLast ? View.GONE : View.VISIBLE, userTriggeredChange);
+        AnimationUtil.fadeViewVisibility(mCompleteNavigationButton, !isLast ? View.GONE : View.VISIBLE, userTriggeredChange);
+        AnimationUtil.fadeViewVisibility(mBackNavigationButton, isFirst && !mShowBackButtonOnFirstStep ? View.GONE : View.VISIBLE, userTriggeredChange);
 
         final StepViewModel viewModel = mStepAdapter.getViewModel(newStepPosition);
 
@@ -732,7 +732,7 @@ private void onUpdate(int newStepPosition, boolean animateButtons) {
 
         setCompoundDrawablesForNavigationButtons(viewModel.getBackButtonStartDrawableResId(), viewModel.getNextButtonEndDrawableResId());
 
-        mStepperType.onStepSelected(newStepPosition);
+        mStepperType.onStepSelected(newStepPosition, userTriggeredChange);
         mListener.onStepSelected(newStepPosition);
         Step step = mStepAdapter.findStep(newStepPosition);
         if (step != null) {
diff --git a/material-stepper/src/main/java/com/stepstone/stepper/internal/type/AbstractStepperType.java b/material-stepper/src/main/java/com/stepstone/stepper/internal/type/AbstractStepperType.java
@@ -57,10 +57,11 @@ public AbstractStepperType(StepperLayout stepperLayout) {
     }
 
     /**
-     * Called when a step gets selected as the new current step
+     * Called when a step gets selected as the new current step.
      * @param newStepPosition new current step position
+     * @param userTriggeredChange <code>true</code> if current step position changed as a direct result of user interaction
      */
-    public abstract void onStepSelected(int newStepPosition);
+    public abstract void onStepSelected(int newStepPosition, boolean userTriggeredChange);
 
     /**
      * Called to set whether the stepPosition has an error or not, changing it's appearance.
diff --git a/material-stepper/src/main/java/com/stepstone/stepper/internal/type/DotsStepperType.java b/material-stepper/src/main/java/com/stepstone/stepper/internal/type/DotsStepperType.java
@@ -54,8 +54,8 @@ public DotsStepperType(StepperLayout stepperLayout) {
      * {@inheritDoc}
      */
     @Override
-    public void onStepSelected(int newStepPosition) {
-        mDottedProgressBar.setCurrent(newStepPosition, true);
+    public void onStepSelected(int newStepPosition, boolean userTriggeredChange) {
+        mDottedProgressBar.setCurrent(newStepPosition, userTriggeredChange);
     }
 
     /**
diff --git a/material-stepper/src/main/java/com/stepstone/stepper/internal/type/ProgressBarStepperType.java b/material-stepper/src/main/java/com/stepstone/stepper/internal/type/ProgressBarStepperType.java
@@ -47,8 +47,8 @@ public ProgressBarStepperType(StepperLayout stepperLayout) {
      * {@inheritDoc}
      */
     @Override
-    public void onStepSelected(int newStepPosition) {
-        mProgressBar.setProgress(newStepPosition + 1);
+    public void onStepSelected(int newStepPosition, boolean userTriggeredChange) {
+        mProgressBar.setProgressCompat(newStepPosition + 1, userTriggeredChange);
     }
 
     /**
diff --git a/material-stepper/src/main/java/com/stepstone/stepper/internal/type/TabsStepperType.java b/material-stepper/src/main/java/com/stepstone/stepper/internal/type/TabsStepperType.java
@@ -62,7 +62,7 @@ public TabsStepperType(StepperLayout stepperLayout) {
      * {@inheritDoc}
      */
     @Override
-    public void onStepSelected(int newStepPosition) {
+    public void onStepSelected(int newStepPosition, boolean userTriggeredChange) {
         if (!stepperLayout.isShowErrorStateEnabled()) {
             mStepErrors.clear();
         }
diff --git a/material-stepper/src/main/java/com/stepstone/stepper/internal/widget/ColorableProgressBar.java b/material-stepper/src/main/java/com/stepstone/stepper/internal/widget/ColorableProgressBar.java
@@ -16,14 +16,18 @@
 
 package com.stepstone.stepper.internal.widget;
 
+import android.animation.ObjectAnimator;
 import android.content.Context;
 import android.content.res.TypedArray;
 import android.graphics.drawable.Drawable;
 import android.graphics.drawable.LayerDrawable;
+import android.os.Build;
 import android.support.annotation.ColorInt;
 import android.support.annotation.RestrictTo;
 import android.support.v4.content.ContextCompat;
 import android.util.AttributeSet;
+import android.util.Property;
+import android.view.animation.DecelerateInterpolator;
 import android.widget.ProgressBar;
 
 import com.stepstone.stepper.R;
@@ -33,10 +37,30 @@
 
 /**
  * A {@link ProgressBar} which exposes methods for coloring primary progress and progress background colors individually.
+ * It also allows to animate progress changes.
  */
 @RestrictTo(LIBRARY)
 public class ColorableProgressBar extends ProgressBar {
 
+    /**
+     * Interpolator used for smooth progress animations.
+     * This is copied from {@link ProgressBar} on Android Nougat.
+     */
+    private static final DecelerateInterpolator PROGRESS_ANIM_INTERPOLATOR =
+            new DecelerateInterpolator();
+
+    /**
+     * Duration of smooth progress animations.
+     * This is copied from {@link ProgressBar} on Android Nougat.
+     */
+    private static final int PROGRESS_ANIM_DURATION = 80;
+
+    /**
+     * A multiplier to be used when setting the current progress of this progress bar.
+     * It is needed to animate the progress changes below Android Nougat.
+     */
+    private static final int PROGRESS_RANGE_MULTIPLIER = 100;
+
     @ColorInt
     private int mProgressColor;
 
@@ -83,6 +107,11 @@ public void setProgressDrawableTiled(Drawable d) {
         // no-op
     }
 
+    @Override
+    public synchronized void setMax(int max) {
+        super.setMax(max * PROGRESS_RANGE_MULTIPLIER);
+    }
+
     public void setProgressColor(@ColorInt int progressColor) {
         this.mProgressColor = progressColor;
         updateProgressDrawable();
@@ -93,11 +122,39 @@ public void setProgressBackgroundColor(@ColorInt int backgroundColor) {
         updateProgressDrawable();
     }
 
+    public void setProgressCompat(int progress, boolean animate) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+            setProgress(progress * PROGRESS_RANGE_MULTIPLIER, animate);
+        } else if (animate) {
+            final ObjectAnimator animator = ObjectAnimator.ofInt(this, PROGRESS_PROPERTY, getProgress(), progress * PROGRESS_RANGE_MULTIPLIER);
+            animator.setDuration(PROGRESS_ANIM_DURATION);
+            animator.setInterpolator(PROGRESS_ANIM_INTERPOLATOR);
+            animator.start();
+        } else {
+            setProgress(progress * PROGRESS_RANGE_MULTIPLIER);
+        }
+
+    }
+
     private void updateProgressDrawable() {
         LayerDrawable progressBarDrawable = (LayerDrawable) getProgressDrawable();
         Drawable backgroundDrawable = progressBarDrawable.findDrawableByLayerId(android.R.id.background);
         Drawable progressDrawable = progressBarDrawable.findDrawableByLayerId(android.R.id.progress);
         TintUtil.tintDrawable(backgroundDrawable, mProgressBackgroundColor);
         TintUtil.tintDrawable(progressDrawable, mProgressColor);
     }
+
+    private static final Property<ProgressBar, Integer> PROGRESS_PROPERTY = new Property<ProgressBar, Integer>(Integer.class, "progress") {
+
+        @Override
+        public void set(ProgressBar object, Integer value) {
+            object.setProgress(value);
+        }
+
+        @Override
+        public Integer get(ProgressBar object) {
+            return object.getProgress();
+        }
+    };
+
 }
diff --git a/material-stepper/src/main/java/com/stepstone/stepper/internal/widget/DottedProgressBar.java b/material-stepper/src/main/java/com/stepstone/stepper/internal/widget/DottedProgressBar.java
@@ -25,7 +25,7 @@
 import android.util.AttributeSet;
 import android.view.LayoutInflater;
 import android.view.View;
-import android.view.animation.AccelerateDecelerateInterpolator;
+import android.view.animation.DecelerateInterpolator;
 import android.widget.LinearLayout;
 
 import com.stepstone.stepper.R;
@@ -44,6 +44,8 @@ public class DottedProgressBar extends LinearLayout {
     private static final int DURATION_IMMEDIATE = 0;
     private static final int SCALE_ANIMATION_DEFAULT_DURATION = 300;
 
+    private static final DecelerateInterpolator DEFAULT_INTERPOLATOR = new DecelerateInterpolator();
+
     @ColorInt
     private int mUnselectedColor;
 
@@ -111,21 +113,20 @@ public void setCurrent(int current, boolean shouldAnimate) {
 
     private void update(boolean shouldAnimate) {
         for (int i = 0; i < mDotCount; i++) {
-            final AccelerateDecelerateInterpolator interpolator = new AccelerateDecelerateInterpolator();
             if (i == mCurrent) {
                 getChildAt(i).animate()
                         .scaleX(FULL_SCALE)
                         .scaleY(FULL_SCALE)
                         .setDuration(shouldAnimate ? SCALE_ANIMATION_DEFAULT_DURATION : DURATION_IMMEDIATE)
-                        .setInterpolator(interpolator)
+                        .setInterpolator(DEFAULT_INTERPOLATOR)
                         .start();
                 colorChildAtPosition(i, true);
             } else {
                 getChildAt(i).animate()
                         .scaleX(HALF_SCALE)
                         .scaleY(HALF_SCALE)
                         .setDuration(shouldAnimate ? SCALE_ANIMATION_DEFAULT_DURATION : DURATION_IMMEDIATE)
-                        .setInterpolator(interpolator)
+                        .setInterpolator(DEFAULT_INTERPOLATOR)
                         .start();
                 colorChildAtPosition(i, false);
             }

Original file line number	Diff line number	Diff line change
`@@ -62,7 +62,7 @@ public TabsStepperType(StepperLayout stepperLayout) {`
`62`	`62`	`* {@inheritDoc}`
`63`	`63`	`*/`
`64`	`64`	`@Override`
`65`		`- public void onStepSelected(int newStepPosition) {`
	`65`	`+ public void onStepSelected(int newStepPosition, boolean userTriggeredChange) {`
`66`	`66`	`if (!stepperLayout.isShowErrorStateEnabled()) {`
`67`	`67`	`mStepErrors.clear();`
`68`	`68`	`}`