Bug 1021751 - Homepage contextual hint. r=lucasr

* * *
chained accel bounce builder
* * *
small bounce

mobile/android/base/animation/BounceAnimator.java

@@ -0,0 +1,55 @@
+package org.mozilla.gecko.animation;
+
+import java.util.LinkedList;
+import java.util.List;
+
+import android.view.View;
+import android.view.animation.AccelerateInterpolator;
+
+import com.nineoldandroids.animation.Animator;
+import com.nineoldandroids.animation.AnimatorSet;
+import com.nineoldandroids.animation.ObjectAnimator;
+import com.nineoldandroids.animation.ValueAnimator;
+
+/**
+ * This is an Animator that chains AccelerateInterpolators. It can be used to create a customized
+ * Bounce animation.
+ *
+ * After constructing an instance, animations can be queued up sequentially with the
+ * {@link #queue(Attributes) queue} method.
+ */
+public class BounceAnimator extends ValueAnimator {
+
+    public static final class Attributes {
+        public final float value;
+        public final int durationMs;
+
+        public Attributes(float value, int duration) {
+            this.value = value;
+            this.durationMs = duration;
+        }
+    }
+
+    private final View mView;
+    private final String mPropertyName;
+    private List<Animator> animatorChain = new LinkedList<Animator>();
+
+    public BounceAnimator(View view, String property) {
+        mView = view;
+        mPropertyName = property;
+    }
+
+    public void queue(Attributes attrs) {
+        final ValueAnimator animator = ObjectAnimator.ofFloat(mView, mPropertyName, attrs.value);
+        animator.setDuration(attrs.durationMs);
+        animator.setInterpolator(new AccelerateInterpolator());
+        animatorChain.add(animator);
+    }
+
+    @Override
+    public void start() {
+        AnimatorSet animatorSet = new AnimatorSet();
+        animatorSet.playSequentially(animatorChain);
+        animatorSet.start();
+    }
+}

mobile/android/base/home/HomePagerTabStrip.java

@@ -5,12 +5,21 @@
 
 package org.mozilla.gecko.home;
 
+import org.mozilla.gecko.R;
+import org.mozilla.gecko.animation.BounceAnimator;
+import org.mozilla.gecko.animation.BounceAnimator.Attributes;
+
 import android.content.Context;
 import android.content.res.TypedArray;
 import android.support.v4.view.PagerTabStrip;
 import android.util.AttributeSet;
+import android.view.View;
+import android.view.ViewTreeObserver;
 
-import org.mozilla.gecko.R;
+import com.nineoldandroids.animation.AnimatorSet;
+import com.nineoldandroids.animation.ObjectAnimator;
+import com.nineoldandroids.animation.ValueAnimator;
+import com.nineoldandroids.view.ViewHelper;
 
 /**
  * HomePagerTabStrip is a custom implementation of PagerTabStrip
@@ -19,6 +28,15 @@ import org.mozilla.gecko.R;
 
 class HomePagerTabStrip extends PagerTabStrip {
 
+    private static final String LOGTAG = "PagerTabStrip";
+    private static final int ANIMATION_DELAY_MS = 250;
+    private static final int ALPHA_MS = 10;
+    private static final int BOUNCE1_MS = 350;
+    private static final int BOUNCE2_MS = 200;
+    private static final int BOUNCE3_MS = 100;
+    private static final int BOUNCE4_MS = 100;
+    private static final int INIT_OFFSET = 100;
+
     public HomePagerTabStrip(Context context) {
         super(context);
     }
@@ -31,5 +49,60 @@ class HomePagerTabStrip extends PagerTabStrip {
         a.recycle();
 
         setTabIndicatorColor(color);
+
+        getViewTreeObserver().addOnPreDrawListener(new PreDrawListener());
+    }
+
+    private void animateTitles() {
+        final View prevTextView = getChildAt(0);
+        final View nextTextView = getChildAt(getChildCount() - 1);
+
+        if (prevTextView == null || nextTextView == null) {
+            return;
+        }
+
+        // Set up initial values for the views that will be animated.
+        ViewHelper.setTranslationX(prevTextView, -INIT_OFFSET);
+        ViewHelper.setAlpha(prevTextView, 0);
+        ViewHelper.setTranslationX(nextTextView, INIT_OFFSET);
+        ViewHelper.setAlpha(nextTextView, 0);
+
+        // Alpha animations.
+        final ValueAnimator alpha1 = ObjectAnimator.ofFloat(prevTextView, "alpha", 1);
+        final ValueAnimator alpha2 = ObjectAnimator.ofFloat(nextTextView, "alpha", 1);
+
+        final AnimatorSet alphaAnimatorSet = new AnimatorSet();
+        alphaAnimatorSet.playTogether(alpha1, alpha2);
+        alphaAnimatorSet.setStartDelay(ANIMATION_DELAY_MS);
+        alphaAnimatorSet.setDuration(ALPHA_MS);
+
+        // Bounce animation.
+        final float bounceDistance = getWidth()/100f; // Hack: TextFields still have 0 width here.
+
+        final BounceAnimator prevBounceAnimator = new BounceAnimator(prevTextView, "translationX");
+        prevBounceAnimator.queue(new Attributes(bounceDistance, BOUNCE1_MS));
+        prevBounceAnimator.queue(new Attributes(-bounceDistance/4, BOUNCE2_MS));
+        prevBounceAnimator.queue(new Attributes(0, BOUNCE4_MS));
+        prevBounceAnimator.setStartDelay(ANIMATION_DELAY_MS);
+
+        final BounceAnimator nextBounceAnimator = new BounceAnimator(nextTextView, "translationX");
+        nextBounceAnimator.queue(new Attributes(-bounceDistance, BOUNCE1_MS));
+        nextBounceAnimator.queue(new Attributes(bounceDistance/4, BOUNCE2_MS));
+        nextBounceAnimator.queue(new Attributes(0, BOUNCE4_MS));
+        nextBounceAnimator.setStartDelay(ANIMATION_DELAY_MS);
+
+        // Start animations.
+        alphaAnimatorSet.start();
+        prevBounceAnimator.start();
+        nextBounceAnimator.start();
+    }
+
+    private class PreDrawListener implements ViewTreeObserver.OnPreDrawListener {
+        @Override
+        public boolean onPreDraw() {
+            animateTitles();
+            getViewTreeObserver().removeOnPreDrawListener(this);
+            return true;
+        }
     }
 }

mobile/android/base/moz.build

@@ -125,6 +125,7 @@ gbjar.sources += [
     'AndroidGamepadManager.java',
     'animation/AnimationUtils.java',
     'animation/AnimatorProxy.java',
+    'animation/BounceAnimator.java',
     'animation/HeightChangeAnimation.java',
     'animation/PropertyAnimator.java',
     'animation/Rotate3DAnimation.java',