java图形旋转动画_Android使用Rotate3dAnimation实现3D旋转动画效果的实例代码

Android使用Rotate3dAnimation实现3D旋转动画效果的实例代码

发布时间：2020-09-09 00:22:18

来源：脚本之家

阅读：209

作者：寒江蓑笠

利用Android的ApiDemos的Rotate3dAnimation实现了个图片3D旋转的动画，围绕Y轴进行旋转，还可以实现Z轴的缩放。点击开始按钮开始旋转，点击结束按钮停止旋转。

代码如下：:

Rotate3dAnimation.java

public class Rotate3dAnimation extends Animation {

private final float mFromDegrees;

private final float mToDegrees;

private final float mCenterX;

private final float mCenterY;

private final float mDepthZ;

private final boolean mReverse;

private Camera mCamera;

/**

* Creates a new 3D rotation on the Y axis. The rotation is defined by its

* start angle and its end angle. Both angles are in degrees. The rotation

* is performed around a center point on the 2D space, definied by a pair

* of X and Y coordinates, called centerX and centerY. When the animation

* starts, a translation on the Z axis (depth) is performed. The length

* of the translation can be specified, as well as whether the translation

* should be reversed in time.

*

* @param fromDegrees the start angle of the 3D rotation

* @param toDegrees the end angle of the 3D rotation

* @param centerX the X center of the 3D rotation

* @param centerY the Y center of the 3D rotation

* @param reverse true if the translation should be reversed, false otherwise

*/

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();

}

@Override

protected void applyTransformation(float interpolatedTime, Transformation t) {

final float fromDegrees = mFromDegrees;

float degrees = fromDegrees + ((mToDegrees - fromDegrees) * interpolatedTime);

final float centerX = mCenterX;

final float centerY = mCenterY;

final Camera camera = mCamera;

final Matrix matrix = t.getMatrix();

//保存一次camera初始状态，用于restore()

camera.save();

if (mReverse) {

camera.translate(0.0f, 0.0f, mDepthZ * interpolatedTime);

} else {

camera.translate(0.0f, 0.0f, mDepthZ * (1.0f - interpolatedTime));

}

//围绕Y轴旋转degrees度

camera.rotateY(degrees);

//行camera中取出矩阵，赋值给matrix

camera.getMatrix(matrix);

//camera恢复到初始状态，继续用于下次的计算

camera.restore();

matrix.preTranslate(-centerX, -centerY);

matrix.postTranslate(centerX, centerY);

}

}

Test3DRotateActivity.java

public class Test3DRotateActivity extends Activity {

/** Called when the activity is first created. */

private final String TAG="Test3DRotateActivity";

private ImageView image;

private Button start ,stop;

private Rotate3dAnimation rotation;

private StartNextRotate startNext;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

image = (ImageView) findViewById(R.id.image);

start=(Button) findViewById(R.id.start);

stop = (Button) findViewById(R.id.stop);

start.setOnClickListener(new OnClickListener() {

public void onClick(View v) {

// TODO Auto-generated method stub

//进行360度的旋转

startRotation(0,360);

}

});

stop.setOnClickListener(new OnClickListener() {

public void onClick(View v) {

// TODO Auto-generated method stub

image.clearAnimation();

}

});

}

private void startRotation(float start, float end) {

// 计算中心点

final float centerX = image.getWidth() / 2.0f;

final float centerY = image.getHeight() / 2.0f;

Log.d(TAG, "centerX="+centerX+", centerY="+centerY);

// 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);

//Z轴的缩放为0

rotation =new Rotate3dAnimation(start, end, centerX, centerY, 0f, true);

rotation.setDuration(2000);

rotation.setFillAfter(true);

//rotation.setInterpolator(new AccelerateInterpolator());

//匀速旋转

rotation.setInterpolator(new LinearInterpolator());

//设置监听

startNext = new StartNextRotate();

rotation.setAnimationListener(startNext);

image.startAnimation(rotation);

}

private class StartNextRotate implements AnimationListener{

public void onAnimationEnd(Animation animation) {

// TODO Auto-generated method stub

Log.d(TAG, "onAnimationEnd......");

image.startAnimation(rotation);

}

public void onAnimationRepeat(Animation animation) {

// TODO Auto-generated method stub

}

public void onAnimationStart(Animation animation) {

// TODO Auto-generated method stub

}

}

}

main.xml

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical" >

android:id="@+id/start"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="开始" />

android:id="@+id/stop"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="结束" />

android:id="@+id/image"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:src="@drawable/t1"

/>

代码中用Camera来实现动画，Camera就是一个摄像机，一个物体原地不动，我们带着摄像机按设定的角度进行移动，之后从Camera中取出完成该动画的Matrix，然后画我们的物体，这个就是这个3D动画实现的原理。

具体的解释见代码中注释部分，重点说一下Rotate3dAnimation.java中的

matrix.preTranslate(-centerX, -centerY);

matrix.postTranslate(centerX, centerY);

由于旋转是以(0,0)为中心的,所以为了把界面的中心与(0,0)对齐,就要preTranslate(-centerX, -centerY),旋转完成后,调用postTranslate(centerX, centerY),再把图片移回来,这样看到的动画效果就是activity的界面图片从在centerX为中心绕Y轴旋转了。

你还可以把上面代码改成

matrix.preTranslate(-centerX, 0);

matrix.postTranslate(centerX, 0);

看有什么不同效果。

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