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我是一个初学者，这可能是我在这里失踪的编程基础知识，但这是我将学习这些东西的唯一方法。android studio从不同的方法访问一个对象的属性
下面是我的MainActivity代码。它试图获取最后一个位置的细节，并将它们读入我定义的类（类称为UserCurrentAddress），以便我可以使用这些细节。
我已经在MainActivity类中声明了UserCurrentAddress类，然后在onCreate中实例化了这个类。然后，我使用代码底部的按钮单击（onClickView）来连接API并获取位置。 “handleNewLocation”方法最终会填充UserCurrentAddress对象（并且可以成功运行）。但是，当我尝试从buttonClick事件中的UserCurrentAddress中读取这些详细信息（仅使用Toast）时，它将返回为空。如果我把这个吐司放在“handleNewLocation”中，那么它是正确填充的。 为什么UserCurrentAddress的属性在buttonClick事件中不可见？
我认为通过在活动类中声明它可以在整个过程中看到它。
我意识到我可以在“handleNewLocation”方法中做我需要做的事情，但最好从该事件外部访问这些属性。
我希望我能解释我的问题。
代码：
package com.example.android.trainingapp;
import android.content.IntentSender;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.model.LatLng;
import java.io.IOException;
import java.util.List;
import java.util.Locale;
public class MainActivity extends AppCompatActivity
implements GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
View.OnClickListener{
private GoogleApiClient mGoogleAPIClient;
private UserCurrentAddress userCurrentAddress;
Button bFindLocation;
private LocationRequest mlocationRequest;
private final static int CONNECTION_FAILURE_RESOLUTION_REQUEST = 9000;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bFindLocation = (Button) findViewById(R.id.show_location);
bFindLocation.setOnClickListener(this);
mGoogleAPIClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
mlocationRequest = LocationRequest.create()
.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
.setInterval(10 * 1000)
.setFastestInterval(1 * 1000);
userCurrentAddress = new UserCurrentAddress(null, null, null, null, null, 0, 0, null);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onConnected(Bundle bundle) {
Location location = LocationServices.FusedLocationApi.getLastLocation(mGoogleAPIClient);
if(location==null){
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleAPIClient, mlocationRequest, (LocationListener) this);
}
else{
handleNewLocation(location);
}
}
public void handleNewLocation(Location location){
double currentLatitude, currentLongitude;
String addressOne, addressTwo, streetNumber, country, fullAddress, postCode, myAdress;
currentLatitude = location.getLatitude();
currentLongitude = location.getLongitude();
LatLng latLng = new LatLng(currentLatitude, currentLongitude);
Geocoder geocoder = new Geocoder(this, Locale.getDefault());
try {
List<Address> addresses = geocoder.getFromLocation(currentLatitude, currentLongitude, 1);
if(addresses != null){
Address returnedAddress = addresses.get(0);
StringBuilder strReturnedAddress = new StringBuilder();
for(int i=0; i < returnedAddress.getMaxAddressLineIndex(); i++){
strReturnedAddress.append(returnedAddress.getAddressLine(i)).append(" ");
}
streetNumber = returnedAddress.getSubThoroughfare();
addressOne = returnedAddress.getThoroughfare(); //Beech Rd
addressTwo = returnedAddress.getLocality(); //durban north
postCode = returnedAddress.getPostalCode();
country = returnedAddress.getCountryName();
myAdress = strReturnedAddress.toString();
userCurrentAddress.streetNumber = streetNumber;
userCurrentAddress.addressOne = addressOne;
userCurrentAddress.addressTwo = addressTwo;
userCurrentAddress.postCode = postCode;
userCurrentAddress.country =country ;
userCurrentAddress.latitude = currentLatitude;
userCurrentAddress.longitude = currentLongitude;
userCurrentAddress.fullAddress = myAdress;
Toast.makeText(this, userCurrentAddress.streetNumber, Toast.LENGTH_LONG).show();
}
else{
myAdress = "No Address Returned";
}
} catch (IOException e) {
e.printStackTrace();
myAdress = "Cannot get address";
}
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
/*
* Google Play services can resolve some errors it detects.
* If the error has a resolution, try sending an Intent to
* start a Google Play services activity that can resolve
* error.
*/
if (connectionResult.hasResolution()) {
try {
// Start an Activity that tries to resolve the error
connectionResult.startResolutionForResult(this, CONNECTION_FAILURE_RESOLUTION_REQUEST);
/*
* Thrown if Google Play services canceled the original
* PendingIntent
*/
} catch (IntentSender.SendIntentException e) {
// Log the error
e.printStackTrace();
}
} else {
/*
* If no resolution is available, display a dialog to the
* user with the error.
*/
}
}
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.show_location:
mGoogleAPIClient.connect();
Toast.makeText(this, userCurrentAddress.fullAddress, Toast.LENGTH_LONG).show();
}
}
}
你在哪里试图访问它们？另一个活动，片段，方法？ –