Android 将view 转换为Bitmap出现空指针问题解决办法

/**   * 将View(布局) 转换为bitmap   * @param view   * @return   */  public static Bitmap createBitmap(View view){    view.setDrawingCacheEnabled(true);    /**     * 这里要注意，在用View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED)     * 来测量view 的时候,（如果你的布局中包含有 RelativeLayout ）API 为17 或者 低于17 会包空指针异常     * 解决方法:     * 1 布局中不要包含RelativeLayout     * 2 用 View.MeasureSpec.makeMeasureSpec(256, View.MeasureSpec.EXACTLY) 好像也可以     *     */    view.measure(View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED),        View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));    view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());    view.buildDrawingCache();    Bitmap bitmap = view.getDrawingCache();    return bitmap;  }

/**     * Creates a measure specification based on the supplied size and mode.     *     * The mode must always be one of the following:     * <ul>     * <li>{@link android.view.View.MeasureSpec#UNSPECIFIED}</li>     * <li>{@link android.view.View.MeasureSpec#EXACTLY}</li>     * <li>{@link android.view.View.MeasureSpec#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 android.widget.RelativeLayout} 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);      }    }