android实现天气预报App（1）——全国省、市、县三级列表

野性酷女 2023-08-17 17:05 82阅读 0赞

### 前期准备工作 ###

首先创建XXXWeather项目，具体的我就不多说  
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**这里使用LitePal来管理App的数据库**  
我们在app/build.gradle文件中增加App需要用到的依赖

implementation 'com.google.android.material:material:1.0.0'
     implementation 'org.litepal.android:core:1.4.1'
     implementation 'com.squareup.okhttp3:okhttp:3.10.0'
     implementation 'com.google.code.gson:gson:2.8.2'
     implementation 'com.github.bumptech.glide:glide:4.5.0'

### 获取城市信息 ###

*  我们获取城市数据是来自郭霖大神给的接口`http://guolin.tech/api/china`，具体情况《第一行代码》第十四章会有讲解。
 *  创建db文件夹，在文件夹内部增加三个类，LitePal中的每一个实体类都要继承自DataSupport类的  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwODQwNDU5_size_16_color_FFFFFF_t_70 1]

public class Province extends DataSupport {
        private int id;
        private String provinceName;
        private int provinceCode;
    
       /* public Province(int id, String provinceName, int provinceCode) {
            this.id = id;
            this.provinceName = provinceName;
            this.provinceCode = provinceCode;
        }*/
    
        public int getId() {
            return id;
        }
    
        public void setId(int id) {
            this.id = id;
        }
    
        public int getProvinceCode() {
            return provinceCode;
        }
    
        public void setProvinceCode(int provinceCode) {
            this.provinceCode = provinceCode;
        }
    
        public String getProvinceName() {
            return provinceName;
        }
    
        public void setProvinceName(String provinceName) {
            this.provinceName = provinceName;
        }
    }

public class City extends DataSupport {
        private int id;
        private String cityName;
        private int cityCode;
        private int provinceId;
    
       /* public City(int id, String cityName, int cityCode, int provinceId) {
            this.id = id;
            this.cityName = cityName;
            this.cityCode = cityCode;
            this.provinceId = provinceId;
        }*/
    
        public int getId() {
            return id;
        }
    
        public void setId(int id) {
            this.id = id;
        }
    
        public String getCityName() {
            return cityName;
        }
    
        public void setCityName(String cityName) {
            this.cityName = cityName;
        }
    
        public int getCityCode() {
            return cityCode;
        }
    
        public void setCityCode(int cityCode) {
            this.cityCode = cityCode;
        }
    
        public int getProvinceId() {
            return provinceId;
        }
    
        public void setProvinceId(int provinceId) {
            this.provinceId = provinceId;
        }
    }

public class County extends DataSupport {
        private int id;
        private String countyName;
        private String weatherId;
        private int cityId;
    
        public County(int id, String countyName, String weatherId, int cityId) {
            this.id = id;
            this.countyName = countyName;
            this.weatherId = weatherId;
            this.cityId = cityId;
        }
        public int getId() {
            return id;
        }
    
        public void setId(int id) {
            this.id = id;
        }
    
        public String getCountyName() {
            return countyName;
        }
    
        public void setCountyName(String countyName) {
            this.countyName = countyName;
        }
    
        public String getWeatherId() {
            return weatherId;
        }
    
        public void setWeatherId(String weatherId) {
            this.weatherId = weatherId;
        }
    
        public int getCityId() {
            return cityId;
        }
    
        public void setCityId(int cityId) {
            this.cityId = cityId;
        }
    }

*  接下来就是要配置litepal.xml文件，创建assets文件夹，在目录里创建litepal.xml

*  在AndroidManifest.xml中增加

<application
            android:name="org.litepal.LitePalApplication"

### 遍历省市县数据 ###

*  数据都是从服务端获取的，可以在utils文件夹下增加一个`HttpUtil`类，具体代码如下

public class HttpUtil {
        public static void sendOkHttpRequest(String address, okhttp3.Callback callback) {
            OkHttpClient client = new OkHttpClient();
            Request request = new Request.Builder().url(address).build();
            client.newCall(request).enqueue(callback);
        }
    }

*  由于返回的城市数据都是json格式，我们在创建一个解析和处理json数据的工具类`Utility`,具体代码如下：

public class Utility {
        /**
         * 解析服务器返回的省级数据
         */
        public static boolean handleProvinceResponse(String response) {
            if (!TextUtils.isEmpty(response)) {
                try {
                    JSONArray allProvinces = new JSONArray(response);
                    for (int i = 0; i < allProvinces.length(); i++) {
                        JSONObject provinceObject = allProvinces.getJSONObject(i);
                        Province province = new Province();
                        province.setProvinceName(provinceObject.getString("name"));
                        province.setProvinceCode(provinceObject.getInt("id"));
                        province.save();
                    }
                    return true;
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
            return false;
        }
    
        /**
         * 解析服务器返回的市级数据
         */
        public static boolean handleCityResponse(String response, int provinceId) {
            if (!TextUtils.isEmpty(response)) {
                try {
                    JSONArray allCities = new JSONArray(response);
                    for (int i = 0; i < allCities.length(); i++) {
                        JSONObject cityObject = allCities.getJSONObject(i);
                        City city = new City();
                        city.setCityName(cityObject.getString("name"));
                        city.setCityCode(cityObject.getInt("id"));
                        city.setProvinceId(provinceId);
                        city.save();
                    }
                    return true;
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
            return false;
        }
    
        /**
         * 解析服务器返回的县级数据
         */
        public static boolean handleCountyResponse(String response, int cityId) {
            if (!TextUtils.isEmpty(response)) {
                try {
                    JSONArray allCounties = new JSONArray(response);
                    for (int i = 0; i < allCounties.length(); i++) {
                        JSONObject countyObject = allCounties.getJSONObject(i);
                        County county = new County();
                        county.setCountyName(countyObject.getString("name"));
                        county.setWeatherId(countyObject.getString("weather_id"));
                        county.setCityId(cityId);
                        county.save();
                    }
                    return true;
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
            return false;
        }
    }

*  现在我们就开始写界面布局了，由于城市三级列表我们在后面还要使用，因此就不写成Activity了，写在碎片Fragment里面，方便在后面使用的时候直接在布局里面引用碎片。  
    在layout文件夹里创建choose\_area.xml文件

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:background="#fff"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
    
        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="@color/cardview_dark_background">
            <TextView
                android:id="@+id/title"
                android:text="中国"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="25dp"
                android:layout_centerHorizontal="true"
                android:textColor="#fff"
                android:textSize="20sp"/>
    
            <ImageButton
                android:id="@+id/back"
                android:layout_width="25dp"
                android:layout_height="25dp"
                android:layout_alignParentLeft="true"
                android:layout_alignParentBottom="true"
                android:layout_marginBottom="5dp"
                android:layout_marginLeft="10dp"
                android:background="@drawable/ic_back" />
        </RelativeLayout>
    
        <ListView
            android:id="@+id/list"
            android:layout_width="match_parent"
            android:layout_height="match_parent">
        </ListView>
    
    </LinearLayout>

*  接下来就是创建用于遍历省市县数据的碎片文件了。新建ChooseAreaFragment继承自Fragment

public class ChooseAreaFragment extends Fragment {
    
        public static final int LEVEL_PROVINCE = 0;
        public static final int LEVEL_CITY = 1;
        public static final int LEVEL_COUNTY = 2;
    
        private ProgressBar mProgressBar;
    
        private TextView mTitleText;
        private ImageButton mBackButton;
        private ListView mListView;
        private ArrayAdapter<String> mAdapter;
        private List<String> dataList = new ArrayList<>();
        private List<Province> mProvinceList;
        private List<City> mCityList;
        private List<County> mCountyList;
    
        private Province selectedProvice;
        private City selectedCity;
        private int currentLevel;   //当前选中的级别
    
        @Nullable
        @Override
        public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
            View view = inflater.inflate(R.layout.choose_area, container, false);
            mTitleText = view.findViewById(R.id.title);
            mBackButton = view.findViewById(R.id.back);
            mListView = view.findViewById(R.id.list);
            mAdapter = new ArrayAdapter<>(getContext(), android.R.layout.simple_list_item_1, dataList);
            mListView.setAdapter(mAdapter);
            return view;
    
        }
    
        @Override
        public void onActivityCreated(@Nullable Bundle savedInstanceState) {
            super.onActivityCreated(savedInstanceState);
    
            mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> adapterView, View view, int pos, long id) {
                    if (currentLevel == LEVEL_PROVINCE) {
                        selectedProvice = mProvinceList.get(pos);
                        queryCities();
                    } else if (currentLevel == LEVEL_CITY) {
                        selectedCity = mCityList.get(pos);
                        queryCounties();
                    } else if (currentLevel == LEVEL_COUNTY) {
                        String weatherId = mCountyList.get(pos).getWeatherId();
                        String countyName = mCountyList.get(pos).getCountyName();
                        if (getActivity() instanceof MainActivity) {
    
                            Intent intent = new Intent(getActivity(), WeatherActivity.class);
                            intent.putExtra("weather_id", weatherId);
                            intent.putExtra("county_name",countyName);
                            startActivity(intent);
                            getActivity().finish();
                        } else if (getActivity() instanceof WeatherActivity) {
                            WeatherActivity activity = (WeatherActivity) getActivity();
                            activity.drawerLayout.closeDrawers();
                            activity.mSwipeRefresh.setRefreshing(true);
                            activity.requestWeather(weatherId);
                        }
                    }
                }
            });
    
            mBackButton.setOnClickListener(new View.OnClickListener(){
                @Override
                public void onClick(View view) {
                    if (currentLevel == LEVEL_COUNTY) {
                        queryCities();
                    } else if (currentLevel == LEVEL_CITY) {
                        queryProvinces();
                    }
                }
            });
            queryProvinces();
        }
    
        private void queryProvinces() {
            mTitleText.setText("中国");
            mBackButton.setVisibility(View.GONE);
            mProvinceList = DataSupport.findAll(Province.class);
            if (mProvinceList.size() > 0) {
                dataList.clear();
                for (Province province : mProvinceList) {
                    dataList.add(province.getProvinceName());
                }
                mAdapter.notifyDataSetChanged();
                mListView.setSelection(0);
                currentLevel = LEVEL_PROVINCE;
            } else {
                String address = "http://guolin.tech/api/china";
                queryFromServer(address, "province");
            }
        }
    
        private void queryCities() {
            mTitleText.setText(selectedProvice.getProvinceName());
            mBackButton.setVisibility(View.VISIBLE);
            mCityList = DataSupport.where("provinceId = ?", String.valueOf(selectedProvice.getId())).find(City.class);
            if (mCityList.size() > 0) {
                dataList.clear();
                for (City city : mCityList) {
                    dataList.add(city.getCityName());
                }
                mAdapter.notifyDataSetChanged();
                mListView.setSelection(0);
                currentLevel = LEVEL_CITY;
            } else {
                int provinceCode = selectedProvice.getProvinceCode();
                String address = "http://guolin.tech/api/china/" + provinceCode;
                queryFromServer(address, "city");
            }
    
        }
    
        private void queryCounties() {
            mTitleText.setText(selectedCity.getCityName());
            mBackButton.setVisibility(View.VISIBLE);
            mCountyList = DataSupport.where("cityId = ?", String.valueOf(selectedCity.getId())).find(County.class);
            if (mCountyList.size() > 0) {
                dataList.clear();
                for (County county : mCountyList) {
                    dataList.add(county.getCountyName());
                }
                mAdapter.notifyDataSetChanged();
                mListView.setSelection(0);
                currentLevel = LEVEL_COUNTY;
            } else {
                int provinceCode = selectedProvice.getProvinceCode();
                int cityCode = selectedCity.getCityCode();
                String address = "http://guolin.tech/api/china/" + provinceCode + "/" + cityCode;
                queryFromServer(address, "county");
            }
        }
    
    
        //根据传入的地址和服务类型从服务器上查询省市县数据
        private void queryFromServer(String address, final String type) {
            HttpUtil.sendOkHttpRequest(address, new okhttp3.Callback() {
                @Override
                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, selectedProvice.getId());
                    } else if ("county".equals(type)) {
                        result = Utility.handleCountyResponse(responseText, selectedCity.getId());
                    }
                    if (result) {
                        getActivity().runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                //closeProgressBar();
                                if ("province".equals(type)) {
                                    queryProvinces();
                                } else if ("city".equals(type)) {
                                    queryCities();
                                } else if ("county".equals(type)) {
                                    queryCounties();
                                }
                            }
                        });
                    }
                }
    
                @Override
                public void onFailure(Call call, IOException e) {
                    //通过
                    getActivity().runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            //closeProgressBar();
                            Toast.makeText(getContext(), "加载失败", Toast.LENGTH_SHORT).show();
                        }
                    });
                }
            });
        }
    }

*  我们将碎片添加到活动中它才能显示，因此我们要向activity\_main.xml中添加如下代码：

<?xml version="1.0" encoding="utf-8"?>
    <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <fragment
            android:id="@+id/choose_area_fragment"
            android:name="com.atwang.antaoweather.activity.ChooseAreaFragment"
            android:layout_width="match_parent"
            android:layout_height="match_parent"/>
    
    </FrameLayout>

当然这里还没完，还有一些后续收尾工作。

### 后续工作 ###

*  我们刚才在碎片的布局中自定义了一个标题栏，现在将原生标题栏去掉，在styles.xml中修改  
    `<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">`
 *  最最重要的是访问网络权限，它可不能忘，在AndroidManifest.xml中添加  
    `<uses-permission android:name="android.permission.INTERNET" />`

### 你以为这样就结束了吗？ ###

*  Android高版本访问网络总是会失败，因此我创建了xml文件夹，在里面增加了`network-security-config.xml`文件。

<?xml version="1.0" encoding="utf-8"?>
    <network-security-config>
        <base-config cleartextTrafficPermitted="true" />
    </network-security-config>

同时在在AndroidManifest.xml中`<application`下添加

android:networkSecurityConfig="@xml/network_security_config"

*  这次是结束了，来看图

### 请忽略这个字体 ###

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