首次尝试时文件无法保存

Question

当我第一次运行我的应用程序时，没有创建文件，但是当我再次调用该方法时，它可以正常工作。

这是我打电话刷新的时候：

List<Product> prod = new Select().from(Product.class).queryList();
for (Product products:prod){
    ImageCache  imageCache = new ImageCache();
    Log.i("product", products.getProductDescr());
    imageCache.setProductName(products.getProductName());
    Picasso.with(this)
           .load(products.getProductImage())
           .into(imageCache.getTarget());
}

这是我用方法调用的类：

public class ImageCache {

public  String productName;

public void setProductName(String productName) {
    this.productName = productName;
}

public String getProductName() {
    return productName;
}

public Target getTarget() {
    return target;
}

public void setTarget(Target target) {
    this.target = target;
}

public  Target target = new Target() {
    @Override
    public void onBitmapLoaded(final Bitmap bitmap, Picasso.LoadedFrom from) {
        new Thread(new Runnable() {
            @Override
            public void run() {



                File file = new File(Environment.getExternalStorageDirectory().getPath() +"/Thesis/" +productName+ ".jpg");
                try
                {
                    file.createNewFile();
                    FileOutputStream ostream = new FileOutputStream(file);
                    bitmap.compress(Bitmap.CompressFormat.JPEG, 75, ostream);
                    ostream.close();
                }
                catch (Exception e)
                {
                    e.printStackTrace();
                }

            }
        }).start();
    }
    @Override
    public void onBitmapFailed(Drawable errorDrawable) {
    }

    @Override
    public void onPrepareLoad(Drawable placeHolderDrawable) {
        if (placeHolderDrawable != null) {
        }
    }
};}

解： 创建目标时必须保留强引用以避免垃圾回收。这将通过此示例

成功完成

public class MyClass {
   private Target mTarget = new Target() {...};

  public void getPointMarkerFromUrl(final String url, final OnBitmapDescriptorRetrievedListener listener) {

     Picasso.with(context)
     .load(url)
     .resize(maxSize, maxSize)
     .into(mTarget);
   }
}