Display image from URL - sizing and screen orientation problems

问题

I am trying to display an image from a URL, which may be larger than the screen dimensions. I have it kind of working, but I would like it to scale to fit the screen, and I also have problems when the screen orientation changes. The image is tiny, and I would like it to scale its width to the screen as well. (In both cases, I would like the image to fill the screen width with scrollbars (if necessary for height).

Here is my ImageView:

<ImageView android:id="@+id/ImageView01" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content"
    android:scaleType="fitCenter"
    android:adjustViewBounds="true">
</ImageView>

Here is the java code which loads the image: (some error handling code removed for simplicity)

    Object content = null;
    try{
      URL url = new URL("http://farm1.static.flickr.com/150/399390737_7a3d508730_b.jpg");
      content = url.getContent();
    }
      catch(Exception ex)
    {
        ex.printStackTrace();
    }
    InputStream is = (InputStream)content;
    Drawable image = Drawable.createFromStream(is, "src");
    Image01.setImageDrawable(image);

I have tried different settings for android:scaleType. I'm sorry if this question has been asked before. I've gone through a number of tutorials on the subject, but they don't seem to work for me. Not sure if it has anything to do with the way the image is loaded. (from the web instead of a local resource)

Another issue is that sometimes the image doesn't even load. There are no runtime errors, I just get nothing in the ImageView.

Please let me know if you need more information or clarification.

回答1:

the issue about that "sometimes the image doesn't even load" is related to the context so I used this functions to solve that issue

public Object fetch(String address) throws MalformedURLException,
    IOException {
        URL url = new URL(address);
        Object content = url.getContent();
        return content;
    }  

    private Drawable ImageOperations(Context ctx, String url) {
        try {
            InputStream is = (InputStream) this.fetch(url);
            Drawable d = Drawable.createFromStream(is, "src");
            return d;
        } catch (MalformedURLException e) {
            return null;
        } catch (IOException e) {
            return null;
        }
    }

so to fill the screen width with your image you must have a code like this

    try{
        String url = "http://farm1.static.flickr.com/150/399390737_7a3d508730_b.jpg";           
        Drawable image =ImageOperations(this,url);
        Image01.setImageDrawable(image);
    }
    catch(Exception ex)
    {
        ex.printStackTrace();
    }


    Image01.setMinimumWidth(width);
    Image01.setMinimumHeight(height);

    Image01.setMaxWidth(width);
    Image01.setMaxHeight(height);

UPDATE:: if you load a big size image obviously you will have to wait more time, and download problems could be caused for UnknowHostException.

yes you are right you will save your image locally, the local access is faster than the download.

to avoid problems on rotation change set your configChanges="keyboardHidden|orientation" property inside your Manifest.xml

<activity android:name=".myActivity"
...
         android:configChanges="keyboardHidden|orientation"   >
...
/>

来源：https://stackoverflow.com/questions/3601775/display-image-from-url-sizing-and-screen-orientation-problems

标签

android

imageview

screen-orientation