Android图片翻转动画效果

来源：互联网发布：电影网站源码编辑：程序博客网时间：2024/04/30 21:39

http://blog.csdn.net/hnlshzx2008/article/details/7846621

Android中并没有提供直接做3D翻转的动画，所以关于3D翻转的动画效果需要我们自己实现，那么我们首先来分析一下Animation 和 Transformation。

Animation动画的主要接口，其中主要定义了动画的一些属性比如开始时间，持续时间，是否重复播放等等。而Transformation中则包含一个矩阵和alpha值，矩阵是用来做平移，旋转和缩放动画的，而alpha值是用来做alpha动画的，要实现3D旋转动画我们需要继承自Animation类来实现，我们需要重载 getTransformation和applyTransformation，在getTransformation中Animation会根据动画的属性来产生一系列的差值点，然后将这些差值点传给applyTransformation，这个函数将根据这些点来生成不同的 Transformation。下面是具体实现：

public class Rotate3dAnimation extends Animation {      //开始角度      private final float mFromDegrees;      //结束角度      private final float mToDegrees;      //中心点      private final float mCenterX;      private final float mCenterY;      private final float mDepthZ;      //是否需要扭曲      private final boolean mReverse;      //摄像头      private Camera mCamera;      public Rotate3dAnimation(float fromDegrees, float toDegrees,              float centerX, float centerY, float depthZ, boolean reverse) {          mFromDegrees = fromDegrees;          mToDegrees = toDegrees;          mCenterX = centerX;          mCenterY = centerY;          mDepthZ = depthZ;          mReverse = reverse;      }       @Override     public void initialize(int width, int height, int parentWidth, int parentHeight) {          super.initialize(width, height, parentWidth, parentHeight);          mCamera = new Camera();      }      //生成Transformation      @Override     protected void applyTransformation(float interpolatedTime, Transformation t) {          final float fromDegrees = mFromDegrees;          //生成中间角度          float degrees = fromDegrees + ((mToDegrees - fromDegrees) * interpolatedTime);           final float centerX = mCenterX;          final float centerY = mCenterY;          final Camera camera = mCamera;           final Matrix matrix = t.getMatrix();           camera.save();          if (mReverse) {              camera.translate(0.0f, 0.0f, mDepthZ * interpolatedTime);          } else {              camera.translate(0.0f, 0.0f, mDepthZ * (1.0f - interpolatedTime));          }          camera.rotateY(degrees);          //取得变换后的矩阵          camera.getMatrix(matrix);          camera.restore();           matrix.preTranslate(-centerX, -centerY);          matrix.postTranslate(centerX, centerY);      }  }

其中包括了旋转的开始和结束角度，中心点、是否扭曲、和一个Camera，这里我们主要分析applyTransformation函数，其中第一个参数就是通过getTransformation函数传递的差指点，然后我们根据这个差值通过线性差值算法计算出一个中间角度degrees，Camera类是用来实现绕Y轴旋转后透视投影的，因此我们首先通过 t.getMatrix()取得当前的矩阵，然后通过camera.translate来对矩阵进行平移变换操作，camera.rotateY进行旋转。这样我们就可以很轻松的实现3D旋转效果了，该例子的原意是通过一个列表来供用户选择要实现翻转的图像，所以我们分析至少需要定义两个控件：ListView和ImageView（要翻转的图像），主界面的xml布局定义如下所示。

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:id="@+id/container"     android:layout_width="match_parent"     android:layout_height="match_parent">      <ListView         android:id="@android:id/list"         android:persistentDrawingCache="animation|scrolling"         android:layout_width="match_parent"         android:layout_height="match_parent"         android:layoutAnimation="@anim/layout_bottom_to_top_slide" />      <ImageView         android:id="@+id/picture"         android:scaleType="fitCenter"         android:layout_width="match_parent"         android:layout_height="match_parent"         android:visibility="gone" />  </FrameLayout>

然后准备好需要的资源，在onCreate函数中准备好 ListView和ImageView，因为要旋转所以我们需要保存视图的缓存信息，通过 setPersistentDrawingCache(ViewGroup.PERSISTENT_ANIMATION_CACHE);可以设置该功能，当我们选择列表中的图像资源后在onItemClick中将选择的资源Id对应的图像设置到ImageView中，然后通过applyRotation来启动一个动画，前面有了Rotate3dAnimation的实现，我们要完成3D翻转动画就很简单，直接构建一个Rotate3dAnimation对象，设置其属性（包括动画监听），这里将动画的监听设置为DisplayNextView，可以用来显示下一个视图，在其中的动画结束监听（onAnimationEnd）中，通过一个县城SwapViews来交换两个画面，交换过程则是设置ImageView和ListView的显示相关属性，并构建一个Rotate3dAnimation对象，对另一个界面进行旋转即可，然后启动动画，整个转换过程实际上就是将第一个界面从0度转好90 度，然后就爱你过第二个界面从90度转到0度，这样就形成了一个翻转动画，完整代码如下，我们也加入了一些必要的注解，大家也可以参考APIDemo中的 Transition3d例子。

public class Transition3d extends Activity implements         AdapterView.OnItemClickListener, View.OnClickListener {      //照片列表      private ListView mPhotosList;      private ViewGroup mContainer;      private ImageView mImageView;       // 照片的名字，用于显示在list中      private static final String[] PHOTOS_NAMES = new String[] {              "Lyon",              "Livermore",              "Tahoe Pier",              "Lake Tahoe",              "Grand Canyon",              "Bodie"     };       // 资源id      private static final int[] PHOTOS_RESOURCES = new int[] {              R.drawable.photo1,              R.drawable.photo2,              R.drawable.photo3,              R.drawable.photo4,              R.drawable.photo5,              R.drawable.photo6      };       @Override     protected void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);           setContentView(R.layout.animations_main_screen);           mPhotosList = (ListView) findViewById(android.R.id.list);          mImageView = (ImageView) findViewById(R.id.picture);          mContainer = (ViewGroup) findViewById(R.id.container);           // 准备ListView          final ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,                  android.R.layout.simple_list_item_1, PHOTOS_NAMES);           mPhotosList.setAdapter(adapter);          mPhotosList.setOnItemClickListener(this);           // 准备ImageView          mImageView.setClickable(true);          mImageView.setFocusable(true);          mImageView.setOnClickListener(this);           //设置需要保存缓存          mContainer.setPersistentDrawingCache(ViewGroup.PERSISTENT_ANIMATION_CACHE);      }       /**       * Setup a new 3D rotation on the container view.       *       * @param position the item that was clicked to show a picture, or -1 to show the list       * @param start the start angle at which the rotation must begin       * @param end the end angle of the rotation       */     private void applyRotation(int position, float start, float end) {          // 计算中心点          final float centerX = mContainer.getWidth() / 2.0f;          final float centerY = mContainer.getHeight() / 2.0f;           // Create a new 3D rotation with the supplied parameter          // The animation listener is used to trigger the next animation          final Rotate3dAnimation rotation =                  new Rotate3dAnimation(start, end, centerX, centerY, 310.0f, true);          rotation.setDuration(500);          rotation.setFillAfter(true);          rotation.setInterpolator(new AccelerateInterpolator());          //设置监听          rotation.setAnimationListener(new DisplayNextView(position));           mContainer.startAnimation(rotation);      }       public void onItemClick(AdapterView parent, View v, int position, long id) {          // 设置ImageView          mImageView.setImageResource(PHOTOS_RESOURCES[position]);          applyRotation(position, 0, 90);      }      //点击图像时，返回listview      public void onClick(View v) {          applyRotation(-1, 180, 90);      }       /**       * This class listens for the end of the first half of the animation.       * It then posts a new action that effectively swaps the views when the container       * is rotated 90 degrees and thus invisible.       */     private final class DisplayNextView implements Animation.AnimationListener {          private final int mPosition;           private DisplayNextView(int position) {              mPosition = position;          }           public void onAnimationStart(Animation animation) {          }          //动画结束          public void onAnimationEnd(Animation animation) {              mContainer.post(new SwapViews(mPosition));          }           public void onAnimationRepeat(Animation animation) {          }      }       /**       * This class is responsible for swapping the views and start the second       * half of the animation.       */     private final class SwapViews implements Runnable {          private final int mPosition;           public SwapViews(int position) {              mPosition = position;          }           public void run() {              final float centerX = mContainer.getWidth() / 2.0f;              final float centerY = mContainer.getHeight() / 2.0f;              Rotate3dAnimation rotation;                            if (mPosition > -1) {                  //显示ImageView                  mPhotosList.setVisibility(View.GONE);                  mImageView.setVisibility(View.VISIBLE);                  mImageView.requestFocus();                   rotation = new Rotate3dAnimation(90, 180, centerX, centerY, 310.0f, false);              } else {                  //返回listview                  mImageView.setVisibility(View.GONE);                  mPhotosList.setVisibility(View.VISIBLE);                  mPhotosList.requestFocus();                   rotation = new Rotate3dAnimation(90, 0, centerX, centerY, 310.0f, false);              }               rotation.setDuration(500);              rotation.setFillAfter(true);              rotation.setInterpolator(new DecelerateInterpolator());              //开始动画              mContainer.startAnimation(rotation);          }      }   }