在我的Android应用程序中，我在溢出菜单上给出了事件选项，在事件选项上加载了地图，但是当我按下后退按钮时，应用程序不幸停止了。我也发布了代码nad logcat。
AlertActivity.java
public class Alert_activity extends Activity implements
OnItemSelectedListener{
Spinner s1,s2;
TextView t1;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_alert_activity);
getActionBar().setDisplayHomeAsUpEnabled(true);
s1 = (Spinner)findViewById(R.id.spinner1);
s2 = (Spinner)findViewById(R.id.spinner2);
s1.setOnItemSelectedListener(this);
}
@Override
public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
// TODO Auto-generated method stub
String sp1= String.valueOf(s1.getSelectedItem());
// Toast.makeText(this, sp1, Toast.LENGTH_SHORT).show();
if(sp1.contentEquals("Events")) {
List<String> list = new ArrayList<String>();
list.add("Heavy Rain(mm/hr)");
list.add("Smoke/Fog");
list.add("Heat/Cold Wave");
list.add("Strong Winds");
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,R.layout.simple_spinner_item, list);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
dataAdapter.notifyDataSetChanged();
s2.setAdapter(dataAdapter);
s2.setOnItemSelectedListener(new OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> adapter, View v,
int position, long id) {
// On selecting a spinner item
String item = adapter.getItemAtPosition(position).toString();
Log.d("Inside loop","inside loop");
// Showing selected spinner item
//Toast.makeText(getApplicationContext(),
// "You have selected : " + item, Toast.LENGTH_LONG).show();
Log.d("Item",item);
FragmentTransaction tx = getFragmentManager()
.beginTransaction();
if(item=="Heavy Rain(mm/hr)")
{
tx.replace(android.R.id.content, new heavyrain());
/*Intent in = new Intent(getApplicationContext(),
MainActivity1.class);
startActivityForResult(in, 100);*/
}
else if(item=="Smoke/Fog")
{
tx.replace(android.R.id.content, new smoke_fog());
}
else if(item=="Heat/Cold Wave")
{
tx.replace(android.R.id.content, new smoke_fog());
}
else if(item=="Strong Winds")
{
tx.replace(android.R.id.content, new smoke_fog());
}
tx.commit();
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
});
}
if(sp1.contentEquals("Forecast")) {
List<String> list = new ArrayList<String>();
list.add("Cyclone");
ArrayAdapter<String> dataAdapter2 = new ArrayAdapter<String>(this,
R.layout.simple_spinner_item, list);
dataAdapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
dataAdapter2.notifyDataSetChanged();
s2.setAdapter(dataAdapter2);
s2.setOnItemSelectedListener(new OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> adapter, View v,
int position, long id) {
// On selecting a spinner item
String item = adapter.getItemAtPosition(position).toString();
Log.d("Inside loop","inside loop");
// Showing selected spinner item
//Toast.makeText(getApplicationContext(),
// "You have selected : " + item, Toast.LENGTH_LONG).show();
Log.d("Item",item);
FragmentTransaction tx = getFragmentManager()
.beginTransaction();
if(item=="Cyclone")
{
tx.replace(android.R.id.content, new Cyclone());
/*Intent in = new Intent(getApplicationContext(),
MapActivity.class);
startActivityForResult(in, 100);*/
}
/* else if(item=="Heavy Rain")
{
tx.replace(android.R.id.content, new forecast_heavyrain());
}
else if(item=="Cloudburst")
{
tx.replace(android.R.id.content, new forecast_cloudburst());
}*/
tx.commit();
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
});
}
if(sp1.contentEquals("Nowcast")) {
List<String> list = new ArrayList<String>();
list.add("Heavy Rain");
list.add("Cloudburst");
ArrayAdapter<String> dataAdapter2 = new ArrayAdapter<String>(this,
R.layout.simple_spinner_item, list);
dataAdapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
dataAdapter2.notifyDataSetChanged();
s2.setAdapter(dataAdapter2);
s2.setOnItemSelectedListener(new OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> adapter, View v,
int position, long id) {
// On selecting a spinner item
String item = adapter.getItemAtPosition(position).toString();
Log.d("Inside loop","inside loop");
// Showing selected spinner item
//Toast.makeText(getApplicationContext(),
// "You have selected : " + item, Toast.LENGTH_LONG).show();
Log.d("Item",item);
FragmentTransaction tx = getFragmentManager()
.beginTransaction();
if(item=="Heavy Rain")
{
tx.replace(android.R.id.content, new forecast_heavyrain());
/*Intent in = new Intent(getApplicationContext(),
MainActivity1.class);
startActivityForResult(in, 100);*/
}
else if(item=="Cloudburst")
{
tx.replace(android.R.id.content, new forecast_cloudburst());
/*Intent in = new Intent(getApplicationContext(),
MainActivity1.class);
startActivityForResult(in, 100);*/
}
tx.commit();
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
});
}
private GoogleMap googleMap;
PolylineOptions polylineOptions=new PolylineOptions();
ArrayList<LatLng> points = new ArrayList<LatLng>();
String lat12[] = {"30.5","31.0","31.2","31.8","30.65"};
String long12[] = {"79.9","78.1","78.0","78.8","78.8"};
String time11[]={"6AUG2014 20:45GMT","6AUG2014 20:45GMT","6AUG2014 20:45GMT","6AUG2014 20:45GMT","6AUG2014 22:45GMT"};
TextView rain;
TextView rain_lat;
TextView rain_long;
String[] time=new String[100];
String[] date=new String[100];
String[] rain_lat1=new String[100];
String[] rain_long1=new String[100];
String[] rad_inf1=new String[100];
ArrayList high_rain = new ArrayList();
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View root = (LinearLayout) inflater.inflate(R.layout.forecast_heavyrain, container,false);
initilizeMap();
return root;
}
private void initilizeMap()
{
arrayPoints = new ArrayList<LatLng>();
MapFragment fm = (MapFragment) getFragmentManager().findFragmentById(
R.id.fragment4);
googleMap = fm.getMap();
googleMap.setMyLocationEnabled(true);
googleMap.setOnMapClickListener(this);
googleMap.setOnMapLongClickListener(this);
ArrayList<NameValuePair> params = new ArrayList<NameValuePair>();
JSONParser jsonParser = new JSONParser();
params.add(new BasicNameValuePair("LAT", "LAT"));
params.add(new BasicNameValuePair("LONGITUDE", "LONG"));
Log.d("params", params.toString());
// getting weather details by making HTTP request
// Note that weather details url will use GET request
JSONObject json = jsonParser.makeHttpRequest(url_Weather_details1,
"GET", params);
// check your log for json response
Log.d("Weather Details", json.toString());
// json success tag
int success = 0;
try {
success = json.getInt(TAG_SUCCESS);
}
catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if (success == 1) {
// successfully received weather details
JSONArray stationObj = null;
try {
stationObj = json.getJSONArray(TAG_WEATHER);
// JSON Array
int lengthJsonArr = stationObj.length();
Log.d("length",String.valueOf(lengthJsonArr));
for (int i = 0; i < lengthJsonArr; i++)
//for (int i = 0; i < lat12.length; i++)
{
station = stationObj.getJSONObject(i);
/*String time1=station.getString(TAG_time);
time[i]=time1;*/
String lat1=station.getString(TAG_rain_lat);
rain_lat1[i]=lat1;
String long1=station.getString(TAG_rain_long);
rain_long1[i]=long1;
String date_nowcast=station.getString(TAG_date);
date[i]=date_nowcast;
String time_nowcast=station.getString(TAG_time);
time[i]=time_nowcast;
String rad_inf=station.getString(TAG_rad_inf);
rad_inf1[i]=rad_inf;
}
// Log.d("Length",String.valueOf(time.length));
int i;
for ( i = 0; i < lengthJsonArr; i++)
{
//for(i=0; i<time11.length;i++)
//{
//Log.d("high rain size",String.valueOf(highest_rain.length));
//double high_rain2=Double.parseDouble(time[i]);
double lat2=Double.parseDouble(rain_lat1[i]);
Log.d("Latitude===>",String.valueOf(lat2));
double long2=Double.parseDouble(rain_long1[i]);
Log.d("Longitude===>",String.valueOf(long2));
Log.d("time_nowcast==>",time[i]);
Log.d("Date_nowcast==>",date[i]);
Log.d("Radius of influence==>",rad_inf1[i]);
/*t1=(TextView)getView().findViewById(R.id.rain11);
t1.setText(String.valueOf(high_rain2));*/
// double lat2=Double.parseDouble(lat12[i]);
// Log.d("Latitude===>",String.valueOf(lat2));
/// double long2=Double.parseDouble(long12[i]);
// Log.d("Longitude===>",String.valueOf(long2));
//double high_rain2=Double.parseDouble(time11[i]);
// Log.d("time===>",String.valueOf(time11[i]));
LatLng position = new LatLng(lat2, long2);
CameraPosition cameraPosition;// = new CameraPosition(latLng, 0, 0, 0);
cameraPosition = CameraPosition.fromLatLngZoom(position, (float) 14.0);
Marker marker = googleMap.addMarker(new MarkerOptions().position(new LatLng(lat2, long2)) .title(" Forecast Date: "+date[i]+" Forecast Time:"+ time[i]).snippet(" Radius of Influence:"+rad_inf1[i]+" kms").icon(BitmapDescriptorFactory.fromResource(R.drawable.heavy_rain11)));
points.add(position);
// Log.d("i inside for loop",String.valueOf(i));
}
/* polylineOptions.addAll(points);
polylineOptions.color(Color.RED);
polylineOptions.width(7);
polylineOptions.width(7);
googleMap.addPolyline(polylineOptions);*/
}
catch (Exception e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
else if(success==2)
{
Log.d("success 2","success 2");
}
else if(success==3)
{
Log.d("success 3","success 3");
}
}
@Override
public void onMapLongClick(LatLng arg0) {
// TODO Auto-generated method stub
}
@Override
public void onMapClick(LatLng arg0) {
// TODO Auto-generated method stub
}
public void onDestroyView()
{
super.onDestroyView();
Fragment fragment = (getFragmentManager().findFragmentById(R.id.fragment4));
FragmentTransaction ft = getActivity().getFragmentManager().beginTransaction();
ft.remove(fragment);
ft.commit();
super.onDestroy();
}
@Override
public void onDetach() {
super.onDetach();
try {
Field childFragmentManager = Fragment.class.getDeclaredField("mChildFragmentManager");
childFragmentManager.setAccessible(true);
childFragmentManager.set(this, null);
} catch (NoSuchFieldException e) {
throw new RuntimeException(e);
} catch (IllegalAccessException e) {
throw new RuntimeException(e);
}
}
}
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.items, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
super.onOptionsItemSelected(item);
switch(item.getItemId()){
case R.id.exit:
android.os.Process.killProcess(android.os.Process.myPid());
System.exit(1);
case R.id.Feedback:
LocationFound();
return true;
case R.id.Events:
Alert();
return true;
case android.R.id.home:
finish();
}
return true;
}
private void LocationFound() {
Intent in = new Intent(getApplicationContext(),Feedback.class);
startActivityForResult(in, 100);
}
private void Alert() {
Intent in = new Intent(getApplicationContext(),Alert_activity.class);
startActivityForResult(in, 100);
}
@Override
public void onBackPressed() { //here I capture the event onBackPress
super.onBackPressed();
onStop(); //call onStop
}
}
logcat的
02-01 08:27:22.651: E/AndroidRuntime(12401): FATAL EXCEPTION: main
02-01 08:27:22.651: E/AndroidRuntime(12401): Process: com.example.gpstracking, PID: 12401
02-01 08:27:22.651: E/AndroidRuntime(12401): java.lang.RuntimeException: Unable to destroy activity {com.example.gpstracking/com.example.gpstracking.Alert_activity}: java.lang.IllegalStateException: Activity has been destroyed
02-01 08:27:22.651: E/AndroidRuntime(12401): at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3515)
02-01 08:27:22.651: E/AndroidRuntime(12401): at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3533)
02-01 08:27:22.651: E/AndroidRuntime(12401): at android.app.ActivityThread.access$1400
答案 0 :(得分：0)
尝试在onBackPressed（）方法中使用此代码，而不是调用onStop（）：
@Override
public void onBackPressed(){
moveTaskToBack(true);
}
希望这会有所帮助!!