获取用户的当前城市 [英] Get the user's current city
问题描述
您好，我不久前发布了一个有关同一主题的问题，在听取了您的建议后，我感到我已经接近解决问题.当我在监视器上单击带有以下错误消息的按钮时，该应用程序确实崩溃了:
Hi I posted a question concerning the same topic a while ago, after following your advices I can feel that I'm getting closed to solving my problem. The App does is now crashing as I click on the button with the following error message in the monitor:
FATAL EXCEPTION: main
Process: com.example.apple.myapp1, PID: 10081
java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0
at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
at java.util.ArrayList.get(ArrayList.java:308)
at com.example.apple.myapp1.MainActivity$1.onClick(MainActivity.java:62)
MainActivity.java
MainActivity.java
package com.example.apple.myapp1;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.List;
import java.util.Locale;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONObject;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Context;
import android.location.Address;
import android.location.Geocoder;
import android.os.Bundle;
import android.telephony.TelephonyManager;
import android.telephony.gsm.GsmCellLocation;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.view.View.OnClickListener;
public class MainActivity extends Activity {
double lats, lons;
Geocoder geocoder;
double lat = lats;
double lon = lons;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button btnGetLocation = (Button) findViewById(R.id.button1);
btnGetLocation.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
ProgressDialog mProgressDialog = new ProgressDialog(MainActivity.this);
mProgressDialog.setMessage("Fetching location...");
mProgressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
mProgressDialog.show();
geocoder = new Geocoder(MainActivity.this, Locale.getDefault());
List<Address> addresses = null;
try {
addresses = geocoder.getFromLocation(lat, lon, 1);
} catch (IOException e) {
e.printStackTrace();
}
if (addresses != null) {
String address = addresses.get(0).getAddressLine(0);
String city = addresses.get(0).getLocality();
String state = addresses.get(0).getAdminArea();
String country = addresses.get(0).getCountryName();
String postalCode = addresses.get(0).getPostalCode();
String knownName = addresses.get(0).getFeatureName();
mProgressDialog.dismiss();
TextView cellText = (TextView) findViewById(R.id.cellText);
cellText.setText(address);
} else {
mProgressDialog.dismiss();
TextView cellText = (TextView) findViewById(R.id.cellText);
cellText.setText("Error");
}
}
});
}
}
activity_main.xml
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Please click the button below to get your location" />
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Click Me" />
<TextView
android:id="@+id/cellText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="" />
<TextView
android:id="@+id/lacationText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="" />
</LinearLayout>
推荐答案
在条件if (addresses != null) { } 中，您还应该检查地址的长度，因为可能为0.
in the condition if (addresses != null) { } you should also check for the length of the addresses, since there might be 0.
if (addresses != null && addresses.size() > 0) {
String address = addresses.get(0).getAddressLine(0);
String city = addresses.get(0).getLocality();
String state = addresses.get(0).getAdminArea();
String country = addresses.get(0).getCountryName();
String postalCode = addresses.get(0).getPostalCode();
String knownName = addresses.get(0).getFeatureName();
mProgressDialog.dismiss();
TextView cellText = (TextView) findViewById(R.id.cellText);
cellText.setText(address);
} else {
mProgressDialog.dismiss();
TextView cellText = (TextView) findViewById(R.id.cellText);
cellText.setText("Error");
}
如果找不到至少一个地址，则应考虑向用户显示一个空状态.
if it wasn't able to find at least one address you should consider showing the user an empty state.
似乎您也忘记了在致电 addresses = geocoder.getFromLocation(lat, lon, 1);
It also seems like you forgot to initialize your latitude and longitude before calling addresses = geocoder.getFromLocation(lat, lon, 1);
要正确初始化，请执行以下操作:
To properly initialize this, do the following:
Location location = intent.getParcelableExtra(__YOUR_PACKAGE_NAME__ + ".LOCATION_DATA_EXTRA");
lat = location.getLatitude();
lon = location.getLongitude();
如果您需要更多帮助，请查看android的页面.它应该包含您需要的所有信息.
If you need any more help check out this page from android. It should hold all information you need.
我以为您在我们的过程中会更进一步，但是看来您只是在尝试获取latLong位置的位置，而从未获得过.要获得地址，您必须首先拥有用户的商标.
I kind of assumed you we're further in the process, but it seems you have only tried to get the location of a latLong position, which you have never obtained. To achieve obtaining the address you will have to have the user's lcoation first.
同样，上面提到的页面应解释获取位置所需的一切，但请确保以下几点:
Again, the page mentioned above should explain everything you need to obtain the location, but make sure of the following:
1.有权访问用户的位置(对于Android 6+，请使用运行时权限)
1. Have the permission to access the user's location (for Android 6+ use Runtime permissions)
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.google.android.gms.location.sample.locationupdates" >
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
</manifest>
2.获取GoogleApi的实例并让您的活动实现一些回调
用于回调
public class YourActivity extends AppCompatActivity implements
ConnectionCallbacks, OnConnectionFailedListener
然后在您的OnCreate()中创建一个GoogleApiClient实例.
Then in your OnCreate() create an instance of GoogleApiClient.
protected GoogleApiClient mGoogleApiClient;
public void onCreate(Bundle savedInstanceState) {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
mGoogleApiClient.connect();
}
3.从GoogleApiClient获取位置 为此，请正确实施回调.
3. Obtain the location from the GoogleApiClient Do this by implementing the callbacks properly.
/**
* Represents a geographical location.
*/
protected Location mLastLocation;
@Override
public void onConnected(Bundle connectionHint) {
// Gets the best and most recent location currently available, which may be null
// in rare cases when a location is not available.
mLastLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
if (mLastLocation != null) {
// Determine whether a Geocoder is available.
if (!Geocoder.isPresent()) {
Toast.makeText(this, "no geocoder available", Toast.LENGTH_LONG).show();
return;
}
}
}
4.现在获取经纬度，然后尝试像以前一样获取地址.
lat = mLastLocation.getLatitude();
lon = mLastLocation.getLongitude();
geocoder = new Geocoder(MainActivity.this, Locale.getDefault());
List<Address> addresses = null;
try {
addresses = geocoder.getFromLocation(lat, lon, 1);
} catch (IOException e) {
e.printStackTrace();
}
这应该足以获取设备的实际地址，并向地址解析器询问地址.为了使这个问题简化，我对示例进行了一些更改. Google的示例处理了一些更干净的地址获取.请注意，停止活动等时，您还必须断开GoogleApi的连接.再次，我建议阅读整个教程页面.您可以找到其实现的示例
This should be enough to obtain the actual adress of the device and ask the geocoder for the addresses. I altered the example a bit to simplify for this question. Google's example handles fetching the address a bit more clean. Note that you will also have to disconnect the GoogleApi when stopping your activity and such. Again I recommend reading the entire Tutorial page. You can find en example of their implementation on this page on GitHub
这篇关于获取用户的当前城市的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
