I am developing a maps application which will display a user defined
driving itinerary.
I obtain the driving directions from the Directions Web Service and parse
the json response in a separate thread.
I then hand the resulting itinerary object to my custom overlay for display.
Before appending the overlay to the maps overlay list, I decode the
polyline strings to obtain the coordinates.
My drawing code obtains the projection object and draws out the line - this
is taking 18 seconds ! ! !
Here is my code :
@Override
public void draw(Canvas cv, MapView view, boolean shadow)
{
GeoCoordsE6 point = null; // utility class holding a geopoint and
a point class with a method to handle projection manipulation
int iScreenWidth = view.getWidth();
int iScreenHeight = view.getHeight();
Paint paintLine = null;new Paint();
if(shadow)
{
super.draw(cv, view, shadow);
return;
}
long lStartMs = android.os.SystemClock.uptimeMillis();
paintLine = new Paint();
paintLine.setColor(m_iLineClr);
paintLine.setAntiAlias(true);
paintLine.setStyle(Paint.Style.FILL_AND_STROKE);
paintLine.setStrokeJoin(Paint.Join.ROUND);
paintLine.setStrokeCap(Paint.Cap.ROUND);
paintLine.setStrokeWidth(4);
// get the projection to work with
Projection pj = view.getProjection();
// get the first lat/lng position
point = m_ItinLine.item(0);
// convert the coorinates to screen pixels
point.ResolvePosition(pj);
// store the start position
m_ptStart.x = point.m_pt.x;
m_ptStart.y = point.m_pt.y;
// now walk through the array list
for(int i = 1; i < m_ItinLine.count(); i++)
{
point = m_ItinLine.item(i);
point.ResolvePosition(pj);
m_ptEnd.x = point.m_pt.x;
m_ptEnd.y = point.m_pt.y;
if(m_ptStart.x < 0 && m_ptEnd.x < 0 || // to the left
m_ptStart.y < 0 && m_ptEnd.y < 0 || // above the top
m_ptStart.x > iScreenWidth && m_ptEnd.x > iScreenWidth
|| // to the right
m_ptStart.y > iScreenHeight && m_ptEnd.y >
iScreenHeight) // below the bottom
{
// ignore the drawing
}
else if(m_ptStart.x == m_ptEnd.x && m_ptStart.y == m_ptEnd.y)
continue;
else
{
cv.drawLine(m_ptStart.x, m_ptStart.y, m_ptEnd.x, m_ptEnd.y,
paintLine);
}
m_ptStart.x = m_ptEnd.x;
m_ptStart.y = m_ptEnd.y;
}
long lEndMs = android.os.SystemClock.uptimeMillis();
Log.d("ItineraryOverlay", "Drawing took " + (lEndMs - lStartMs) +
"ms");
super.draw(cv, view, shadow);
}
Knowing that a number of people have done similar tasks, can anyone advise
me as to how to improve the performance ?
Should I be building a path object and fill it with ALL of the points ?
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