Android Sqlite

概述DBHelper  packagecom.example.ex_2;importandroid.content.Context;importandroid.database.sqlite.SQLiteDatabase;importandroid.database.sqlite.SQLiteOpenHelper;importandroid.util.Log;publicclassDbHelperextendsSQLiteOpenHelper{private

DBHelper  

@H_419_6@

package com.example.ex_2;import androID.content.Context;import androID.database.sqlite.sqliteDatabase;import androID.database.sqlite.sqliteOpenHelper;import androID.util.Log;public class DbHelper extends sqliteOpenHelper {    private static final String DATABASE_name = "test.db";  //数据库名字    private static final int DATABASE_VERSION = 1 ;         //数据库版本号    private static final String table_ = "remark";    private static final String TAG = "mydeBUG";    //创建 students 表的 sql 语句    private static final String CReate_sql = "create table if not exists "+            table_ + "("            + "ID integer primary key autoincrement,"            + "Title varchar(100) not null,"            + "content varchar(1000),"            + "creat_time datetime not null,"            + "noti_time datetime not null"            + ");";    public DbHelper(Context context){        super(context, "test.db", null, 1);    }    /*创建数据库    * ID是主键自增*/    @OverrIDe    public voID onCreate(sqliteDatabase db) {        Log.d(TAG, "onCreate: ");        db.execsql(CReate_sql);    }    /**     * 当检测与前一次创建数据库版本不一样时，先删除表再创建新表     */    @OverrIDe    public voID onUpgrade(sqliteDatabase db, int oldVersion, int newVersion) {        db.execsql("DROP table IF EXISTS " + table_);        onCreate(db);    }    /**     * 变更列名     * @param db     * @param oldColumn     * @param newColumn     * @param typeColumn     */    public voID updateColumn(sqliteDatabase db, String oldColumn, String newColumn, String typeColumn){        try{            db.execsql("ALTER table " +                    table_ + " CHANGE " +                    oldColumn + " "+ newColumn +                    " " + typeColumn            );        }catch(Exception e){            e.printstacktrace();        }    }}

VIEw Code

增删改查

package com.example.ex_2;import androID.content.ContentValues;import androID.content.Context;import androID.database.sqlite.sqliteDatabase;import androID.database.Cursor;import androID.util.Log;import java.util.ArrayList;import java.util.List;public class sql {    private static String TAG = "mydegBUG";    private DbHelper dbHelper;    private sqliteDatabase db;    public sql(Context context)    {        Log.d(TAG, "sql: init");        System.out.println("创建数据库");        /* 初始化并创建数据库 */        dbHelper = new DbHelper(context);//        dbHelper.getWritableDatabase();    }    //增    /*    * remark 要存入数据库的实体类     */    public voID add(BeanRemark remark)    {        dbHelper.updateColumn(db, "crea_time", "creat_time", "datetime");        Log.d(TAG, "add: Zeng");        db = dbHelper.getWritableDatabase();    //调用sqliteHelper.OnCreat()        //用容器存储        ContentValues values = new ContentValues();        values.put("Title", remark.getTitle());        values.put("content", remark.getContent());        values.put("noti_time", remark.getNoti_time());        values.put("creat_time", remark.getCreat_time());        long result = db.insert("remark", null, values);        db.close();        Log.d(TAG, "add: " + result);    }    //删    //传入要删除对象的ID  空的就全删    public voID delete(List<String> remarksID) {        sqliteDatabase db = dbHelper.getWritableDatabase();        Log.d(TAG, "delete: " + remarksID);        int result = 0;        if(!remarksID.isEmpty()) {            for(String ID : remarksID)                result = db.delete("remark", "ID = ?", new String[]{ID});        }        else            result = db.delete("remark", null,null);        db.close();        Log.d(TAG, "delete: res = " + result);    }    public voID update(BeanRemark remark) {        sqliteDatabase db = dbHelper.getWritableDatabase();        ContentValues values = new ContentValues();        if(remark.getTitle() != null)   values.put("Title", remark.getTitle());        if(remark.getContent() != null)   values.put("content", remark.getContent());        if(remark.getNoti_time() != null)   values.put("noti_time", remark.getNoti_time());        if(remark.getCreat_time() != null)values.put("creat_time", remark.getCreat_time());        int result = db.update("remark", values, "ID=?", new String[] {""+remark.getID()});        db.close();        Log.d(TAG, "update: res = " +  result);    }    public List<BeanRemark> find(BeanRemark remark) {        sqliteDatabase db = dbHelper.getWritableDatabase();        List<String> selections = new ArrayList();        List<String> vals = new ArrayList();        //判断 remark 里的哪些量不为空 以此来作为where 条件        if(remark.getID() != -1)        {            selections.add("ID = ?");            vals.add((String) (""+remark.getID()));        }        if(remark.getTitle() != null)        {            selections.add("Title = ?");            vals.add((String) remark.getTitle());        }        if(remark.getContent() != null)        {            selections.add("content = ?");            vals.add((String) remark.getContent());        }        if(remark.getNoti_time() != null)        {            selections.add("noti_time = ?");            vals.add((String) remark.getNoti_time());        }        if(remark.getCreat_time() != null)        {            selections.add("Creat_time = ?");            vals.add((String) remark.getCreat_time());        }        String selection = new String();        for(int i = 0; i < selections.size(); i++)        {            if(i != 0) selection += "and";            selection += selections.get(i);        }        if(selections.size() > 1)        {            selection += "and";            selection += selections.get(selections.size()-1);        }        Log.d(TAG, "find: " + selection);        Log.d(TAG, "find2: " + vals.toArray(new String[vals.size()]));        Cursor cursor = db.query("remark", null, selection, vals.toArray(new String[vals.size()]), null, null, null);        List<BeanRemark> remarks = new ArrayList<BeanRemark>();        while (cursor.movetoNext()) {            int ID = cursor.getInt(cursor.getColumnIndex("ID"));            String Title = cursor.getString(cursor.getColumnIndex("Title"));            String content = cursor.getString(cursor.getColumnIndex("content"));            String noti_time = cursor.getString(cursor.getColumnIndex("noti_time"));            String creat_time = cursor.getString(cursor.getColumnIndex("creat_time"));            remarks.add(new BeanRemark(ID, Title, creat_time, noti_time, content));        }        db.close();        return remarks;    }    public List<BeanRemark> findAll()    {        sqliteDatabase db = dbHelper.getWritableDatabase();        Cursor cursor = db.query("remark", null, null, null, null, null,null);        List<BeanRemark> remarks = new ArrayList<BeanRemark>();        BeanRemark remark = null;        while (cursor.movetoNext()) {            int ID = cursor.getInt(cursor.getColumnIndex("ID"));            String Title = cursor.getString(cursor.getColumnIndex("Title"));            String content = cursor.getString(cursor.getColumnIndex("content"));            String noti_time = cursor.getString(cursor.getColumnIndex("noti_time"));            String creat_time = cursor.getString(cursor.getColumnIndex("creat_time"));            remarks.add(new BeanRemark(ID, Title, creat_time, noti_time, content));        }        db.close();        return remarks;    }}

VIEw Code

使用

package com.example.ex_2;import androID.os.Bundle;import androID.util.Log;import androID.vIEw.VIEw;import androID.vIEw.VIEw.OnClickListener;import androID.Widget.button;import androIDx.appcompat.app.AppCompatActivity;import java.util.ArrayList;import java.util.List;public class Test extends AppCompatActivity {    private static String TAG = "mydeBUG";    private sql sql;    private button btn1,btn2,btn3,btn4;    @OverrIDe    protected voID onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentVIEw(R.layout.activity_test);        sql = new sql(this);        Log.d(TAG, "onCreate: " + new BeanRemark());        Log.d(TAG, "onCreate: " + sql);        btn1 = findVIEwByID(R.ID.Zeng);        btn1.setonClickListener(new mClick());        btn2 = findVIEwByID(R.ID.shan);        btn2.setonClickListener(new mClick());        btn3 = findVIEwByID(R.ID.gai);        btn3.setonClickListener(new mClick());        btn4 = findVIEwByID(R.ID.cha);        btn4.setonClickListener(new mClick());    }    class mClick implements OnClickListener    {        @OverrIDe        public voID onClick(VIEw arg)        {            switch (arg.getID())            {                case R.ID.Zeng:                    sql.add(new BeanRemark("wang", Time.CurTime(), "2019-12-20 16:32:00","sds"));                    sql.add(new BeanRemark("wang", Time.CurTime(), "2019-12-20 16:32:00","sss"));                    sql.add(new BeanRemark("li", Time.CurTime(), "2019-12-20 16:32:00","sds"));                    Log.d(TAG, "onClick: Zeng");                    break;                case R.ID.shan:                    Log.d(TAG, "onClick: shan");                    List<BeanRemark> List4 = sql.find(new BeanRemark(null, null, null, "sds"));                    List<String> lisID = new ArrayList();                    for(BeanRemark item : List4)                        lisID.add(""+item.getID());                    sql.delete(lisID);                    break;                case R.ID.gai:                    Log.d(TAG, "onClick: gai");                    sql.update(new BeanRemark(2,null,null,null,"你是傻逼"));                    break;                case R.ID.cha:                    Log.d(TAG, "onClick: cha");                    List<BeanRemark> List = sql.findAll();                    Log.d(TAG, "onClick: " + List + "\n");                    List<BeanRemark> List2 = sql.find(new BeanRemark(null, null, null, "sds"));                    Log.d(TAG, "onClick: " + List2);                    List<BeanRemark> List3 = sql.find(new BeanRemark(2,null,null,null,null));                    Log.d(TAG, "onClick: find 2 : " + List3);                    break;            }        }    }}

VIEw Code

实体类

package com.example.ex_2;public class BeanRemark {    private int ID = -1;    private String Title;    private String creat_time;    private String noti_time;    private String content;    public BeanRemark() {    }    public BeanRemark(int ID) {        this.ID = ID;    }    public BeanRemark(String Title, String creat_time, String noti_time, String content) {        this.Title = Title;        this.creat_time = creat_time;        this.noti_time = noti_time;        this.content = content;    }    public BeanRemark(int ID, String Title, String creat_time, String noti_time, String content) {        this.ID = ID;        this.Title = Title;        this.creat_time = creat_time;        this.noti_time = noti_time;        this.content = content;    }    public int getID() {        return ID;    }    public voID setID(int ID) {        this.ID = ID;    }    public String getTitle() {        return Title;    }    public voID setTitle(String Title) {        this.Title = Title;    }    public String getCreat_time() {        return creat_time;    }    public voID setCreat_time(String creat_time) {        this.creat_time = creat_time;    }    public String getNoti_time() {        return noti_time;    }    public voID setNoti_time(String noti_time) {        this.noti_time = noti_time;    }    public String getContent() {        return content;    }    public voID setContent(String content) {        this.content = content;    }    @OverrIDe    public String toString() {        return "BeanRemark{" +                "ID=" + ID +                ", Title='" + Title + '\'' +                ", creat_time='" + creat_time + '\'' +                ", noti_time='" + noti_time + '\'' +                ", content='" + content + '\'' +                '}';    }}

VIEw Code 总结

以上是内存溢出为你收集整理的Android Sqlite全部内容，希望文章能够帮你解决Android Sqlite所遇到的程序开发问题。

如果觉得内存溢出网站内容还不错，欢迎将内存溢出网站推荐给程序员好友。