此代码正在使用 Google API(第8级)。
当我更新OverlayItem以使用Canvas自定义drawable时 对象似乎在错误的位置绘制像素。在这 例如,我正试图在路易斯安那州画一个圆圈。查看时 整个地图圆圈从地图上绘制出来。当你放大到新的 奥尔良,你会看到圆圈接近适当的纬度和 经度。热点似乎在正确的位置,没有 圆圈被绘制的地方。
如果在draw方法中,canvas恢复方法被称为circle 画在正确的位置。
此外,如果未使用自定义drawable,则会在中绘制图标 正确的位置(不使用Canvas“恢复”)。
以下是显示此行为的代码。我尝试添加“setBounds” 和“boundCenterBottom”,因为其他人似乎表明了这一点 解决了他们的“错位”问题。虽然 说实话,我不确定为什么需要这些电话。
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public class MapsActivity extends MapActivity
{
/** Called when the activity is first created. */
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
MapView mapView = (MapView) findViewById(R.id.mapView);
mapView.setBuiltInZoomControls(true);
// Itemized Overlay
List<Overlay> mapOverlays = mapView.getOverlays();
Drawable defaultIcon =
this.getResources().getDrawable(R.drawable.icon);
MyItemizedOverlay itemizedoverlay = new
MyItemizedOverlay(defaultIcon, this);
// Overlay Item
GeoPoint pt = new GeoPoint(30000000, -90000000);
OverlayItem item = new OverlayItem(pt,"New Orleans",
"Louisiana");
// Custom Drawable
CustomDrawable customDrawable = new CustomDrawable(pt,
mapView);
boolean showProblem = true;
if (showProblem)
{
item.setMarker(customDrawable);
}
else
{
item.setMarker(defaultIcon);
}
// Add item we want to overlay
itemizedoverlay.addOverlay(item);
// Add overlay
mapOverlays.add(itemizedoverlay);
}
protected boolean isRouteDisplayed()
{
return false;
}
}
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public class MyItemizedOverlay extends ItemizedOverlay<OverlayItem>
{
private ArrayList<OverlayItem> mOverlays = new
ArrayList<OverlayItem>();
private Context mContext;
public MyItemizedOverlay(Drawable defaultMarker, Context context)
{
super(boundCenterBottom(defaultMarker));
mContext = context;
}
public void addOverlay(OverlayItem item)
{
mOverlays.add(item);
populate();
}
public void removeOverlay(OverlayItem item)
{
mOverlays.remove(item);
}
public void removeOverlay(int item)
{
mOverlays.remove(item);
}
protected OverlayItem createItem(int i)
{
OverlayItem item = mOverlays.get(i);
Drawable drawable = item.getMarker(0);
if (drawable != null)
{
int w = drawable.getIntrinsicWidth();
int h = drawable.getIntrinsicHeight();
drawable.setBounds(0, 0, w, h);
item.setMarker(boundCenterBottom(drawable));
}
return item;
}
public void draw(android.graphics.Canvas canvas, MapView mapView,
boolean shadow)
{
if (shadow)
return;
super.draw(canvas, mapView, shadow);
}
public int size()
{
return mOverlays.size();
}
protected boolean onTap(int index)
{
OverlayItem item = mOverlays.get(index);
AlertDialog.Builder dialog = new
AlertDialog.Builder(mContext);
dialog.setTitle(item.getTitle());
dialog.setMessage(item.getSnippet());
dialog.show();
return true;
}
}
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public class CustomDrawable extends ShapeDrawable
{
private int radius = 10;
private GeoPoint point = null;
private MapView mapView = null;
public CustomDrawable(GeoPoint point, MapView mapView)
{
this.point = point;
this.mapView = mapView;
}
public void draw(Canvas canvas)
{
// TODO This (somewhat) fixes projection problem?
//canvas.restore();
Projection projection = mapView.getProjection();
Point pt = projection.toPixels(point, null);
canvas.drawCircle(pt.x, pt.y, radius,
getPaint());
}
public int getIntrinsicHeight()
{
return 2 * radius;
}
public int getIntrinsicWidth()
{
return 2 * radius;
}
}
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答案 0 :(得分:1)
您的CustomDrawable
不应该相对于地图进行自我定位。它应该只是在其范围内绘制,而不是引用MapView
或其Projection
。 ItemizedOverlay
负责为Drawable
定位OverlayItem
。