第九次作业

xml

<?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"
    tools:context=".MainActivity">

   <LinearLayout
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       android:background="#55000000"
       android:orientation="vertical"
       android:paddingLeft="30dp"
       android:paddingRight="30dp">
      <LinearLayout
          android:layout_marginTop="80dp"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:gravity="center_vertical"
          android:orientation="horizontal" >

         <TextView
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:text="通讯录"
             android:textColor="#fff"
             android:textSize="50dp" />
      </LinearLayout>

     
   <EditText
       android:id="@+id/userid"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:layout_marginTop="30dp"
       android:background="@null"
       android:hint="请输入姓名"
       android:maxLength="13"
       android:singleLine="true"
       android:textColor="#fff"
       android:textSize="25sp"
       android:textColorHint="#eee" />

   <View
       android:layout_width="match_parent"
       android:layout_height="1px"
       android:layout_marginTop="10dp"
       android:background="#eee" />
   <EditText
       android:id="@+id/password"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:layout_marginTop="10dp"
       android:background="@null"
       android:hint="请输入手机号码"
       android:inputType="textPassword"
       android:maxLength="13"
       android:singleLine="true"
       android:textColor="#fff"
       android:textSize="25dp"
       android:textColorHint="#eee" />
   <View
       android:layout_width="match_parent"
       android:layout_height="1px"
       android:layout_marginTop="10dp"
       android:background="#eee" />

   <LinearLayout
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:layout_marginTop="10dp"
       android:orientation="horizontal" >

      <Button
          android:id="@+id/btn_1"
          android:layout_width="0dp"
          android:layout_height="wrap_content"
          android:layout_weight="1"
          android:text="添加"/>
      <Button
          android:id="@+id/btn_2"
          android:layout_width="0dp"
          android:layout_height="wrap_content"
          android:layout_weight="1"
          android:text="查询"/>
      <Button
          android:id="@+id/btn_3"
          android:layout_width="0dp"
          android:layout_height="wrap_content"
          android:layout_weight="1"
          android:text="修改"/>
      <Button
          android:id="@+id/btn_4"
          android:layout_width="0dp"
          android:layout_height="wrap_content"
          android:layout_weight="1"
          android:text="删除"/>
   </LinearLayout>

</LinearLayout>

</LinearLayout>

java

package com.example.director;

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

import java.security.cert.Extension;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{
    MyHelper myHelper;
    private EditText userid;
    private EditText password;
    private Button btn_1;
    private Button btn_2;
    private Button btn_3;
    private Button btn_4;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        myHelper =new MyHelper(this);
        init();
    }

    private void init() {
        userid=(EditText)findViewById(R.id.userid);
        password=(EditText)findViewById(R.id.password);
        btn_1=(Button) findViewById(R.id.btn_1);
        btn_2=(Button) findViewById(R.id.btn_2);
        btn_3=(Button) findViewById(R.id.btn_3);
        btn_4=(Button) findViewById(R.id.btn_4);
        btn_1.setOnClickListener(this);
        btn_2.setOnClickListener(this);
        btn_3.setOnClickListener(this);
        btn_4.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        String name ,phone;
        SQLiteDatabase db;
        ContentValues values;
       switch (v.getId()){
           //添加数据
           case R.id.btn_1:
               name=userid.getText().toString();
               phone=password.getText().toString();
               db=myHelper.getWritableDatabase();
               values=new ContentValues();
               values.put("name",name);
               values.put("phone",phone);
               db.insert("information",null,values);
               Toast.makeText(this,"信息已添加",Toast.LENGTH_SHORT).show();
               db.close();
               break;

               //查询数据
           case R.id.btn_2:
               db =myHelper.getReadableDatabase();
               Cursor cursor=db.query("information",null,null,null,null,null,null);
               if (cursor.getCount()==0){
                   Toast.makeText(this,"没有数据",Toast.LENGTH_SHORT).show();
               }else{
                   cursor.moveToFirst();

               }
               while (cursor.moveToNext()){

               }
                   cursor.close();
                   db.close();
                   break;


                     //修改数据
           case R.id.btn_3:
               db=myHelper.getWritableDatabase();
               values=new ContentValues();
               values.put("phone",phone=password.getText().toString());
               db.update("information",values,"name=?",new String[]{userid.getText().toString()});
               Toast.makeText(this,"信息已修改",Toast.LENGTH_SHORT).show();
               db.close();
               break;

               //删除数据
           case  R.id.btn_4:
               db=myHelper.getWritableDatabase();
               db.delete("information",null,null);
               Toast.makeText(this,"信息已删除",Toast.LENGTH_SHORT).show();
               db.close();
               break;

       }
    }
}
2.2.2

package com.example.director;

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

class MyHelper extends SQLiteOpenHelper {
    public MyHelper(Context context) {
        super(context,"itcast.db",null,1);

    }


    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE information (_id INTEGER PRIMARY KEY AUTOINCREMENT,name VARCHAR(20),phone VARCHAR(20))");
    }

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

    }


}