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/*
* Copyright 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.android.animationsdemo;
import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.AnimatorSet;
import android.animation.ObjectAnimator;
import android.content.Intent;
import android.graphics.Point;
import android.graphics.Rect;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.NavUtils;
import android.view.MenuItem;
import android.view.View;
import android.view.animation.DecelerateInterpolator;
import android.widget.ImageView;
/**
* A sample showing how to zoom an image thumbnail to full-screen, by animating the bounds of the
* zoomed image from the thumbnail bounds to the screen bounds.
*
* <p>In this sample, the user can touch one of two images. Touching an image zooms it in, covering
* the entire activity content area. Touching the zoomed-in image hides it.</p>
*/
public class ZoomActivity extends FragmentActivity {
/**
* Hold a reference to the current animator, so that it can be canceled mid-way.
*/
private Animator mCurrentAnimator;
/**
* The system "short" animation time duration, in milliseconds. This duration is ideal for
* subtle animations or animations that occur very frequently.
*/
private int mShortAnimationDuration;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_zoom);
// Hook up clicks on the thumbnail views.
final View thumb1View = findViewById(R.id.thumb_button_1);
thumb1View.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
zoomImageFromThumb(thumb1View, R.drawable.image1);
}
});
final View thumb2View = findViewById(R.id.thumb_button_2);
thumb2View.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
zoomImageFromThumb(thumb2View, R.drawable.image2);
}
});
// Retrieve and cache the system's default "short" animation time.
mShortAnimationDuration = getResources().getInteger(android.R.integer.config_shortAnimTime);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
// Navigate "up" the demo structure to the launchpad activity.
// See http://developer.android.com/design/patterns/navigation.html for more.
NavUtils.navigateUpTo(this, new Intent(this, MainActivity.class));
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* "Zooms" in a thumbnail view by assigning the high resolution image to a hidden "zoomed-in"
* image view and animating its bounds to fit the entire activity content area. More
* specifically:
*
* <ol>
* <li>Assign the high-res image to the hidden "zoomed-in" (expanded) image view.</li>
* <li>Calculate the starting and ending bounds for the expanded view.</li>
* <li>Animate each of four positioning/sizing properties (X, Y, SCALE_X, SCALE_Y)
* simultaneously, from the starting bounds to the ending bounds.</li>
* <li>Zoom back out by running the reverse animation on click.</li>
* </ol>
*
* @param thumbView The thumbnail view to zoom in.
* @param imageResId The high-resolution version of the image represented by the thumbnail.
*/
private void zoomImageFromThumb(final View thumbView, int imageResId) {
// If there's an animation in progress, cancel it immediately and proceed with this one.
if (mCurrentAnimator != null) {
mCurrentAnimator.cancel();
}
// Load the high-resolution "zoomed-in" image.
final ImageView expandedImageView = (ImageView) findViewById(R.id.expanded_image);
expandedImageView.setImageResource(imageResId);
// Calculate the starting and ending bounds for the zoomed-in image. This step
// involves lots of math. Yay, math.
final Rect startBounds = new Rect();
final Rect finalBounds = new Rect();
final Point globalOffset = new Point();
// The start bounds are the global visible rectangle of the thumbnail, and the
// final bounds are the global visible rectangle of the container view. Also
// set the container view's offset as the origin for the bounds, since that's
// the origin for the positioning animation properties (X, Y).
thumbView.getGlobalVisibleRect(startBounds);
findViewById(R.id.container).getGlobalVisibleRect(finalBounds, globalOffset);
startBounds.offset(-globalOffset.x, -globalOffset.y);
finalBounds.offset(-globalOffset.x, -globalOffset.y);
// Adjust the start bounds to be the same aspect ratio as the final bounds using the
// "center crop" technique. This prevents undesirable stretching during the animation.
// Also calculate the start scaling factor (the end scaling factor is always 1.0).
float startScale;
if ((float) finalBounds.width() / finalBounds.height()
> (float) startBounds.width() / startBounds.height()) {
// Extend start bounds horizontally
startScale = (float) startBounds.height() / finalBounds.height();
float startWidth = startScale * finalBounds.width();
float deltaWidth = (startWidth - startBounds.width()) / 2;
startBounds.left -= deltaWidth;
startBounds.right += deltaWidth;
} else {
// Extend start bounds vertically
startScale = (float) startBounds.width() / finalBounds.width();
float startHeight = startScale * finalBounds.height();
float deltaHeight = (startHeight - startBounds.height()) / 2;
startBounds.top -= deltaHeight;
startBounds.bottom += deltaHeight;
}
// Hide the thumbnail and show the zoomed-in view. When the animation begins,
// it will position the zoomed-in view in the place of the thumbnail.
thumbView.setAlpha(0f);
expandedImageView.setVisibility(View.VISIBLE);
// Set the pivot point for SCALE_X and SCALE_Y transformations to the top-left corner of
// the zoomed-in view (the default is the center of the view).
expandedImageView.setPivotX(0f);
expandedImageView.setPivotY(0f);
// Construct and run the parallel animation of the four translation and scale properties
// (X, Y, SCALE_X, and SCALE_Y).
AnimatorSet set = new AnimatorSet();
set
.play(ObjectAnimator.ofFloat(expandedImageView, View.X, startBounds.left,
finalBounds.left))
.with(ObjectAnimator.ofFloat(expandedImageView, View.Y, startBounds.top,
finalBounds.top))
.with(ObjectAnimator.ofFloat(expandedImageView, View.SCALE_X, startScale, 1f))
.with(ObjectAnimator.ofFloat(expandedImageView, View.SCALE_Y, startScale, 1f));
set.setDuration(mShortAnimationDuration);
set.setInterpolator(new DecelerateInterpolator());
set.addListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
mCurrentAnimator = null;
}
@Override
public void onAnimationCancel(Animator animation) {
mCurrentAnimator = null;
}
});
set.start();
mCurrentAnimator = set;
// Upon clicking the zoomed-in image, it should zoom back down to the original bounds
// and show the thumbnail instead of the expanded image.
final float startScaleFinal = startScale;
expandedImageView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (mCurrentAnimator != null) {
mCurrentAnimator.cancel();
}
// Animate the four positioning/sizing properties in parallel, back to their
// original values.
AnimatorSet set = new AnimatorSet();
set
.play(ObjectAnimator.ofFloat(expandedImageView, View.X, startBounds.left))
.with(ObjectAnimator.ofFloat(expandedImageView, View.Y, startBounds.top))
.with(ObjectAnimator
.ofFloat(expandedImageView, View.SCALE_X, startScaleFinal))
.with(ObjectAnimator
.ofFloat(expandedImageView, View.SCALE_Y, startScaleFinal));
set.setDuration(mShortAnimationDuration);
set.setInterpolator(new DecelerateInterpolator());
set.addListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
thumbView.setAlpha(1f);
expandedImageView.setVisibility(View.GONE);
mCurrentAnimator = null;
}
@Override
public void onAnimationCancel(Animator animation) {
thumbView.setAlpha(1f);
expandedImageView.setVisibility(View.GONE);
mCurrentAnimator = null;
}
});
set.start();
mCurrentAnimator = set;
}
});
}
}
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