私はこれを数日間解決しようとしましたが、役に立ちませんでした。Xamarin.Android 用の ImageZoom 関数を作成しようとしています。次に、Xamarin.iOS 用の ImageZoom 関数の作成に移ります。
私がやっているのは、ここにある Android のサンプル コードです: https://developer.android.com/training/animation/zoom.html
関連するコードもここに含めます。
Class ImageZoom
{
int mShortAnimationDuration;
private Animator mCurrentAnimator;
private void zoomImageFromThumb(final View thumbView, int imageResId) {
// If there's an animation in progress, cancel it
// immediately and proceed with this one.
mShortAnimationDuration = Android.Resource.Integer.ConfigShortAnimTime;
if (mCurrentAnimator != null) {
mCurrentAnimator.cancel();
}
// Load the high-resolution "zoomed-in" image.
final ImageView expandedImageView = (ImageView) findViewById(
R.id.expanded_image);
expandedImageView.setImageResource(imageResId);
// Calculate the starting and ending bounds for the zoomed-in image.
// This step involves lots of math. Yay, math.
final Rect startBounds = new Rect();
final Rect finalBounds = new Rect();
final Point globalOffset = new Point();
// The start bounds are the global visible rectangle of the thumbnail,
// and the final bounds are the global visible rectangle of the container
// view. Also set the container view's offset as the origin for the
// bounds, since that's the origin for the positioning animation
// properties (X, Y).
thumbView.getGlobalVisibleRect(startBounds);
findViewById(R.id.container)
.getGlobalVisibleRect(finalBounds, globalOffset);
startBounds.offset(-globalOffset.x, -globalOffset.y);
finalBounds.offset(-globalOffset.x, -globalOffset.y);
// Adjust the start bounds to be the same aspect ratio as the final
// bounds using the "center crop" technique. This prevents undesirable
// stretching during the animation. Also calculate the start scaling
// factor (the end scaling factor is always 1.0).
float startScale;
if ((float) finalBounds.width() / finalBounds.height()
> (float) startBounds.width() / startBounds.height()) {
// Extend start bounds horizontally
startScale = (float) startBounds.height() / finalBounds.height();
float startWidth = startScale * finalBounds.width();
float deltaWidth = (startWidth - startBounds.width()) / 2;
startBounds.left -= deltaWidth;
startBounds.right += deltaWidth;
} else {
// Extend start bounds vertically
startScale = (float) startBounds.width() / finalBounds.width();
float startHeight = startScale * finalBounds.height();
float deltaHeight = (startHeight - startBounds.height()) / 2;
startBounds.top -= deltaHeight;
startBounds.bottom += deltaHeight;
}
// Hide the thumbnail and show the zoomed-in view. When the animation
// begins, it will position the zoomed-in view in the place of the
// thumbnail.
thumbView.setAlpha(0f);
expandedImageView.setVisibility(View.VISIBLE);
// Set the pivot point for SCALE_X and SCALE_Y transformations
// to the top-left corner of the zoomed-in view (the default
// is the center of the view).
expandedImageView.setPivotX(0f);
expandedImageView.setPivotY(0f);
// Construct and run the parallel animation of the four translation and
// scale properties (X, Y, SCALE_X, and SCALE_Y).
AnimatorSet set = new AnimatorSet();
set
.play(ObjectAnimator.ofFloat(expandedImageView, View.X,
startBounds.left, finalBounds.left))
.with(ObjectAnimator.ofFloat(expandedImageView, View.Y,
startBounds.top, finalBounds.top))
.with(ObjectAnimator.ofFloat(expandedImageView, View.SCALE_X,
startScale, 1f)).with(ObjectAnimator.ofFloat(expandedImageView,
View.SCALE_Y, startScale, 1f));
set.setDuration(mShortAnimationDuration);
set.setInterpolator(new DecelerateInterpolator());
set.addListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
mCurrentAnimator = null;
}
@Override
public void onAnimationCancel(Animator animation) {
mCurrentAnimator = null;
}
});
set.start();
mCurrentAnimator = set;
// Upon clicking the zoomed-in image, it should zoom back down
// to the original bounds and show the thumbnail instead of
// the expanded image.
final float startScaleFinal = startScale;
expandedImageView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (mCurrentAnimator != null) {
mCurrentAnimator.cancel();
}
// Animate the four positioning/sizing properties in parallel,
// back to their original values.
AnimatorSet set = new AnimatorSet();
set.play(ObjectAnimator
.ofFloat(expandedImageView, View.X, startBounds.left))
.with(ObjectAnimator
.ofFloat(expandedImageView,
View.Y,startBounds.top))
.with(ObjectAnimator
.ofFloat(expandedImageView,
View.SCALE_X, startScaleFinal))
.with(ObjectAnimator
.ofFloat(expandedImageView,
View.SCALE_Y, startScaleFinal));
set.setDuration(mShortAnimationDuration);
set.setInterpolator(new DecelerateInterpolator());
set.addListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
thumbView.setAlpha(1f);
expandedImageView.setVisibility(View.GONE);
mCurrentAnimator = null;
}
@Override
public void onAnimationCancel(Animator animation) {
thumbView.setAlpha(1f);
expandedImageView.setVisibility(View.GONE);
mCurrentAnimator = null;
}
});
set.start();
mCurrentAnimator = set;
}
});
}
}
文字と単語の大文字化を変更し、Rect() を処理することは問題ありません。私が抱えている主な問題は、C# で 2 つの Java Animator Listener を実装することです。
set.addListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
mCurrentAnimator = null;
}
@Override
public void onAnimationCancel(Animator animation) {
mCurrentAnimator = null;
}
});
&
set.addListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
thumbView.setAlpha(1f);
expandedImageView.setVisibility(View.GONE);
mCurrentAnimator = null;
}
@Override
public void onAnimationCancel(Animator animation) {
thumbView.setAlpha(1f);
expandedImageView.setVisibility(View.GONE);
mCurrentAnimator = null;
}
});
上記により、次のエラーが発生します。
抽象クラスまたはインターフェイス「AnimatorListener」のインスタンスを作成できません
上記のエラーが発生する理由は理解していますが、Java と同じ効果を得るために C# でオーバーライドされたメソッドの一部だけを使用して 2 つの AnimatorListenerAdapter を実際に実装する方法がわかりません。コード例を含む回答は大歓迎です!