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继续修改昨天的项目,将activity_main.xml文件修改为:
- <?xml version="1.0" encoding="utf-8"?>
- <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
- xmlns:app="http://schemas.android.com/apk/res-auto"
- xmlns:tools="http://schemas.android.com/tools"
- android:layout_width="match_parent"
- android:layout_height="match_parent"
- android:orientation="vertical"
- tools:context="com.example.xinwei.databasekotlin.MainActivity">
- <Button
- android:id="@+id/idbutton"
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:text="创建数据库并插入数据"/>
- <EditText
- android:id="@+id/idinputtext"
- android:layout_width="match_parent"
- android:layout_height="wrap_content"
- android:hint="请输入要查询的人"/>
- <Button
- android:id="@+id/idquerybutton"
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:text="读取数据"/>
- <TextView
- android:id="@+id/idreadtext"
- android:layout_width="wrap_content"
- android:layout_height="wrap_content" />
- </LinearLayout>
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将MainActivity.kt文件修改为:
- package com.example.xinwei.databasekotlin
- import android.content.ContentValues
- import android.database.Cursor
- import android.database.sqlite.SQLiteDatabase
- import android.database.sqlite.SQLiteQueryBuilder
- import android.support.v7.app.AppCompatActivity
- import android.os.Bundle
- import android.util.Log
- import android.widget.Toast
- import kotlinx.android.synthetic.main.activity_main.*
- class MainActivity : AppCompatActivity() {
- var myDatabase:SQLiteDatabase?=null
- var contentValues=ContentValues()
- override fun onCreate(savedInstanceState: Bundle?) {
- super.onCreate(savedInstanceState)
- setContentView(R.layout.activity_main)
- val myDatabaseHelper=CreateDatabase(this,"myDatabase",null,1)
- myDatabase=myDatabaseHelper.writableDatabase
- idbutton.setOnClickListener {
- dummyDataArray.add(MyData("jerryxjr1220","30","男"))
- dummyDataArray.add(MyData("wei_Y","18","男"))
- dummyDataArray.add(MyData("alltolove","37","男"))
- insertValues(0)
- insertValues(1)
- insertValues(2)
- }
- idquerybutton.setOnClickListener{
- var inputText=idinputtext.text
- var projection= arrayOf("id","name","age","gent")
- var curser=queryData(projection,"name like ?", arrayOf("%${inputText}%"),"name")
- if (curser.moveToFirst()){
- do {
- var id=curser.getInt(curser.getColumnIndex("id"))
- var name=curser.getString(curser.getColumnIndex("name"))
- var age=curser.getString(curser.getColumnIndex("age"))
- var gent=curser.getString(curser.getColumnIndex("gent"))
- contentValues.put("id",id)
- contentValues.put("name",name)
- contentValues.put("age",age)
- contentValues.put("gent",gent)
- }while (curser.moveToNext())
- curser.close()
- idreadtext.text=contentValues.toString()
- }
- }
- }
- fun insertValues(id:Int){
- contentValues.put("name",dummyDataArray[id].name)
- contentValues.put("age",dummyDataArray[id].age)
- contentValues.put("gent",dummyDataArray[id].gent)
- myDatabase!!.insert("MyTable","",contentValues)
- contentValues.clear()
- Toast.makeText(this,"数据已添加",Toast.LENGTH_SHORT).show()
- }
- fun queryData(projection:Array<String>?,selection:String,selectionArg:Array<String>,sorOrder:String):Cursor{
- val db=SQLiteQueryBuilder()
- db.tables="MyTable"
- var curser=db.query(myDatabase,projection,selection,selectionArg,null,null,sorOrder)
- return curser
- }
- }
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在queryData这个函数里就是查找数据的方法,基本都是固定格式照抄就行。因为手机输入法换成中文很麻烦,在数据库里我又新加进两个英文名字的版主。启动手机app后我们先点一下添加数据的按钮,然后在文本框里输入版主的名字就可以查找到版主的资料了,版主们的资料是我胡编的啊,可别当真 。效果图为:
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