code: private void initTextTimeWidth() {
          mTimeTextWidth = 0;
          for (int i = 0; i < 24; i++) {
              // Measure time string and get max width.
              String time = getDateTimeInterpreter().interpretTime(i);
              if (time == null)
                  throw new IllegalStateException("A DateTimeInterpreter must not return null time");
              mTimeTextWidth = Math.max(mTimeTextWidth, mTimeTextPaint.measureText(time));
          }
      }
docs: Initialize time column width. Calculate value with all possible hours (supposed widest text).