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我发现GC在我的地图活动中频繁释放内存,我无法找出原因,当地图开始构建标题时发生这种情况,即当我们滑动地图时。最终,由于内存超出限制的异常,活动停止强制退出。该活动指出存储在数组列表中的各个位置的地理点。图像封闭显示这一点。Android MapView中内存使用率高的原因
public class DetailMapTab extends MapActivity{
private MapView map=null;
private MyLocationOverlay me=null;
private SitesOverlay sites=null;
String placename;
int position;
String lat;
String lon;
ArrayList<HashMap<String, String>> mylist =new ArrayList<HashMap<String, String>>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mapdetail);
//position -> is the selected record of the list
//mylist -> contains record sets to display like name , lat and lon of various location
placename=mylist.get(position).get("Name");
lat=mylist.get(position).get("Latitude");
lon=mylist.get(position).get("Longitude");
map=(MapView)findViewById(R.id.map);
map.getController().setCenter(getPoint(Double.valueOf(lat),Double.valueOf(lon)));
map.getController().setZoom(17);
map.setBuiltInZoomControls(true);
sites=new SitesOverlay();
map.getOverlays().add(sites);
me=new MyLocationOverlay(this, map);
map.getOverlays().add(me);
}//oncreate
@Override
public void onResume() {
super.onResume();
me.enableCompass();
}
@Override
public void onPause() {
super.onPause();
me.disableCompass();
}
@Override
protected boolean isRouteDisplayed() {
return(false);
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_S) {
map.setSatellite(!map.isSatellite());
return(true);
}
else if (keyCode == KeyEvent.KEYCODE_Z) {
map.displayZoomControls(true);
return(true);
}
else if (keyCode == KeyEvent.KEYCODE_H) {
return(true);
}
return(super.onKeyDown(keyCode, event));
}
private GeoPoint getPoint(double lat, double lon) {
return(new GeoPoint((int)(lat*1000000.0),(int)(lon*1000000.0)));
}
private class SitesOverlay extends ItemizedOverlay<CustomItem> {
private List<CustomItem> items=new ArrayList<CustomItem>();
public SitesOverlay() {
super(null);
//show selected record geo-point with a new map pin1
items.add(new CustomItem(getPoint(Double.valueOf(lat),Double.valueOf(lon))," ", placename,getMarker(R.drawable.pin1)));
//show the geo-points names with pin2
for(int i=0;i<mylist.size();i++)
{
if(position!=i)
{
items.add(new CustomItem(getPoint(Double.valueOf(mylist.get(i).get("Latitude")),Double.valueOf(mylist.get(i).get("Longitude"))),"",mylist.get(i).get("Name"),getMarker(R.drawable.pin2)));
}
}
}
}
populate();
}
@Override
protected CustomItem createItem(int i) {
return(items.get(i));
}
@Override
public void draw(Canvas canvas, MapView mapView,boolean shadow) {
super.draw(canvas, mapView, shadow);
}
@Override
protected boolean onTap(int i) {
//OverlayItem item=getItem(i);
Toast.makeText(getApplicationContext(),items.get(i).getSnippet(),Toast.LENGTH_SHORT).show();
return(true);
}
@Override
public int size() {
return(items.size());
}
private Drawable getMarker(int resource) {
Drawable marker=getResources().getDrawable(resource);
marker.setBounds(0, 0, marker.getIntrinsicWidth(),marker.getIntrinsicHeight());
boundCenterBottom(marker);
return(marker);
}
}
class CustomItem extends OverlayItem {
Drawable marker=null;
CustomItem(GeoPoint pt, String name, String snippet, Drawable marker) {
super(pt, name, snippet);
this.marker=marker;
}
@Override
public Drawable getMarker(int stateBitset) {
Drawable result= marker;
setState(result, stateBitset);
return(result);
}
}
public void onDestroy(){
super.onDestroy();
map=null;
me=null;
sites=null;
gr=null;
placename=null;
lat=null;
lon=null;
mylist =null;
System.gc();
}
}
我很高兴知道原因。示,当我滑动地图
11-11 15:39:55.072: DEBUG/dalvikvm(222): GC freed 439 objects/83360 bytes in 106ms
11-11 15:39:56.052: DEBUG/dalvikvm(107): GC freed 3568 objects/197464 bytes in 138ms
11-11 15:39:57.451: DEBUG/dalvikvm(222): GC freed 135 objects/41456 bytes in 101ms
11-11 15:39:59.891: DEBUG/dalvikvm(222): GC freed 94 objects/42112 bytes in 134ms
11-11 15:44:27.481: DEBUG/dalvikvm(104): GC freed 7472 objects/406240 bytes in 140ms
我试过没有标签的相同代码,只有5分,但我的自定义OverlayItem类获取不断调用,因为我滑动map.Placing自定义OverlayItem类getMarker方法上的日志语句证明了这一点。任何更好的方式来编写自定义的OverlayItem类? – ganesh 2010-11-12 10:31:57
@ganesh:“但我的自定义OverlayItem类继续调用,因为我滑动地图” - 当然。 “你有没有更好的方法来编写自定义的OverlayItem类?” - 你似乎正在处理我的一个样本,显然需要优化。 :-(getMarker()'方法应该返回预先配置的'Drawables',而不是通过你(和我)每次的代码。我的道歉 - 我的实现适用于四标记地图,但没有比这更多的了,我会在即将到来的更新中修正它。 – CommonsWare 2010-11-12 12:06:57