我创建了一个使用谷歌地图获取用户当前位置并绘制路线的应用程序。最近我将此应用程序转换为具有五个选项卡的 TabHost。因此，我现在需要一种在用户单击该选项卡时清除并重新启动地图的方法。我怎样才能做到这一点。下面是我的地图的 layout.xml 和活动代码。
activity_map_view.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<Button
android:id="@+id/btn_draw"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text=" Get Directions"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true" />
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<Button
android:id="@+id/btn_find"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/str_btn_find"
android:layout_alignParentRight="true" />
<EditText
android:id="@+id/et_location"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:inputType="text"
android:hint="@string/hnt_et_location"
android:layout_toLeftOf="@id/btn_find" />
</RelativeLayout>
<fragment
android:id="@+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"
class="com.google.android.gms.maps.SupportMapFragment"/>
</LinearLayout>
下面是我的 MapviewActivity.java 的创建方法
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
markerList = new ArrayList<Marker>();
if (EvacRouteTableActivity.evacRouteStr !=null){
fuelStopBundle = EvacRouteTableActivity.evacRouteStr;
evacName = EvacRouteTableActivity.evacRouteStr;
} else if (FuelStopActivity.type != null){
fuelStopBundle = FuelStopActivity.type;
shelorfuelAddress = FuelStopActivity.type;
} else if (ShelterActivity.type != null){
fuelStopBundle = ShelterActivity.type;
shelorfuelAddress = ShelterActivity.type;
}
//List<EvacRoute> evacRouteList = new ArrayList<EvacRoute>(DALController.sharedInstance().getAllEvacRoutes());
lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
List<FuelStop> fuelStopList = new ArrayList<FuelStop>();
List<Shelter> shelterList = new ArrayList<Shelter>();
final boolean isGPS = lm.isProviderEnabled(LocationManager.GPS_PROVIDER);
setContentView(R.layout.activity_map_view);
MapAsyncClass ac = new MapAsyncClass(MapViewActivity.this);
ac.execute();
Button btn_find = (Button) findViewById(R.id.btn_find);
btn_directions = (Button) findViewById(R.id.btn_draw);
// Getting reference to btn_find of the layout activity_main
final EditText etLocation = (EditText) findViewById(R.id.et_location);
if (isGPS){
btn_find.setVisibility(View.GONE);
etLocation.setVisibility(View.GONE);
} else {
btn_find.setVisibility(View.VISIBLE);
etLocation.setVisibility(View.VISIBLE);
btn_directions.setVisibility(View.GONE);
}
//shelorfuelAddress = fuelStopBundle.getString("key");
/**
* This will make sure that if the user selects the
*/
if (fuelStopBundle != null && evacName != null){
//showCurrentLocationOnMap();
// Defining button click event listener for the find button
findClickListener = new OnClickListener() {
@Override
public void onClick(View v) {
// Getting user input location
String location = etLocation.getText().toString();
if(location!=null && !location.equals("")){
currentLocation = getLocationFromAddress(location);
AsyncTask<String, Void, List<Address>> execute = new GeocoderTask().execute(location);
String latStr = String.valueOf(latitude);
String longStr = String.valueOf(longitude);
try {
evacRoute = DALController.sharedInstance().getEvacuationRoutewithoutgps(evacName, currentLocation, latStr, longStr);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (URISyntaxException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ParserConfigurationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SAXException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
showEvacuationRoute(evacRoute);
}
}
};
}
showCurrentLocationOnMap();
if (isGPS){
// Defining button click event listener for the find button
OnClickListener directionsClickListener = new OnClickListener() {
@Override
public void onClick(View v) {
if (shelorfuelAddress!=null){
Intent intent = new Intent(android.content.Intent.ACTION_VIEW,
Uri.parse("http://maps.google.com/maps?saddr=<"+latitude+">,<"+longitude+">&daddr=<"+currentFuelLat+">,<"+currentFuellong+">"));
startActivity(intent);
} else {
LatLng destLatLng = DALController.sharedInstance().getDestPoint();
Double latDouble = destLatLng.latitude;
Double longDouble = destLatLng.longitude;
Intent intent = new Intent(android.content.Intent.ACTION_VIEW,
Uri.parse("http://maps.google.com/maps?saddr=<"+latitude+">,<"+longitude+">&daddr=<"+latDouble+">,<"+longDouble+">"));
startActivity(intent);
}
}
};
btn_directions.setOnClickListener(directionsClickListener);
}
btn_find.setOnClickListener(findClickListener);
/**
* this ensures that if the user clicked on the Mapview from the MainActivity
* that ten shelters and ten fueling points will show on the map
*/
if (shelorfuelAddress==null && isGPS){
// Setting button click event listener for the find button
btn_find.setOnClickListener(findClickListener);
fuelStopList = DALController.sharedInstance().getAllFuelStops();
shelterList = DALController.sharedInstance().getAllShelters();
if (fuelStopList == null){
} else {
for (FuelStop fuelStop : fuelStopList){
try {
ShowFuelStop(fuelStop.getAddress());
} catch (IOException e) {
e.printStackTrace();
}
}
}
for (Shelter shelter : shelterList){
try {
ShowShelters(shelter.getAddress());
} catch (IOException e) {
e.printStackTrace();
}
}
}
mMenu = new CustomMenu(this, this, getLayoutInflater());
mMenu.setHideOnSelect(true);
mMenu.setItemsPerLineInPortraitOrientation(4);
mMenu.setItemsPerLineInLandscapeOrientation(8);
//load the menu items
loadMenuItems();
}