这是出勤数据库适配器类！这提供了我们需要在按钮点击时执行的更新和插入代码！
package com.vidhi.grietportal;
import android.content.ContentValues;
import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
public class AttendanceDataBaseAdapter
{
public final String DATABASE_NAME="login.db";
static final int DATABASE_VERSION=1;
static final int NAME_COLUMN=1;
public SQLiteDatabase db;
private final Context context;
private DataBaseHelper dbhelper;
public AttendanceDataBaseAdapter(Context _context)
{
context=_context;
dbhelper=new DataBaseHelper(context, DATABASE_NAME, null,DATABASE_VERSION);
}
public AttendanceDataBaseAdapter open() throws SQLException
{
db=dbhelper.getWritableDatabase();
return this;
}
public void close()
{
db.close();
}
public SQLiteDatabase getDatabaseInstance()
{
return db;
}
public void insertEntry(String roll,String name,String percent)
{
ContentValues newcontent=new ContentValues();
newcontent.put("ROLLNO",roll);
newcontent.put("STUNAME", name);
newcontent.put("PERCENTAGE",percent);
db.insert("ATTENDANCE",null, newcontent);
}
public void updateEntry(String roll,String name,String percent)
{
ContentValues newupdate=new ContentValues();
newupdate.put("ROLLNO", roll);
newupdate.put("STUNAME",name);
newupdate.put("PERCENTAGE", percent);
String where="ROLLNO=?";
db.update("ATTENDANCE", newupdate, where, new String[] {roll});
}
public void show()
{
db.execSQL("SELECT * from ATTENDANCE");
}
}
这是包含更新页面布局的 .xml 文件。
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/bckg1"
android:gravity="top"
android:orientation="vertical" >
<TextView
android:id="@+id/gotomenu"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="46dp"
android:layout_marginRight="18dp"
android:text="Go to Main Menu"
android:textColor="#221778"
android:textSize="15sp" />
<EditText
android:id="@+id/entryforroll"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/rollno"
android:layout_alignParentRight="true"
android:layout_toRightOf="@+id/attendancepercent"
android:ems="10"
android:inputType="textPersonName"
android:hint="Enter Roll Number" >
<requestFocus />
</EditText>
<TextView
android:id="@+id/rollno"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginTop="58dp"
android:text="Roll Number:"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textColor="#221778"
android:textStyle="bold" />
<Button
android:id="@+id/show"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/gotomenu"
android:layout_toLeftOf="@+id/gotomenu"
android:text="Show"
android:textColor="#221778"
android:textStyle="bold"
/>
<Button
android:id="@+id/insert"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/show"
android:layout_alignLeft="@+id/name"
android:layout_marginBottom="36dp"
android:text="Insert"
android:textColor="#221778"
android:textStyle="bold"
/>
<Button
android:id="@+id/update"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/insert"
android:layout_alignBottom="@+id/insert"
android:layout_alignRight="@+id/gotomenu"
android:text="Update"
android:textColor="#221778"
android:textStyle="bold"
/>
<TextView
android:id="@+id/attendancepercent"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/insert"
android:layout_alignParentLeft="true"
android:layout_marginBottom="23dp"
android:text="Attendance %:"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textColor="#221778"
android:textStyle="bold" />
<TextView
android:id="@+id/name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/rollno"
android:layout_marginTop="24dp"
android:text="Name:"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textColor="#221778"
android:textSize="22sp"
android:textStyle="bold" />
<EditText
android:id="@+id/entryforname"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/name"
android:layout_alignLeft="@+id/show"
android:ems="10"
android:inputType="textPersonName"
android:hint="Enter Name" />
<EditText
android:id="@+id/entryforpercentage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/attendancepercent"
android:layout_toRightOf="@+id/show"
android:ems="10"
android:hint="Enter %" />
</RelativeLayout>
Update.java 文件：我只是用来详细说明要做什么！
package com.vidhi.grietportal;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
public class Update extends Activity {
Button b1,b2,b3;
EditText e1,e2,e3;
AttendanceDataBaseAdapter adb;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.update);
adb= new AttendanceDataBaseAdapter(this);
adb=adb.open();
b1=(Button)findViewById(R.id.insert);
b2=(Button)findViewById(R.id.update);
b3=(Button)findViewById(R.id.show);
e1=(EditText)findViewById(R.id.entryforroll);
e2=(EditText)findViewById(R.id.entryforname);
e3=(EditText)findViewById(R.id.entryforpercentage);
final String roll=e1.getText().toString();
final String name=e2.getText().toString();
final String percent=e3.getText().toString();
b1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
adb.insertEntry(roll,name,percent);
}
});
b2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
adb.updateEntry(roll,name,percent);
}
});
b3.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
adb.show();
}
});
}
}
DataBaseHelper.java ：（这对我的应用程序中的两个表都是通用的）
package com.vidhi.grietportal;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
public class DataBaseHelper extends SQLiteOpenHelper {
private static final String TABLE1 = "login";
private static final String TABLE2 = "ATTENDANCE";
private static final String COLUMN_ID = "id";
private static final String COLUMN_TITLE1 = "username";
private static final String COLUMN_TITLE2 = "password";
private static final String COLUMN_ID1 = "id1";
private static final String COLUMN_TITLE3 = "ROLLNO";
private static final String COLUMN_TITLE4 = "STUNAME";
private static final String COLUMN_TITLE5 = "PERCENTAGE";
public static final String TABLE1_CREATION = "create table " + TABLE1 + " (" + COLUMN_ID + " integer primary key autoincrement, " + COLUMN_TITLE1 + " varchar,"+COLUMN_TITLE2+"varchar"+")";
public static final String TABLE2_CREATION = "create table " + TABLE2 + " (" + COLUMN_ID1 + " integer primary key autoincrement, " + COLUMN_TITLE3 + " varchar,"+COLUMN_TITLE4+"varchar,"+COLUMN_TITLE5+"varchar"+")";
public DataBaseHelper(Context context, String name, CursorFactory factory, int version) {
super(context, name, factory, version);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(TABLE1_CREATION);
db.execSQL(TABLE2_CREATION);
}
@Override
public void onUpgrade(SQLiteDatabase db, int paramInt1, int paramInt2) {
db.execSQL("DROP TABLE " + TABLE1_CREATION + ";");
db.execSQL("DROP TABLE " + TABLE2_CREATION + ";");
onCreate(db);
}
}
有人可以帮帮我吗？我也无法在文件资源管理器中打开数据文件夹！