DatabaseHelper.java

/** * 继承sqliteOpenHelper * * @author Harvey * */
public class DatabaseHelper extends sqliteOpenHelper {  * 数据库名称 /.db可有可无 */
    static final String DATABASE_NAME = "test.db";  * 数据库版本,版本号不能为0 final int DATABASE_VERSION = 1;  * 构造方法 * * @param context public DatabaseHelper(Context context) { // CursorFactory设置为null,使用默认值
        this(context,DATABASE_NAME,null,DATABASE_VERSION); }  * 必须要有此构造方法 * *  context * 代表应用的上下文 *  name * 代表数据库的名称 *  factory * 代表记录集游标工厂，是专门用来生成记录集游标，记录集游标是对查询结果进行迭代的 *  version * 代表数据库的版本，如果以后升级软件的时候，需要更改 public DatabaseHelper(Context context,String name,CursorFactory factory,255); font-size:12px!important; line-height:1.5!important">int version) {  必须通过super调用父类当中的构造函数
        super(context,name,factory,version); }  * 在用户第一次使用软件时，会创建数据库，而该方法在数据库初次创建时被调用，此方法中特别适合 * 生成数据库表的结构，它只会被调用一次，它的唯一一个参数是操作数据库的工具类，这个 * 工具类提供了对数据的添、删、改、查等方法，用这个类实现对sql语句的执行 */ @Override void onCreate(sqliteDatabase db) { db.execsql("CREATE TABLE person (personid INTEGER PRIMARY KEY AUTOINCREMENT,name VARCHAR(20),age INTEGER)"); }  * version版本号发生改变时，此方法会被调用，在这个方法中比较适合实现软件更新时修改数据库表结构的工作 void onUpgrade(sqliteDatabase db,255); font-size:12px!important; line-height:1.5!important">int oldVersion,255); font-size:12px!important; line-height:1.5!important">int newVersion) {  数据库更新的语句
        db.execsql("ALTER TABLE person ADD COLUMN other STRING"); } }

Person.java

class Person { * id private Integer id; * name private String name; * age private Integer age; public Person() { } public Integer getId() { return id; } void setId(Integer id) { this.id = id; } public String getName() { return name; } void setName(String name) { this.name = name; } public Integer getAge() { return age; } void setAge(Integer age) { this.age = age; } @Override public String toString() { return "id:" + id + "\nage:" + age + "\nname:" + name; } }

sqliteTestActivity.java（第一种方法）

* 数据库使用测试 * * admin * class sqliteTestActivity extends Activity implements OnClickListener { private Button addBtn,addListBtn,delBtn,updateBtn,queryBtn,countBtn,pagingBtn,otherBtn; private TextView text; private DatabaseHelper databaseHelper; @Override void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); init(); } private void init() { addBtn = (Button) findViewById(R.id.add); addListBtn = (Button) findViewById(R.id.addList); delBtn = (Button) findViewById(R.id.delete); updateBtn = (Button) findViewById(R.id.update); queryBtn = (Button) findViewById(R.id.query); countBtn = (Button) findViewById(R.id.count); pagingBtn = (Button) findViewById(R.id.paging); otherBtn = (Button) findViewById(R.id.other); 设置监听 addBtn.setOnClickListener(this); addListBtn.setOnClickListener(this); delBtn.setOnClickListener(this); updateBtn.setOnClickListener(this); queryBtn.setOnClickListener(this); countBtn.setOnClickListener(this); pagingBtn.setOnClickListener(this); otherBtn.setOnClickListener(this); text = (TextView) findViewById(R.id.text); databaseHelper = new DatabaseHelper(this); } @Override void onClick(View v) { * 添加对象 */ if (v.equals(addBtn)) { Person person = new Person(); person.setName("Eric"); person.setAge(23); addData(person); } * 添加对象集合 if (v.equals(addListBtn)) { ArrayList<Person> personList = new ArrayList<Person>(); Person person = new Person(); person.setName("Tom"); person.setAge(20); personList.add(person); Person person1 = new Person(); person1.setName("Jack"); person1.setAge(21); personList.add(person1); Person person2 = new Person(); person2.setName("Harvey"); person2.setAge(22); personList.add(person2); addData(personList); } * 删除数据 if (v.equals(delBtn)) { deleteData(1); } * 更新数据 if (v.equals(updateBtn)) { Person person = new Person(); person.setId(2); person.setName("Bob"); person.setAge(35); updateData(person); } * 查询数据 if (v.equals(queryBtn)) { queryData(3); } * 数据总数 if (v.equals(countBtn)) { System.out.println("查询总数=====" + countData()); } * 分页 if (v.equals(pagingBtn)) { getScrollData(0,3); } if (v.equals(otherBtn)) { other(); } } void addData(Person person) { sqliteDatabase db = databaseHelper.getWritableDatabase(); 创建或者打开一个可写数据库插入数据 db.execsql("INSERT INTO person(name,age) VALUES(?,?)",255); font-size:12px!important; line-height:1.5!important">new Object[] { person.getName(),person.getAge() }); Log.i("sqliteTestActivity","name:" + person.getName() + "\nage:" + person.getAge()); } * 添加对象集合 * * personList void addData(ArrayList<Person> personList) { sqliteDatabase db = databaseHelper.getWritableDatabase(); 创建或者打开一个可写数据库 db.beginTransaction(); 开始事务 try { for (Person person : personList) { db.execsql("INSERT INTO person(name,"name:" + person.getName() + "\nage:" + person.getAge()); } db.setTransactionSuccessful(); 设置事务成功完成 } finally { db.endTransaction(); 结束事务 } } * 删除数据 * * id void deleteData(Integer id) { sqliteDatabase db = databaseHelper.getWritableDatabase(); 创建或者打开一个可写数据库 db.execsql("delete from person where personid=?",255); font-size:12px!important; line-height:1.5!important">new Object[] { id }); } void updateData(Person person) { sqliteDatabase db = databaseHelper.getWritableDatabase(); db.execsql("update person set name=?,age=? where personid=?",person.getAge(),person.getId() }); } void queryData(Integer id) { sqliteDatabase db = databaseHelper.getReadableDatabase(); 创建或者打开一个查询数据库 Cursor cursor = db.rawQuery("select * from person where personid=?",255); font-size:12px!important; line-height:1.5!important">new String[] { String.valueOf(id) }); 迭代记录集 if (cursor.moveToNext()) { Person person = new Person(); person.setId(cursor.getInt(cursor.getColumnIndex("personid"))); person.setName(cursor.getString(cursor.getColumnIndex("name"))); person.setAge(cursor.getInt(cursor.getColumnIndex("age"))); 将查到的字段，放入person System.out.println(person.toString()); text.setText(person.toString()); } cursor.close(); 游标关闭 } * 获取记录总数 * * @return long countData() { sqliteDatabase db = databaseHelper.getReadableDatabase(); 没有占位符参数的话，直接用null Cursor cursor = db.rawQuery("select * from person",255); font-size:12px!important; line-height:1.5!important">null); int count = cursor.getCount(); cursor.close(); return count; } * 分页 * * offset * count void getScrollData(int offset,255); font-size:12px!important; line-height:1.5!important">int count) { ArrayList<Person> persons = new ArrayList<Person>(); sqliteDatabase db = databaseHelper.getReadableDatabase(); offset开始索引 count 记录条数 Cursor cursor = db.rawQuery("select personid,age from person limit ?,?",255); font-size:12px!important; line-height:1.5!important">new String[] { String.valueOf(offset),String.valueOf(count) }); while (cursor.moveToNext()) { Person person = new Person(); person.setId(cursor.getInt(cursor.getColumnIndex("personid"))); person.setName(cursor.getString(cursor.getColumnIndex("name"))); person.setAge(cursor.getInt(cursor.getColumnIndex("age"))); persons.add(person); Log.i("sqliteTestActivity","name:" + person.getName() + "\nage:" + person.getAge()); } System.out.println("大小================" + persons.size()); cursor.close(); } void other() { Intent intent = new Intent(sqliteTestActivity.this,OtherActivity.class); startActivity(intent); } }

OtherActivity.java（第二种方法）

class OtherActivity private DatabaseHelper databaseHelper; private ArrayList<Person> personList; @Override super.onCreate(savedInstanceState); setContentView(R.layout.other); init(); } void init() { addBtn = (Button) findViewById(R.id.add); addListBtn = (Button) findViewById(R.id.addList); delBtn = (Button) findViewById(R.id.delete); updateBtn = (Button) findViewById(R.id.update); queryBtn = (Button) findViewById(R.id.query); countBtn = (Button) findViewById(R.id.count); pagingBtn = (Button) findViewById(R.id.paging); 设置监听 addBtn.setOnClickListener(new Person(); person.setName("Eric"); person.setAge(3); addData(person); } if (v.equals(addListBtn)) { personList = new Person(); person.setName("Tom"); person.setAge(2); personList.add(person); Person person1 = new Person(); person1.setName("Jack"); person1.setAge(3); personList.add(person1); Person person2 = new Person(); person2.setName("Harvey"); person2.setAge(6); personList.add(person2); addData(personList); } new Person(); person.setId(3); person.setName("Bob"); person.setAge(0); updateData(person); } if (v.equals(countBtn)) { System.out.println("查询个数=====" + countData()); } ); } } * 添加数据创建或者打开一个可写数据库 ContentValues contentValues = new ContentValues(); contentValues.put("name",person.getName()); contentValues.put("age",person.getAge()); db.insert("person",contentValues); } * 添加集合数据 * * for (Person person : personList) { ContentValues contentValues = sqliteTestActivity",0); font-size:12px!important; line-height:1.5!important"> 创建或者打开一个可写数据库 db.delete("person","personid=?",255); font-size:12px!important; line-height:1.5!important">new String[] { String.valueOf(id) }); } void updateData(Person person) { ContentValues contentValues = sqliteDatabase db = databaseHelper.getWritableDatabase(); * 第一个参数表示表名 /第二个参数表示更新的数据/第三个参数表示sql语句的中条件部分的语句 /第四个参数占位符的值 */ db.update("person",contentValues,255); font-size:12px!important; line-height:1.5!important">new String[] { String.valueOf(person.getId()) }); } 创建或者打开一个查询数据库 * 第一个参数表示表名 /第二个参数表示查找需要返回的字段/第三个参数表示sql语句的中条件部分的语句 * /第四个参数占位符的值/第五个参数表示分组 * 可设为null/第六个参数表示sql语句中的having，可设为null/第七个参数表示结果的排序，可设为null */ Cursor cursor = db.query("person",255); font-size:12px!important; line-height:1.5!important">new String[] { "personid","name","age" },"personid=?",255); font-size:12px!important; line-height:1.5!important">new String[] { String.valueOf(id) },null,255); font-size:12px!important; line-height:1.5!important">new Person(); person.setId(cursor.getInt(cursor.getColumnIndex("personid"))); person.setName(cursor.getString(cursor.getColumnIndex("name"))); person.setAge(cursor.getInt(cursor.getColumnIndex("age"))); long countData() { sqliteDatabase db = databaseHelper.getReadableDatabase(); Cursor cursor = db.query("person",255); font-size:12px!important; line-height:1.5!important">new String[] { "*" },255); font-size:12px!important; line-height:1.5!important">int count = cursor.getCount(); cursor.close(); 游标关闭 new ArrayList<Person>(); sqliteDatabase db = databaseHelper.getReadableDatabase(); Cursor cursor = db.query("person",offset + "," + count); new Person(); person.setId(cursor.getInt(cursor.getColumnIndex("personid"))); person.setName(cursor.getString(cursor.getColumnIndex("name"))); person.setAge(cursor.getInt(cursor.getColumnIndex("age"))); persons.add(person); Log.i("OtherActivity","name:" + person.getName() + "\nage:" + person.getAge()); } System.out.println("大小================" + persons.size()); cursor.close(); } }

原文链接：https://www.f2er.com/sqlite/199495.html