1.student类
public class Student {
int id;
String name;
String sex;
String address;
int money;
public Student(int id, String name, String sex, String address, int money) {
super();
this.id = id;
this.name = name;
this.sex = sex;
this.address = address;
this.money = money;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public int getMoney() {
return money;
}
public void setMoney(int money) {
this.money = money;
}
@Override
public String toString() {
return "Student [id=" + id + ", name=" + name + ", sex=" + sex
+ ", address=" + address + ", money=" + money + "]";
}
}2.studentDao
import java.util.ArrayList;
import java.util.List; import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase; public class StudentDao { /**
* 插入数据
*/ public boolean insert(Student stu) {
SQLiteDatabase db = SQLiteDBHelper.getSqLiteDatabase();
try {
db.execSQL("insert into student (name,sex,address,money) values(?,?,?,?)",
new Object[]{stu.getName(),stu.getSex(),stu.getAddress(),stu.getMoney()});
db.close();
return true;
} catch (Exception e) {
// TODO: handle exception
} return false;
}
/**
* 删除数据
* @param student
*/
public void delete(int id) {
SQLiteDatabase db = SQLiteDBHelper.getSqLiteDatabase();
//db.execSQL("delete from student where _id = ?", new Object[]{student.getId()});
db.execSQL("delete from student where _id = "+id);
db.close();
} /**
* 更新数据
*/ public void update(Student stu) {
SQLiteDatabase db = SQLiteDBHelper.getSqLiteDatabase();
db.execSQL("update student set name = ?,sex=?,address=?,money=? where _id = ?",
new Object[]{stu.getName(),stu.getSex(),stu.getAddress(),stu.getMoney(),stu.getId()});
db.close();
} /**
* 根据Id查询数据
* @param id
* @return
*/
public Student findById(int id) {
SQLiteDatabase db = SQLiteDBHelper.getSqLiteDatabase();
Cursor cursor = db.rawQuery("select * from student where _id = ?", new String[]{id+""});
Student student = null;
if (cursor.moveToNext()) {
int _id = cursor.getInt(cursor.getColumnIndex("_id"));
String name = cursor.getString(cursor.getColumnIndex("name"));
String sex = cursor.getString(cursor.getColumnIndex("sex"));
String address = cursor.getString(cursor.getColumnIndex("address"));
int money = cursor.getInt(cursor.getColumnIndex("money"));
student = new Student(_id, name, sex, address, money);
}
return student;
} /**
* 查询全部数据
* @return
*/
public List<Student> findAll() {
List<Student> list = new ArrayList<Student>();
SQLiteDatabase db = SQLiteDBHelper.getSqLiteDatabase(); Cursor cursor = db.rawQuery("select * from student", null);
Student student = null;
while (cursor.moveToNext()) {
int _id = cursor.getInt(cursor.getColumnIndex("_id"));
String name = cursor.getString(cursor.getColumnIndex("name"));
String sex = cursor.getString(cursor.getColumnIndex("sex"));
String address = cursor.getString(cursor.getColumnIndex("address"));
int money = cursor.getInt(cursor.getColumnIndex("money"));
student = new Student(_id, name, sex, address, money);
list.add(student);
}
return list;
} }
3.SqliteDbHelper
import java.io.File;
import android.database.sqlite.SQLiteDatabase;
import com.qf.day14_sqlitedatabase02.SDcardHelper;
public class SQLiteDBHelper {
private static String DB_PATH = SDcardHelper.getSDCardPath();
private static String DB_NAME = "student.db";
static {
SQLiteDatabase db = SQLiteDatabase.openOrCreateDatabase(DB_PATH+File.separator+DB_NAME, null);
db.execSQL("create table if not exists student(_id integer primary key autoincrement," +
"name varchar(20)," +
"sex varchar(4)," +
"address varchar(100)," +
"money integer)");
db.close();
}
public static SQLiteDatabase getSqLiteDatabase() {
return SQLiteDatabase.openOrCreateDatabase(DB_PATH+File.separator+DB_NAME, null);
}
}4.SDcardHelper
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException; import android.os.Environment;
import android.os.StatFs; public class SDcardHelper {
/**
* 判断Sdcard是否可用
*/ public static boolean isSDcardMounted() {
boolean state = Environment.getExternalStorageState().
equals(Environment.MEDIA_MOUNTED);
return state;
} /**
* 获取SDcard目录
* @return
*/
public static String getSDCardPath() {
String path = Environment.getExternalStorageDirectory().getAbsolutePath();
return path;
} /**
* 返回总大小
* @return
*/
public static long getSDCardSize() {
if (isSDcardMounted()) {
//
StatFs sf = new StatFs(getSDCardPath());
long count = sf.getBlockCount();
long size = sf.getBlockSize();
return count * size;
}
return 0;
} /**
* 返回剩余空间
*/ public static long getSDCardFreeSize() {
if (isSDcardMounted()) {
StatFs sFs = new StatFs(getSDCardPath());
long count = sFs.getFreeBlocks();
long size = sFs.getBlockSize();
return count * size;
}
return 0;
} /**
* 获取可用空间
*/ public static long getSDCardAvailableSize() {
if (isSDcardMounted()) {
StatFs sFs = new StatFs(getSDCardPath());
long count = sFs.getAvailableBlocks();
long size = sFs.getBlockSize();
return count * size;
}
return 0;
} /**
*
* @param data 保存的数据
* @param dir 保存的文件或者目录
* @param filename 保存的文件名
* @return
*/
public static boolean saveFileToSDCard(byte[] data, String dir,String filename) {
if (isSDcardMounted()) {//判断Sdcard是否可用
File filedir = new File(getSDCardPath() + File.separator + dir);
if (!filedir.exists()) {//是否存在目录，不存在则创建
filedir.mkdirs();
} if (getSDCardAvailableSize() >= data.length) {//判断空间是否够用
FileOutputStream fos = null;
try {
fos = new FileOutputStream(new File(filedir+File.separator+filename));
fos.write(data);
fos.flush();
return true;
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally {
if (fos != null) {
try {
fos.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
} return false;
} public static byte[] readFileFromSDCard(String filepath) {
if (isSDcardMounted()) {
File file = new File(filepath);
ByteArrayOutputStream byteArrayOutputStream = null;
if (file.exists()) {
FileInputStream fileInputStream = null;
try {
fileInputStream = new FileInputStream(file);
byteArrayOutputStream = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int length = 0;
while ((length = fileInputStream.read(buffer)) != -1) {
byteArrayOutputStream.write(buffer, 0, length);
} return byteArrayOutputStream.toByteArray();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
if (fileInputStream != null) {
try {
fileInputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
} }
}
return null;
}
}
5.mainActivity
import java.util.List; import com.qf.day14_sqlitedatabase02.bean.Student;
import com.qf.day14_sqlitedatabase02.dao.StudentDao; import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Toast; public class MainActivity extends Activity {
StudentDao studentDao = new StudentDao();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
/**
* 数据库的Id从1开始，不是下标
* @param v
*/
public void insert(View v) {
studentDao.insert(new Student(2, "老冯", "男", "航海路阳光城", 30000000));
studentDao.insert(new Student(2, "老魏", "男", "东建材", 30000));
studentDao.insert(new Student(2, "老欧", "男", "西海岸", 900000));
studentDao.insert(new Student(2, "萍姐", "女", "农业东路中州大道", 100000));
studentDao.insert(new Student(2, "和珅", "男", "清朝紫荆城", 9000000)); }
public void delete(View v) {
studentDao.delete(1);
}
public void update(View v) {
studentDao.update(new Student(3, "标哥", "男", "南京", 10));
}
public void findId(View v) {
Student student = studentDao.findById(4);
Toast.makeText(this, student.toString(), Toast.LENGTH_SHORT).show();
}
public void findAll(View v) {
List<Student> list = studentDao.findAll();
Toast.makeText(this, list.toString(), Toast.LENGTH_SHORT).show();
}
}