代码
先是获取数据和解析数据的数据库和代码，这些书上已经有了就不赘言
了。
ChooseAreaActivity：
一、在ChooseAreaActivity开头要先进行两个判断：
1、判断这个Activity从何而来：当数据库里没有城市信息，即用户第一次用这个APP时会先进入这个Activity，而通过WeatherAddActivity添加城市时也会跳入这个Activity。
SharedPreferences prefs=PreferenceManager.getDefaultSharedPreferences(this);
flag=prefs.getBoolean("Where",false);
2、判断数据库里有多少行数据：
List countyAdditions=DataSupport.findAll(County_Addition.class);
for(County_Addition countyAddition:countyAdditions){
number++;
}
二、接着根据这两个判断执行不同代码：
1、(flag==false)&&(number>0)：数据库中已有城市数据，说明用户非第一次使用这个APP，直接跳过该Activity。
if((flag==false)&&(number>0)){
Intent intent1=new Intent(ChooseAreaActivity.this,WeatherActivity.class);
startActivity(intent1);
finish();
}
除了上面这个情况外，接下来都会进入ListView的点击事件。
2、number==0：说明数据库为空，先存储你点击的城市信息。
2.1、flag==true：说明是从WeatherAddActivity进入该Activity的，直接finish()；
2.2、flag==false：说明用户第一次使用该APP。
if(number==0){
countySave.setDef(true);
countySave.setCountyWeatherId(countyList.get(position).getWeatherId());
countySave.setWeatherName(countyList.get(position).getCountyName());
countySave.setCountyWeather("");
countySave.save();
if(flag==true)
finish();
else if(flag==false) {
Intent intent3 = new Intent(ChooseAreaActivity.this, WeatherActivity.class);
startActivity(intent3);
finish();
}
}
3、number!=0：是从WeatherAddActivity跳到该Activity的。
3.1、点击的城市已在数据库中：
Boolean flag2=true;
List countyAdditions=DataSupport.findAll(County_Addition.class);
for(County_Addition countyAddition:countyAdditions){
if(countyAddition.getWeatherName().equals(countyList.get(position).getCountyName())){
Toast.makeText(ChooseAreaActivity.this,"已添加该城市",Toast.LENGTH_SHORT).show();
flag2=false;
}
}
3.2、点击的城市未在数据库中：存储点击的城市数据，并退回到WeatherAddActivity。
if(flag2){
countySave.setDef(false);
countySave.setCountyWeatherId(countyList.get(position).getWeatherId());
countySave.setWeatherName(countyList.get(position).getCountyName());
countySave.setCountyWeather("");
countySave.save();
finish();
}
4、已被添加的城市在ListView中的显示方式：
countyList=DataSupport.where("cityId=?",String.valueOf(selectedCity.getId())).find(County.class);
if(countyList.size()>0){
dataList.clear();
Boolean flag=false;
for(County county:countyList){
List countyAdditions=DataSupport.findAll(County_Addition.class);
for(County_Addition countyAddition:countyAdditions){
if(countyAddition.getWeatherName().equals(county.getCountyName())){
flag=true;
break;
}
}
if(flag){
dataList.add("√|"+county.getCountyName());
flag=false;
} else
dataList.add(county.getCountyName());
}
adapter.notifyDataSetChanged();
listView.setSelection(0);
}
前面只写了修改的部分，最后献上ChooseAreaActivity的所有代码，有些乱。
public class ChooseAreaActivity extends AppCompatActivity {
public static final int LEVEL_PROVINCE=0;
public static final int LEVEL_CITY=1;
public static final int LEVEL_COUNTY=2;
private int number=0;
private ProgressDialog progressDialog;
private TextView title;
private Button btn_back;
private ListView listView;
private ArrayAdapter adapter;
private List dataList=new ArrayList<>();
private List provinceList;
private List cityList;
private List countyList;
private Province selectedProvince;
private City selectedCity;
private int currentLevel;
private County_Addition county_addition;
private Boolean flag=false;
@Nullable
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_choose_area);
inited();
//判断是否是从WeatherAddActivity跳过来的
SharedPreferences prefs= PreferenceManager.getDefaultSharedPreferences(this);
flag=prefs.getBoolean("Where",false);
//判断城市添加表里有多少组数据
List countyAdditions=DataSupport.findAll(County_Addition.class);
Log.d("TAG","number:"+number+"");
for(County_Addition countyAddition:countyAdditions){
number++;
}
Log.d("ChooseAreaActivity",number+"");
Log.d("ChooseAreaActivity",flag+"");
if((flag==false)&&(number>0)){
Intent intent1=new Intent(ChooseAreaActivity.this,WeatherActivity.class);
startActivity(intent1);
finish();
}
SharedPreferences.Editor editor= PreferenceManager.
getDefaultSharedPreferences(ChooseAreaActivity.this).edit();
editor.putBoolean("Where",false);
editor.apply();
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView parent, View view, int position, long id) {
if(currentLevel==LEVEL_PROVINCE){
selectedProvince=provinceList.get(position);
queryCities();
}else if(currentLevel==LEVEL_CITY){
selectedCity=cityList.get(position);
queryCounties();
}else if(currentLevel==LEVEL_COUNTY){
County_Addition countySave=new County_Addition();
Log.d("TAG","number:"+number+"");
if(number==0){
countySave.setDef(true);
countySave.setCountyWeatherId(countyList.get(position).getWeatherId());
countySave.setWeatherName(countyList.get(position).getCountyName());
countySave.setCountyWeather("");
countySave.save();
if(flag==true)
finish();
else if(flag==false) {
Intent intent3 = new Intent(ChooseAreaActivity.this, WeatherActivity.class);
startActivity(intent3);
finish();
}
}else{
Boolean flag2=true;
List countyAdditions=DataSupport.findAll(County_Addition.class);
for(County_Addition countyAddition:countyAdditions){
Log.d("Choose",countyList.get(position).getCountyName());
Log.d("Choose",countyAddition.getWeatherName());
if(countyAddition.getWeatherName().equals(countyList.get(position).getCountyName())){
Toast.makeText(ChooseAreaActivity.this,"已添加该城市",Toast.LENGTH_SHORT).show();
flag2=false;
}
Log.d("Choose",flag2+"");
}
if(flag2){
countySave.setDef(false);
countySave.setCountyWeatherId(countyList.get(position).getWeatherId());
countySave.setWeatherName(countyList.get(position).getCountyName());
countySave.setCountyWeather("");
countySave.save();
finish();
}
}
}
}
});
btn_back.setOnClickListener(new View.OnClickListener(){
public void onClick(View view){
if(currentLevel==LEVEL_COUNTY){
queryCities();
}
if(currentLevel==LEVEL_CITY){
queryProvinces();
}
}
});
queryProvinces();
}
private void inited(){
title=(TextView)findViewById(R.id.text_title);
btn_back=(Button)findViewById(R.id.btn_back);
listView=(ListView)findViewById(R.id.listView);
adapter=new ArrayAdapter<>(this,android.R.layout.simple_list_item_1,dataList);
listView.setAdapter(adapter);
county_addition=new County_Addition();
}
private void queryProvinces(){
title.setText("中国");
btn_back.setVisibility(View.GONE);
provinceList= DataSupport.findAll(Province.class);
if(provinceList.size()>0){
dataList.clear();
for(Province province:provinceList){
dataList.add(province.getProvinceName());
}
adapter.notifyDataSetChanged();
listView.setSelection(0);
currentLevel=LEVEL_PROVINCE;
}else{
String address="http://guolin.tech/api/china";
queryFromServer(address,"province");
}
}
private void queryCities(){
title.setText(selectedProvince.getProvinceName());
btn_back.setVisibility(View.VISIBLE);
cityList=DataSupport.where("provinceId=?",String.valueOf(selectedProvince.getId())).find(City.class);
if(cityList.size()>0){
dataList.clear();
for(City city:cityList){
dataList.add(city.getCityName());
}
adapter.notifyDataSetChanged();
listView.setSelection(0);
currentLevel=LEVEL_CITY;
}else{
int provinceCode=selectedProvince.getProvinceCode();
String address="http://guolin.tech/api/china/"+provinceCode;
queryFromServer(address,"city");
}
}
private void queryCounties(){
title.setText(selectedCity.getCityName());
btn_back.setVisibility(View.VISIBLE);
countyList=DataSupport.where("cityId=?",String.valueOf(selectedCity.getId())).find(County.class);
if(countyList.size()>0){
dataList.clear();
Boolean flag=false;
for(County county:countyList){
List countyAdditions=DataSupport.findAll(County_Addition.class);
for(County_Addition countyAddition:countyAdditions){
if(countyAddition.getWeatherName().equals(county.getCountyName())){
flag=true;
break;
}
}
if(flag){
dataList.add("√|"+county.getCountyName());
flag=false;
} else
dataList.add(county.getCountyName());
}
adapter.notifyDataSetChanged();
listView.setSelection(0);
currentLevel=LEVEL_COUNTY;
}else{
int provinceCode=selectedProvince.getProvinceCode();
int cityCode=selectedCity.getCityCode();
String address="http://guolin.tech/api/china/"+provinceCode+"/"+cityCode;
queryFromServer(address,"county");
}
}
private void queryFromServer(String address, final String type){
showProgressDialog();
HttpUtil.sendOkHttpRequest(address, new Callback() {
public void onResponse(Call call, Response response) throws IOException {
String responseText=response.body().string();
boolean result=false;
if("province".equals(type)){
result= Utility.handleProvinceResponse(responseText);
}else if("city".equals(type)){
result=Utility.handleCityResponse(responseText,selectedProvince.getId());
}else if("county".equals(type)){
result=Utility.handleCountyResponse(responseText,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();
}
}
});
}
}
public void onFailure(Call call, IOException e) {
runOnUiThread(new Runnable() {
@Override
public void run() {
closeProgressDialog();
Toast.makeText(ChooseAreaActivity.this,"加载失败",Toast.LENGTH_SHORT).show();
}
});
}
});
}
private void showProgressDialog(){
if(progressDialog==null){
progressDialog=new ProgressDialog(ChooseAreaActivity.this);
progressDialog.setMessage("正在加载...");
progressDialog.setCanceledOnTouchOutside(false);
}
progressDialog.show();
}
private void closeProgressDialog(){
if(progressDialog!=null){
progressDialog.dismiss();
}
}
}
NEXT：
酷欧天气2.0（三）——查看已添加城市WeatherAddActivity
https://www.jianshu.com/p/986559f4f8bf