加载图像时淡入动画使用毕加索

我想在Imageview上加载图像时显示淡入淡出效果.我正在使用毕加索来缓存图像并在图像视图中显示.我已经搜索了很多,但无法找到任何解决方案.

我之前使用过,我知道在某些版本中他们有.fade(int Duration)方法在加载时淡化图像,但我再也找不到这个方法了.

这就是我现在正在做的事情

Picasso.with(context)
                .load(viewHolder.data.imageList.get(0).url)
                .networkPolicy(NetworkPolicy.OFFLINE)
                .placeholder(R.drawable.a_place_holder_list_view)
                .error(R.drawable.a_place_holder_list_view)
                .into(viewHolder.ivUser, context.loadImage(viewHolder.ivUser, viewHolder.data.imageList.get(0).url));


public Callback loadImage(RoundedImageView ivUser, String url) {
    return new callback(ivUser, url);
}

public class callback implements Callback {

    RoundedImageView imageView;
    String url;

    public callback(RoundedImageView imageView, String url) {
        this.imageView = imageView;
        this.url = url;
    }

    @Override
    public void onSuccess() {

    }

    @Override
    public void onError() {
        Picasso.with(BaseActivity.this)
                .load(url)
                .placeholder(R.drawable.a_place_holder_list_view)
                .error(R.drawable.a_place_holder_list_view)
                .into(imageView, new Callback() {
                    @Override
                    public void onSuccess() {

                    }

                    @Override
                    public void onError() {
                        Log.v("Picasso", "Could not fetch image");
                    }
                });
    }
}

请帮助我,我已经被困在这很长一段时间了.提前致谢.

引用杰克沃顿商学院的答案在这里:

如果图像来自除内存缓存之外的任何位置,则应自动应用淡入淡出.

如果你检查PicassoDrawable班级

boolean fade = loadedFrom != MEMORY && !noFade;
if (fade) {
  this.placeholder = placeholder;
  animating = true;
  startTimeMillis = SystemClock.uptimeMillis();
}
.
.
.
@Override public void draw(Canvas canvas) {
if (!animating) {
  super.draw(canvas);
} else {
.
.
.

fade effect 已经应用于从n/w而不是内存/缓存加载的图像 FADE_DURATION = 200f; //ms

要强制褪色,再次引用杰克沃顿的答案在这里:

您可以指定noFade(),然后始终在图像加载的回调中播放动画.您还可以依赖同步调用的回调来确定是否需要播放动画.

final AtomicBoolean playAnimation = new AtomicBoolean(true);
Picasso.with(context).load(..).into(imageView, new Callback() {
  @Override public void onLoad() {
    if (playAnimation.get()) {
      //play fade
      Animation fadeOut = new AlphaAnimation(0, 1);
      fadeOut.setInterpolator(new AccelerateInterpolator());
      fadeOut.setDuration(1000);
      imageView.startAnimation(fadeOut);

      Animation fadeOutPlaceholder = new AlphaAnimation(1, 0);
      fadeOutPlaceholder.setInterpolator(new AccelerateInterpolator());
      fadeOutPlaceholder.setDuration(1000);
      placeHolderImageView.startAnimation(fadeOutPlaceholder);
    }
  }
  //..
});
playAnimation.set(false);