Properly reserve display space for non-digits
Bug: 22882700
We did not correctly calculate the extra space we might need to add
a decimal point to a scientific notation results. We also
incorrectly assumed that minus signs are the same width as a
digit. As a workaround we now reserve extra space for the possible
non-digit characters to ensure that a result is never inadvertently
truncated.
Change-Id: I79b499121703cd51bbbf3e1d85b2285a2dd5e025
diff --git a/src/com/android/calculator2/CalculatorResult.java b/src/com/android/calculator2/CalculatorResult.java
index 8d3dfee..1efa67b 100644
--- a/src/com/android/calculator2/CalculatorResult.java
+++ b/src/com/android/calculator2/CalculatorResult.java
@@ -102,7 +102,9 @@
// we switch to scientific notation with positive exponent.
private static final int SCI_NOTATION_EXTRA = 1;
// Extra digits for standard scientific notation. In this case we
- // have a deecimal point and no ellipsis.
+ // have a decimal point and no ellipsis.
+ // We assume that we do not drop digits to make room for the decimal
+ // point in ordinary scientific notation. Thus >= 1.
private ActionMode mActionMode;
private final ForegroundColorSpan mExponentColorSpan;
@@ -180,10 +182,24 @@
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
final TextPaint paint = getPaint();
- final int newWidthConstraint = MeasureSpec.getSize(widthMeasureSpec)
- - (getPaddingLeft() + getPaddingRight())
- - (int) Math.ceil(Layout.getDesiredWidth(KeyMaps.ELLIPSIS, paint));
+ final Context context = getContext();
final float newCharWidth = Layout.getDesiredWidth("\u2007", paint);
+ // Digits are presumed to have no more than newCharWidth.
+ // We sometimes replace a character by an ellipsis or, due to SCI_NOTATION_EXTRA, add
+ // an extra decimal separator beyond the maximum number of characters we normally allow.
+ // Empirically, our minus sign is also slightly wider than a digit, so we have to
+ // account for that. We never have both an ellipsis and two minus signs, and
+ // we assume an ellipsis is no narrower than a minus sign.
+ final float decimalSeparatorWidth = Layout.getDesiredWidth(
+ context.getString(R.string.dec_point), paint);
+ final float minusExtraWidth = Layout.getDesiredWidth(
+ context.getString(R.string.op_sub), paint) - newCharWidth;
+ final float ellipsisExtraWidth = Layout.getDesiredWidth(KeyMaps.ELLIPSIS, paint)
+ - newCharWidth;
+ final int extraWidth = (int) (Math.ceil(Math.max(decimalSeparatorWidth + minusExtraWidth,
+ ellipsisExtraWidth)) + Math.max(minusExtraWidth, 0.0f));
+ final int newWidthConstraint = MeasureSpec.getSize(widthMeasureSpec)
+ - (getPaddingLeft() + getPaddingRight()) - extraWidth;
synchronized(mWidthLock) {
mWidthConstraint = newWidthConstraint;
mCharWidth = newCharWidth;
@@ -474,9 +490,7 @@
// Return something conservatively big, to force sufficient evaluation.
return MAX_WIDTH;
} else {
- // Always allow for the ellipsis character which already accounted for in the width
- // constraint.
- return result + 1;
+ return result;
}
}