Java 如何将对象从asynctask返回到android中的主类
我想将文档返回到我的主类，但即使使用全局变量dosen也不起作用，这是因为asynctask没有完成任务。我想是否有一个解决方案来获取对象表单asynctask？ 我已经在onPostExecute中尝试了这种矫揉造作的方式，但是如果我在asynctask之外，对象将变为null 这是一节课：Java 如何将对象从asynctask返回到android中的主类,java,android,android-asynctask,Java,Android,Android Asynctask,我想将文档返回到我的主类，但即使使用全局变量dosen也不起作用，这是因为asynctask没有完成任务。我想是否有一个解决方案来获取对象表单asynctask？ 我已经在onPostExecute中尝试了这种矫揉造作的方式，但是如果我在asynctask之外，对象将变为null 这是一节课： private class RequestTask extends AsyncTask<String, Void, Document> { protected Document
private class RequestTask extends AsyncTask<String, Void, Document> {
protected Document doInBackground(String... url) {
try {
HttpClient httpClient = new DefaultHttpClient();
HttpContext localContext = new BasicHttpContext();
HttpPost httpPost = new HttpPost(url[0]);
HttpResponse response = httpClient.execute(httpPost,
localContext);
InputStream in = response.getEntity().getContent();
DocumentBuilder builder = DocumentBuilderFactory.newInstance()
.newDocumentBuilder();
return builder.parse(in);
} catch (IOException e) {
e.printStackTrace();
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(Document doc) {
super.onPostExecute(doc);
if (mDirectionListener != null) {
mDirectionListener.onResponse(getStatus(doc), doc,
GoogleDirection.this);
}
}
private String getStatus(Document doc) {
NodeList nl1 = doc.getElementsByTagName("status");
Node node1 = nl1.item(0);
if (isLogging) {
Log.i("GoogleDirection", "Status : " + node1.getTextContent());
}
return node1.getTextContent();
}
}
私有类RequestTask扩展了AsyncTask{
受保护文档doInBackground（字符串…url）{
试一试{
HttpClient HttpClient=新的DefaultHttpClient（）；
HttpContext localContext=新的BasicHttpContext（）；
HttpPost HttpPost=新的HttpPost（url[0]）；
HttpResponse response=httpClient.execute（httpPost，
本地上下文）；
InputStream in=response.getEntity（）.getContent（）；
DocumentBuilder=DocumentBuilderFactory.newInstance（）
.newDocumentBuilder（）；
返回builder.parse（in）；
}捕获（IOE异常）{
e、 printStackTrace（）；
}捕获（ParserConfiguration异常e）{
e、 printStackTrace（）；
}捕获（SAXE异常）{
e、 printStackTrace（）；
}
返回null；
}
后期执行时受保护的无效（文档文档）{
super.onPostExecute（doc）；
if（mDirectionListener！=null）{
mDirectionListener.onResponse（getStatus（doc）、doc、，
谷歌（GoogleDirection.this）；
}
}
私有字符串getStatus（文档文档）{
NodeList nl1=doc.getElementsByTagName（“状态”）；
节点node1=nl1。项（0）；
如果（isLogging）{
Log.i（“谷歌方向”，“状态：+node1.getTextContent（））；
}
返回node1.getTextContent（）；
}
}
import android.annotation.SuppressLint;
import android.content.Context;
import android.os.AsyncTask;
import android.util.DisplayMetrics;
import android.util.Log;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.PolylineOptions;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.BasicHttpContext;
import org.apache.http.protocol.HttpContext;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
@SuppressLint("NewApi")
public class GoogleDirection {
public final static String MODE_WALKING = "walking";
private OnDirectionResponseListener mDirectionListener = null;
private boolean isLogging = false;
private Context myContext = null;
private Document test;
public GoogleDirection(Context context) {
myContext = context;
}
public String request(LatLng start, LatLng end, String mode) {
final String url = "http://maps.googleapis.com/maps/api/directions/xml?" +
"origin=" + start.latitude + "," + start.longitude +
"&destination=" + end.latitude + "," + end.longitude +
"&sensor=false&units=metric&mode=" + mode;
if (isLogging) {
//Display information in logcat (report success)
Log.i("GoogleDirection", "URL : " + url);
}
new RequestTask().execute(url);
return url;
}
public void setLogging(boolean state) {
isLogging = state;
}
public String getStatus(Document doc) {
NodeList nl1 = doc.getElementsByTagName("status");
Node node1 = nl1.item(0);
if (isLogging) {
Log.i("GoogleDirection", "Status : " + node1.getTextContent());
}
return node1.getTextContent();
}
public String[] getDurationText(Document doc) {
NodeList nl1 = doc.getElementsByTagName("duration");
String[] arr_str = new String[nl1.getLength() - 1];
for (int i = 0; i < (nl1.getLength() - 1); i++) {
Node node1 = nl1.item(i);
NodeList nl2 = node1.getChildNodes(); //Return child of a node (Duration have text and value)
Node node2 = nl2.item(getNodeIndex(nl2, "text"));
arr_str[i] = node2.getTextContent();
if (isLogging) {
Log.i("GoogleDirection",
"DurationText : " + node2.getTextContent());
}
}
return arr_str;
}
public int[] getDurationValue(Document doc) {
NodeList nl1 = doc.getElementsByTagName("duration");
int[] arr_int = new int[nl1.getLength() - 1];
for (int i = 0; i < (nl1.getLength() - 1); i++) {
Node node1 = nl1.item(i);
NodeList nl2 = node1.getChildNodes();
Node node2 = nl2.item(getNodeIndex(nl2, "value"));
arr_int[i] = Integer.parseInt(node2.getTextContent());
if (isLogging) {
Log.i("GoogleDirection", "Duration : " +
node2.getTextContent());
}
}
return arr_int;
}
public String getTotalDurationText(Document doc) {
NodeList nl1 = doc.getElementsByTagName("duration");
Node node1 = nl1.item(nl1.getLength() - 1);
NodeList nl2 = node1.getChildNodes();
Node node2 = nl2.item(getNodeIndex(nl2, "text"));
if (isLogging) {
Log.i("GoogleDirection", "TotalDuration : " +
node2.getTextContent());
}
return node2.getTextContent();
}
public int getTotalDurationValue(Document doc) {
NodeList nl1 = doc.getElementsByTagName("duration");
Node node1 = nl1.item(nl1.getLength() - 1);
NodeList nl2 = node1.getChildNodes();
Node node2 = nl2.item(getNodeIndex(nl2, "value"));
if (isLogging) {
Log.i("GoogleDirection", "TotalDuration : " +
node2.getTextContent());
}
return Integer.parseInt(node2.getTextContent());
}
public String[] getDistanceText(Document doc) {
NodeList nl1 = doc.getElementsByTagName("distance");
String[] arr_str = new String[nl1.getLength() - 1];
for (int i = 0; i < (nl1.getLength() - 1); i++) {
Node node1 = nl1.item(i);
NodeList nl2 = node1.getChildNodes();
Node node2 = nl2.item(getNodeIndex(nl2, "text"));
arr_str[i] = node2.getTextContent();
if (isLogging) {
Log.i("GoogleDirection",
"DurationText : " + node2.getTextContent());
}
}
return arr_str;
}
public int[] getDistanceValue(Document doc) {
NodeList nl1 = doc.getElementsByTagName("distance");
int[] arr_int = new int[nl1.getLength() - 1];
for (int i = 0; i < (nl1.getLength() - 1); i++) {
Node node1 = nl1.item(i);
NodeList nl2 = node1.getChildNodes();
Node node2 = nl2.item(getNodeIndex(nl2, "value"));
arr_int[i] = Integer.parseInt(node2.getTextContent());
if (isLogging) {
Log.i("GoogleDirection", "Duration : " +
node2.getTextContent());
}
}
return arr_int;
}
public String getTotalDistanceText(Document doc) {
NodeList nl1 = doc.getElementsByTagName("distance");
Node node1 = nl1.item(nl1.getLength() - 1);
NodeList nl2 = node1.getChildNodes();
Node node2 = nl2.item(getNodeIndex(nl2, "text"));
if (isLogging) {
Log.i("GoogleDirection", "TotalDuration : " +
node2.getTextContent());
}
return node2.getTextContent();
}
public int getTotalDistanceValue(Document doc) {
NodeList nl1 = doc.getElementsByTagName("distance");
Node node1 = nl1.item(nl1.getLength() - 1);
NodeList nl2 = node1.getChildNodes();
Node node2 = nl2.item(getNodeIndex(nl2, "value"));
if (isLogging) {
Log.i("GoogleDirection", "TotalDuration : " +
node2.getTextContent());
}
return Integer.parseInt(node2.getTextContent());
}
public String getStartAddress(Document doc) {
NodeList nl1 = doc.getElementsByTagName("start_address");
Node node1 = nl1.item(0);
if (isLogging) {
Log.i("GoogleDirection", "StartAddress : " +
node1.getTextContent());
}
return node1.getTextContent();
}
public String getEndAddress(Document doc) {
NodeList nl1 = doc.getElementsByTagName("end_address");
Node node1 = nl1.item(0);
if (isLogging) {
Log.i("GoogleDirection", "StartAddress : " +
node1.getTextContent());
}
return node1.getTextContent();
}
public String getCopyRights(Document doc) {
NodeList nl1 = doc.getElementsByTagName("copyrights");
Node node1 = nl1.item(0);
if (isLogging) {
Log.i("GoogleDirection", "CopyRights : " + node1.getTextContent());
}
return node1.getTextContent();
}
public ArrayList<LatLng> getDirection(Document doc) {
NodeList nl1;
NodeList nl2;
NodeList nl3;
ArrayList<LatLng> listGeopoints = new ArrayList<LatLng>();
nl1 = doc.getElementsByTagName("step");
if (nl1.getLength() > 0) {
for (int i = 0; i < nl1.getLength(); i++) {
Node node1 = nl1.item(i);
nl2 = node1.getChildNodes();
Node locationNode = nl2.item(getNodeIndex(nl2, "start_location"));
nl3 = locationNode.getChildNodes();
Node latNode = nl3.item(getNodeIndex(nl3, "lat"));
double lat = Double.parseDouble(latNode.getTextContent());
Node lngNode = nl3.item(getNodeIndex(nl3, "lng"));
double lng = Double.parseDouble(lngNode.getTextContent());
listGeopoints.add(new LatLng(lat, lng));
locationNode = nl2.item(getNodeIndex(nl2, "polyline"));
nl3 = locationNode.getChildNodes();
latNode = nl3.item(getNodeIndex(nl3, "points"));
ArrayList<LatLng> arr = decodePoly(latNode.getTextContent());
for (int j = 0; j < arr.size(); j++) {
listGeopoints.add(new LatLng(arr.get(j).latitude,
arr.get(j).longitude));
}
locationNode = nl2.item(getNodeIndex(nl2, "end_location"));
nl3 = locationNode.getChildNodes();
latNode = nl3.item(getNodeIndex(nl3, "lat"));
lat = Double.parseDouble(latNode.getTextContent());
lngNode = nl3.item(getNodeIndex(nl3, "lng"));
lng = Double.parseDouble(lngNode.getTextContent());
listGeopoints.add(new LatLng(lat, lng));
}
}
return listGeopoints;
}
public ArrayList<LatLng> getSection(Document doc) {
NodeList nl1;
NodeList nl2;
NodeList nl3;
ArrayList<LatLng> listGeopoints = new ArrayList<LatLng>();
nl1 = doc.getElementsByTagName("step");
if (nl1.getLength() > 0) {
for (int i = 0; i < nl1.getLength(); i++) {
Node node1 = nl1.item(i);
nl2 = node1.getChildNodes();
Node locationNode = nl2.item(getNodeIndex(nl2, "end_location"));
nl3 = locationNode.getChildNodes();
Node latNode = nl3.item(getNodeIndex(nl3, "lat"));
double lat = Double.parseDouble(latNode.getTextContent());
Node lngNode = nl3.item(getNodeIndex(nl3, "lng"));
double lng = Double.parseDouble(lngNode.getTextContent());
listGeopoints.add(new LatLng(lat, lng));
}
}
return listGeopoints;
}
public PolylineOptions getPolyline(Document doc, int width, int color) {
ArrayList<LatLng> arr_pos = getDirection(doc);
PolylineOptions rectLine = new PolylineOptions().width(dpToPx(width))
.color(color);
for (int i = 0; i < arr_pos.size(); i++)
rectLine.add(arr_pos.get(i));
return rectLine;
}
private int getNodeIndex(NodeList nl, String nodename) {
for (int i = 0; i < nl.getLength(); i++) {
if (nl.item(i).getNodeName().equals(nodename)) {
return i;
}
}
return -1;
}
private ArrayList<LatLng> decodePoly(String encoded) {
ArrayList<LatLng> poly = new ArrayList<LatLng>();
int index = 0;
int len = encoded.length();
int lat = 0;
int lng = 0;
while (index < len) {
int b;
int shift = 0;
int result = 0;
do {
b = encoded.charAt(index++) - 63;
result |= ((b & 0x1f) << shift);
shift += 5;
} while (b >= 0x20);
int dlat = (((result & 1) != 0) ? (~(result >> 1)) : (result >> 1));
lat += dlat;
shift = 0;
result = 0;
do {
b = encoded.charAt(index++) - 63;
result |= ((b & 0x1f) << shift);
shift += 5;
} while (b >= 0x20);
int dlng = (((result & 1) != 0) ? (~(result >> 1)) : (result >> 1));
lng += dlng;
LatLng position = new LatLng((double) lat / 1E5, (double) lng / 1E5);
poly.add(position);
}
return poly;
}
//Convert dp to pixel
private int dpToPx(int dp) {
DisplayMetrics displayMetrics = myContext.getResources()
.getDisplayMetrics();
int px = Math.round(dp * (displayMetrics.xdpi / DisplayMetrics.DENSITY_DEFAULT));
return px;
}
public void setOnDirectionResponseListener(
OnDirectionResponseListener listener) {
mDirectionListener = listener;
}
public interface OnDirectionResponseListener {
public void onResponse(String status, Document doc, GoogleDirection gd);
}
private class RequestTask extends AsyncTask<String, Void, Document> {
protected Document doInBackground(String... url) {
try {
HttpClient httpClient = new DefaultHttpClient();
HttpContext localContext = new BasicHttpContext();
HttpPost httpPost = new HttpPost(url[0]);
HttpResponse response = httpClient.execute(httpPost,
localContext);
InputStream in = response.getEntity().getContent();
DocumentBuilder builder = DocumentBuilderFactory.newInstance()
.newDocumentBuilder();
return builder.parse(in);
} catch (IOException e) {
e.printStackTrace();
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(Document doc) {
super.onPostExecute(doc);
if (mDirectionListener != null) {
mDirectionListener.onResponse(getStatus(doc), doc,
GoogleDirection.this);
}
}
private String getStatus(Document doc) {
NodeList nl1 = doc.getElementsByTagName("status");
Node node1 = nl1.item(0);
if (isLogging) {
Log.i("GoogleDirection", "Status : " + node1.getTextContent());
}
return node1.getTextContent();
}
}
}
导入android.annotation.SuppressLint；
导入android.content.Context；
导入android.os.AsyncTask；
导入android.util.DisplayMetrics；
导入android.util.Log；
导入com.google.android.gms.maps.model.LatLng；
导入com.google.android.gms.maps.model.PolylineOptions；
导入org.apache.http.HttpResponse；
导入org.apache.http.client.HttpClient；
导入org.apache.http.client.methods.HttpPost；
导入org.apache.http.impl.client.DefaultHttpClient；
导入org.apache.http.protocol.BasicHttpContext；
导入org.apache.http.protocol.HttpContext；
导入org.w3c.dom.Document；
导入org.w3c.dom.Node；
导入org.w3c.dom.NodeList；
导入org.xml.sax.SAXException；
导入java.io.IOException；
导入java.io.InputStream；
导入java.util.ArrayList；
导入javax.xml.parsers.DocumentBuilder；
导入javax.xml.parsers.DocumentBuilderFactory；
导入javax.xml.parsers.parserConfiguration异常；
@SuppressLint（“新API”）
公共类谷歌指南{
公共最终静态字符串模式\u WALKING=“WALKING”；
private OnDirectionResponseListener mDirectionListener=null；
私有布尔isLogging=false；
私有上下文myContext=null；
私人文件测试；
公共谷歌方向（上下文）{
myContext=上下文；
}
公共字符串请求（LatLng开始、LatLng结束、字符串模式）{
最终字符串url=”http://maps.googleapis.com/maps/api/directions/xml?" +
“origin=“+start.latitude+”，“+start.longitude”+
“&destination=“+end.latitude+”，“+end.longitude”+
“&sensor=false&units=metric&mode=“+mode；
如果（isLogging）{
//在logcat中显示信息（报告成功）
Log.i（“谷歌方向”，“URL:+URL”）；
}
新建RequestTask（）.execute（url）；
返回url；
}
公共void setLogging（布尔状态）{
isLogging=状态；
}
公共字符串getStatus（文档文档）{
NodeList nl1=doc.getElementsByTagName（“状态”）；
节点node1=nl1。项（0）；
如果（isLogging）{
Log.i（“谷歌方向”，“状态：+node1.getTextContent（））；
}
返回node1.getTextContent（）；
}
公共字符串[]getDurationText（文档文档）{
NodeList nl1=doc.getElementsByTagName（“持续时间”）；
String[]arr_str=新字符串[nl1.getLength（）-1]；
对于（int i=0；i<（nl1.getLength（）-1）；i++）{
节点node1=nl1.项目（i）；
NodeList nl2=node1.getChildNodes（）；//返回节点的子节点（持续时间包含文本和值）
节点node2=nl2.item（getNodeIndex（nl2，text））；
arr_str[i]=node2.getTextContent（）；
如果（isLogging）{
Log.i（“谷歌方向”，
“DurationText:+node2.getTextContent（））；
}
}
返回arr_str；
}
public int[]getDurationValue（文档文档）{
NodeList nl1=doc.getElementsByTagName（“持续时间”）；
int[]arr_int=new int[nl1.getLength（）-1]；
对于（int i=0；i<（nl1.getLength（）-1）；i++）{
节点node1=nl1.项目（i）；
NodeList nl2=node1.getChildNodes（）；
节点node2=nl2.item（getNodeIndex（nl2，value））；
arr_int[i]=Integer.parseInt（node2.getTextContent（））；
如果（isLogging）{
Log.i（“谷歌方向”，“持续时间：”+
node2.getTextContent（））；
}
}
返回arr_int；
}
公共字符串getTotalDurationText（文档文档）{
NodeList nl1=doc.getElementsByTagName（“持续时间”）；
节点node1=nl1.item（nl1.getLength（）-1）；
NodeList nl2=node1.getChildNodes（）；
节点node2=nl2.item（getNodeIndex（nl2，text））；
如果（isLogging）{
Log.i（“谷歌方向”，“Tot”
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import org.w3c.dom.Document;
public class MapsActivity extends FragmentActivity {
private GoogleMap mMap; // Might be null if Google Play services APK is not available.
private GoogleDirection gd;
private LatLng Arret=new LatLng(30.413647, -9.555608);
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
gd = new GoogleDirection(this);
setUpMapIfNeeded();
}
@Override
protected void onResume() {
super.onResume();
setUpMapIfNeeded();
}
/**
* Sets up the map if it is possible to do so (i.e., the Google Play services APK is correctly
* installed) and the map has not already been instantiated.. This will ensure that we only ever
* call {@link #setUpMap()} once when {@link #mMap} is not null.
* <p>
* If it isn't installed {@link SupportMapFragment} (and
* {@link com.google.android.gms.maps.MapView MapView}) will show a prompt for the user to
* install/update the Google Play services APK on their device.
* <p>
* A user can return to this FragmentActivity after following the prompt and correctly
* installing/updating/enabling the Google Play services. Since the FragmentActivity may not
* have been completely destroyed during this process (it is likely that it would only be
* stopped or paused), {@link #onCreate(Bundle)} may not be called again so we should call this
* method in {@link #onResume()} to guarantee that it will be called.
*/
private void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the map.
if (mMap == null) {
// Try to obtain the map from the SupportMapFragment.
mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
.getMap();
mMap.setMyLocationEnabled(true);
// Check if we were successful in obtaining the map.
if (mMap != null) {
setUpMap();
}
}
}
/**
* This is where we can add markers or lines, add listeners or move the camera. In this case, we
* just add a marker near Africa.
* <p>
* This should only be called once and when we are sure that {@link #mMap} is not null.
*/
private void setUpMap() {
MyLocation loc=new MyLocation(this);
mMap.addMarker(new MarkerOptions().position(new LatLng(loc.getLatitude(),loc.getLongitude()))
.icon(BitmapDescriptorFactory.defaultMarker(
BitmapDescriptorFactory.HUE_BLUE)));
mMap.addMarker(new MarkerOptions().position(Arret)
.icon(BitmapDescriptorFactory.defaultMarker(
BitmapDescriptorFactory.HUE_BLUE)));
gd.setOnDirectionResponseListener(new GoogleDirection.OnDirectionResponseListener() {
@Override
public void onResponse(String status, Document doc, GoogleDirection gd) {
mMap.addPolyline(gd.getPolyline(doc, 3, Color.RED));
gd.getTotalDurationValue(doc);
}
});
gd.setLogging(true);
//LatLng test=new LatLng((loc.getLatitude()+0.1f),(loc.getLongitude()+0.5f));
gd.request(new LatLng(loc.getLatitude(),loc.getLongitude()), Arret , GoogleDirection.MODE_WALKING);
}
}
public interface OnTaskCompleted{
void onTaskCompleted(Document doc);
}
public YourActivity implements OnTaskCompleted{
//your Activity
}
public YourTask extends AsyncTask<Object,Object,Object>{
private OnTaskCompleted listener;
// all your stuff
public YourTask(OnTaskCompleted listener){
this.listener=listener;
}
protected void onPostExecute(Object o){
listener.onTaskCompleted(doc);
}
}
private class RequestTask extends AsyncTask<String, Void, Document> {
private MainClass myClass
public RequestTask(MainClass myClass){
this.myClass = myClass
}
...
protected void onPostExecute(Document doc) {
super.onPostExecute(doc);
myClass.myMethod(doc);
}
...
}
protected void onPostExecute(Document doc) {
documentIsReady(doc);
}
}
public void documentIsReady(Document doc)
{
//Do somehting
}