Android webview takes screenshot only from top of the page

问题

I am doing a very simple task of taking a screenshot from my webView into a Bitmap... I do it like this:

webView.setDrawingCacheEnabled(true);
Bitmap bitmap = Bitmap.createBitmap(webView.getDrawingCache(false));
webView.setDrawingCacheEnabled(false);
Canvas canvas = new Canvas(bitmap);
webView.draw(canvas);

The problem is that the final bitmap is always showing the top of my web page content! I actually need it to take the screenshot from where I have scrolled the content but this is not simply happening! I have been searching the net for two hours now but no one else seems to have a similar problem. any idea what could have gone wrong?

回答1:

I guess, this is on Lollipop? If so, make sure you call WebView.enableSlowWholeDocumentDraw() (doc) before your first call to setContentView() that inflates a layout with WebView.

回答2:

I came across the same problem and solved it the follwoing way:

First call WebView.enableSlowWholeDocumentDraw() before setContentView(). Then take the screenshot over the whole content of the webview and then crop the bitmap to the actual view size with the desired scroll offset:

// the minimum bitmap height needs to be the view height
int bitmapHeight = (webView.getMeasuredHeight() < webView.getContentHeight())
         ? webView.getContentHeight() : webView.getMeasuredHeight();

Bitmap bitmap = Bitmap.createBitmap(
         webView.getMeasuredWidth(), bitmapHeight, Bitmap.Config.ARGB_8888);

Canvas canvas = new Canvas(bitmap);
webView.draw(canvas);

// prevent IllegalArgumentException for createBitmap: 
// y + height must be <= bitmap.height()
int scrollOffset = (scrollTo + webView.getMeasuredHeight() > bitmap.getHeight())
         ? bitmap.getHeight() : scrollTo;

Bitmap resized = Bitmap.createBitmap(
         bitmap, 0, scrollOffset, bitmap.getWidth(), webView.getMeasuredHeight());

来源：https://stackoverflow.com/questions/31295237/android-webview-takes-screenshot-only-from-top-of-the-page