第一行代码的酷欧天气ChooseAreaActivity，showProgressDialog();总是显示报错，根据原版的代码修改后依然如此，想知道是什么原因。
以下是代码：
package activity;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.text.TextUtils;
import android.view.View;
import android.view.Window;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import com.baoyu.coolweather1.R;
import model.City;
import model.CoolWeatherDB;
import model.County;
import model.Province;
import util.HttpCallbackListener;
import util.HttpUtil;
import util.Utility;
public class ChooseAreaActivity extends Activity {
public static final int LEVEL_PROVINCE = 0;
public static final int LEVEL_CITY = 1;
public static final int LEVEL_COUNTY = 2;
private ProgressDialog progressDialog;
private TextView titleText;
private ListView listView;
private ArrayAdapter<String> adapter;
private CoolWeatherDB coolWeatherDB;
private List<String> dataList = new ArrayList<String>();
/*
* 省列表
* */
private List<Province> provinceList;
/*
* 市列表
* */
private List<City> cityList;
/*
* 县列表
* */
private List<County> countyList;
/*
* 选中的省份
* */
private Province selectedProvince;
/*
* 选中的城市
* */
private City selectedCity;
/*
* 当前选中的级别
* */
private int currentLevel;
/*
* 是否从WeatherActivity中跳转过来
* */
private boolean isFromWeatherActivity;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
isFromWeatherActivity = getIntent().getBooleanExtra("from_weather_activity", false);
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
//已经选择了城市且不是从WeatherActivity跳转过来，才会直接转到WeatherActivity
if (prefs.getBoolean("city_selected", false) && !isFromWeatherActivity) {
Intent intent = new Intent(this, WeatherActivity.class);
startActivity(intent);
finish();
return;
}
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.choose_area);
listView = (ListView) findViewById(R.id.list_view);
titleText = (TextView) findViewById(R.id.title_text);
adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, dataList);
listView.setAdapter(adapter);
coolWeatherDB = CoolWeatherDB.getInstance(this);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View view, int index, long arg3) {
if (currentLevel == LEVEL_PROVINCE) {
selectedProvince = provinceList.get(index);
queryCities();
} else if (currentLevel == LEVEL_CITY) {
selectedCity = cityList.get(index);
queryCounties();
} else if (currentLevel == LEVEL_COUNTY) {
String countyCode = countyList.get(index).getCountyCode();
Intent intent = new Intent(ChooseAreaActivity.this, WeatherActivity.class);
intent.putExtra("county_code", countyCode);
startActivity(intent);
finish();
}
}
});
queryProvinces();//加载省级数据
}
/*
* 查询全国所有的省，优先从数据库查询，如果没有查询到再去服务器上查询
* */
private void queryProvinces(){
provinceList = coolWeatherDB.loadProvinces();
if (provinceList.size() > 0) {
dataList.clear();
for (Province province : provinceList) {
dataList.add(province.getProvinceName());
}
adapter.notifyDataSetChanged();
listView.setSelection(0);
titleText.setText("中国");
currentLevel = LEVEL_PROVINCE;
} else {
queryFromServer(null, "province");
}
}
/*
* 查询选中省内所有的市，优先从数据库中查询，如果没有查询到再去服务器上查询
* */
private void queryCities() {
cityList = coolWeatherDB.loadCities(selectedProvince.getId());
if (cityList.size() > 0) {
dataList.clear();
for (City city : cityList) {
dataList.add(city.getCityName());
}
adapter.notifyDataSetChanged();
listView.setSelection(0);
titleText.setText(selectedProvince.getProvinceName());
currentLevel = LEVEL_CITY;
} else {
queryFromServer(selectedProvince.getProvinceCode(), "city");
}
}
/*
* 查询选中市内所有的县，优先从数据库中查询，如果没有查询到再去服务器上查询
* */
private void queryCounties() {
countyList = coolWeatherDB.loadCounties(selectedCity.getId());
if (countyList.size() > 0) {
dataList.clear();
for (County county : countyList) {
dataList.add(county.getCountyName());
}
adapter.notifyDataSetChanged();
listView.setSelection(0);
titleText.setText(selectedCity.getCityName());
currentLevel = LEVEL_COUNTY;
} else {
queryFromServer(selectedCity.getCityCode(), "county");
}
}
/*
*根据传入的代号和类型从服务器上查询省市县数据
* */
private void queryFromServer(final String code, final String type) {
String address;
if (!TextUtils.isEmpty(code)) {
address = "http://www.weather.com.cn/data/list3/city" + code + ".xml";
} else {
address = "http://www.weather.com.cn/data/list3/city.xml";
}
showProgressDialog();
HttpUtil.sendHttpRequest(address, new HttpCallbackListener() {
@Override
public void onFinish(String response) {
boolean result = false;
if ("province".equals(type)) {
result = Utility.handleProvincesResponse(coolWeatherDB, response);
} else if ("city".equals(type)) {
result = Utility.handleCitiesResponse(coolWeatherDB, response, selectedProvince.getId());
} else if ("county".equals(type)) {
result = Utility.handleCountiesResponse(coolWeatherDB, response,selectedCity.getId());
}
if (result) {
runOnUiThread(new Runnable() {
@Override
public void run() {
closeProgressDialog();
if ("province".equals(type)) {
queryProvinces();
} else if ("city".equals(type)) {
queryCities();
} else if ("county".equals(type)) {
queryCounties();
}
}
});
}
}
@Override
public void onError(Exception e) {
runOnUiThread(new Runnable() {
@Override
public void run() {
closeProgressDialog();
Toast.makeText(ChooseAreaActivity.this, "加载失败",Toast.LENGTH_SHORT).show();
}
});
}
});
}
/*
* 显示进度对话框
* */
private void closeProgressDialog() {
if (progressDialog == null) {
progressDialog = new ProgressDialog(this);
progressDialog.setMessage("正在加载...");
progressDialog.setCanceledOnTouchOutside(false);
}
progressDialog.show();
}
/*
* 关闭进度对话框
* */
private void closeProgressDialog() {
if (progressDialog != null) {
progressDialog.dismiss();
}
}
/*
* 捕获Back按键，根据当前的级别来判断，此时应返回市列表、省列表、还是直接退出
* */
@Override
public void onBackPressed() {
if (currentLevel == LEVEL_COUNTY) {
queryCities();
} else if (currentLevel == LEVEL_CITY) {
queryProvinces();
} else {
if (isFromWeatherActivity) {
Intent intent = new Intent(this, WeatherActivity.class);
startActivity(intent);
}
finish();
}
}
}
