技術標籤：安卓學習

文章目錄

• 前言
• 一、Ormlte
• 二、使用Ormlite
• • 1.引入庫
  • 2.新建ContactsInfo(聯絡人資訊表)
  • 3.新建DatabaseHelper(生成資料庫結構資訊)
  • 4.測試
• 三、完善通訊錄的關於Ormlite的功能
• • 1.新增聯絡人
  • 2.讀取聯絡人
  • 3.查詢聯絡人
  • 4.效果圖
• 遇到的問題
• • • 問題1
• 總結

前言

ormlite看起來挺簡單，其實做起來挺惱火的，昨天做了很久，但是沒實現效果，就沒有寫部落格

一、Ormlte

Ormlite全稱Object Relational Mapping，是一個非常輕量級的資料庫操作框架，它的底層是根據反射機制來實現的。
ormlite的使用：

新建表，借用別人的圖：

增刪改查：ORMLite簡介和增刪改查方法的使用

二、使用Ormlite

1.引入庫

這個我在上一個裡面寫到了：安卓開發學習——day6

2.新建ContactsInfo(聯絡人資訊表)

注意：生成空的構造方法，不然報錯；生成get|set方法，方便呼叫

package com.example.task3.entity;

import com.j256.ormlite.field.DatabaseField;
import com.j256.ormlite.table.DatabaseTable;

//表名
@DatabaseTable(tableName = "contacts"
 
)
public class ContactsInfo {
    @DatabaseField(columnName = "id", generatedId = true)
    public int id; //設定主鍵

    @DatabaseField(columnName = "contactName")
    private String contactName;

    @DatabaseField(columnName = "contactCompany")
    private String contactCompany;
 


    @DatabaseField(columnName = "contactTel")
    private String contactTel;

    public ContactsInfo() {
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getContactName() {
        return contactName;
    }

    public void setContactName(String contactName) {
        this.contactName = contactName;
    }

    public String getContactCompany() {
        return contactCompany;
    }

    public void setContactCompany(String contactCompany) {
        this.contactCompany = contactCompany;
    }

    public String getContactTel() {
        return contactTel;
    }

    public void setContactTel(String contactTel) {
        this.contactTel = contactTel;
    }
}

3.新建DatabaseHelper(生成資料庫結構資訊)

繼承繼承OrmLiteSqliteOpenHelper類，重寫 onCreate\onUpgrade方法

package com.example.task3.db;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;

import com.example.task3.entity.ContactsInfo;
import com.j256.ormlite.android.apptools.OrmLiteSqliteOpenHelper;
import com.j256.ormlite.dao.Dao;
import com.j256.ormlite.support.ConnectionSource;
import com.j256.ormlite.table.TableUtils;

import java.sql.SQLException;


/**
 * 定義資料庫的工具類，繼承OrmLiteSqliteOpenHelper類，重寫 onCreate\onUpgrade方法
 */
public class DatabaseHelper extends OrmLiteSqliteOpenHelper {

    //定義資料庫存放位置，便於以後檢視
    public static final String DATABASE_PATH = "mydb.db";
    //定義資料庫的版本號，當資料庫需要升級時進行更改
    public static final int DATABASE_VERSION = 1;

    public DatabaseHelper(Context context) {
        super(context, DATABASE_PATH, null, DATABASE_VERSION);
    }

    public Dao<ContactsInfo, Integer> contactsInfoDao;

    public Dao<ContactsInfo, Integer> getContactsInfoDao() {
        if (contactsInfoDao == null) {
            try {
                contactsInfoDao = getDao(ContactsInfo.class);
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        return contactsInfoDao;
    }


    /***
     * 第一次建立資料庫建立
     * @param database
     * @param connectionSource
     */
    @Override
    public void onCreate(SQLiteDatabase database, ConnectionSource connectionSource) {
        try {
            TableUtils.createTable(connectionSource, ContactsInfo.class);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    /***
     * 升級資料庫時呼叫
     * @param database
     * @param connectionSource
     * @param oldVersion
     * @param newVersion
     */
    @Override
    public void onUpgrade(SQLiteDatabase database, ConnectionSource connectionSource, int oldVersion, int newVersion) {
        if (newVersion > oldVersion) {
            try {
                TableUtils.dropTable(connectionSource, ContactsInfo.class, true);
                TableUtils.createTableIfNotExists(connectionSource, ContactsInfo.class);
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    @Override
    public void close() {
        super.close();
        if (contactsInfoDao != null) {
            contactsInfoDao = null;
        }
    }
}

4.測試

xml只需要3個輸入框和兩個按鈕

package com.example.task3;

import android.database.SQLException;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

import com.example.task3.db.DatabaseHelper;
import com.example.task3.entity.ContactsInfo;
import com.j256.ormlite.dao.Dao;

import java.util.List;

public class TestOrmActivity extends AppCompatActivity implements View.OnClickListener {

    private EditText edtName;
    private EditText edtCompany;
    private EditText edtTel;

    private Button btnInsert;
    private Button btnRead;

    private DatabaseHelper dbHelper;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_test_orm);

        edtName = findViewById(R.id.edt_name);
        edtCompany = findViewById(R.id.edt_company);
        edtTel = findViewById(R.id.edt_tel);

        btnInsert = findViewById(R.id.btn_);
        btnRead = findViewById(R.id.btn_read);

        btnInsert.setOnClickListener(this);
        btnRead.setOnClickListener(this);


    }



    @Override
    public void onClick(View view) {
        if (dbHelper==null){
            dbHelper = new DatabaseHelper(TestOrmActivity.this);
        }
        int id = view.getId();
        switch (id){
            case R.id.btn_:
                //插入資料
                String name  = edtName.getText().toString();
                String company = edtCompany.getText().toString();
                String tel = edtTel.getText().toString();
                //獲取操作表的dao物件
                Dao<ContactsInfo,Integer> contactsInfoDao = dbHelper.getContactsInfoDao();
                //插入對應的資料
                ContactsInfo contactsInfo = new ContactsInfo();
                contactsInfo.setContactName(name);
                contactsInfo.setContactCompany(company);
                contactsInfo.setContactTel(tel);
                try {
                    //通過操作實體物件的形式將資料插入到表中
                    contactsInfoDao.createIfNotExists(contactsInfo);
                } catch (SQLException | java.sql.SQLException e) {
                    e.printStackTrace();
                }


                break;
            case R.id.btn_read:
                //讀取資料
                Dao<ContactsInfo ,Integer> contactsInfoList = dbHelper.getContactsInfoDao();
                try {
                    List<ContactsInfo> contactsInfoDataList =  contactsInfoList.queryForAll();

                    StringBuffer strBuffer = new StringBuffer();
                    for(int i =0;i<contactsInfoDataList.size();i++){
                        strBuffer.append("第"+i+"位置的word="+contactsInfoDataList.get(i).getContactName()+"；單詞的含義"+contactsInfoDataList.get(i).getContactTel()+"\n");
                    }

                    Toast.makeText(TestOrmActivity.this, strBuffer.toString(), Toast.LENGTH_SHORT).show();

                } catch (SQLException | java.sql.SQLException e) {
                    e.printStackTrace();
                }

                break;

        }
    }
}

三、完善通訊錄的關於Ormlite的功能

1.新增聯絡人

package com.example.task3;

import android.content.Intent;
import android.database.SQLException;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

import com.example.task3.db.DatabaseHelper;
import com.example.task3.entity.ContactsInfo;
import com.j256.ormlite.dao.Dao;

public class AddActivity extends AppCompatActivity implements View.OnClickListener {
    private ImageView ok;
    private ImageView cancel;
    private EditText edtName;
    private EditText edtCompany;
    private EditText edtTel;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_add);

        ok = findViewById(R.id.ok);
        cancel = findViewById(R.id.cancel);
        edtName = findViewById(R.id.edt_name);
        edtCompany = findViewById(R.id.edt_company);
        edtTel = findViewById(R.id.edt_tel);

        ok.setOnClickListener(this);
        cancel.setOnClickListener(this);

    }

    private DatabaseHelper dbHelper;

    @Override
    public void onClick(View v) {
        if (dbHelper == null) {
            dbHelper = new DatabaseHelper(AddActivity.this);
        }
        int id = v.getId();
        switch (id) {
            case R.id.ok:
                //插入資料
                String name = edtName.getText().toString();
                String company = edtCompany.getText().toString();
                String tel = edtTel.getText().toString();
                //獲取操作表的dao物件
                Dao<ContactsInfo, Integer> contactsInfoDao = dbHelper.getContactsInfoDao();
                //插入對應的資料
                ContactsInfo contactsInfo = new ContactsInfo();
                contactsInfo.setContactName(name);
                contactsInfo.setContactCompany(company);
                contactsInfo.setContactTel(tel);
                try {
                    //通過操作實體物件的形式將資料插入到表中
                    contactsInfoDao.createIfNotExists(contactsInfo);
                } catch (SQLException | java.sql.SQLException e) {
                    e.printStackTrace();
                }

                Toast.makeText(AddActivity.this, "新增" + edtName.getText().toString() + "成功"
                        , Toast.LENGTH_LONG).show();

                Intent intent = new Intent(AddActivity.this, MainActivity.class);
                startActivity(intent);

                break;
            case R.id.cancel:
                intent = new Intent(AddActivity.this, MainActivity.class);
                startActivity(intent);

                break;

        }
    }
}

2.讀取聯絡人

package com.example.task3;

import android.content.Intent;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;

import com.example.task3.db.DatabaseHelper;
import com.example.task3.entity.ContactsInfo;
import com.j256.ormlite.dao.Dao;

import java.sql.SQLException;
import java.util.List;

public class MainActivity extends AppCompatActivity{

    private TextView tvAdd;
    private EditText edtSo;
    private ListView lvContacts;
    private ImageView find;

    private ContactAdapter adapter;

    DatabaseHelper dbHelper = new DatabaseHelper(this);


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        tvAdd = findViewById(R.id.tv_add);
        edtSo = findViewById(R.id.edt_find_contact);
        lvContacts = findViewById(R.id.lv_contacts);
        find = findViewById(R.id.find);

        try {
            Dao<ContactsInfo, Integer> dao = dbHelper.getDao(ContactsInfo.class);

            List<ContactsInfo> contact = dao.queryBuilder().selectColumns("contactName").query();

            adapter = new ContactAdapter(MainActivity.this,contact);
            lvContacts.setAdapter(adapter);
        } catch (SQLException e) {
            e.printStackTrace();
        }

        edtSo.setOnEditorActionListener(new TextView.OnEditorActionListener() {
            @Override
            public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
                String text = edtSo.getText().toString().trim();
                try {
                    Dao<ContactsInfo, Integer> dao = dbHelper.getDao(ContactsInfo.class);
                    List<ContactsInfo> contact = dao.queryBuilder().where().like("contactName","%"+text+"%").query();

                    //初始化介面卡
                    ContactAdapter findAdapter = new ContactAdapter(MainActivity.this, contact);
                    lvContacts.setAdapter(findAdapter);
                } catch (SQLException e) {
                    e.printStackTrace();
                }
                return false;
            }
        });



        tvAdd.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, AddActivity.class);

                startActivity(intent);
            }
        });


    }

}

3.查詢聯絡人

4.效果圖

遇到的問題

問題1

ormlite E/SQLiteLog: (1) no such table: contacts

解決方法：
已經建立過諸如contacts表之後,部署到手機上,此時資料庫已經初始化完成.但是現在有需求又新加了一個表,此時程式碼都寫完了,此時部署到手機上,呼叫新表裡面的ContactInfoDao.create(bean)方法會出現no such table錯誤.
把原來安裝的app解除安裝重新部署。

總結

ormlite資料庫因為沒有找到較為完整的教程，所以用時比較久，寫的還不夠完善。