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首先，我第一次在三週前關注了Java，所以如果這段代碼很糟糕，請耐心等待。這是學校的一項任務，我要在原型應用程序上構建併爲其提供UI，因此適配器基本上就是我爲此所做的所有工作。Android - 無法向上滾動
我的問題是，只要我觸摸滾動，我就會被拋到列表的底部，並且無法向下滾動而無法回滾。
/**
* VaxjoWeather.java
* Created: May 9, 2010
* Jonas Lundberg, LnU
*/
package dv106.weather;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StringWriter;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.List;
import android.app.ListActivity;
import android.content.Context;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
/**
* This is a first prototype for a weather app. It is currently
* only downloading weather data for Växjo.
*
* This activity downloads weather data and constructs a WeatherReport,
* a data structure containing weather data for a number of periods ahead.
*
* The WeatherHandler is a SAX parser for the weather reports
* (forecast.xml) produced by www.yr.no. The handler constructs
* a WeatherReport containing meta data for a given location
* (e.g. city, country, last updated, next update) and a sequence
* of WeatherForecasts.
* Each WeatherForecast represents a forecast (weather, rain, wind, etc)
* for a given time period.
*
* The next task is to construct a list based GUI where each row
* displays the weather data for a single period.
*
*
* @author jlnmsi
*
*/
public class VaxjoWeather extends ListActivity {
//private InputStream input;
private WeatherReport report = null;
//private ArrayList<WeatherForecast> forecastList = new ArrayList<WeatherForecast>();
private WeatherAdapter adapter;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
adapter = new WeatherAdapter(this);
setListAdapter(adapter);
//getListView().setTranscriptMode(ListView.TRANSCRIPT_MODE_DISABLED);
try {
URL url = new URL("http://www.yr.no/sted/Sverige/Kronoberg/V%E4xj%F6/forecast.xml");
AsyncTask task = new WeatherRetriever().execute(url);
} catch (IOException ioe) {
ioe.printStackTrace();
}
//adapter.notifyDataSetChanged();
}
private void PrintReportToConsole() {
if (this.report != null) {
/* Print location meta data */
//System.out.println(report);
/* Print forecasts */
int count = 0;
for (WeatherForecast forecast : report) {
count++;
adapter.add(forecast);
}
}
else {
System.out.println("Weather report has not been loaded.");
}
//adapter.notifyDataSetChanged();
}
private class WeatherRetriever extends AsyncTask<URL, Void, WeatherReport> {
protected WeatherReport doInBackground(URL... urls) {
try {
return WeatherHandler.getWeatherReport(urls[0]);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
protected void onProgressUpdate(Void... progress) {
}
protected void onPostExecute(WeatherReport result) {
report = result;
PrintReportToConsole();
}
}
// custom ArrayAdpater to show, weather icon, temperature, and precipation.
class WeatherAdapter extends ArrayAdapter<WeatherForecast> {
public WeatherAdapter(Context context) {
super(context,R.layout.forecast);
}
@Override // Called when updating the ListView
public View getView(int position, View convertView, ViewGroup parent) {
View row;
if (convertView == null) { // Create new row view object
LayoutInflater inflater = getLayoutInflater();
row = inflater.inflate(R.layout.forecast,parent,false);
}
else // reuse old row view to save time/battery
row = convertView;
// TextView for Temperature
TextView temperature = (TextView)row.findViewById(R.id.temperature);
temperature.setText(Integer.toString(this.getItem(position).getTemp())+" °C");
// TextView for out Precipation.
TextView precipation = (TextView)row.findViewById(R.id.rain);
precipation.setText(String.valueOf(this.getItem(position).getRain())+" mm");
// Image Icon for forecast.
ImageView icon = (ImageView)row.findViewById(R.id.icon);
String iconPath = "ic_";
if (this.getItem(position).getWeatherCode() <= 9){
iconPath = iconPath+"0"+(Integer.toString(this.getItem(position).getWeatherCode()));
}
else {
iconPath = iconPath+(Integer.toString(this.getItem(position).getWeatherCode()));
}
int resId = getResources().getIdentifier(iconPath, "drawable", getPackageName());
// If the resource ID is invalid, as in the image not existing, we'll add the postfix for periods.
if (resId == 0){
// Set the icon image source dependent on period code given.
if(this.getItem(position).getPeriodCode() == 3){
iconPath = iconPath +"n";
}
else if (this.getItem(position).getPeriodCode() == 2){
iconPath = iconPath +"d";
}
else {
iconPath = iconPath +"m";
}
resId = getResources().getIdentifier(iconPath, "drawable", getPackageName());
icon.setImageResource(resId);
}
// Or if everything checked out, we'll just run with the resource ID and find our Icon.
else {
icon.setImageResource(resId);
}
return row;
}
}
}
我試圖將另一個標準arrayadapter，實際上得到了相同的不必要的滾動效果，所以我不知道它是什麼的一部分我有問題與。