Java tutorial
/* * 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 android.example.com.animationdemos; 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/> * <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: * <p/> * <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; } }); } }