SQLiteDatabase填充spinner（populating spinner from SQLiteDatabase）

1. 按行读取assets下txt数据，并初始化到SQLiteDatabase

1. 进入project下，右击main创建assets文件夹，添加txt文件

2. 在SQLiteOpenHelper下：

(1) 写读取txt并插入数据库的方法：readFromAssets(SQLiteDatabase db) 并在onCreate( )里调用.

(2) getAllNation()用于之后获取数据库数据填充spinner

public class DBManager {    // Database Version    private static final int DATABASE_VERSION = 1;    // Database Name    private static final String DATABASE_NAME = "users.db";    private final Context context;    private static final String SQL_CREATE_ENTRIES =            "CREATE TABLE " + NationalityDBStructure.tableEntry.TABLE_NAME + " (" +                    " _id INTEGER PRIMARY KEY AUTOINCREMENT, " +                    NationalityDBStructure.tableEntry.COLUMN_NAME +                    " )";    private static final String SQL_DELETE_ENTRIES =            "DROP TABLE IF EXISTS " + NationalityDBStructure.tableEntry.TABLE_NAME;    private NationalityOpenHelper myDBHelper;    private SQLiteDatabase db;    private String[] projection = {            NationalityDBStructure.tableEntry.COLUMN_NAME};    // we can obtain a reference to it and call it    // in the DBManager constructor    public DBManager(Context ctx) {        this.context = ctx;        myDBHelper = new NationalityOpenHelper(context);    }    // open db    public DBManager open() throws SQLException {        db = myDBHelper.getWritableDatabase();        return this;    }    // close db    public void close() {        myDBHelper.close();    }    /**     * 2. Getting all labels     * returns list of labels     * */    public List<String> getAllNation(){        List<String> labels = new ArrayList<String>();//        SQLiteDatabase db = myDBHelper.getReadableDatabase();        Cursor cursor = db.query(NationalityDBStructure.tableEntry.TABLE_NAME, projection, null, null,                null, null, null);        // looping through all rows and adding to list        if (cursor.moveToFirst()) {            do {                //add first entry into labels                labels.add(cursor.getString(0));            } while (cursor.moveToNext());        }        // closing connection        cursor.close();        db.close();        // returning lables        return labels;    }

    private class NationalityOpenHelper extends SQLiteOpenHelper {        public NationalityOpenHelper(Context context){            super(context, DATABASE_NAME, null, DATABASE_VERSION);        }// 1. this method        private void readFromAssets(SQLiteDatabase db) {            try {                ContentValues values = new ContentValues();                InputStream is = context.getAssets().open("nationdata.txt");                InputStreamReader reader = new InputStreamReader(is);                BufferedReader br = new BufferedReader(reader);                String s1;                while ((s1 = br.readLine()) != null) {                    //添加记录                    values.put(NationalityDBStructure.tableEntry.COLUMN_NAME, s1);                    //调用insert()方法插入数据                    db.insert(NationalityDBStructure.tableEntry.TABLE_NAME, null, values);                }                br.close();                reader.close();            } catch (Exception e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }        @Override        public void onCreate(SQLiteDatabase db){            db.execSQL(SQL_CREATE_ENTRIES);

    // call it here            readFromAssets(db);        }        @Override        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion){            // This database is only a cache for online data, so its upgrade policy is// to simply to discard the data and start over            db.execSQL(SQL_DELETE_ENTRIES);            onCreate(db);        }        public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {            onUpgrade(db, oldVersion, newVersion);        }    }}

2. populating spinner from SQLiteDatabase（数据库数据填充spinner）

public class RegisterActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener {    protected DBManager dbManager;    Spinner msp_nation;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_register);        dbManager = new DBManager(this);        // Spinner element        msp_nation = (Spinner) findViewById(R.id.sp_nationality);        mtv_showDoB = (TextView) findViewById(R.id.tv_showDoB);        mtv_login = (TextView) findViewById(R.id.tv_login);        // Spinner click listener        msp_nation.setOnItemSelectedListener(this);        // Loading spinner data from database        loadSpinnerData();    }       /**     * Function to load the spinner data from SQLite database     * */    public void loadSpinnerData(){

// 第一次open()会初始化数据库（调用onCreate()）        try {            dbManager.open();        } catch (SQLException e) {            e.printStackTrace();        }        // Spinner Drop down elements        List<String> lables = dbManager.getAllNation();        // Creating adapter for spinner        ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,                android.R.layout.simple_spinner_item, lables);        // Drop down layout style - list view with radio button        dataAdapter                .setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);        // attaching data adapter to spinner        msp_nation.setAdapter(dataAdapter);        dbManager.close();    }    //    @Override    public void onItemSelected(AdapterView<?> parent, View view, int position,                               long id) {        // On selecting a spinner item        String label = parent.getItemAtPosition(position).toString();        // Showing selected spinner item        Toast.makeText(parent.getContext(), "You selected: " + label,                Toast.LENGTH_LONG).show();    }    //    @Override    public void onNothingSelected(AdapterView<?> arg0) {        // TODO Auto-generated method stub    }}

效果：