谷歌封装操作数据库的方法

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" >

    <EditText

        android:id="@+id/etname"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:hint="请输入用户名" />

    <EditText

        android:id="@+id/etage"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:hint="请输入年龄" />

    <Button

        android:onClick="addper"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:text="添加" />

    

    <ListView 

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:id="@+id/lv"></ListView>

</LinearLayout>

TWOACTIVITY

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" >

    

<TextView 

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

    android:id="@+id/tv"/>

</LinearLayout>

THREE

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" >

    

<TextView 

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

    android:id="@+id/tv"/>

</LinearLayout>

public class MainActivity extends Activity {

private ListView lv;
private Empdao dao;
private List<Emp> li;
private Emp em;
private EditText etname;
private EditText etage;
private Myadpter my;

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

etname = (EditText) findViewById(R.id.etname);
etage = (EditText) findViewById(R.id.etage);
my = new Myadpter();
lv = (ListView) findViewById(R.id.lv);
//listview的长按点击事件
lv.setOnItemLongClickListener(new OnItemLongClickListener() {

@Override
public boolean onItemLongClick(AdapterView<?> arg0, View arg1,
final int arg2, long arg3) {

                //创建AlertDialog
AlertDialog.Builder builder = new Builder(MainActivity.this);
//设置内容
builder.setMessage("是否删除");
//确认
builder.setNegativeButton("确认", new OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {

                         //根据集合的id查询
dao.delete(li.get(arg2));

                         //重新查询
li = dao.select();

                         //刷新
my.notifyDataSetChanged();

}
});

                //取消框
builder.setPositiveButton("取消", new OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {

}
});
//展示
builder.show();

return false;
}
});

        //listview的短按点击事件
lv.setOnItemClickListener(new OnItemClickListener() {

private EditText tv;
private EditText et;

@Override
public void onItemClick(AdapterView<?> arg0, View arg1,
final int arg2, long arg3) {

                //创建AlertDialog
AlertDialog.Builder builder = new Builder(MainActivity.this);

                //加载布局
final View view = View.inflate(MainActivity.this,
R.layout.three, null);

                 //根据id查找
tv = (EditText) view.findViewById(R.id.tv);
et = (EditText) view.findViewById(R.id.et);

tv.setText(li.get(arg2).getName());

                
et.setText(li.get(arg2).getAge() + "");
//设置内容
builder.setMessage(li.get(arg2).toString());
builder.setView(view);
//确认
builder.setPositiveButton("确认", new OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {

String name = tv.getText().toString();
String age = et.getText().toString();

int int1 = Integer.parseInt(age);

Emp emp = new Emp(li.get(arg2).getId(), name, int1);

Toast.makeText(MainActivity.this,
name + age, 0).show();

dao.update(emp);

li = dao.select();

my.notifyDataSetChanged();

}
});

builder.show();

}
});

dao = new Empdao(this);
}

public void addper(View v) {
String string = etage.getText().toString();
int int1 = Integer.parseInt(string);
em = new Emp(0, etname.getText().toString(), int1);
dao.add(em);

li = dao.select();

lv.setAdapter(my);

}

class Myadpter extends BaseAdapter {

@Override
public int getCount() {
// TODO Auto-generated method stub
return li.size();
}

@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return null;
}

@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
convertView = View.inflate(MainActivity.this,
R.layout.two_activity, null);
}

TextView tv = (TextView) convertView.findViewById(R.id.tv);

tv.setText(li.get(position).getId() + "   "+ li.get(position).getName() + "  "+li.get(position).getAge());

return convertView;
}

}

}

public class MySQLitehelper extends SQLiteOpenHelper{

//创建库
public MySQLitehelper(Context context) {
super(context, "xwj.dp", null, 1);

}

    //创建表
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("create table person (id integer primary key,name varchar(20),age int(5))");

}

  
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub

}

}

public class Empdao {

MySQLitehelper ml;

public Empdao(Context cxt) {
ml = new MySQLitehelper(cxt);
}

// 添加数据的方法
public void add(Emp emp) {

SQLiteDatabase database = ml.getWritableDatabase();

ContentValues values = new ContentValues();

values.put("name", emp.getName());

values.put("age", emp.getAge());

database.insert("person", null, values);

database.close();
}

// 查询数据的方法
public List<Emp> select() {
List<Emp> list = new ArrayList<Emp>();

SQLiteDatabase database = ml.getWritableDatabase();
Cursor query = database.query("person", null, null, null, null, null,
null);

while (query.moveToNext()) {
int id = query.getInt(0);
String name = query.getString(1);
int age = query.getInt(2);

Emp e = new Emp(id, name, age);
list.add(e);
}

database.close();
return list;

}

// 删除的方法
public void delete(Emp emp) {

SQLiteDatabase database = ml.getWritableDatabase();
database.delete("person", "id=?", new String[] { emp.getId() + "" });

database.close();

}

// 修改数据的方法

public void update(Emp emp) {

SQLiteDatabase database = ml.getWritableDatabase();

ContentValues values = new ContentValues();

values.put("name", emp.getName());
values.put("age", emp.getAge());
database.update("person", values, "id=?", new String[] {emp.getId()
+ "" });

database.close();
}

}

public class Emp {

private int id;

private String name;

private int age;

public Emp() {
super();
// TODO Auto-generated constructor stub

}

public Emp(int id, String name, int age) {
super();
this.id = id;
this.name = name;
this.age = age;

}

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 int getAge() {
return age;

}

public void setAge(int age) {
this.age = age;

}

@Override

public String toString() {
return "Emp [id=" + id + ", name=" + name + ", age=" + age + "]";

}

}