Leeshy's Blog鸿蒙开发实践——电话簿
目录
电话簿
项目简介
项目结构
├─ entry.src.main
├─ com.example.address_book
├─slice
├─ UserAddSlice
├─ UserListSlice
└─ MainAbilitySlice
├─ DataBaseAbility
├─ MainAbility
└─ MyApplication
└─ resources.base.layout
├─ ability_main.xml
├─ user_add.xml
└─ user_list.xml
效果
数据库结构
- 数据库UserStore：本地、关系型
- 表users
- 属性userId：int、主键、自增
- 属性userName：text、不为空
- 属性userTel：text、唯一
- 属性userAddr：text
- 表users
MainAbilitySlice
核心代码：
MainAbilitySlice的onStart方法：
Button btn1 = (Button) findComponentById(ResourceTable.Id_btn1);
btn1.setClickedListener(listener->present(new UserAddSlice(),new Intent()));
Button btn2 = (Button) findComponentById(ResourceTable.Id_btn2);
btn2.setClickedListener(listener->present(new UserListSlice(),new Intent()));
执行简单的页面跳转。
DataBaseAbility
核心代码：
DataBaseAbility类：
private RdbStore rdbStore;
private StoreConfig config = StoreConfig.newDefaultConfig("UserStore.db");
RdbStore对象：表示与数据库的连接，通过此对象可以完成对数据表中数据的CRUD操作 StoreConfig对象：关联数据⽂件配置(数据库)
private RdbOpenCallback callback = new RdbOpenCallback() {
@Override
public void onCreate(RdbStore rdbStore) {
//使⽤rdbStore对象执⾏SQL创建数据表
rdbStore.executeSql("create table if not exists users(" +
"userId integer primary key autoincrement," +
"userName text not null," +
"userTel text not null unique," +
"userAddr text)");
}
};
RdbOpenCallback.onCreate()：数据库创建时被回调，初始化，创建数据表users（当其不存在时）。
DataBaseAbility类的onStart方法：
@Override
public void onStart(Intent intent) {
super.onStart(intent);
HiLog.info(LABEL_LOG, "DataBaseAbility onStart");
//初始化与数据库的连接
DatabaseHelper helper = new DatabaseHelper(this);
rdbStore = helper.getRdbStore(config,1,callback);
}
重写insert方法：
public int insert(Uri uri, ValuesBucket value) {
int i = -1;
String path = uri.getLastPath();
if("users".equalsIgnoreCase(path)){
i = (int)rdbStore.insert("users",value);
}
return i;
}
重写query、delete、update方法：
public ResultSet query(Uri uri, String[] columns, DataAbilityPredicates predicates) {
RdbPredicates rdbPredicates = DataAbilityUtils.createRdbPredicates(predicates, "users");
ResultSet resultSet = rdbStore.query(rdbPredicates, columns);
return resultSet;
}
public int delete(Uri uri, DataAbilityPredicates predicates) {
RdbPredicates rdbPredicates = DataAbilityUtils.createRdbPredicates(predicates, "users");
int i = rdbStore.delete(rdbPredicates);
return i;
}
public int update(Uri uri, ValuesBucket value, DataAbilityPredicates predicates) {
RdbPredicates rdbPredicates = DataAbilityUtils.createRdbPredicates(predicates, "users");
int i = rdbStore.update(value, rdbPredicates);
return i;
}
UserAddSlice
核心代码：
public class UserAddSlice extends AbilitySlice {
private DataAbilityHelper dataAbilityHelper;
@Override
public void onStart(Intent intent) {
super.onStart(intent);
super.setUIContent(ResourceTable.Layout_user_add);
dataAbilityHelper = DataAbilityHelper.creator(this);
//获取组件对象
Button btn_add = (Button) findComponentById(ResourceTable.Id_btn_add);
TextField tf1 = (TextField) findComponentById(ResourceTable.Id_textField1);
TextField tf2 = (TextField) findComponentById(ResourceTable.Id_textField2);
TextField tf3 = (TextField) findComponentById(ResourceTable.Id_textField3);
//绑定事件监听器
btn_add.setClickedListener(component -> {
String userName = tf1.getText();
String userTel = tf2.getText();
String userAddr = tf3.getText();
//构造VB
ValuesBucket valuesBucket = new ValuesBucket();
valuesBucket.putString("userName",userName);
valuesBucket.putString("userTel",userTel);
valuesBucket.putString("userAddr",userAddr);
//插入数据
try{
Uri uri = Uri.parse("dataability:///com.example.address_book.DataBaseAbility/users");
int i = dataAbilityHelper.insert(uri,valuesBucket);
System.out.println("------------>>>>>>"+i);
}catch (DataAbilityRemoteException e){
e.printStackTrace();
}
});
}
}
-
数据库的相关操作要依靠dataAbilityHelper。
-
从TextField组件中获取输入的信息。
-
设置监听器，将获得的信息插入数据表。
-
插入数据通过ValuesBucket储存，指数据表的一行。
UserListSlice
核心代码：
public class UserListSlice extends AbilitySlice {
private DataAbilityHelper dataAbilityHelper;
@Override
protected void onStart(Intent intent) {
super.onStart(intent);
this.setUIContent(ResourceTable.Layout_user_list);
Text text = (Text) findComponentById(ResourceTable.Id_infoText);
text.setText("");
dataAbilityHelper = DataAbilityHelper.creator(this);
//查询所有联系⼈信息
Uri uri = Uri.parse("dataability:///com.example.address_book.DataBaseAbility/users");
String[] colums = {"userId","userName","userTel","userAddr"};
DataAbilityPredicates dataAbilityPredicates = new DataAbilityPredicates();
try {
ResultSet rs = dataAbilityHelper.query(uri,colums,dataAbilityPredicates);
//从rs中获取查询结果
int rowCount = rs.getRowCount();
if(rowCount>0){
rs.goToFirstRow();
do{
int userId = rs.getInt( 0);
String userName = rs.getString(1);
String userTel = rs.getString(2);
String userAddr = rs.getString(3);
String info = " ["+userId+","+userName+","+userTel+","+userAddr+"]";
text.setText( text.getText()+info );
}while(rs.goToNextRow());
}
} catch (DataAbilityRemoteException e) {
e.printStackTrace();
}
}
}
- 通过调用查询接口来查询。
- ResultSet为查询结果集，类似于指针，指向结果的第一行。
结束语
项目源码
https://github.com/leeshy-tech/HarmonyOS_example/tree/main/address_book