另外，当我仅更改屏幕方向时，数据就会更新。
当我敬酒数据时，它会在5秒钟后发生变化，但这并不是为什么数据没有更新的原因。onPreExecute()每5秒钟也会工作一次
1.这是我的update.java文件
public class update extends Activity implements LocationListener {
protected String mLatitudeText;
protected String mLongitudeText;
protected String mCode = "1001";
protected java.net.URL url;
protected HttpURLConnection conn;
android.os.Handler customHandler;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
requestPermissions(new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION}, 0);
return;
}
LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
lm.requestLocationUpdates(LocationManager.PASSIVE_PROVIDER, 5, 0, (android.location.LocationListener) this);
Location mLastLocation = lm.getLastKnownLocation(LocationManager.PASSIVE_PROVIDER);
mLatitudeText = (String.valueOf(mLastLocation.getLatitude()));
mLongitudeText = (String.valueOf(mLastLocation.getLongitude()));
final android.os.Handler handler = new android.os.Handler();
Timer timer = new Timer();
TimerTask backtask = new TimerTask() {
@Override
public void run() {
handler.post(new Runnable() {
public void run() {
try {
LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Location mLastLocation = lm.getLastKnownLocation(LocationManager.PASSIVE_PROVIDER);
mLatitudeText = (String.valueOf(mLastLocation.getLatitude()));
mLongitudeText = (String.valueOf(mLastLocation.getLongitude()));
String[] s = new String[3];
s[0]=mCode;
s[1]=mLatitudeText;
s[2]=mLongitudeText;
Toast.makeText(getApplicationContext(), mLatitudeText + " and " + mLongitudeText, Toast.LENGTH_LONG).show();
makePOST.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR,s);
} catch (Exception e) {
// TODO Auto-generated catch block
}
}
});
}
};
timer.schedule(backtask, 0, 5000);
}
AsyncTask<String, Void, String> makePOST=new AsyncTask<String, Void, String>(){
protected void onPreExecute() {
Toast.makeText(update.this, "onPreExecute", Toast.LENGTH_LONG).show();
}
protected String doInBackground(String... params) {
try {
mCode=params[0];
mLongitudeText=params[1];
mLongitudeText=params[2];
url = new URL("http://student.96.lt/Android/update.php");
conn = (HttpURLConnection) url.openConnection();
conn.setDoOutput(true);
conn.setDoInput(true);
conn.setRequestMethod("POST");
String postdat = "code" + "=" + URLEncoder.encode(mCode, "UTF-8") + "&" + "latitude" + "=" + URLEncoder.encode(mLatitudeText, "UTF-8") + "&" + "longitude" + "=" + URLEncoder.encode(mLongitudeText, "UTF-8");
//String postdat=mLatitudeText;
conn.setFixedLengthStreamingMode(postdat.getBytes().length);
conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
OutputStream OS = conn.getOutputStream();
BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(OS, "UTF-8"));
bufferedWriter.write(postdat);
bufferedWriter.flush();
// Get output
bufferedWriter.close();
} catch (java.net.MalformedURLException ex) {
//Toast.makeText(this, ex.toString(), duration ).show();
} catch (java.io.IOException ex) {
//Toast.makeText(this, ex.toString(), duration).show();
}
return null;
}
};
@Override
public void onLocationChanged (Location location){
}
@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
}
}
请帮助我，我才刚刚入门。
最佳答案
一个任务只能运行一次。要再次运行相同的代码，您需要创建一个新的AsyncTask对象。它会抛出一个异常来告诉您，但是您忽略了所有异常（通常是一个坏主意）。