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      1 /*
      2  * Copyright (C) 2013 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.example.android.bouncer;
     18 
     19 import android.animation.ValueAnimator;
     20 import android.animation.ValueAnimator.AnimatorUpdateListener;
     21 import android.app.Activity;
     22 import android.content.Context;
     23 import android.graphics.Bitmap;
     24 import android.graphics.BitmapFactory;
     25 import android.graphics.Canvas;
     26 import android.graphics.Paint;
     27 import android.os.Bundle;
     28 import android.util.AttributeSet;
     29 import android.view.View;
     30 
     31 /**
     32  * This example shows simple uses of ValueAnimator, ObjectAnimator, and interpolators
     33  * to control how a shape is moved around on the screen.
     34  *
     35  * The Bouncer1, Bouncer2, and Vouncer3 files are exactly like this one except for variations
     36  * in how the animation is set up and run.
     37  *
     38  * Watch the associated video for this demo on the DevBytes channel of developer.android.com
     39  * or on YouTube at https://www.youtube.com/watch?v=vCTcmPIKgpM.
     40  */
     41 public class Bouncer extends Activity {
     42 
     43     @Override
     44     public void onCreate(Bundle savedInstanceState) {
     45         super.onCreate(savedInstanceState);
     46         setContentView(R.layout.activity_bouncer);
     47     }
     48 
     49     /**
     50      * A custom view is used to paint the green background and the shape.
     51      */
     52     static class MyView extends View {
     53 
     54         Bitmap mBitmap;
     55         Paint paint = new Paint();
     56         int mShapeX, mShapeY;
     57         int mShapeW, mShapeH;
     58 
     59         public MyView(Context context, AttributeSet attrs, int defStyle) {
     60             super(context, attrs, defStyle);
     61             setupShape();
     62         }
     63 
     64         public MyView(Context context, AttributeSet attrs) {
     65             super(context, attrs);
     66             setupShape();
     67         }
     68 
     69         public MyView(Context context) {
     70             super(context);
     71             setupShape();
     72         }
     73 
     74         private void setupShape() {
     75             mBitmap = BitmapFactory.decodeResource(getResources(),
     76                     R.drawable.electricsheep);
     77             mShapeW = mBitmap.getWidth();
     78             mShapeH = mBitmap.getHeight();
     79             setOnClickListener(new View.OnClickListener() {
     80                 @Override
     81                 public void onClick(View v) {
     82                     startAnimation();
     83                 }
     84             });
     85         }
     86 
     87         /**
     88          * Moving the shape in x or y causes an invalidation of the area it used to occupy
     89          * plus the area it now occupies.
     90          */
     91         public void setShapeX(int shapeX) {
     92             int minX = mShapeX;
     93             int maxX = mShapeX + mShapeW;
     94             mShapeX = shapeX;
     95             minX = Math.min(mShapeX, minX);
     96             maxX = Math.max(mShapeX + mShapeW, maxX);
     97             invalidate(minX, mShapeY, maxX, mShapeY + mShapeH);
     98         }
     99 
    100         /**
    101          * Moving the shape in x or y causes an invalidation of the area it used to occupy
    102          * plus the area it now occupies.
    103          */
    104         public void setShapeY(int shapeY) {
    105             int minY = mShapeY;
    106             int maxY = mShapeY + mShapeH;
    107             mShapeY = shapeY;
    108             minY = Math.min(mShapeY, minY);
    109             maxY = Math.max(mShapeY + mShapeH, maxY);
    110             invalidate(mShapeX, minY, mShapeX + mShapeW, maxY);
    111         }
    112 
    113         @Override
    114         protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    115             mShapeX = (w - mBitmap.getWidth()) / 2;
    116             mShapeY = 0;
    117         }
    118 
    119         @Override
    120         protected void onDraw(Canvas canvas) {
    121             canvas.drawBitmap(mBitmap, mShapeX, mShapeY, paint);
    122         }
    123 
    124         void startAnimation() {
    125             // This version uses ValueAnimator, which requires adding an update
    126             // listener and manually updating the shape position on each frame.
    127             ValueAnimator anim = getValueAnimator();
    128             anim.start();
    129         }
    130 
    131         ValueAnimator getValueAnimator() {
    132             ValueAnimator anim = ValueAnimator.ofFloat(0, 1);
    133             anim.addUpdateListener(new AnimatorUpdateListener() {
    134                 @Override
    135                 public void onAnimationUpdate(ValueAnimator animation) {
    136                     setShapeY((int) (animation.getAnimatedFraction() *
    137                             (getHeight() - mShapeH)));
    138                 }
    139             });
    140             return anim;
    141         }
    142 
    143     }
    144 }
    145