ViewPager + Picasso + URL字符串数组中的多个图像

Question

请帮我。 我正在使用Chris Banes的示例PhotoView（ https://github.com/chrisbanes/PhotoView ）中的示例ViewPagerActivity，我想使用Picasso URL图像更改可绘制对象。 因此，我试图通过URL的Picasso String数组在HackyViewPager中放入多个图像。

我的xml ViewPager：

<my.package.HackyViewPager
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/view_pager"
android:layout_width="match_parent"
android:layout_height="200dp" />

在onCreate中：

...      
ViewPager viewPager = (HackyViewPager) findViewById(R.id.view_pager);
viewPager.setAdapter(new SamplePagerAdapter());

我有一个从单个String stringDefinitionGemstonesPhoto获取的URL的String数组

String[] strAry = stringDefinitionGemstonesPhoto.split(",");

而SamplePageAdapter中的最终代码是：

static class SamplePagerAdapter extends PagerAdapter {

    private String stringDefinitionGemstonesPhoto = ("https://geology.com/minerals/photos/calcite-marble-127.jpg, https://geology.com/minerals/photos/calcite-concrete.jpg");
    private  String[] strAry = stringDefinitionGemstonesPhoto.split(",");


    @Override
    public int getCount() {
        return strAry.length;
    }

    @Override
    public View instantiateItem(ViewGroup container, int position) {
        PhotoView photoView = new PhotoView(container.getContext());

        System.out.println(strAry[position]);
        Picasso.get().load(strAry[position]).into(photoView);

        container.addView(photoView, ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
        return photoView;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        container.removeView((View) object);
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == object;
    }

}

当我滑动时，仅显示一张图像，下一张照片为空白。 在日志系统中，打印出正确分割的链接。 怎么了？

Answer 1

我发现有问题，那就是

for(int i= 0; i < numbers.length; i++){
                System.out.println(strAry[i]);
                System.out.println(strAry[position]);
                Picasso.get().load(strAry[position]).into(photoView);
            }

应该

            System.out.println(strAry[position]);
            Picasso.get().load(strAry[position]).into(photoView);

UPDATE

我发现了一个问题，即Picasso或Glide在instantiateItem()不能很好地工作， 请参阅更多

因此，我的解决方案不再使用上述lib，我们尝试手动请求url，由于性能问题，这种方法并不是更好，但它确实有效。

这是我的解决方案

class SamplePagerAdapter extends PagerAdapter {

    private String stringDefinitionGemstonesPhoto = ("https://geology.com/minerals/photos/calcite-marble-127.jpg, https://geology.com/minerals/photos/calcite-concrete.jpg");
    private String[] strAry = stringDefinitionGemstonesPhoto.split(",");


    @Override
    public int getCount() {
        return strAry.length;
    }

    @NonNull
    @Override
    public Object instantiateItem(@NonNull ViewGroup container, int position) {
        PhotoView photoView = new PhotoView(container.getContext());
        try {
            new DownloadImageTask(photoView)
                    .execute(strAry[position]);
        } catch (Exception ex) {
            Log.e("Error", ex.getMessage());
        }

        container.addView(photoView, ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
        return photoView;
    }

    @Override
    public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
        container.removeView((View) object);
    }

    @Override
    public boolean isViewFromObject(@NonNull View view, @NonNull Object object) {
        return view == object;
    }

    public class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
        private ImageView bmImage;

        DownloadImageTask(ImageView bmImage) {
            this.bmImage = bmImage;
        }

        protected Bitmap doInBackground(String... urls) {
            String urlDisplay = urls[0];
            Bitmap myImage = null;
            try {
                InputStream in = new java.net.URL(urlDisplay).openStream();
                myImage = BitmapFactory.decodeStream(in);
            } catch (Exception e) {
                Log.e("Error", e.getMessage());
                e.printStackTrace();
            }
            return myImage;
        }

        protected void onPostExecute(Bitmap result) {
            bmImage.setImageBitmap(result);
        }
    }
}

Answer 2

无需单独使用数字数组，更新适配器类

static class SamplePagerAdapter extends PagerAdapter {

    private static String[] strAry = stringDefinitionGemstonesPhoto.split(",");


    @Override
    public int getCount() {
        return strAry.length;
    }

    @Override
    public View instantiateItem(ViewGroup container, int position) {
        PhotoView photoView = new PhotoView(container.getContext());

            System.out.println(strAry[position]);
            Picasso.get().load(strAry[position]).into(photoView);

        container.addView(photoView, ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
        return photoView;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        container.removeView((View) object);
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == object;
    }

}