android - 在 Fragments 中显示解析的 XML 数据，仅在应用启动和位置更改时解析
问题描述
问候，
我是 android 新手，我正在尝试制作自己的天气应用程序。它可以正常工作，但是如果我在选项卡之间切换，数据会再次被解析，这会导致应用程序在数据加载时冻结。
我希望我的应用程序在第一次启动时解析数据，然后保存数据并在位置已更改或 X 时间已过时再次解析（假设为 20 分钟）
编辑：很清楚，我只需要一些指导来了解如何实现这一目标的正确方向。我应该将数据存储在本地 xml 中而不是直接解析吗？或者还有其他存储解析数据的方法吗？
到目前为止，这是我的代码：
显示数据的选项卡之一
public class Tab2Fragment extends Fragment {
private static final String TAG = "Tab2Fragment";
ArrayList<Dan> dnevi2;
GPSTracker gps;
Postaje postaje;
String[] najblizjaPostaja;
boolean update = true;
TextView[] vNaprej;
TextView[] vNaprej2;
ImageView[] ikone;
int count = 0;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.vreme_napoved,container,false);
postaje = new Postaje();
najblizjaPostaja = postaje.getPostajeNapoved(getContext());
//..
views
..//
napoved();
ShowIt();
setRetainInstance(true);
return view;
}
@Override
public void onResume() {
super.onResume();
setRetainInstance(true);
ShowIt();
if(update) {
napoved();
update = false;
}
}
private void ShowIt(){
for (Dan dan : dnevi2) {
String text = dan.getDatum() + "\n" + dan.getRazmere();
String text2 = dan.getMinTemp() + getString(R.string.celzija) + " / " + dan.getMaxTemp() + getString(R.string.celzija);
vNaprej[count].setText(text);
vNaprej2[count].setText(text2);
ikone[count].setImageResource(dan.getIcon());
count++;
}count=0;
}
private void napoved() {
// 4 DNEVNA NAPOVED-->
XmlPullParserFactory pullParserFactory;
try {
pullParserFactory = XmlPullParserFactory.newInstance();
final XmlPullParser parserVnaprej = pullParserFactory.newPullParser();
final URL urlVnaprej = new URL(najblizjaPostaja[0]);
parserVnaprej.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
Thread threadVnaprej = new Thread(new Runnable() {
@Override
public void run() {
try {
final InputStream insVnaprej = urlVnaprej.openStream();
parserVnaprej.setInput(insVnaprej, null);
dnevi2 = parseVnaprej(parserVnaprej);
insVnaprej.close();
} catch (XmlPullParserException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
});
threadVnaprej.start();
threadVnaprej.join();
//catches
//
public ArrayList<Dan> parseVnaprej(XmlPullParser parserVnaprej) throws XmlPullParserException,IOException
{
ArrayList<Dan> Dan = null;
int eventType = parserVnaprej.getEventType();
Dan dnevi2 = null;
while (eventType != XmlPullParser.END_DOCUMENT){
String name;
switch (eventType){
case XmlPullParser.START_DOCUMENT:
Dan = new ArrayList();
break;
case XmlPullParser.START_TAG:
name = parserVnaprej.getName();
if (name.equals("metData")) {
dnevi2 = new Dan();
} else if (dnevi2 != null) {
if (name.equals("valid_day")) {
dnevi2.setDatum(CETStran(parserVnaprej.nextText()));
} else if (name.equals("tn")) {
dnevi2.setMinTemp(parserVnaprej.nextText());
}else if (name.equals("tx")) {
dnevi2.setMaxTemp(parserVnaprej.nextText());
}else if (name.equals("nn_shortText")) {
String text=parserVnaprej.nextText();
dnevi2.setRazmere(text);
dnevi2.setIcon(Ikona(text));
}else if (name.equals("dd_longText")) {
dnevi2.setVeter(parserVnaprej.nextText());
}
}
break;
case XmlPullParser.END_TAG:
name = parserVnaprej.getName();
if (name.equalsIgnoreCase("metData") && dnevi2 != null){
if (Dan != null) {
Dan.add(dnevi2);
}
}
}
eventType = parserVnaprej.next();
}
return Dan;
}
Postaje（气象站）
public class Postaje {
GPSTracker gps;
Context mContext;
double lat;
double lon;
String postaja;
String[] najblizjaPostaja;
String[] najblizjaPostajaNapoved;
String base = ("http://meteo.arso.gov.si/uploads/probase/www/");
int count;
private boolean asked = false;
double latMin = 0;
double lonMin = 0;
double latMax = 0;
double lonMax = 0;
float[] izid = new float[1];
double testing = 10000000;
public String getPostaja() {
return postaja;
}
public void setPostaja(String postaja) {
this.postaja = postaja;
}
public double getLat() {
return lat;
}
public void setLat(double lat) {
this.lat = lat;
}
public double getLon() {
return lon;
}
public void setLon(double lon) {
this.lon = lon;
}
String[] urlPostajeTrenutno = new String[]{
urls
};
String[] urlPostajeZjutrajPopoldne = new String[]{
urls
};
String[] urlPostajeTriDni = new String[]{
urls
};
String[] urlModelskaNapoved = new String[]{
urls
};
XmlPullParserFactory postajePullParserFactory;
public String[] getPostajeTrenutno(Context context) {
gps = new GPSTracker(context);
najblizjaPostaja = new String[5];
try {
postajePullParserFactory = XmlPullParserFactory.newInstance();
final XmlPullParser parserPostajeTrenutno = postajePullParserFactory.newPullParser();
parserPostajeTrenutno.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
Thread threadVremeTrenutno = new Thread(new Runnable() {
@Override
public void run() {
try {
for (count = 0; count < urlPostajeTrenutno.length; count++) {
final URL postajeTrenutnoURL = new URL(base + urlPostajeTrenutno[count]);
final InputStream trenutno = postajeTrenutnoURL.openStream();
parserPostajeTrenutno.setInput(trenutno, null);
ArrayList<Postaje> postajeTrenutnoList = parsePostajaTrenutno(parserPostajeTrenutno);
for (Postaje postaje : postajeTrenutnoList) {
Location.distanceBetween(gps.getLatitude(), gps.getLongitude(), postaje.getLat(), postaje.getLon(), izid);
if (testing > izid[0]) {
testing = izid[0];
najblizjaPostaja[0] = base + urlPostajeTrenutno[count];
}
}
trenutno.close();
}
testing = 10000000;
for (count = 0; count < urlPostajeZjutrajPopoldne.length; count++) {
final URL postajeZjutrajPopoldneURL = new URL(base + urlPostajeZjutrajPopoldne[count]);
final InputStream trenutno = postajeZjutrajPopoldneURL.openStream();
parserPostajeTrenutno.setInput(trenutno, null);
ArrayList<Postaje> postajeTrenutnoList = parsePostajaTrenutno(parserPostajeTrenutno);
for (Postaje postaje : postajeTrenutnoList) {
Location.distanceBetween(gps.getLatitude(), gps.getLongitude(), postaje.getLat(), postaje.getLon(), izid);
if (testing > izid[0]) {
testing = izid[0];
najblizjaPostaja[1] = base + urlPostajeZjutrajPopoldne[count];
Log.e("Postaje...",najblizjaPostaja[1]);
}
}
trenutno.close();
}
testing = 10000000;
//cathes
}
});
threadVremeTrenutno.start();
threadVremeTrenutno.join();
//catches
return najblizjaPostaja;
}
public String[] getPostajeNapoved(Context context) {
gps = new GPSTracker(context);
if(!asked) {
gps.canGetLocation();
asked = true;
}
najblizjaPostajaNapoved = new String[5];
try {
postajePullParserFactory = XmlPullParserFactory.newInstance();
final XmlPullParser parserPostajeTrenutno = postajePullParserFactory.newPullParser();
parserPostajeTrenutno.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
Thread threadVremeNapoved = new Thread(new Runnable() {
@Override
public void run() {
try {
for (count = 0; count < urlPostajeTriDni.length; count++) {
final URL postajeTrenutnoURL = new URL(base + urlPostajeTriDni[count]);
final InputStream trenutno = postajeTrenutnoURL.openStream();
parserPostajeTrenutno.setInput(trenutno, null);
ArrayList<Postaje> postajeTrenutnoList = parsePostajaTrenutno(parserPostajeTrenutno);
for (Postaje postaje : postajeTrenutnoList) {
Location.distanceBetween(gps.getLatitude(), gps.getLongitude(), postaje.getLat(), postaje.getLon(), izid);
if (testing > izid[0]) {
testing = izid[0];
najblizjaPostajaNapoved[0] = base + urlPostajeTriDni[count];
}
}
trenutno.close();
}
testing = 10000000;
for (count = 0; count < urlModelskaNapoved.length; count++) {
final URL postajeTrenutnoURL = new URL(base + urlModelskaNapoved[count]);
final InputStream trenutno = postajeTrenutnoURL.openStream();
parserPostajeTrenutno.setInput(trenutno, null);
ArrayList<Postaje> postajeTrenutnoList = parsePostajaTrenutno(parserPostajeTrenutno);
for (Postaje postaje : postajeTrenutnoList) {
Location.distanceBetween(gps.getLatitude(), gps.getLongitude(), postaje.getLat(), postaje.getLon(), izid);
if (testing > izid[0]) {
testing = izid[0];
najblizjaPostajaNapoved[1] = base + urlModelskaNapoved[count];
}
}
trenutno.close();
}
testing = 10000000;
//caches
}
});
threadVremeNapoved.start();
threadVremeNapoved.join();
//caches
return najblizjaPostajaNapoved;
}
private ArrayList<Postaje> parsePostajaTrenutno (XmlPullParser parserPostajeTrenutno) throws
XmlPullParserException, IOException {
ArrayList<Postaje> Postaje = null;
int eventType = parserPostajeTrenutno.getEventType();
Postaje postajeTrenutnoList = null;
while (eventType != XmlPullParser.END_DOCUMENT) {
String name;
switch (eventType) {
case XmlPullParser.START_DOCUMENT:
Postaje = new ArrayList();
break;
case XmlPullParser.START_TAG:
name = parserPostajeTrenutno.getName();
if (name.equals("metData")) {
postajeTrenutnoList = new Postaje();
} else if (postajeTrenutnoList != null) {
if (name.equals("domain_lat")) {
postajeTrenutnoList.setLat(Double.valueOf(parserPostajeTrenutno.nextText()));
} else if (name.equals("domain_lon")) {
postajeTrenutnoList.setLon(Double.valueOf(parserPostajeTrenutno.nextText()));
}
break;
}
break;
case XmlPullParser.END_TAG:
name = parserPostajeTrenutno.getName();
if (name.equalsIgnoreCase("metData") && postajeTrenutnoList != null) {
Postaje.add(postajeTrenutnoList);
}
}
eventType = parserPostajeTrenutno.next();
}
return Postaje;
}
}
我的全球定位系统
public class GPSTracker extends Service implements LocationListener {
boolean asked = false;
public Boolean update = true;
private final Context mContext;
// flag for GPS status
boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
Location location; // location
double latitude; // latitude
double longitude; // longitude
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 100000; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 20; // 1 minute
// Declaring a Location Manager
protected LocationManager locationManager;
private static final int PERMISSION_REQUEST_CODE = 1;
private static final String TAG_RUNTIME_PERMISSION = "TAG_RUNTIME_PERMISSION";
public GPSTracker(Context context) {
this.mContext = context;
if (getUpdate()) {
getLocation();
}
}
public Location getLocation() {
try {
locationManager = (LocationManager) mContext
.getSystemService(LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
showSettingsAlert();
} else {
this.canGetLocation = true;
if (isNetworkEnabled) {
if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
requestRuntimePermission(getApplication(), Manifest.permission.ACCESS_FINE_LOCATION, PERMISSION_REQUEST_CODE);
}
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("Network", "Network");
if (locationManager != null) {
location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
setUpdate(false);
}
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
/**
* Stop using GPS listener
* Calling this function will stop using GPS in your app
* */
public void stopUsingGPS(){
if(locationManager != null){
locationManager.removeUpdates(GPSTracker.this);
}
}
/**
* Function to get latitude
* */
public double getLatitude(){
if(location != null){
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
/**
* Function to get longitude
* */
public double getLongitude(){
if(location != null){
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
public boolean getUpdate(){
return update;
}
public void setUpdate(boolean update){
this.update = update;
}
/**
* Function to check GPS/wifi enabled
* @return boolean
* */
public boolean canGetLocation() {
if(!asked) {
requestRuntimePermission(getApplication(), Manifest.permission.ACCESS_FINE_LOCATION, PERMISSION_REQUEST_CODE);
asked=true;
}
return this.canGetLocation;
}
/**
* Function to show settings alert dialog
* On pressing Settings button will lauch Settings Options
* */
public void showSettingsAlert(){
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
// Setting Dialog Title
alertDialog.setTitle("GPS is settings");
// Setting Dialog Message
alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");
// On pressing Settings button
alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int which) {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
Button positiveButton = ((AlertDialog) dialog).getButton(AlertDialog.BUTTON_POSITIVE);
positiveButton.setBackgroundColor(Color.parseColor("#FFE1FCEA"));
positiveButton.setTextColor(Color.parseColor("#000"));
}
});
// on pressing cancel button
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
private boolean hasRuntimePermission(Context context, String runtimePermission) {
boolean ret = false;
// Get current android os version.
int currentAndroidVersion = Build.VERSION.SDK_INT;
// Build.VERSION_CODES.M's value is 23.
if (currentAndroidVersion > Build.VERSION_CODES.M) {
// Only android version 23+ need to check runtime permission.
if (ContextCompat.checkSelfPermission(context, runtimePermission) == PackageManager.PERMISSION_GRANTED) {
ret = true;
}
} else {
ret = true;
}
return ret;
}
//
// /* Request app user to allow the needed runtime permission.
// It will popup a confirm dialog , user can click allow or deny. */
private void requestRuntimePermission(Application activity, String runtimePermission, int requestCode) {
Log.e(TAG, "requesting" );
requestPermissions((Activity)mContext, new String[]{runtimePermission}, requestCode);
}
@Override
public void onLocationChanged(Location location) {
setUpdate(true);
}
@Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
@Override
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub
return null;
}
}
解决方案
您将需要 Indeterminate ProgressBar 旋转直到每次加载数据。加载数据时，只需禁用后台点击以避免冲突。
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