android實現天氣預報App（1）——全國省、市、縣三級列表

前期準備工作

首先創建XXXWeather項目，具體的我就不多說

這裏使用LitePal來管理App的數據庫
我們在app/build.gradle文件中增加App需要用到的依賴

 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'

獲取城市信息

我們獲取城市數據是來自郭霖大神給的接口http://guolin.tech/api/china，具體情況《第一行代碼》第十四章會有講解。
創建db文件夾，在文件夾內部增加三個類，LitePal中的每一個實體類都要繼承自DataSupport類的

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;
    }
}

接下來就是要配置litepal.xml文件，創建assets文件夾，在目錄裏創建litepal.xml

<litepal>
    <dbname value="xxx_weather" />
    <version value="1"/>
    <list>
        <mapping class="com.xxx.xxxweather.db.Province" />
        <mapping class="com.xxx.xxxweather.db.City" />
        <mapping class="com.xxx.xxxweather.db.County" />
    </list>
</litepal>

在AndroidManifest.xml中增加

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

遍歷省市縣數據

數據都是從服務端獲取的，可以在utils文件夾下增加一個HttpUtil類，具體代碼如下

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);
    }
}

由於返回的城市數據都是json格式，我們在創建一個解析和處理json數據的工具類Utility,具體代碼如下：

public class Utility {
    /**
     * 解析服務器返回的省級數據
     */
    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;
    }

    /**
     * 解析服務器返回的市級數據
     */
    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;
    }

    /**
     * 解析服務器返回的縣級數據
     */
    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;
    }
}

現在我們就開始寫界面佈局了，由於城市三級列表我們在後面還要使用，因此就不寫成Activity了，寫在碎片Fragment裏面，方便在後面使用的時候直接在佈局裏面引用碎片。
在layout文件夾裏創建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="中國"
            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>

接下來就是創建用於遍歷省市縣數據的碎片文件了。新建ChooseAreaFragment繼承自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;   //當前選中的級別

    @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("中國");
        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");
        }
    }


    //根據傳入的地址和服務類型從服務器上查詢省市縣數據
    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) {
                //通過
                getActivity().runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        //closeProgressBar();
                        Toast.makeText(getContext(), "加載失敗", Toast.LENGTH_SHORT).show();
                    }
                });
            }
        });
    }
}

我們將碎片添加到活動中它才能顯示，因此我們要向activity_main.xml中添加如下代碼：

<?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>

當然這裏還沒完，還有一些後續收尾工作。

後續工作

我們剛纔在碎片的佈局中自定義了一個標題欄，現在將原生標題欄去掉，在styles.xml中修改
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
最最重要的是訪問網絡權限，它可不能忘，在AndroidManifest.xml中添加
<uses-permission android:name="android.permission.INTERNET" />

你以爲這樣就結束了嗎？

Android高版本訪問網絡總是會失敗，因此我創建了xml文件夾，在裏面增加了network-security-config.xml文件。

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

同時在在AndroidManifest.xml中<application下添加

android:networkSecurityConfig="@xml/network_security_config"

這次是結束了，來看圖

android實現天氣預報App（1）——全國省、市、縣三級列表

前期準備工作

獲取城市信息

遍歷省市縣數據

後續工作

你以爲這樣就結束了嗎？

請忽略這個字體

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