Upstream oodles of Chrome for Android code into Chromium.

chrome/android/java_staging/src/org/chromium/chrome/browser/widget/NumberRollView.java

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.widget;
+
+import android.animation.Animator;
+import android.animation.ObjectAnimator;
+import android.content.Context;
+import android.util.AttributeSet;
+import android.util.Property;
+import android.widget.FrameLayout;
+import android.widget.TextView;
+
+import com.google.android.apps.chrome.R;
+
+import org.chromium.ui.interpolators.BakedBezierInterpolator;
+
+import java.text.NumberFormat;
+
+/**
+ * View that shows an integer number. It provides a smooth roll animation on changing the
+ * number.
+ */
+public class NumberRollView extends FrameLayout {
+    private TextView mUpNumber;
+    private TextView mDownNumber;
+    private float mNumber;
+    private Animator mLastRollAnimator;
+
+    /**
+     * A Property wrapper around the <code>number</code> functionality handled by the
+     * {@link NumberRollView#setNumberRoll(float)} and {@link NumberRollView#getNumberRoll()}
+     * methods.
+     */
+    public static final Property<NumberRollView, Float> NUMBER_PROPERTY =
+            new Property<NumberRollView, Float>(Float.class, "") {
+        @Override
+        public void set(NumberRollView view, Float value) {
+            view.setNumberRoll(value);
+        }
+
+        @Override
+        public Float get(NumberRollView view) {
+            return view.getNumberRoll();
+        }
+    };
+
+    /**
+     * Constructor for inflating from XML.
+     */
+    public NumberRollView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    @Override
+    protected void onFinishInflate() {
+        super.onFinishInflate();
+        mUpNumber = (TextView) findViewById(R.id.up);
+        mDownNumber = (TextView) findViewById(R.id.down);
+
+        assert mUpNumber != null;
+        assert mDownNumber != null;
+
+        setNumberRoll(mNumber);
+    }
+
+    /**
+     * Sets a number to display.
+     * @param animate Whether it should smoothly animate to the number.
+     */
+    public void setNumber(int number, boolean animate) {
+        if (mLastRollAnimator != null) mLastRollAnimator.cancel();
+
+        if (animate) {
+            Animator rollAnimator = ObjectAnimator.ofFloat(this, NUMBER_PROPERTY, number);
+            rollAnimator.setInterpolator(BakedBezierInterpolator.TRANSFORM_CURVE);
+            rollAnimator.start();
+            mLastRollAnimator = rollAnimator;
+        } else {
+            setNumberRoll(number);
+        }
+    }
+
+    /**
+     * Gets the current number roll position.
+     */
+    private float getNumberRoll() {
+        return mNumber;
+    }
+
+    /**
+     * Sets the number roll position.
+     */
+    private void setNumberRoll(float number) {
+        mNumber = number;
+        int downNumber = (int) number;
+        int upNumber = downNumber + 1;
+
+        NumberFormat numberFormatter = NumberFormat.getIntegerInstance();
+        String newString = numberFormatter.format(upNumber);
+        if (!newString.equals(mUpNumber.getText().toString())) mUpNumber.setText(newString);
+
+        newString = numberFormatter.format(downNumber);
+        if (!newString.equals(mDownNumber.getText().toString())) mDownNumber.setText(newString);
+
+        float offset = number % 1.0f;
+
+        mUpNumber.setTranslationY(mUpNumber.getHeight() * (offset - 1.0f));
+        mDownNumber.setTranslationY(mDownNumber.getHeight() * offset);
+
+        mUpNumber.setAlpha(offset);
+        mDownNumber.setAlpha(1.0f - offset);
+    }
+}