Android 如果GPS未打开，活动崩溃；如果GPS不可用，是否可以使用粗略的位置？
当我在设备上关闭GPS的情况下加载此活动时，它会使应用程序崩溃 我该如何着手解决这个问题 如果可能的话，如果GPS被关闭，而不是使用粗略的位置，这也将是令人惊讶的，不知道这将是多么容易 非常感谢您的帮助，代码如下：Android 如果GPS未打开，活动崩溃；如果GPS不可用，是否可以使用粗略的位置？,android,Android,当我在设备上关闭GPS的情况下加载此活动时，它会使应用程序崩溃 我该如何着手解决这个问题 如果可能的话，如果GPS被关闭，而不是使用粗略的位置，这也将是令人惊讶的，不知道这将是多么容易 非常感谢您的帮助，代码如下： public class SunriseSunset extends Activity implements OnClickListener { public Button getLocation; public Button setLocationJapan;
public class SunriseSunset extends Activity implements OnClickListener {
public Button getLocation;
public Button setLocationJapan;
public TextView LongCoord;
public TextView LatCoord;
public double longitude;
public double latitude;
public LocationManager lm;
public Spinner Locationspinner;
public DateDialogFragment frag;
public Button date;
public Calendar now;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.sunrisesunset);
// Show the Up button in the action bar.
setupActionBar();
//Setting onClickListener for Calculate Sunrise/Sunset Button
findViewById(R.id.CalculateSunriseSunset).setOnClickListener(this);
//Sets up LocationManager to enable GPS data to be accessed.
lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 1,
new MyLocationListener());
//Declares Latitude and Longitude TextViews
LatCoord = (TextView) findViewById(R.id.LatCoord);
LongCoord = (TextView) findViewById(R.id.LongCoord);
//Declares for Location Spinner/Dropdown
addListenerOnSpinnerItemSelection();
//Date shit
now = Calendar.getInstance();
date = (Button)findViewById(R.id.date_button);
date.setText(DateFormat.format("dd MMMM yyyy", Calendar.getInstance()));
date.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
showDialog();
}
});
}
/**
* Set up the {@link android.app.ActionBar}.
*/
private void setupActionBar() {
getActionBar().setDisplayHomeAsUpEnabled(true);
}
// More date shit
@SuppressLint("CommitTransaction")
public void showDialog() {
FragmentTransaction ft = getFragmentManager().beginTransaction(); //get the fragment
frag = DateDialogFragment.newInstance(this, new DateDialogFragmentListener(){
public void updateChangedDate(int year, int month, int day){
now.set(year, month, day);
date.setText(DateFormat.format("dd MMMM yyyy", now));
}
}, now);
frag.show(ft, "DateDialogFragment"); }
public interface DateDialogFragmentListener{
//this interface is a listener between the Date Dialog fragment and the activity to update the buttons date
public void updateChangedDate(int year, int month, int day);
}
public void addListenerOnSpinnerItemSelection() {
Locationspinner = (Spinner) findViewById(R.id.Locationspinner);
Locationspinner
.setOnItemSelectedListener(new LocationOnItemSelectedListener(
this));
}
//Sets locations for all the cities in the spinner
public void setLocationAuckland() {LatCoord.setText("-36.85248273");LongCoord.setText("174.76391734");}
public void setLocationBuenoAires() {LatCoord.setText("-34.606358325");LongCoord.setText("-58.38727463");}
public void setLocationCalgary()
protected void showCurrentLocation() {
// TODO Auto-generated method stub
// This is called to find current location based on GPS data and sends
// these values to the LongCoord and LatCoord TextViews
Location location = lm
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
latitude = location.getLatitude();
longitude = location.getLongitude();
LongCoord.setText(Double.toString(longitude));
LatCoord.setText(Double.toString(latitude));
}
@Override
public void onClick(View arg0) {
Button b = (Button) findViewById(R.id.CalculateSunriseSunset);
b.setClickable(false);
new LongRunningGetIO().execute();
}
public class LongRunningGetIO extends AsyncTask<Void, Void, String> {
//Reads in the web service
protected String getASCIIContentFromEntity(HttpEntity entity)
throws IllegalStateException, IOException {
InputStream in = entity.getContent();
StringBuffer out = new StringBuffer();
int n = 1;
while (n > 0) {
byte[] b = new byte[4096];
n = in.read(b);
if (n > 0)
out.append(new String(b, 0, n));
}
return out.toString();
}
private final ProgressDialog dialog = new ProgressDialog(SunriseSunset.this);
protected void onPreExecute() {
this.dialog.setMessage("Calculating...");
this.dialog.show();
}
@SuppressLint("SimpleDateFormat")
@Override
protected String doInBackground(Void... params) {
HttpClient httpClient = new DefaultHttpClient();
HttpContext localContext = new BasicHttpContext();
// Finds todays date and adds that into the URL in simple date format DD/MM
SimpleDateFormat df = new SimpleDateFormat("dd/MM");
String formattedDate = df.format(now.getTime());
String finalURL = "http://www.earthtools.org/sun/"
+ LatCoord.getText().toString().trim() + "/"
+ LongCoord.getText().toString().trim() + "/"
+ formattedDate + "/99/0";
HttpGet httpGet = new HttpGet(finalURL);
String text = null;
try {
HttpResponse response = httpClient.execute(httpGet,
localContext);
HttpEntity entity = response.getEntity();
text = getASCIIContentFromEntity(entity);
} catch (Exception e) {
return e.getLocalizedMessage();
}
return text;
}
protected void onPostExecute(String results) {
//Closes dialog box onPostExecute
if (this.dialog.isShowing()) {
this.dialog.dismiss();
}
//Finds TextViews for Sunrise and Sunset values and posts results
if (results != null) {
try {
DocumentBuilderFactory dbFactory = DocumentBuilderFactory
.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
InputSource s = new InputSource(new StringReader(results));
Document doc = dBuilder.parse(s);
doc.getDocumentElement().normalize();
TextView tvSunrise = (TextView) findViewById(R.id.Sunrise);
TextView tvSunset = (TextView) findViewById(R.id.Sunset);
tvSunrise.setText(doc.getElementsByTagName("sunrise").item(0).getTextContent());
tvSunset.setText(doc.getElementsByTagName("sunset").item(0).getTextContent());
} catch (Exception e) {
e.printStackTrace();
}
}
Button b = (Button) findViewById(R.id.CalculateSunriseSunset);
b.setClickable(true);
}
}
class MyLocationListener implements LocationListener {
@Override
public void onLocationChanged(Location location) {
// TODO Auto-generated method stub
}
@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 boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.home, menu);
return true;
}
public boolean onPrepareOptionsMenu(Menu menu) {
// preparation code here
return super.onPrepareOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
NavUtils.navigateUpFromSameTask(this);
return true;
}
if (item.getItemId() == R.id.LessonsTutorials) {
startActivity(new Intent(this, Lessons.class));
}
if (item.getItemId() == R.id.PhotoTools) {
startActivity(new Intent(this, Tools.class));
}
if (item.getItemId() == R.id.Glossary) {
startActivity(new Intent(this, Glossary.class));
}
if (item.getItemId() == R.id.Help) {
startActivity(new Intent(this, Help.class));
}
return super.onOptionsItemSelected(item);
}
}
protected void showCurrentLocation() {
// TODO Auto-generated method stub
// This is called to find current location based on GPS data and sends
// these values to the LongCoord and LatCoord TextViews
Location location = lm
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
latitude = location.getLatitude();
longitude = location.getLongitude();
LongCoord.setText(Double.toString(longitude));
LatCoord.setText(Double.toString(latitude));
}
任何提供者都可能不可用。因此，在请求更新之前，请务必检查
if (lm.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 1,
new MyLocationListener());
} else if (lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER)) {
lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 1000, 1,
new MyLocationListener());
}
private boolean pending;
private LocationListener listener;
private LocationManager lm;
@Override
protected void onCreate(Bundle state) {
//your stuff
listener = new MyLocationListener();
}
@Override
protected void onPostCreate(Bundle state) {
super.onPostCreate(state);
if (lm != null) {
requestLocation();
}
}
private void requestLocation() {
if (!pending) {
if (lm.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 1,
listener);
pending = true;
} else if (lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER)) {
lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 1000, 1,
listener);
pending = true;
}
}
}
@Override
protected void onDestroy() {
super.onDestroy();
if (pending) {
lm.removeUpdates();
}
}
protected void showCurrentLocation() {
// these values to the LongCoord and LatCoord TextViews
Location location = lm
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
LongCoord.setText(Double.toString(longitude));
LatCoord.setText(Double.toString(latitude));
}
}
任何提供者都可能不可用。因此，在请求更新之前，请务必检查
if (lm.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 1,
new MyLocationListener());
} else if (lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER)) {
lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 1000, 1,
new MyLocationListener());
}
private boolean pending;
private LocationListener listener;
private LocationManager lm;
@Override
protected void onCreate(Bundle state) {
//your stuff
listener = new MyLocationListener();
}
@Override
protected void onPostCreate(Bundle state) {
super.onPostCreate(state);
if (lm != null) {
requestLocation();
}
}
private void requestLocation() {
if (!pending) {
if (lm.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 1,
listener);
pending = true;
} else if (lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER)) {
lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 1000, 1,
listener);
pending = true;
}
}
}
@Override
protected void onDestroy() {
super.onDestroy();
if (pending) {
lm.removeUpdates();
}
}
protected void showCurrentLocation() {
// these values to the LongCoord and LatCoord TextViews
Location location = lm
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
LongCoord.setText(Double.toString(longitude));
LatCoord.setText(Double.toString(latitude));
}
}
stacktrace是否来自logcat？是否已将权限添加到添加的manifest@SankarV logcat输出above@John-是的，两个权限都在清单文件中：）我想我有你问题的答案，但是我无法向你发布答案。当我尝试向你发布答案时，我收到了此消息-“您的帖子似乎包含未正确格式化为代码的代码。“…那么，让我试着用某种方式从logcat向您提供答案StackTrace？您是否将权限添加到了manifest@SankarV logcat输出中？”above@John-是的，两个权限都在清单文件中：）我想我有你问题的答案，但我无法将答案发布给你当我试着把答案贴在你的帖子上时，得到了这个消息——“你的帖子似乎包含的代码格式不正确。“…让我试着用某种方式为你提供答案最好的方式是用某种方法来回答。这取决于你的目标是什么。如果要在活动创建后请求，可以在onCreate（）中调用它。如果要在每次活动获得焦点时请求，请在onResume（）中调用它。您还必须检查位置更新是否已挂起，并且在不需要更新时不要忘记停止更新，请在onDestroy（）或onPause（）中使用lm.removeUpdates（侦听器）（如果在onResume（）中）或者点击按钮事件。这取决于您。实现了该示例，但它仍然崩溃，并给出了相同的信息：为什么您不学习找出自己的错误？它仍然存在吗（SunriseSunset.java:148）导致NullPointerException的原因是什么？此时您的lm似乎为null。最好的方法是将其放在某个方法中。这取决于您的目标。若要在活动创建后请求，可以在onCreate（）中调用它。若要在每次活动获得焦点时请求，请在onResume（）中调用它。您还必须检查位置更新是否已挂起，并且在不需要更新时不要忘记停止更新，请在onDestroy（）或onPause（）中使用lm.removeUpdates（侦听器）（如果在onResume（）中）或者点击按钮事件。这取决于您。实现了该示例，但它仍然崩溃，并给出了相同的消息：为什么您不学习找出自己的错误？是否仍然（SunriseSunset.java:148）导致NullPointerException？看起来您当时的lm为null。