练习

package com.hanqi.cunchu;

import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class shujuku1 extends AppCompatActivity {
    EditText name, id, sex, age;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.shujuku1);
        id = (EditText) findViewById(R.id.i1);
        name = (EditText) findViewById(R.id.i2);
        sex = (EditText) findViewById(R.id.i3);
        age = (EditText) findViewById(R.id.i4);
    }
    public  void  b1(View view){
        m mdb = new m("test2",1);

        //得到连接
        SQLiteDatabase sqLiteDatabase= mdb.getWritableDatabase();

        //关闭连接
        sqLiteDatabase.close();

    }
    public  void  b2(View view){
        //使用工具类得到数据库对象
        m mdb = new m("test2",4);

        //得到连接
        SQLiteDatabase sqLiteDatabase= mdb.getWritableDatabase();

        //关闭连接
        sqLiteDatabase.close();
    }
    public  void  b3(View view){
        SQLiteDatabase sd=new m("test2",4).getReadableDatabase();
        ContentValues cv=new ContentValues();
        cv.put("_id",id.getText().toString());
        cv.put("name",name.getText().toString());
        cv.put("age",age.getText().toString());
        cv.put("sex",sex.getText().toString());
        sd.insert("NewTable", null, cv);
        sd.close();
    }

    public  void  b5(View view){
        SQLiteDatabase sd=new  m("test",4).getReadableDatabase();
        String s="1=1";
        if(id.getText().length()>0){
            s+=" and _id="+id.getText().toString();
        }
        if(name.getText().length()>0){
            s+=" and name="+name.getText().toString();
        }
        if(sex.getText().length()>0){
            s+=" and sex="+sex.getText().toString();
        }
        if(age.getText().length()>0){
            s+=" and age="+age.getText().toString();
        }
        Cursor c = sd.query("NewTable", null, s, null, null, null, null);

        while (c.moveToNext()){
            String ss=c.getString(c.getColumnIndex("_id"))+" "+c.getString(1);
        }
        c.close();
        sd.close();
    }
    public void b6(View v){
        SQLiteDatabase sd=new m("test2",4).getReadableDatabase();
        ContentValues cv=new ContentValues();
        cv.put("name",name.getText().toString());
        cv.put("age",age.getText().toString());
        cv.put("sex",sex.getText().toString());
        sd.update("NewTable", cv, "_id=?", new String[]{id.getText().toString()});
        sd.close();

    }
    public void b7(View v){
        SQLiteDatabase sd=new m("test2",4).getReadableDatabase();

        sd.delete("NewTable", "_id=?", new String[]{id.getText().toString()});
    }
    public void b8(View v){
        SQLiteDatabase sd=new m("test2",4).getReadableDatabase();
        sd.beginTransaction();
        try {
            ContentValues cv = new  ContentValues();
           cv.put("name","呵呵哒");
            ContentValues cv2 = new  ContentValues();
            cv2.put("name", "呵呵哒2");
          int i=  sd.update("NewTable",cv,"_id=1",null);
//            if(i>0){
//            throw new RuntimeException("呵呵哒");
//            }
         int k=   sd.update("NewTable",cv,"_id=1",null);
            sd.setTransactionSuccessful();
            Toast.makeText(shujuku1.this, "改变的记录条数"+(i+k), Toast.LENGTH_SHORT).show();
    }
        catch (Exception e){
            e.printStackTrace();
        }
        finally {
            sd.endTransaction();
            sd.close();
        }
    }
        class m extends SQLiteOpenHelper{
        public m(String dbname,int ver){
            super(shujuku1.this,dbname,null,ver);
        }

        @Override
            public void onCreate(SQLiteDatabase db) {
            String sql="CREATE TABLE  "main"."NewTable" ("_id"  INTEGER NOT NULL," +
                    ""name"  varchar(20),"sex"  char(1)," +
                    ""age"  INTEGER,PRIMARY KEY ("_id")
" +
                    ")
" +
                    ";";
            db.execSQL(sql);
            Log.e("tag", "创建完成");
            //2.执行初始化数据的语句，insert语句

            ContentValues cv=new ContentValues();
            cv.put("name","张三");
            cv.put("sex","男");
            cv.put("age",15);

            //z执行插入
            long l= db.insert("NewTable",null,cv);

            Log.e("tag", "初始化数据" + l);

        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

            if(newVersion==4){
                ContentValues cv=new ContentValues();
                cv.put("name","李四");

                String sql="update NewTable set name='李四' where _id=1";
                String s[]={"1","18"};

                //调用db的更新方法
                int i= db.update("NewTable",cv,"_id=? and age<?",s);

                Log.e("tag", "升级数据 数据条数=" + i);
                db.execSQL(sql);
            }
        }

            @Override
            public void onOpen(SQLiteDatabase db) {
                super.onOpen(db);
            }
        }
}