Hardware Acceleration stops working on new APIs

Question

I need to enable hardware acceleration on one of my WebViews. So far, I've found out that if I build my project with a target API of 11 or 13 (Android 3.0 and 3.2, respectively), hardware acceleration gets enabled and everything's fine. But the weird part is that when I build my project with API 17 or 18, all my efforts to turn on hardware acceleration get ignored for some reason.

So far I've tried:

1) Setting android:hardwareAccelerated="true" in my tag in the manifest

2) Same, but for the activity containing the WebView

3) The following code in my Activity's onCreate (before setting content view):

getWindow().setFlags(WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED, WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED);

4) The same, but using getWindow().addFlags(WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED);

In all cases, webView.isHardwareAccelerated() returns false, even when it's working.

Please help, it would be pretty lame to be stuck on API 13 because of this...

Whoever downvoted, could you please explain why? I have no idea what I've done wrong... — npace, Jan 25 '16 at 12:38

Vikram · Accepted Answer · 2013-09-02T09:24:40.627

4

Tested on API 18:

Perform the check by posting a Runnable to the WebView:

WebView webView = (WebView) findViewById(R.id.webview_id);

// Shows: "Is hardware accelerated? false"
// Toast.makeText(YourActivity.this, "Is hardware accelerated? " + 
                                             // webView.isHardwareAccelerated(),
                                                 // Toast.LENGTH_LONG).show();

webView.post(new Runnable() {

    @Override
    public void run() {
        Shows: "Is hardware accelerated? true"
        Toast.makeText(YourActivity.this, "Is hardware accelerated? " + 
                                              webView.isHardwareAccelerated(),
                                                  Toast.LENGTH_LONG).show();

        if (webView.isHardwareAccelerated()) {
            // isAccelerated();
        } else {
            // isNotAccelerated();
        }
    }
});

From resource page on Hardware Acceleration:

Hardware acceleration is enabled by default if your Target API level is >=14, but can also be explicitly enabled.

If the image you are displaying is still pixelated, try setting:

webView.setLayerType(View.LAYER_TYPE_SOFTWARE, null);

and see if pixelation of the image gets better.

Consider reading the resource page on Hardware Acceleration.

edited Sep 02 '13 at 09:24

answered Sep 02 '13 at 07:06

Vikram

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Thanks for the answer. Interestingly enough, if I log webView.isHardwareAccelerated() before posting the runnable, it returns false. Inside the runnable, it returns true. That doesn't help though, because hw acceleration is still clearly off - the image I'm displaying is pixelated. (Note: when building with target API 11 or 13, the image is not pixelated.) I tried setting the window's hw acceleration flags and then invalidating the webView in the runnable, but it still didn't work. – npace Sep 02 '13 at 07:53
1

@npace `because hw acceleration is still clearly off` Actually, no. From resource page on Hardware Acceleration: `Hardware acceleration is enabled by default if your Target API level is >=14, but can also be explicitly enabled.` It's a long shot, but try setting `webView.setLayerType(View.LAYER_TYPE_SOFTWARE, null);` and see if pixelation of the image gets better. – Vikram Sep 02 '13 at 08:05
Wow. That actually worked... I constantly get amazed by Android's little quirks like that, although they make polishing your product a complete pain. Please edit your answer to include that bit about the software layer type so I can accept it, etc. By the way, do you have any idea why setting the layer type to "software" worked? – npace Sep 02 '13 at 08:16
`I constantly get amazed by Android's little quirks like that...` Man, tell me about it. Anyway, I updated my answer. `By the way, do you have any idea why setting the layer type to "software" worked?` I included a link to the resource page on Hardware Acceleration. Take a look at it. One of the sections is `Unsupported Drawing Operations`. I tried looking through android.webkit.webview's source code, but could not find an example that explains why the `long shot` suggestion worked. Sorry about that. – Vikram Sep 02 '13 at 09:33
I can confirm, setting target API to 14 makes the trick, also, isHardwareAccelerated() has to be called in runnable posted to webView. – MartinC Feb 27 '14 at 13:56

Hardware Acceleration stops working on new APIs

1 Answers1