Solution to the problem of null pointer when converting view to Bitmap on Android

Solution to the problem of null pointer when converting view to Bitmap on Android

When working on Android projects, there may be such a requirement to convert a View or layout file into a Bitmap object.

The methods are actually almost the same. But there are some small details that need to be paid attention to. I have used this function recently in the project. I will share it now. I hope it can help you meet the fruit.

The person with the problem.

First is the code for conversion:

/**
    * Convert View (Layout) to bitmap
    * @param view
    * @return
    */
  public static Bitmap createBitmap(View view){
    (true);
    /**
      * Please note here that when using (0, )
      * When measuring the view, if your layout contains RelativeLayout, the API is 17 or below 17 will contain a null pointer exception
      * Solution:
      * 1 Do not include RelativeLayout in the layout
      * 2 Use (256, ) It seems to be OK
      *
      */
    ((0, ),
        (0, ));
    (0, 0, (), ());
    ();
    Bitmap bitmap = ();
    return bitmap;
  }

The above is the method of converting to Bitmap, but be careful, use it(0, )

When measuring the view, if your layout contains RelativeLayout API is 17 or below 17, it will contain a null pointer exception. Encountering this problem in the project

I don’t know what happened, but I found out later when I looked at the source code. Here is the official explanation of this method:

/**
     * Creates a measure specification based on the supplied size and mode.
     *
     * The mode must always be one of the following:
     * <ul>
     * <li>{@link #UNSPECIFIED}</li>
     * <li>{@link #EXACTLY}</li>
     * <li>{@link #AT_MOST}</li>
     * </ul>
     *
     * <p><strong>Note:</strong> On API level 17 and lower, makeMeasureSpec's
     * implementation was such that the order of arguments did not matter
     * and overflow in either value could impact the resulting MeasureSpec.
     * {@link } was affected by this bug.
     * Apps targeting API levels greater than 17 will get the fixed, more strict
     * behavior.</p>
     *
     * @param size the size of the measure specification
     * @param mode the mode of the measure specification
     * @return the measure specification based on size and mode
     */
    public static int makeMeasureSpec(int size, int mode) {
      if (sUseBrokenMakeMeasureSpec) {
        return size + mode;
      } else {
        return (size & ~MODE_MASK) | (mode & MODE_MASK);
      }
    }

This bug was fixed in systems above API 17. Here are two solutions:

1. Do not include Relativelayout layout in the layout file

2. It seems to be OK with (256, )

The above is the solution to the problem of converting view to Bitmap to Android. If you have any questions, please leave a message or go to the community of this site to communicate and discuss. Thank you for your support for this site!