本文參考郭霖《第一行代碼》第2版

public class DBActivity extends AppCompatActivity {

    private static final String TAG = "DBActivity";
    private MyDatabaseHelper dbHelper;

    @Override
    protected void onCreate(Bundle savedInstance) {
        super.onCreate(savedInstance);
        setContentView(R.layout.activity_db);

        dbHelper = new MyDatabaseHelper(DBActivity.this, "BookStore.db", null, 4);
        //綁定view
        Button createDatabase = findViewById(R.id.create_database);
        Button addData = findViewById(R.id.add_data);
        Button updateData = findViewById(R.id.update_data);
        Button deleteData = findViewById(R.id.delete_data);
        Button queryData = findViewById(R.id.query_data);
        //設(shè)置監(jiān)聽器
        createDatabase.setOnClickListener(v -> {
            //創(chuàng)建數(shù)據(jù)庫
            dbHelper.getWritableDatabase();
        });
        //添加數(shù)據(jù)
        addData.setOnClickListener(v -> {
            SQLiteDatabase db = dbHelper.getWritableDatabase();
            ContentValues values = new ContentValues();
            //開始裝第一組數(shù)據(jù)
            values.put("name", "第一行代碼");
            values.put("author", "guolin");
            values.put("pages", 570);
            values.put("price", 30);
            db.insert("Book", null, values);
            values.clear();
            //開始裝第二組數(shù)據(jù)
            values.put("name", "瘋狂Android講義");
            values.put("author", "ligang");
            values.put("pages", 510);
            values.put("price", 50.5);
            db.insert("Book", null, values);
        });
        //更新數(shù)據(jù)
        updateData.setOnClickListener(v -> {
            SQLiteDatabase db = dbHelper.getWritableDatabase();
            ContentValues values = new ContentValues();
            values.put("price", 9.99);
            db.update("Book", values, "name = ?", new String [] {"第一行代碼"});
        });
        //刪除數(shù)據(jù)
        deleteData.setOnClickListener(v -> {
            SQLiteDatabase db = dbHelper.getWritableDatabase();
            db.delete("Book", "pages < ?", new String[]{"550"});
        });
        //查詢數(shù)據(jù)
        queryData.setOnClickListener(v -> {
            SQLiteDatabase db = dbHelper.getWritableDatabase();
            //查詢Book表中所有的數(shù)據(jù)
            Cursor cursor = db.query("Book", null, null, null, null, null, null);
            if (cursor.moveToFirst()){
                do {
                    //遍歷Cursor對象棘脐，取出數(shù)據(jù)并打印
                    String name = cursor.getString(cursor.getColumnIndex("name"));
                    String author = cursor.getString(cursor.getColumnIndex("author"));
                    int pages = cursor.getInt(cursor.getColumnIndex("pages"));
                    double price = cursor.getDouble(cursor.getColumnIndex("price"));
                    Log.d(TAG, "book name is " + name);
                    Log.d(TAG, "book author is " + author);
                    Log.d(TAG, "book pages is " + pages);
                    Log.d(TAG, "book price is " + price);
                }while (cursor.moveToNext());
            }
            cursor.close();
        });
    }
}

下面是繼承SQLiteOpenHelper的數(shù)據(jù)庫幫助類的源代碼：

public class MyDatabaseHelper extends SQLiteOpenHelper {

    public static final String CREATE_BOOK = "create table Book ("
            + "id integer primary key autoincrement, "
            + "author text, "
            + "price real, "
            + "pages integer, "
            + "name text)";

    public static final String CREATE_CATEGORY = "create table Category ("
            + "id integer primary key autoincrement, "
            + "category_name text, "
            + "category_code integer)";

    private Context mContext;

    public MyDatabaseHelper(Context context, String name,
                            SQLiteDatabase.CursorFactory factory, int version){
        super(context, name, factory, version);
        mContext = context;
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL(CREATE_BOOK);
        db.execSQL(CREATE_CATEGORY);
        Toast.makeText(mContext, "Create succeeded", Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        db.execSQL("drop table if exists Book");
        db.execSQL("drop table if exists Category");
        onCreate(db);

    }
}

備注：用adb查看db文件：

adb shell 
if （手機root ） 會顯示 # else 會顯示$ 
如果沒有root 執(zhí)行 su root
cd /data/data/packagename/databases
sqlite3  BookStore.db
.table   //查看所有表
.schema   //查看建表語句

特別注意：查詢語句最后需要加“卵贱；”

select * from Book;