本文介紹了從其他方法訪問變量的處理方法，對大家解決問題具有一定的參考價值，需要的朋友們下面隨著小編來一起學習吧！
問題描述
我正在嘗試使用當前位置在 android 中提交用戶注冊表單.我是 android 和 java 開發的新手.當我嘗試在我的名稱值對代碼中訪問 onLocationChanged 方法的 myLat 和 myLan 時，它無法找到這兩個變量.如何訪問我的名稱值對代碼中的兩個變量.
i am trying to submit user registration form in android with current location. I am new to android and java development. when i try to access myLat and myLan of the onLocationChanged method in my name value pairs code , it is unable to find both the variables. How can i access both the variables in my name value pair code.
package com.imran;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import com.google.android.gcm.GCMRegistrar;
import com.google.android.maps.MyLocationOverlay;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.StrictMode;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import android.app.Activity;
import android.content.Context;
public class Register extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_register);
final EditText email_id = (EditText) findViewById(R.id.email_id) ;
final EditText name = (EditText) findViewById(R.id.name);
final EditText password = (EditText) findViewById(R.id.password);
Button button = (Button) findViewById(R.id.button1) ;
//generate GCM id
GCMRegistrar.checkDevice(this);
GCMRegistrar.checkManifest(this);
final String regId = GCMRegistrar.getRegistrationId(this);
if (regId.equals("")) {
GCMRegistrar.register(this, "12356");
} else {
String TAG = null;
Log.v(TAG, regId);
}
//generate GCM id ended
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
//get current location
LocationManager manager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
LocationListener listner = new LocationListener() {
@Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String arg0) {
// TODO Auto-generated method stub
}
@Override
public void onProviderDisabled(String arg0) {
// TODO Auto-generated method stub
}
@Override
public void onLocationChanged(Location location) {
double myLonDouble = location.getLongitude();
final String myLon = Double.toString(myLonDouble);
double myLatDouble = location.getLatitude();
final String myLat = Double.toString(myLatDouble);
}
};
manager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, listner);
//end get current location
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
//postData();
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://xyz.com/folder/register.php");
try {
// Add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("email", email_id.getText().toString()));
nameValuePairs.add(new BasicNameValuePair("name", name.getText().toString()));
nameValuePairs.add(new BasicNameValuePair("password", password.getText().toString()));
nameValuePairs.add(new BasicNameValuePair("regid", regId));
nameValuePairs.add(new BasicNameValuePair("uid", "2"));
nameValuePairs.add(new BasicNameValuePair("lat",myLat ));
nameValuePairs.add(new BasicNameValuePair("lon",myLon));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// Execute HTTP Post Request
//Toast.makeText(this, resId, duration)
HttpResponse response = httpclient.execute(httppost);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (IOException e) {
// TODO Auto-generated catch block
}
}
});
}
}
推薦答案
你應該好好學習一下 范圍和成員變量.問題是，您不能在一個方法中聲明一件事，然后嘗試從另一個方法訪問它.
You should probably study up on scope and member variables. The thing is, you can't declare one thing in one method then attempt to access it from another method.
所以，我們將那個東西聲明為成員變量，并在一個方法中定義它，然后它可以在另一個方法中使用.
So, we declare that thing as a member variable, and define it in one method, then it can be used in another method.
像這樣(我已經用 ** 標記了我的評論):
Like so (I've marked my comments with **):
public class Register extends Activity {
// "private" means it can only be accessed from this class
private String myLat = null; // ** Declare myLat
private String myLon = null; // ** Declare myLon
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_register);
final EditText email_id = (EditText) findViewById(R.id.email_id) ;
final EditText name = (EditText) findViewById(R.id.name);
final EditText password = (EditText) findViewById(R.id.password);
Button button = (Button) findViewById(R.id.button1) ;
//generate GCM id
GCMRegistrar.checkDevice(this);
GCMRegistrar.checkManifest(this);
final String regId = GCMRegistrar.getRegistrationId(this);
if (regId.equals("")) {
GCMRegistrar.register(this, "12356");
} else {
String TAG = null;
Log.v(TAG, regId);
}
//generate GCM id ended
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
//get current location
LocationManager manager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
LocationListener listner = new LocationListener() {
@Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String arg0) {
// TODO Auto-generated method stub
}
@Override
public void onProviderDisabled(String arg0) {
// TODO Auto-generated method stub
}
@Override
public void onLocationChanged(Location location) {
double myLonDouble = location.getLongitude();
myLon = Double.toString(myLonDouble); // ** Define myLon
double myLatDouble = location.getLatitude();
myLat = Double.toString(myLatDouble); // ** Define myLat
}
};
manager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, listner);
//end get current location
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
// ** Check if they have been defined
if (myLat == null || myLon == null)
return;
//postData();
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://xyz.com/folder/register.php");
try {
// Add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("email", email_id.getText().toString()));
nameValuePairs.add(new BasicNameValuePair("name", name.getText().toString()));
nameValuePairs.add(new BasicNameValuePair("password", password.getText().toString()));
nameValuePairs.add(new BasicNameValuePair("regid", regId));
nameValuePairs.add(new BasicNameValuePair("uid", "2"));
nameValuePairs.add(new BasicNameValuePair("lat",myLat ));
nameValuePairs.add(new BasicNameValuePair("lon",myLon));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// Execute HTTP Post Request
//Toast.makeText(this, resId, duration)
HttpResponse response = httpclient.execute(httppost);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (IOException e) {
// TODO Auto-generated catch block
}
}
});
}
}
這篇關于從其他方法訪問變量的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！
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