问题
i m maikng an app using Maps. I m drawing circle on a specific point using itemized overlay and it works pretty fine. But i want to change the radius of that circle with the seekbar progress value. Can any body guide me to this Thanks in advance.
回答1:
To Draw the Circle with on map We have to use itemozied Overlay But to change it with the Progress of Seek Bar We need to do the Following thing that will work with Seek Bar and also if you want to set the zoom level using seek bar It is handled in the following code Snippet
Note: I have used seek bar with min value of 0 and max value of 9
public void seekBarProgressEvent()
{
seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
}
@Override
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
// TODO Auto-generated method stub
mapView.getOverlays().clear();
if(progress==0)
{
zoomLevel=17f;
}
else if(progress==1)
{
zoomLevel=16f;
}
else if(progress==2)
{
zoomLevel=15f;
}
else if(progress==3)
{
zoomLevel=14f;
}
else if(progress==4)
{
zoomLevel=14f;
}
else if(progress==5)
{
zoomLevel=13.50f;
}
else if(progress==6)
{
zoomLevel=13.10f;
}
else if(progress==7)
{
zoomLevel=12.85f;
}
else if(progress==8)
{
zoomLevel=12.10f;
}
else if(progress==9)
{
zoomLevel=11.85f;
}
//intent.putExtra("radius", radius);
//zoomLevel-=seekBar.getProgress();
Log.i("ZoomLevel", ""+zoomLevel);
mapView.getController().setZoom((int)zoomLevel);
Drawable drawable = getApplicationContext().getResources().getDrawable(R.drawable.mapmarker);
// in Itemized overlay i m drawing circle of Defined Radius like 100m 200m 300m etc
itemizedoverlay = new FolloowMapOverlay(drawable, getApplicationContext(),(radius));
MapPoint = new GeoPoint((int)(mylat*1E6), (int)(mylon*1E6));
OverlayItem overlayitem = new OverlayItem(MapPoint, "Current Location", "");
currentLocationOverlay = new CurrentLocationOverlay(drawable, getApplicationContext());
currentLocationOverlay.addOverlay(overlayitem);
mapView.getOverlays().add(itemizedoverlay);
mapView.getOverlays().add(currentLocationOverlay);
mapView.invalidate();
mapController.setCenter(MapPoint);
mapController.animateTo(MapPoint);
}
});
}
The following is my Draw Circle method in my itemized overlay class
private void drawCircleAtPoint(GeoPoint point, Canvas canvas, MapView mapView) {
Projection projection = mapView.getProjection();
Point pt2 = new Point();
projection.toPixels(point, pt2);
// method that is used to conver the radius to pixel that takes input the radius and draw it on the coresponding pixels
float circleRadius = projection.metersToEquatorPixels(radius) * (1/ FloatMath.cos((float) Math.toRadians(MapController.mylat)));
Paint circlePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
Paint rectangle=new Paint(Paint.ANTI_ALIAS_FLAG);
Log.d("Circular Radius", ""+circleRadius+" "+radius);
circlePaint.setColor(0x99000000);
circlePaint.setStyle(Style.STROKE);
canvas.drawCircle((float)pt2.x, (float)pt2.y, circleRadius, circlePaint);
}
回答2:
I introduce a good sample and tutorial provided from Google, which is a Android official guide.
First, visit this site in the Google Dev guide.
Second, get the sample code referred to that guide above at HERE in Google Dev guide.
Third, find "PolylineDemoActivity.java" in src/ directory of the sample code above. I think that that is what you want to know.
You can change the radius of the circle using the seekbar progress value~!
For more information, please contact me.
来源：https://stackoverflow.com/questions/14210684/dynamically-change-itemized-overlay-draw-circle-using-seek-bar-progress