Android實現(xiàn)省市區(qū)三級聯(lián)動的效果

/**     * 將assets下的資源復(fù)制到應(yīng)用程序的databases目錄下     * @param context 上下文     * @param fileName assets下的資源的文件名     */    public static void copyAssetsToDB(Context context, String fileName) throws IOException {        //數(shù)據(jù)庫的存儲路徑,該路徑在：data/data/包名/databases目錄下，        String destPath = context.getDatabasePath("").getPath();        Log.i("tag","path---->"+destPath);        File file = new File(destPath);        if (!file.exists()) {            file.mkdirs();  //創(chuàng)建目錄        }else {            return;        }
        //打開assest文件，獲得輸入流        InputStream is = context.getAssets().open(fileName);        BufferedInputStream bis = new BufferedInputStream(is);
        //獲得寫入文件的輸出流        FileOutputStream fos = new FileOutputStream(destPath +File.separator + fileName);        BufferedOutputStream bos = new BufferedOutputStream(fos);
        byte[] data = new byte[2 * 1024];        int len;        while ((len = bis.read(data)) != -1){            bos.write(data, 0, len);        }
        bos.flush();        bis.close();        bos.close();    }

//打開數(shù)據(jù)庫文件的完整路徑，來獲得sqlite數(shù)據(jù)庫對象SQLiteDatabase database = SQLiteDatabase.openOrCreateDatabase(dbPath, null);//數(shù)據(jù)庫查詢操作Cursor cursor = database.rawQuery(sql, null);        if (cursor != null) {            while (cursor.moveToNext()) {               //......查詢結(jié)果的操作            }            cursor.close();        }

    xmlns:tools="http://schemas.android.com/tools"    android:id="@+id/activity_main"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context="com.zx.copydatabase.MainActivity"    android:orientation="horizontal"    android:gravity="center"    android:padding="10dp">
                android:id="@+id/province_picker"        android:layout_width="0dp"        android:layout_height="wrap_content"        android:layout_weight="1"        android:focusable="true"        android:focusableInTouchMode="true"/>
            android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="省"        android:textColor="#000"        android:layout_marginLeft="10dp"        android:layout_marginRight="10dp"/>
                android:id="@+id/city_picker"        android:layout_width="0dp"        android:layout_height="wrap_content"        android:layout_weight="1"        android:focusable="true"        android:focusableInTouchMode="true"/>
            android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="市"        android:textColor="#000"        android:layout_marginLeft="10dp"        android:layout_marginRight="10dp"/>
                android:id="@+id/area_picker"        android:layout_width="0dp"        android:layout_height="wrap_content"        android:layout_weight="1"        android:focusable="true"        android:focusableInTouchMode="true"/>
            android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="區(qū)"        android:textColor="#000"        android:layout_marginLeft="10dp"        android:layout_marginRight="10dp"/>

public class MainActivity extends AppCompatActivity {
    private static final String DB_NAME = "mydb.db"; //數(shù)據(jù)庫名稱
    private NumberPicker provincePicker, cityPicker, areaPicker; //省市區(qū)選擇器    private AddressManager manager; //自定義的地址管理器
    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);

        //拷貝assets下的文件"mydb.db"到 應(yīng)用的databases目錄下        try {            MyUtils.copyAssetsToDB(this, DB_NAME);        } catch (IOException e) {            e.printStackTrace();        }
        //初始化“地址管理器”對象        manager = new AddressManager(getDatabasePath(DB_NAME).getPath());
        initView();        initProvince();    }
    //初始化View    private void initView() {        provincePicker = (NumberPicker) findViewById(R.id.province_picker);        cityPicker = (NumberPicker) findViewById(R.id.city_picker);        areaPicker = (NumberPicker) findViewById(R.id.area_picker);    }
    //設(shè)置“省份”選擇器的數(shù)據(jù)    private void initProvince() {        List provinceList = manager.getProvinces(); //獲取所有的省份        //設(shè)置省份的值        final String[] provinces = provinceList.toArray(new String[provinceList.size()]);        provincePicker.setDisplayedValues(provinces);        provincePicker.setMinValue(0); //設(shè)置第一個值        provincePicker.setMaxValue(provinces.length - 1); //設(shè)置最后一個值        //默認的省份的位置        int defaultProvince = provinces.length / 2 == 0 ? provinces.length / 2 : provinces.length / 2 + 1;        provincePicker.setValue(defaultProvince); //設(shè)置當前值
        //根據(jù)當前默認的省份來設(shè)置對應(yīng)的市        showCityByProvince(provinces[provincePicker.getValue()]);
        //省份的選擇事件        provincePicker.setOnValueChangedListener(new NumberPicker.OnValueChangeListener() {            @Override            public void onValueChange(NumberPicker picker, int oldVal, int newVal) {                Log.i("tag", "newVal--->" + newVal);                showCityByProvince(provinces[newVal]);            }        });    }
    //根據(jù)選擇的省份名來顯示城市名    private void showCityByProvince(String province) {        List cityList = manager.getCities(province);        //設(shè)置城市的值        final String[] cities = cityList.toArray(new String[cityList.size()]);        cityPicker.setDisplayedValues(null); //清空之前的選擇的數(shù)據(jù)        cityPicker.setMinValue(0); //設(shè)置第一個值        cityPicker.setMaxValue(cities.length - 1); //設(shè)置最后一個值        cityPicker.setDisplayedValues(cities);
        //根據(jù)當前默認的城市來設(shè)置對應(yīng)的區(qū)        showAreaByCity(cities[cityPicker.getValue()]);
        //城市的選擇事件        cityPicker.setOnValueChangedListener(new NumberPicker.OnValueChangeListener() {            @Override            public void onValueChange(NumberPicker picker, int oldVal, int newVal) {                showAreaByCity(cities[newVal]);            }        });    }
    //根據(jù)選擇的城市名來顯示區(qū)名    private void showAreaByCity(String city) {        List areaList = manager.getAreas(city);        //設(shè)置區(qū)的值        String[] areas = areaList.toArray(new String[areaList.size()]);        areaPicker.setDisplayedValues(null);        areaPicker.setMinValue(0); //設(shè)置第一個值        areaPicker.setMaxValue(areas.length - 1); //設(shè)置最后一個值        areaPicker.setDisplayedValues(areas);    }}

/** * "省市區(qū)"數(shù)據(jù)庫操作類 */
public class AddressManager {
    //ssq表的字段的名字    private static final String TABLE_NAME = "ssq"; //表名    private static final String PROVINCE = "province"; //省份名稱    private static final String CITY = "city"; //市的名稱    private static final String AREA = "area"; //區(qū)的名稱
    private SQLiteDatabase database; //sqlite數(shù)據(jù)庫對象
    /**     * @param dbPath 數(shù)據(jù)庫中“省市區(qū)”表的路徑     */    public AddressManager(String dbPath) {        database = SQLiteDatabase.openOrCreateDatabase(dbPath, null);    }
    /**     * 查詢所有省份     *     * @return 所有的省份名稱     */    public List getProvinces() {
        String sql = "select distinct " + PROVINCE + " from " + TABLE_NAME;        Cursor cursor = database.rawQuery(sql, null);        List provinceList = new ArrayList<>();        if (cursor != null) {            while (cursor.moveToNext()) {                String province = cursor.getString(cursor.getColumnIndex("province"));                Log.i("tag", "province----->" + province);                provinceList.add(province);            }            cursor.close();        }        return provinceList;    }
    /**     * 查詢指定省份或直轄市的所有市的集合     *     * @param province 省份名稱     * @return 查詢到的所有城市     */    public List getCities(String province) {        String sql = "select distinct " + CITY + " from " + TABLE_NAME + " where " + PROVINCE + " = ?";        Cursor cursor = database.rawQuery(sql, new String[]{province});        List addressList = new ArrayList<>();        while (cursor.moveToNext()) {            String city = cursor.getString(cursor.getColumnIndex(CITY));            Log.i("tag", "city----->" + city);            addressList.add(city);        }        //關(guān)閉游標        cursor.close();        return addressList;    }

    /**     * 查詢指定市的所有區(qū)的列表的List集合     *     * @param city 市的名稱     * @return 查詢到的所有區(qū)     */    public List getAreas(String city) {        //獲取指定市的所有區(qū)的列表的sql語句        String sql = "select distinct " + AREA + " from " + TABLE_NAME + " where " + CITY + " = ?";        Cursor cursor = database.rawQuery(sql, new String[]{city});        List addressList = new ArrayList<>();        while (cursor.moveToNext()) {            //獲取區(qū)的名稱            String area = cursor.getString(cursor.getColumnIndex(AREA));            Log.i("tag", "area----->" + area);            //把所有的區(qū)添加到List集合            addressList.add(area);        }        //關(guān)閉游標        cursor.close();        return addressList;    }}

np = (NumberPicker) findViewById(R.id.numberPicker1);  String[] city = {"北京","上海","廣州","深圳","成都","天津"};  np.setDisplayedValues(city);  np.setMinValue(0);   //設(shè)置顯示的第一個數(shù)據(jù)np.setMaxValue(city.length - 1);    //設(shè)置顯示的最后一個數(shù)據(jù)

private void updateCitySelector() {    int oldMax = cityPicker.getMaxValue();    int newMax = mCitys.length - 1;    if(newMax > oldMax) {        cityPicker.setDisplayedValues(mCitys);        cityPicker.setMaxValue(newMax);    } else {        cityPicker.setMaxValue(newMax);        cityPicker.setDisplayedValues(mCitys);    }}

private void updateCitySelector() {    cityPicker.setDisplayedValues(null);    cityPicker.setMaxValue(mCitys.length - 1);    cityPicker.setDisplayedValues(mCitys);}