动画在列表视图中添加项目和项目移动，例如Google Plus应用

Question

当用户在列表视图中滚动时，我想重现列表视图项的效果。

我想重现与Google Plus应用程序相同的效果。

我该怎么做？

更新：

以下是我的getView（）代码的摘录：

    final float centerX = rowView.getWidth() / 2.0f;
    final float centerY = rowView.getHeight() / 2.0f;

    rowView.startAnimation(new Rotate3dAnimation(0.0f, -90.0f, centerX, centerY, 310.0f, true));

更新2：

02-12 16:01:17.198: E/AndroidRuntime(21625): java.lang.NullPointerException
02-12 16:01:17.198: E/AndroidRuntime(21625):    at com.rss.home.ArticleListAdapterHome.getView(ArticleListAdapterHome.java:129)
02-12 16:01:17.198: E/AndroidRuntime(21625):    at android.widget.AbsListView.obtainView(AbsListView.java:2263)
02-12 16:01:17.198: E/AndroidRuntime(21625):    at android.widget.ListView.makeAndAddView(ListView.java:1790)
02-12 16:01:17.198: E/AndroidRuntime(21625):    at android.widget.ListView.fillDown(ListView.java:691)
02-12 16:01:17.198: E/AndroidRuntime(21625):    at android.widget.ListView.fillFromTop(ListView.java:752)

Answer 1

感谢视频。
对我来说，这看起来像3D旋转。动画可能是在适配器的getView方法中启动的。这意味着有三个步骤：

1. 检查自定义ListAdapter，例如here。你也会发现很多问题/答案
2. Click here了解如何在getView
中开始制作动画
3. 检查this answer here。它描述了在哪里可以找到3D动画
的示例

我自己没有检查3D动画，但ListAdapter和Animation不应该是一个大问题。

---

修改：
您不必从xml加载动画。你可以这样做：

public View getView(int position, View view, ViewGroup viewGroup) {
    // normal handling
    // ...
    // now apply animation
    view.startAnimation(new Rotate3dAnimation(/*params*/));
}

---

<强> EDIT2 ：
我现在已经对它进行了测试，以下是我改变它以使其正常工作的内容：

1. 我忘了设置动画的持续时间，我确实设置了这个
2. 视图的高度和宽度未在getView中设置，因此删除了参数centerX和centerY并添加了View view并将其赋予rowView }
3. 动画正在使用camera.rotateY，但需要将其更改为camera.rotateX

这是我更新的Rotate3dAnimation：

package de.malaka.player.animation;

import android.view.View;
import android.view.animation.Animation;
import android.view.animation.Transformation;
import android.graphics.Camera;
import android.graphics.Matrix;

/**
 * An animation that rotates the view on the Y axis between two specified angles.
 * This animation also adds a translation on the Z axis (depth) to improve the effect.
 */
public class Rotate3dAnimation extends Animation {
private final float mFromDegrees;
private final float mToDegrees;
private final float mDepthZ;
private final View mView;
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 depthZ, boolean reverse, View view) {
    mFromDegrees = fromDegrees;
    mToDegrees = toDegrees;
    mDepthZ = depthZ;
    mReverse = reverse;
    mView = view;
}

@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 = mView.getWidth()/2;
    final float centerY = mView.getHeight()/2;
    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.rotateX(degrees);
    camera.getMatrix(matrix);
    camera.restore();

    matrix.preTranslate(-centerX, -centerY);
    matrix.postTranslate(centerX, centerY);
}
}

这就是我在适配器中使用它的方式：

Animation anim = new Rotate3dAnimation(90.0f, 0.0f, 100.0f, false, convertView);
anim.setDuration(1000l);
convertView.startAnimation(anim);

现在持续时间很长，但这样你可以调整值。