Bitmap from TextView (getDrawingCache) always null

Question

I am trying to extract the bitmap associated to the displayed TextView instance, but it always returns a null value. What Am I doing wrong? Should I use textview.draw(canvas) instead?

    TextView textview = (TextView) findViewById(R.id.text_title);
    textview.setDrawingCacheEnabled(true);
    textview.buildDrawingCache();        
    Bitmap bmp = textview.getDrawingCache();

This will work - http://stackoverflow.com/questions/11560882/call-to-getdrawingcache-fails-on-api-8-everytime — Ron, Jul 19 '12 at 18:45
@userSeven7s it will work only when we give a value for _width_ and _height_ attributes only. If we use attribute value like **wrap_content**, that is not working. — AnujAroshA, Sep 07 '12 at 03:46
@AnujAroshA No. My view too was `wrap_content`ed. You should get the view's height and width after its inflated. Where do you do it? I recommend the `onFinishInflate()` or later in the activity life cycle. — Ron, Sep 07 '12 at 04:49

score 12 · Accepted Answer · edited Jan 29 '20 at 08:16

12

Do this before getting drawing cache it will solve the problem

view.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), 
            MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());

and then getDrawingCache() will return a bitmap and draw that bitmap on your canvas.

and if you are using bitmaps in your app prefer to clear them from memory by calling recycle() method on them so that bitmap get cleared from the memory for your safe side to avoid outOfMemoryException

edited Jan 29 '20 at 08:16

shb

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answered Jan 13 '12 at 08:42

varun bhardwaj

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This worked for me. Can you explain the reason for this? – aysonje Jan 30 '14 at 13:46
@aysonje this is simulating the rendering pass on the view. – Nathan Schwermann Apr 14 '14 at 18:05

score 7 · Answer 2 · edited May 23 '17 at 11:45

7

Android has a maximum drawing cache size. If the drawing cache would be bigger than that, getDrawingCache() returns null. See the answer to this question.

You can find a workaround in the answer to this question.

edited May 23 '17 at 11:45

Community

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answered Jul 14 '11 at 19:08

Ellen Spertus

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score 1 · Answer 3 · edited Sep 19 '11 at 19:26

1

view.getDrawingCache();

should be:

textview.getDrawingCache();

edited Sep 19 '11 at 19:26

CoolBeans

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answered Apr 06 '11 at 13:02

user694790

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Of course, my mistake while writing the post. Anyway, it's still the same question, with a null value (and not a NullPointerException) – randomuser Apr 06 '11 at 13:15

Bitmap from TextView (getDrawingCache) always null

3 Answers3

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