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.
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.
1、从小到大，旋转360°的动画效果
public class MyAnimation extends Animation {
private int halfWidth;
private int halfHeight;
@Override
public void initialize(int width, int height, int parentWidth,
int parentHeight) {
super.initialize(width, height, parentWidth, parentHeight);
System.out.println("MyAnimation initialize");
setDuration(1000);
setFillAfter(true);
halfWidth = width/2;
halfHeight = height/2;
}
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
System.out.println("Myanimation applyTransformation");
final Matrix matrix = t.getMatrix();
matrix.preScale(interpolatedTime, interpolatedTime);
matrix.preRotate(interpolatedTime * 360);
matrix.preTranslate(-halfWidth, -halfHeight);
matrix.postTranslate(halfWidth, halfHeight);
}
}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
2、从远到近，在z面旋转360°的动画效果
public class MyAnimation extends Animation {
private int halfWidth;
private int halfHeight;
private Camera camera = new Camera();
@Override
public void initialize(int width, int height, int parentWidth,
int parentHeight) {
super.initialize(width, height, parentWidth, parentHeight);
System.out.println("MyAnimation initialize");
setDuration(1000);
setFillAfter(true);
halfWidth = width/2;
halfHeight = height/2;
}
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
System.out.println("Myanimation applyTransformation");
final Matrix matrix = t.getMatrix();
camera.save(); //camera.save() 这句话是将当前的摄像头位置保存下来
camera.translate(0.0f, 0.0f, (3000-3000*interpolatedTime));
camera.rotateY(360*interpolatedTime);
camera.getMatrix(matrix); //将我们刚才定义的一系列变换应用到变换矩阵上面
matrix.preTranslate(-halfWidth, -halfHeight);
matrix.postTranslate(halfWidth, halfHeight);
camera.restore(); //将camera的位置恢复
}
}Camera类，中文意思是摄像头，这是一个逻辑概念，把我们手机的屏幕比作摄像头窗口，透过这个窗口，我们看到里面显示的东西（就是我们应用的界面），当然如果我们从不同的角度来看屏幕中的物体，自然就会呈现出一种立体效果
首先我们得到了一个变换矩阵，camera.save() 这句话是将当前的摄像头位置保存下来，以便变换进行完成后恢复成原位，接下来调用camera.translate，这个方法接受3个参数，分别是x,y,z三个轴的偏移量，我们这里只将z轴进行了偏移，已开始的偏移是3000，随着时间的推移，这个偏移会越来越小。这就会形成这样一个效果，我们的View从一个很远的地方向我们移过来，越来越近，最终移到了我们的窗口上面RotateY是给我们的View加上旋转效果，在移动的过程中，视图还会移Y轴为中心进行旋转。随后的 camera.getMatrix(matrix) ，这个是将我们刚才定义的一系列变换应用到变换矩阵上面，调用完这句之后，我们就可以将camera的位置恢复了，以便下一次再使用。
转载网址：http://www.eoeandroid.com/thread-40674-1-1.html
3、绕Y轴旋转180°的动画效果
public class MyAnimation 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 camera = new Camera();
public MyAnimation(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);
System.out.println("MyAnimation initialize");
setDuration(1000);
setFillAfter(true);
}
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
System.out.println("Myanimation applayTranformation");
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 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);
camera.getMatrix(matrix);
camera.restore();
matrix.preTranslate(-centerX, -centerY);
matrix.postTranslate(centerX, centerY);
}
}4、沿Y轴旋转90°时，两个图片的切换
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Animation的实现，我们要完成3D翻转动画就很简单，直接构建一个Animation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，通过一个现成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Animation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
1、定义的动画效果和上一样
2、actiivty类
public class MainActivity 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.sample_0, R.drawable.sample_1, R.drawable.sample_2,
R.drawable.sample_3, R.drawable.sample_4, R.drawable.sample_5 };
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
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);
}
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);
}
/**
* 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 MyAnimation rotation = new MyAnimation(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);
}
/**
* 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;
MyAnimation rotation;
if (mPosition > -1) {
// 显示ImageView
mPhotosList.setVisibility(View.GONE);
mImageView.setVisibility(View.VISIBLE);
mImageView.requestFocus();
rotation = new MyAnimation(90, 0, centerX, centerY, 0f, false);
} else {
// 返回listview
mImageView.setVisibility(View.GONE);
mPhotosList.setVisibility(View.VISIBLE);
mPhotosList.requestFocus();
rotation = new MyAnimation(90, 0, centerX, centerY, 310.0f,
false);
}
rotation.setDuration(500);
rotation.setFillAfter(true);
rotation.setInterpolator(new DecelerateInterpolator());
// 开始动画
mContainer.startAnimation(rotation);
}
}
}转载地址：http://www.eoeandroid.com/thread-102460-1-1.html
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