回调怪异的行为（Android版，毕加索库） [英] Callback weird behaviour (Android, Picasso library)

问题描述

我使用的毕加索库来管理我的图片上传和缓存。当我试图执行此code：

I am using Picasso library to manage my image uploading and caching. When I am trying to execute this code:

    Picasso.with(this)
        .load(AppServer.getImageUrl() + "/" + eventInfo.getImageName())
        .placeholder(R.drawable.calendar)
        .error(R.drawable.calendar)
        .into(new Target()
        {

            @Override
            public void onPrepareLoad(Drawable drawable) 
            {
            }

            @Override
            public void onBitmapLoaded(Bitmap photo, Picasso.LoadedFrom from)
            {
                cropImage(photo); //not getting here
            }

            @Override
            public void onBitmapFailed(Drawable arg0) 
            {
            }
        });  

我并不是进入的int onBitmapLoaded 回调。只有当我关闭（回去）的活动，并重新打开它，我看到的图像（进入 onBitmapLoaded ）。

I am not entering int the onBitmapLoaded callback. Only if I close the activity (going back) and re opening it I see the image (entering into onBitmapLoaded).

但是，如果我将只是增加一些吐司消息到上prepareLoad 回调每一件事工作正常。这里是满code：

But if I will change my code by just adding some Toast message into the onPrepareLoad callback every thing works fine. here is the full code:

    Picasso.with(this)
        .load(AppServer.getImageUrl() + "/" + eventInfo.getImageName())
        .placeholder(R.drawable.calendar)
        .error(R.drawable.calendar)
        .into(new Target()
        {

            @Override
            public void onPrepareLoad(Drawable drawable) 
            {
                Toast.makeText(thisActivity, "message", Toast.LENGTH_LONG).show();
            }

            @Override
            public void onBitmapLoaded(Bitmap photo, Picasso.LoadedFrom from)
            {
                cropImage(photo);
            }

            @Override
            public void onBitmapFailed(Drawable arg0) 
            {
            }
        });

为什么吐司使得它的工作？有什么错呢？

Why the Toast makes it work? what is wrong with it?

推荐答案

我声明了一个目标实例作为类成员解决的问题。然后初始化它。像这样的：

I solved the issue by declaring a Target instance as class member. then initialised it. Like this:

    target = new Target()
    {

        @Override
        public void onPrepareLoad(Drawable drawable) 
        {
        }

        @Override
        public void onBitmapLoaded(Bitmap photo, Picasso.LoadedFrom from)
        {
            cropEventImage(photo);
        }

        @Override
        public void onBitmapFailed(Drawable arg0) 
        {
        }
    };

    Picasso.with(this)
        .load(AppServer.getImageUrl() + "/" + eventInfo.getImageName())
        .placeholder(R.drawable.calendar)
        .error(R.drawable.calendar)
        .into(target);

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