BitmapFactory.decodeStream 无异常返回 null

发布于 2024-10-06 19:02:55 字数 1238 浏览 6 评论 0原文

我尝试从服务器加载远程图像，感谢 stackoverflow 上的大量代码示例，我有了一个可以在 3 个图像中的 2 个中运行的解决方案。我真的不知道第三张图片有什么问题，有时当让代码在调试器中运行时，图片正在加载。另外，如果我先加载问题图片，其他两张图片有时不会加载。

代码如下：

public static Drawable getPictureFromURL(Context ctx, String url, final int REQUIRED_SIZE) throws NullPointerException {
    //Decode image size
    BitmapFactory.Options o = new BitmapFactory.Options();
    int scale = 1;
    if (o.outWidth > REQUIRED_SIZE) {
        scale = (int) Math.pow(2, (int) Math.round(Math.log(REQUIRED_SIZE / (double) Math.max(o.outHeight, o.outWidth)) / Math.log(0.5)));
    }
    Log.i(Prototype.TAG, "scale: "+scale); 

    //Decode with inSampleSize
    BitmapFactory.Options o2 = new BitmapFactory.Options();
    o2.inSampleSize = scale;
    Bitmap bmp;
    try {
        bmp = BitmapFactory.decodeStream((InputStream) Tools.fetch(url), null, o2);
        if(bmp!=null)
            return new BitmapDrawable(ctx.getResources(), bmp);
        else
            return null;
    } catch (Exception e) {
        Log.e(Prototype.TAG, "Exception while decoding stream", e);
        return null;
    }
}

在调试过程中，我发现 o.outWidth 为 -1，这表明存在错误，但没有抛出异常，所以我无法真正判断出了什么问题。 InputStream总是返回一个有效值，我知道该图片存在于服务器上。

最好的祝愿，丹尼尔

原文

I try to load a remote image from a server and thanks to a lot of code examples on stackoverflow I have a solution which works in 2 out of 3 images. I don't really know what the problem is with the third picture and sometimes when letting the code run in the debugger the picture is loading. Also if I load the problem picture first the other two pictures are sometimes not loaded.

Here is the code:

public static Drawable getPictureFromURL(Context ctx, String url, final int REQUIRED_SIZE) throws NullPointerException {
    //Decode image size
    BitmapFactory.Options o = new BitmapFactory.Options();
    int scale = 1;
    if (o.outWidth > REQUIRED_SIZE) {
        scale = (int) Math.pow(2, (int) Math.round(Math.log(REQUIRED_SIZE / (double) Math.max(o.outHeight, o.outWidth)) / Math.log(0.5)));
    }
    Log.i(Prototype.TAG, "scale: "+scale); 

    //Decode with inSampleSize
    BitmapFactory.Options o2 = new BitmapFactory.Options();
    o2.inSampleSize = scale;
    Bitmap bmp;
    try {
        bmp = BitmapFactory.decodeStream((InputStream) Tools.fetch(url), null, o2);
        if(bmp!=null)
            return new BitmapDrawable(ctx.getResources(), bmp);
        else
            return null;
    } catch (Exception e) {
        Log.e(Prototype.TAG, "Exception while decoding stream", e);
        return null;
    }
}

During debugging I found out that o.outWidth is -1 which indicates an error, but no Exception is thrown, so I can't really tell what went wrong. The InputStream always returned a valid value, and I know that the picture exists on the server.

Best wishes,
Daniel

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青衫负雪 2024-10-13 19:02:55

我找到了答案这里并将 fetch 方法更新为：

private static InputStream fetch(String address) throws MalformedURLException,IOException {
    HttpGet httpRequest = new HttpGet(URI.create(address) );
    HttpClient httpclient = new DefaultHttpClient();
    HttpResponse response = (HttpResponse) httpclient.execute(httpRequest);
    HttpEntity entity = response.getEntity();
    BufferedHttpEntity bufHttpEntity = new BufferedHttpEntity(entity);
    InputStream instream = bufHttpEntity.getContent();
    return instream;
}

I found the answer here and updated the fetch method to:

private static InputStream fetch(String address) throws MalformedURLException,IOException {
    HttpGet httpRequest = new HttpGet(URI.create(address) );
    HttpClient httpclient = new DefaultHttpClient();
    HttpResponse response = (HttpResponse) httpclient.execute(httpRequest);
    HttpEntity entity = response.getEntity();
    BufferedHttpEntity bufHttpEntity = new BufferedHttpEntity(entity);
    InputStream instream = bufHttpEntity.getContent();
    return instream;
}

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