作业

**XML布局文件

**JAVA代码

**mainActivity

package com.example.mpyypm.sql;

import android.database.Cursor;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private ListView studentList;
private Button btnzj;
private Button btnsc;
private EditText etname;

private MyCursorAdapter adapter;
private StudentDAO studentDao;
private Student student;
private Cursor cursor;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

studentList = (ListView) findViewById(R.id.list_view);
etname=(EditText)findViewById(R.id.et_name);
btnzj = (Button) findViewById(R.id.btn_add);
btnzj.setOnClickListener(this);
btnsc = (Button) findViewById(R.id.btn_delect);
btnsc.setOnClickListener(this);

// 创建Adapter:CursorAdpater
studentDao = new StudentDAO(this);
if(cursor != null) {
adapter = new MyCursorAdapter(this, cursor);
studentList.setAdapter(adapter);
}

// ListView的item点击事件
studentList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
Cursor cursor = (Cursor) adapterView.getItemAtPosition(i);
if(cursor != null) {
cursor.moveToPosition(i);
student = new Student();
student.setName(cursor.getString(cursor.getColumnIndex("name")));
}
}
});
}

public void onClick(View view) {
switch (view.getId()) {
case R.id.btn_add:
String name = etname.getText().toString();
//对必填项做非空判断
if (TextUtils.isEmpty(name)) {
Toast.makeText(MainActivity.this, "姓名不能为空", Toast.LENGTH_SHORT).show();
return;
}
//将这些数据存储到数据库
//组装name对象
Student student = new Student(name);
//调用nameDAO的insert()方法插入数据库
StudentDAO studentDAO = new StudentDAO(this);
studentDAO.insert(student);
Cursor cursor = studentDao.selectAll();
adapter.changeCursor(cursor);
Toast.makeText(this, "添加成功", Toast.LENGTH_SHORT).show();
break;
case R.id.btn_delect:
if (studentList!= null) {
cursor.moveToFirst();
student = new Student();
student.set_id(cursor.getInt(cursor.getColumnIndex("_id")));
studentDao.delete(student.get_id());
studentDao = new StudentDAO(this);
cursor = studentDao.selectAll();
adapter = new MyCursorAdapter(this, cursor);
studentList.setAdapter(adapter);
Toast.makeText(MainActivity.this, "删除成功", Toast.LENGTH_SHORT).show();
}
Toast.makeText(MainActivity.this, "记录为空", Toast.LENGTH_SHORT).show();
break;
}

}
}

**Student

package com.example.mpyypm.sql;

import java.io.Serializable;

/**
* Created by mpyypm on 2017/5/15.
*/

public class Student implements Serializable {
private int _id;
private String name;
public Student(){
}
public Student(String name){
this.name=name;
}

public int get_id() {
return _id;
}

public void set_id(int _id) {
this._id = _id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}
}

**MyCursorAdapter

package com.example.mpyypm.sql;

import android.content.Context;
import android.database.Cursor;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CursorAdapter;
import android.widget.TextView;

/**
* Created by mpyypm on 2017/5/15.
*/

public class MyCursorAdapter extends CursorAdapter {
public MyCursorAdapter(Context context, Cursor cursor) {
super(context, cursor, 0);
}

@Override
public View newView(Context context, Cursor cursor, ViewGroup viewGroup) {
return LayoutInflater.from(context).inflate(R.layout.activity_main, viewGroup, false);
}

//给item的每个主键赋值
@Override
public void bindView(View view, Context context, Cursor cursor) {
TextView name = (TextView) view.findViewById(R.id.et_name);

name.setText(cursor.getString(cursor.getColumnIndex("name")));

}
}

**MyDBHelper

public class MyDBHelper extends SQLiteOpenHelper {
//student表创建语句，字段包括：关键字id，姓名name，班级classmte，年龄age
private String sql="create table student(_id integer primary key autoincrement,"
+"name text not null ,classmate text not null,age integer)";

public MyDBHelper(Context context) {
super(context,"studentInfo",null,1);
}
//当app中没有数据库或数据库的版本为1的时候会被调用，且调用一次

@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(sql);
}
//升级数据库表，当newVersion>oldVersion，会被调用
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("drop table if exists stdent");
onCreate(db);
}
}

**StudentDAO

package com.example.mpyypm.sql;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

/**
* Created by mpyypm on 2017/5/15.
*/

public class StudentDAO {
private Context context;
private MyDBHelper helper;
private SQLiteDatabase db;

public StudentDAO(Context context) {
helper = new MyDBHelper(context);
}

public void insert(Student student){
db = helper.getWritableDatabase();

// 第一种方法
// 2. 生成数据集合
ContentValues values = new ContentValues();
values.put("name", student.getName());
// 3. 执行语句
db.insert("student", null, values);
}

public Cursor selectAll() {
db = helper.getReadableDatabase();
Cursor cursor = db.query("student",null,null,null,null,null,null);
return cursor;
}
public void delete(int id){
db = helper.getWritableDatabase();
//根据数据的id号来删除数据
db.delete("student","_id=?",new String[]{String.valueOf(id)});
}
}