Android数据库（sqlite）之Room

说在前面：

1、使用Room需要添加的依赖：

dependencies {

  def room_version = "2.2.3"

  implementation "androidx.room:room-runtime:$room_version"

  annotationProcessor "androidx.room:room-compiler:$room_version" // For Kotlin use kapt instead of annotationProcessor

  // optional - Kotlin Extensions and Coroutines support for Room

  implementation "androidx.room:room-ktx:$room_version"

  // optional - RxJava support for Room

  implementation "androidx.room:room-rxjava2:$room_version"

  // optional - Guava support for Room, including Optional and ListenableFuture

  implementation "androidx.room:room-guava:$room_version"

  // Test helpers

  testImplementation "androidx.room:room-testing:$room_version"

}

2、数据库可视化工具安装及使用说明

http://www.sqlitebrowser.org/

3、涉及到的知识：

工程案例：

一、APP描述：对Word实体进行增删改

二、编写思路：

1、画界面：

1）上边是一个ScrollView（数据多的时候可滑动),ScrollView内有一个TextView

2）下边是四个按键，分别代表，插入、删除、删除所有、修改。

2、创建实体（Entity）：

package com.me.roombasic;

import androidx.room.ColumnInfo;

import androidx.room.Entity;

import androidx.room.PrimaryKey;

@Entity

public class Word {

    @PrimaryKey(autoGenerate = true)

    private int id;

    @ColumnInfo(name = "姓名")

    private String name;

    @ColumnInfo(name = "外号")

    private  String other;

    public Word(String name, String other) {

        this.name = name;

        this.other = other;

    }

    public int getId() {

        return id;

    }

    public void setId(int id) {

        this.id = id;

    }

    public String getName() {

        return name;

    }

    public void setName(String name) {

        this.name = name;

    }

    public String getOther() {

        return other;

    }

    public void setOther(String other) {

        this.other = other;

    }

}

3、创建dao

package com.me.roombasic;

import androidx.room.Dao;

import androidx.room.Delete;

import androidx.room.Insert;

import androidx.room.Query;

import androidx.room.Update;

import java.util.List;

@Dao

public interface WordDao {

    @Insert

    void  insertWord(Word ...words );

    @Update

    void updateWord(Word... words);

    @Delete

    void deleteWord(Word... words);

    @Query("DELETE FROM WORD")

    void deleteAllWords();

    @Query("SELECT * FROM WORD ORDER BY ID DESC")

    List<Word>  getAllWords();

}

4、创建database

package com.me.roombasic;

import androidx.room.Database;

import androidx.room.RoomDatabase;

@Database(entities = {Word.class},version = 1,exportSchema = false)

public abstract class WordDatabase extends RoomDatabase {

    public abstract WordDao getWordDao();

}

5、暂时在mainActive.java中为TextView、Button绑定数据和监听：

package com.me.roombasic;

import androidx.appcompat.app.AppCompatActivity;

import androidx.room.Room;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.TextView;

import java.util.List;

public class MainActivity extends AppCompatActivity {

    WordDao wordDao;

    WordDatabase wordDatabase;

    Button buttonInsert,buttonUpdate,buttonDelete,buttonQuery;

    TextView textView;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        textView = findViewById(R.id.textView);

        buttonInsert = findViewById(R.id.buttoninster);

        buttonUpdate = findViewById(R.id.buttonupdate);

        buttonDelete = findViewById(R.id.buttondelete);

        buttonQuery = findViewById(R.id.buttonquery);

        wordDatabase = Room.databaseBuilder(this,WordDatabase.class,"word_database")

                .allowMainThreadQueries()

                .build();

        wordDao = wordDatabase.getWordDao();

        updateView();

        buttonInsert.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                Word word1 = new Word("谷子腾","恶霸");

                Word word2 = new Word("张凯鑫","胖鑫");

                Word word3 = new Word("王正帅","笑天");

                wordDao.insertWord(word1,word2,word3);

                updateView();

            }

        });

        buttonUpdate.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                Word word2 = new Word("张凯鑫","bujv");

                word2.setId(2);

                wordDao.updateWord(word2);

                updateView();

            }

        });

        buttonDelete.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                Word word2 = new Word("张凯鑫","胖鑫");

                word2.setId(3);

                wordDao.deleteWord(word2);

                updateView();

            }

        });buttonQuery.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                wordDao.deleteAllWords();

                updateView();

            }

        });

    }

    void updateView(){

        List<Word> list = wordDao.getAllWords();

        String text = "";

        for(int i=0;i<list.size();i++){

            text += list.get(i).getId() + ":" + list.get(i).getName() + "=" + list.get(i).getOther() + "\n";

        }

        textView.setText(text);

    }

}

巴特西

Android数据库（sqlite）之Room

说在前面：

工程案例：

一、APP描述：对Word实体进行增删改

二、编写思路：

1、画界面：

2、创建实体（Entity）：

3、创建dao

4、创建database

5、暂时在mainActive.java中为TextView、Button绑定数据和监听：

6、效果演示：

未完待续。。。。

最新文章

热门文章