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问题:

I am working on Android. Trying to display the "favicon" (aka "shortcut icon") or web pages.

So I already have the code to get the URL of this icon from any website, and download it onto my Android.

Now I am trying to make a Bitmap out of it, but always get null as a result.

The code:

String src = String.format("file:///data/data/com.intuitiveui.android/files/%s",prefName);
// prefName is "facebook.ico", and I do see tht file in my DDMS file browser. It's
// a valid icon file.

Bitmap res = BitmapFactory.decodeFile(src);
// This returns null

TIA

回答1:

Here is a list of the supported Android media formats. ICO is not among them. You might be able to find a Java-based ICO decoder, though.

回答2:

SKIA library provides decoder class for ICO file. I was able to display an ICO file in the emulator. Haven't tried it yet in an actual android device though.

Bitmap bmap = BitmapFactory.decodeFile("/sdcard/vlc.ico");

回答3:

I had a similar problem. BitmapFactory.decode decoded *.ico on emulator but not on my Galaxy S. Solution for me was:

                ByteArrayOutputStream bos = new ByteArrayOutputStream();
                int read=0;
                while((read = inputStream.read()) != -1){
                     bos.write(read);
                }

                byte[] ba = bos.toByteArray(); 
                Bitmap icon = BitmapFactory.decodeByteArray(ba, 0, ba.length);//new FlushedInputStream(inputStream));

回答4:

The WebView component has a getFavicon() method so it's definitely possible to decode ICO files in Android. You could have a look at the Android source to see how ICO files are parsed. I've had a quick look but can't find the relevant part.

Alternatively, you should be use the SDK to get favicons for you. However, I've had a quick try and can't get it to work.

For what it's worth here's my test code, noting again that this doesn't work:

    String url = "http://stackoverflow.com";
    WebView wv = new WebView(this);
    wv.setWebViewClient(new WebViewClient() {
        @Override
        public void onPageFinished(WebView view, String url) {
            Log.i("HelloAndroid","Loaded " + url);              
            Log.i("HelloAndroid","Icon " + (view.getFavicon() == null ? "not" : "") + " found");
        }

    });
    WebIconDatabase wid = WebIconDatabase.getInstance();
    wid.requestIconForPageUrl(url, new WebIconDatabase.IconListener() {
        public void onReceivedIcon(String url, Bitmap icon) {
            Log.i("HelloAndroid","Found Icon for " + url);
        }
    });
    wv.loadUrl("http://stackoverflow.com");
    Log.i("HelloAndroid","Loading " + url);

The problem may be down to the fact that I'm not adding the WebView to a visible View. If you do get this to work I'd be interested to hear what you did.

So sorry for giving two half complete answers, but I thought it was worth posting what I found.

回答5:

No accepted answer util now, I will share my findings here.

Windows .ico file format is a little complicated, it might contains one or more small images at multiple sizes and color depths, such that they may be scaled appropriately. Refer ICO_(file_format)

So when using unix "file" command to check the icon file type, you might get the following result:

a.ico : MS Windows icon resource - 1 icon, 32x32
b.ico : MS Windows icon resource - 9 icons, 256x256

Note a.ico and b.ico contains different number of icons.

I tried to use BitmapFactory.decodeFile to decode these icons.

Two Android devices with Android 4.3 can only decode a.ico, but can not decode b.ico.
Devices with Android 4.4 or later can decode both a.ico and b.ico.

As I only have limited Android devices, I can't give any conclusion. Maybe anyone else could help.

So if you really want to decode .ico files, you may try: