support for multiline paragraph style indentation

This change is likely incomplete and perhaps not right in other ways.
The gist of the change is that the span can return the number of lines
to which to apply the "leading margin".
Some specific things that should be looked at:

1) if the user has nested multiple
LeadingMarginSpans then they will inherit the "line count" feature.
This is wrong but I didn't want to spend time fixing it until it
was clear that this overall approach was acceptible.

2) The units for how many lines should indented is "lines" rather than
something like dips.

3) I wasn't sure what our strategy was for binary compatibility so
I didn't want to modify the methods in LeadingMarginSpan.  Instead I
made another interface with extends LeadingMarginSpan that has the
extra method to return the line count.

1 files changed, 13 insertions, 2 deletions

diff --git a/core/java/android/text/Layout.java b/core/java/android/text/Layout.java
index a92800d011ee..afc686401656 100644
--- a/core/java/android/text/Layout.java
+++ b/core/java/android/text/Layout.java
@@ -294,7 +294,12 @@ public abstract class Layout {
                                                      lbaseline, lbottom, buf,
                                                      start, end, par, this);
 
-                            left += margin.getLeadingMargin(par);
+                            boolean useMargin = par;
+                            if (margin instanceof LeadingMarginSpan.LeadingMarginSpan2) {
+                                int count = ((LeadingMarginSpan.LeadingMarginSpan2)margin).getLeadingMarginLineCount();
+                                useMargin = count > i;
+                            }
+                            left += margin.getLeadingMargin(useMargin);
                         }
                     }
                 }
@@ -1293,7 +1298,13 @@ public abstract class Layout {
                                                         LeadingMarginSpan.class);
 
                 for (int i = 0; i < spans.length; i++) {
-                    left += spans[i].getLeadingMargin(par);
+                    boolean margin = par;
+                    LeadingMarginSpan span = spans[i];
+                    if (span instanceof LeadingMarginSpan.LeadingMarginSpan2) {
+                        int count = ((LeadingMarginSpan.LeadingMarginSpan2)span).getLeadingMarginLineCount();
+                        margin = count >= line;
+                    }
+                    left += span.getLeadingMargin(margin);
                 }
             }
         }