android.view.Animation を拡張するクラスがあります。
package diffusi.on.com.fifteen_puzzle;
import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
public class CustomAnimation extends Animation {
private boolean _isLast = false;
private View _currentTarget = null;
public interface AnimationListener {
void onAnimationEnd(CustomAnimation animation);
void onAnimationRepeat(CustomAnimation animation);
void onAnimationStart(CustomAnimation animation);
}
public static void animateSetOfViews(
View[] viewsSet,
int animResId,
int[] startTimeOffsets,
Context context,
AnimationListener animationListener
) {
CustomAnimation animation;
int startTimeOffset;
boolean isLastAnim;
for (int intA = 0; intA < viewsSet.length; intA++) {
isLastAnim = intA == viewsSet.length - 1;
animation = (CustomAnimation) AnimationUtils.loadAnimation(context, animResId);
if (intA <= startTimeOffsets.length - 1) {
startTimeOffset = startTimeOffsets[intA];
} else startTimeOffset = 0;
animation.applyToView(viewsSet[intA], startTimeOffset, isLastAnim, animationListener);
}
}
public CustomAnimation() {
}
public CustomAnimation(Context context, AttributeSet attrs) {
super(context, attrs);
}
public boolean isLast() {
return this._isLast;
}
public View getCurrentTarget() {
return this._currentTarget;
}
private void applyToView(View view, int startTimeOffset, boolean isLast, AnimationListener listener) {
this._isLast = isLast;
this._currentTarget = view;
this.setStartOffset(startTimeOffset);
this.setAnimationListener((Animation.AnimationListener) listener);
this._currentTarget.startAnimation(this);
}
}
IDE でエラーなしでコンパイルされます。しかし、runtame では、次の行で例外 (ClassCastEcxeption) をスローします: animation = (CustomAnimation) AnimationUtils.loadAnimation(context, animResId)
Animation を拡張する CustomAnimation に Animation インスタンスをアップキャストできないのはなぜですか?