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技術社區[雲棲]
Android圖片翻轉動畫效果
https://blog.csdn.net/hnlshzx2008/article/details/7846621
Android中並沒有提供直接做3D翻轉的動畫，所以關於3D翻轉的動畫效果需要我們自己實現，那麼我們首先來分析一下Animation 和 Transformation。
Animation動畫的主要接口，其中主要定義了動畫的 一些屬性比如開始時間，持續時間，是否重複播放等等。而Transformation中則包含一個矩陣和alpha值，矩陣是用來做平移，旋轉和縮放動畫 的，而alpha值是用來做alpha動畫的，要實現3D旋轉動畫我們需要繼承自Animation類來實現，我們需要重載 getTransformation和applyTransformation，在getTransformation中Animation會根據動畫的 屬性來產生一係列的差值點，然後將這些差值點傳給applyTransformation，這個函數將根據這些點來生成不同的 Transformation。下麵是具體實現：
public class Rotate3dAnimation extends Animation {
//開始角度
private final float mFromDegrees;
//結束角度
private final float mToDegrees;
//中心點
private final float mCenterX;
private final float mCenterY;
private final float mDepthZ;
//是否需要扭曲
private final boolean mReverse;
//攝像頭
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;
//生成中間角度
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);
//取得變換後的矩陣
camera.getMatrix(matrix);
camera.restore();
matrix.preTranslate(-centerX, -centerY);
matrix.postTranslate(centerX, centerY);
}
}
其中包括了旋轉的開始和結束角度，中心點、是否扭曲、和一 個Camera，這裏我們主要分析applyTransformation函數，其中第一個參數就是通過getTransformation函數傳遞的差 指點，然後我們根據這個差值通過線性差值算法計算出一個中間角度degrees，Camera類是用來實現繞Y軸旋轉後透視投影的，因此我們首先通過 t.getMatrix()取得當前的矩陣，然後通過camera.translate來對矩陣進行平移變換操作，camera.rotateY進行旋 轉。這樣我們就可以很輕鬆的實現3D旋轉效果了，該例子的原意是通過一個列表來供用戶選擇要實現翻轉的圖像，所以我們分析至少需要定義兩個控 件：ListView和ImageView（要翻轉的圖像），主界麵的xml布局定義如下所示。
<FrameLayout xmlns:andro
android:
android:layout_width="match_parent"
android:layout_height="match_parent">
<ListView
android:
android:persistentDrawingCache="animation|scrolling"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layoutAnimation="@anim/layout_bottom_to_top_slide" />
<ImageView
android:
android:scaleType="fitCenter"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:visibility="gone" />
</FrameLayout>
然後準備好需要的資源，在onCreate函數中準備好 ListView和ImageView，因為要旋轉所以我們需要保存視圖的緩存信息，通過 setPersistentDrawingCache(ViewGroup.PERSISTENT_ANIMATION_CACHE);可以設置該功能， 當我們選擇列表中的圖像資源後在onItemClick中將選擇的資源Id對應的圖像設置到ImageView中，然後通過applyRotation來 啟動一個動畫，前麵有了Rotate3dAnimation的實現，我們要完成3D翻轉動畫就很簡單，直接構建一個Rotate3dAnimation對 象，設置其屬性（包括動畫監聽），這裏將動畫的監聽設置為DisplayNextView，可以用來顯示下一個視圖，在其中的動畫結束監聽 （onAnimationEnd）中，通過一個縣城SwapViews來交換兩個畫麵，交換過程則是設置ImageView和ListView的顯示相關 屬性，並構建一個Rotate3dAnimation對象，對另一個界麵進行旋轉即可，然後啟動動畫，整個轉換過程實際上就是將第一個界麵從0度轉好90 度，然後就愛你過第二個界麵從90度轉到0度，這樣就形成了一個翻轉動畫，完整代碼如下，我們也加入了一些必要的注解，大家也可以參考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，用於顯示在list中
private static final String[] PHOTOS_NAMES = new String[] {
"Lyon",
"Livermore",
"Tahoe Pier",
"Lake Tahoe",
"Grand Canyon",
"Bodie"
};
// 資源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);
// 準備ListView
final ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, PHOTOS_NAMES);
mPhotosList.setAdapter(adapter);
mPhotosList.setOnItemClickListener(this);
// 準備ImageView
mImageView.setClickable(true);
mImageView.setFocusable(true);
mImageView.setOnClickListener(this);
//設置需要保存緩存
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) {
// 計算中心點
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());
//設置監聽
rotation.setAnimationListener(new DisplayNextView(position));
mContainer.startAnimation(rotation);
}
public void onItemClick(AdapterView parent, View v, int position, long id) {
// 設置ImageView
mImageView.setImageResource(PHOTOS_RESOURCES[position]);
applyRotation(position, 0, 90);
}
//點擊圖像時，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) {
}
//動畫結束
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) {
//顯示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());
//開始動畫
mContainer.startAnimation(rotation);
}
}
}
最後更新：2017-04-02 15:15:14