本文介绍了如何做一个标签主机切换标签时，我清楚所有的点和标记路线的地图的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我创建了一个使用谷歌地图来获取用户当前位置，并绘制路线的应用程序。最近我转换这个程序为TabHost与五个选项卡。正因为如此我现在需要一种方法来清除并重新启动，每当用户点击该选项卡上的地图。我怎样才能做到这一点。下面是layout.xml和活动code为地图。
activity_map_view.xml
＆LT;？XML版本=1.0编码=UTF-8＆GT？;
＆LT; LinearLayout中的xmlns：机器人=http://schemas.android.com/apk/res/android
机器人：layout_width =match_parent
机器人：layout_height =match_parent
机器人：方向=垂直＆GT;
＆LT;按钮
机器人：ID =@ + ID / BTN_DRAW
机器人：layout_width =FILL_PARENT
机器人：layout_height =WRAP_CONTENT
机器人：文字=获取路线
机器人：layout_alignParentBottom =真
机器人：layout_centerHorizontal =真/＆GT; ＆LT; RelativeLayout的
机器人：layout_width =FILL_PARENT
机器人：layout_height =WRAP_CONTENT
机器人：方向=横向＆GT; ＆LT;按钮
机器人：ID =@ + ID / btn_find
机器人：layout_width =WRAP_CONTENT
机器人：layout_height =WRAP_CONTENT
机器人：文字=@字符串/ str_btn_find
机器人：layout_alignParentRight =真/＆GT; ＆LT;的EditText
机器人：ID =@ + ID / et_location
机器人：layout_width =FILL_PARENT
机器人：layout_height =WRAP_CONTENT
安卓的inputType =TEXT
机器人：提示=@字符串/ hnt_et_location
机器人：layout_toLeftOf =@ ID / btn_find/＆GT; ＆LT; / RelativeLayout的＆GT; ＆LT;片段
机器人：ID =@ + ID /图
机器人：layout_width =match_parent
机器人：layout_height =match_parent
类=com.google.android.gms.maps.SupportMapFragment/＆GT;
＆LT; / LinearLayout中＆GT;
和下面是我的就是我的上创建MapviewActivity.java方法
@覆盖
保护无效的onCreate（捆绑savedInstanceState）{
super.onCreate（savedInstanceState）;
markerList =新的ArrayList＆LT;标志物GT;（）; 如果（EvacRouteTableActivity.evacRouteStr！= NULL）{
fuelStopBundle = EvacRouteTableActivity.evacRouteStr;
evacName = EvacRouteTableActivity.evacRouteStr; }否则如果（FuelStopActivity.type！= NULL）{
fuelStopBundle = FuelStopActivity.type;
shelorfuelAddress = FuelStopActivity.type;
}否则如果（ShelterActivity.type！= NULL）{
fuelStopBundle = ShelterActivity.type;
shelorfuelAddress = ShelterActivity.type;
}
//列表＆LT; EvacRoute＆GT; evacRouteList =新的ArrayList＆LT; EvacRoute＆GT;（DALController.sharedInstance（）getAllEvacRoutes（））;
LM =（的LocationManager）getSystemService（Context.LOCATION_SERVICE）;
清单＆LT; FuelStop＆GT; fuelStopList =新的ArrayList＆LT; FuelStop＆GT;（）;
清单＆LT;＆住房GT; shelterList =新的ArrayList＆LT;＆住房GT;（）;
最终布尔isGPS = lm.isProviderEnabled（LocationManager.GPS_PROVIDER）;
的setContentView（R.layout.activity_map_view）;
MapAsyncClass AC =新MapAsyncClass（MapViewActivity.this）;
ac.execute（）;
按钮btn_find =（按钮）findViewById（R.id.btn_find）;
btn_directions =（按钮）findViewById（R.id.btn_draw）;
//获取参考btn_find布局activity_main的 最终的EditText etLocation =（EditText上）findViewById（R.id.et_location）;
如果（isGPS）{
btn_find.setVisibility（View.GONE）;
etLocation.setVisibility（View.GONE）;
}其他{
btn_find.setVisibility（View.VISIBLE）; etLocation.setVisibility（View.VISIBLE）;
btn_directions.setVisibility（View.GONE）;
}
// shelorfuelAddress = fuelStopBundle.getString（钥匙）;
/ **
*这将确保，如果用户选择了
* / 如果（fuelStopBundle = NULL＆放大器;！＆安培;！evacName = NULL）{ // showCurrentLocationOnMap（）;
//定义按钮点击事件侦听器查找按钮
findClickListener =新OnClickListener（）{
@覆盖
公共无效的onClick（视图v）{ //获取用户输入的位置
。字符串位置= etLocation.getText（）的toString（）;
如果（位置= NULL＆放大器;！＆安培;！location.equals（））{
currentLocation = getLocationFromAddress（位置）; AsyncTask的＆LT;弦乐，太虚，列表与LT;地址＆gt;＆GT;执行=新的地缘coderTask（）执行（位置）。
字符串latStr =将String.valueOf（纬度）;
字符串LongStr中=将String.valueOf（经度）; 尝试{
。evacRoute = DALController.sharedInstance（）getEvacuationRoutewithoutgps（evacName，currentLocation，latStr，LongStr中）;
}赶上（ClientProtocolException E）{
// TODO自动生成catch块
e.printStackTrace（）;
}赶上（的URISyntaxException E）{
// TODO自动生成catch块
e.printStackTrace（）;
}赶上（IOException异常五）{
// TODO自动生成catch块
e.printStackTrace（）;
}赶上（的ParserConfigurationException E）{
// TODO自动生成catch块
e.printStackTrace（）;
}赶上（SAXException的E）{
// TODO自动生成catch块
e.printStackTrace（）;
}
showEvacuationRoute（evacRoute）;
}
}
};
}
showCurrentLocationOnMap（）; 如果（isGPS）{
//定义按钮点击事件侦听器查找按钮
OnClickListener directionsClickListener =新OnClickListener（）{
@覆盖
公共无效的onClick（视图v）{
如果（shelorfuelAddress！= NULL）{
意向意图=新意图（android.content.Intent.ACTION_VIEW，
Uri.parse(\"http://maps.google.com/maps?saddr=<\"+latitude+\">,<\"+longitude+\">&daddr=<\"+currentFuelLat+\">,<\"+currentFuellong+\">\"));
startActivity（意向）;
}其他{
经纬度destLatLng = DALController.sharedInstance（）getDestPoint（）。
双latDouble = destLatLng.latitude;
双longDouble = destLatLng.longitude;
意向意图=新意图（android.content.Intent.ACTION_VIEW，
Uri.parse(\"http://maps.google.com/maps?saddr=<\"+latitude+\">,<\"+longitude+\">&daddr=<\"+latDouble+\">,<\"+longDouble+\">\"));
startActivity（意向）;
}
}
};
btn_directions.setOnClickListener（directionsClickListener）;
} btn_find.setOnClickListener（findClickListener）; / **
*这确保当用户点击的MapView从在MainActivity
*这10收容所十加油点会在地图上显示
* /
如果（shelorfuelAddress == NULL和放大器;＆安培; isGPS）{
//设置按钮点击事件侦听器查找按钮
btn_find.setOnClickListener（findClickListener）;
fuelStopList = DALController.sharedInstance（）getAllFuelStops（）。
shelterList = DALController.sharedInstance（）getAllShelters（）。
如果（fuelStopList == NULL）{ }其他{
对于（FuelStop fuelStop：fuelStopList）{
尝试{
ShowFuelStop（fuelStop.getAddress（））;
}赶上（IOException异常五）{
e.printStackTrace（）;
}
}
} 对于（住房住所：shelterList）{ 尝试{
ShowShelters（shelter.getAddress（））;
}赶上（IOException异常五）{
e.printStackTrace（）;
}
} } mMenu =新CustomMenu（这个，这个，getLayoutInflater（））;
mMenu.setHideOnSelect（真）;
mMenu.setItemsPerLineInPortraitOrientation（4）;
mMenu.setItemsPerLineInLandscapeOrientation（8）;
//加载菜单项
loadMenuItems（）;
}
解决方案
我发现随着时间的map.clear（）的工作，但在这里得到重新添加到地图中，因为使用一些全局变量的对象我需要。因此，我不得不做一个map.clear（）在onResume（），然后做一些对象释放。一旦我这样做，它的工作，居然重新分配与垃圾回收在地图上帮作为Java有收集仍然有一个参考项问题的对象。请参见下面code。
@覆盖
公共无效onResume（）{
super.onResume（）;
如果（图！= NULL）{
onCreateCalled + = 1;
如果（onCreateCalled＆GT; = 3）{
如果（fuelPolyLine！= NULL）{
fuelPolyLine.remove（）;
fuelPolyLine = NULL;
fuelSto prectLine = NULL;
}
如果（shelterPolyLine！= NULL）{
shelterPolyLine.remove（）;
shelterPolyLine = NULL;
shelterRectLine = NULL;
}
如果（evacPolyLine！= NULL）{
evacPolyLine.remove（）;
evacPolyLine = NULL;
evacRouteRectLine = NULL;
}
map.clear（）;
currentLocation = NULL;
地图= NULL;
的MarkerOptions = NULL;
evacRoute = NULL;
LM = NULL;
LL = NULL;
MF = NULL;
setupMap（）; }
}
}
I created an App that uses Google Maps to get the users current location and draw routes. Recently I converted this app to a TabHost with five tabs. Because of this I now need a way to clear and restart the map whenever a user clicks on that tab. How can I do this. Below is the layout.xml and activity code for my map.
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>
And below is my is my on create method for MapviewActivity.java
@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();
}
解决方案
I found with time the the map.clear() was working but objects where getting re added to the map because of the use of some of the global variables that I needed. So I had to do a map.clear() on the onResume() then do some object deallocation. Once I did this it worked, and actually deallocating the objects helped with garbage collection on the map as java has problems collecting items that still have a reference. See Code below.
@Override
public void onResume(){
super.onResume();
if (map != null){
onCreateCalled += 1;
if (onCreateCalled >=3){
if (fuelPolyLine != null){
fuelPolyLine.remove();
fuelPolyLine = null;
fuelStoprectLine = null;
}
if (shelterPolyLine != null){
shelterPolyLine.remove();
shelterPolyLine = null;
shelterRectLine = null;
}
if (evacPolyLine != null){
evacPolyLine.remove();
evacPolyLine = null;
evacRouteRectLine = null;
}
map.clear();
currentLocation = null;
map = null;
markerOptions = null;
evacRoute = null;
lm = null;
ll = null;
mf = null;
setupMap();
}
}
}
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