private void zoomImageFromThumb(final View thumbView, int imageResId){
// If there's an animation in progress, cancel it
// immediately and proceed with this one.
if (mCurrentAnimator != null) {
mCurrentAnimator.cancel();
}
Drawable expanded_image_background=getResources().getDrawable(R.drawable.background_expanded_image);
// Load the high-resolution "zoomed-in" image.
final ImageView expandedImageView = (ImageView) findViewById(R.id.expanded_image);
expandedImageView.setImageResource(imageResId);
expandedImageView.bringToFront();
// 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;
}
});
}
目前我正在制作动画，我在imageview上有一个图像，如果我点击它，它会被缩小（填入屏幕），然后它会被放大。
我使用 this function 来制作动画。但我也有imageview的背景（可绘制文件夹），我希望它在缩小和缩小时增加（和减少）它的不透明度。我知道我必须使用setAlpha（），但我无法弄清楚它放在哪里。请帮忙......
答案 0 :(得分：0)
如果它被绘制为位图，您可以这样做：
Paint alphaPaint = new Paint();
alphaPaint.setAlpha(ALPHA);
canvas.drawBitmap(bitmap, x, y, alphaPaint);
控制由你决定的Alpha
修改
根据你告诉我的内容：
Paint alphaPaint = new Paint();
alphaPaint.setAlpha(ALPHA);
alphaPaint.setColor(Color.BLACK);
canvas.drawRect(rect, alphaPaint);
答案 1 :(得分：0)
您需要创建两个背景可绘制，一个具有完全不透明度，另一个具有0不透明度，然后您可以使用此代码从一个绘图到另一个绘制动画。
我创建了一个包含两个drawable的drawable数组。
Drawable[] drawables = {ContextCompat.getDrawable(mActivity, R.drawable.firstBackgroundDrawable),ContextCompat.getDrawable(mActivity, R.drawable.secndBackgroundDrawable)};
TransitionDrawable trans = new TransitionDrawable(drawables);
imageID.setBackground(trans);
trans.setCrossFadeEnabled(true);
trans.startTransition(5000);
在startTransition(duration)中，您可以设置动画持续时间。
答案 2 :(得分：0)
your_image_name.animate（）setDuration（300）。阿尔法（0F）;
your_image_name = ImageView，可能是任何东西！ （文字/按钮/布局）
alpha（0f）= f表示浮点数（0 = 0％，1 = 100％）
alpha（0.5f）= 50％alpha
如果你想在放大/缩小的同时更改alpha，那么在你开始放大动画时就这样做了！