NullPointerException on bitmap.getPixels()

Question

Can someone help me? I keep getting this NullPointerException error.

03-23 22:50:43.519: E/AndroidRuntime(1978): java.lang.NullPointerException
03-23 22:50:43.519: E/AndroidRuntime(1978):     at         android.graphics.Bitmap.checkPixelsAccess(Bitmap.java:1365)
03-23 22:50:43.519: E/AndroidRuntime(1978):     at  android.graphics.Bitmap.getPixels(Bitmap.java:1310)
03-23 22:50:43.519: E/AndroidRuntime(1978):     at com.example.ocrtry.Entry2.downSample(Entry2.java:227)
03-23 22:50:43.519: E/AndroidRuntime(1978):     at com.example.ocrtry.MainActivity$1.onClick(MainActivity.java:42)

I tried putting a try and catch statement at downSample and i dont even get an output. Here is the code for downSample

public void downSample()
{
  int w = bmInput.getWidth();
  int h = bmInput.getHeight();
  int[] pixels = null;
  bmInput.getPixels(pixels, 0, w, 0, 0, w, h);
  pixelMap = (int[])pixels;
  findBounds(w, h);

  SampleData data = sample.getData();

  ratioX = (double) (downSampleRight - downSampleLeft)
  / (double) data.getWidth();
  ratioY = (double) (downSampleBottom - downSampleTop)
  / (double) data.getHeight();

  for (int y = 0; y < data.getHeight(); y++)
  {
     for (int x = 0; x < data.getWidth(); x++)
     {
     if (downSampleQuadrant(x, y))
       data.setData(x, y, true);
     else
       data.setData(x, y, false);
     }
 }
}

Jerry101 · Accepted Answer · 2014-03-24 03:37:13Z

3

The problem is downSample() calls

bmInput.getPixels(pixels, 0, w, 0, 0, w, h);

with a null pixels array.

You need to allocate the array, and make it a suitable size.

int[] pixels = new int[w * h];

How you can debug a case like this: The stack trace shows the problem detected within Bitmap.getPixels() called from downSample(). That means the relevant line of your code is where it calls getPixels() (you can also tell by the line number Entry2.java:227 in the stack trace). If bmInput was null it would throw a NPE trying to call a getPixels() method. (Actually, it would've thrown a NPE on the first line of the method, trying to call bmInput.getWidth().) So pixels is the only remaining value that could be null. Then looking one line earlier in the code, it sets bmInput to null.

edited Mar 24, 2014 at 3:37

answered Mar 24, 2014 at 3:29

Jerry101

13.7k7 gold badges51 silver badges68 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

NullPointerException on bitmap.getPixels()

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related