android SQLiteDatebase 实践

android 平台下建立的一个数据库小实例。实现了数据的增、删、改、通过对话框的形式去修改、删除数据

MdbHelper类:

package training.android.com; import android.content.ContentValues; import android.content.Context; import android.database.Cursor; import android.database.SQLException; import android.database.sqlite.SQLiteDatabase; import android.util.Log; public class MdbHelper { private SQLiteDatabase mdb; private sqldataHelper mdbhelp; private final Context cxt; public static final String KeyRowID = "_id"; public static final String KeyRowname = "StudentName"; public static final String KeyRowAge = "StudentAge"; public static final String KeyRowClass = "StudentClass"; public static final String KeyRowSchool = "StudentSchool"; private static final String TableName = "Student";// public MdbHelper(Context ct) { this.cxt = ct; } public MdbHelper open() throws SQLException { mdbhelp = new sqldataHelper(cxt, 1); setMdb(mdbhelp.getWritableDatabase()); return this; } public void close() { mdbhelp.close(); } public void InsertStudent(int studnetid, String studentname, String studentage, String studentclass, String studentschool) { ContentValues values = new ContentValues(); values.put(KeyRowID, studnetid); values.put(KeyRowname, studentname); values.put(KeyRowAge, studentage); values.put(KeyRowClass, studentclass); values.put(KeyRowSchool, studentschool); mdb.insert(TableName, null, values); } public void UpdateStudent(int studentid, String studentname, String studentage, String studentclass, String studentschool) { ContentValues values = new ContentValues(); values.put(KeyRowname, studentname); values.put(KeyRowAge, studentage); values.put(KeyRowClass, studentclass); values.put(KeyRowSchool, studentschool); mdb.update(TableName, values, KeyRowID + "=" + studentid, null); } public Cursor simpleStudent(long studentid) throws SQLException { return mdb.query(TableName, new String[] { KeyRowID, KeyRowname, KeyRowAge, KeyRowClass, KeyRowSchool }, KeyRowID + "=" + studentid, null, null, null, null); // return mdb.query(TableName, new String[]{KeyRowID, // KeyRowname,KeyRowAge,KeyRowClass,KeyRowSchool}, // KeyRowID+"="+studentid, null, null, null, null); // return mdb.query(TableName, new String[]{KeyRowID, // KeyRowname,KeyRowAge,KeyRowClass,KeyRowSchool}, // KeyRowID+"="+studentid, null, null, null, null); } public boolean deletestudent(long rowId) { return mdb.delete(TableName, KeyRowID + "=" + rowId, null) > 0; //(4) } public Cursor fetchMyTableById(long rowId) throws SQLException { return mdb.query(TableName, new String[] { KeyRowID, KeyRowname, KeyRowAge, KeyRowClass, KeyRowSchool }, KeyRowID + "=" + rowId, null, null, null, null); } public Cursor QueryStudentALl() { return mdb.query(TableName, new String[] { KeyRowID, KeyRowname, KeyRowAge, KeyRowClass, KeyRowSchool }, null, null, null, null, null, null); } public void setMdb(SQLiteDatabase mdb) { this.mdb = mdb; } public SQLiteDatabase getMdb() { return mdb; } }

SQLiteOpenHelper继承:

package training.android.com; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; public class sqldataHelper extends SQLiteOpenHelper { private static final String Databasename="SmsStudent"; private static final String TableName = "Student";// public static final String KeyRowID = "_id"; public static final String KeyRowname = "StudentName"; public static final String KeyRowAge = "StudentAge"; public static final String KeyRowClass = "StudentClass"; public static final String KeyRowSchool = "StudentSchool"; private static final String StudentTableSql = "CREATE TABLE IF NOT EXISTS " + TableName + "(" + KeyRowID + " INTEGER PRINAMARY KEY," + KeyRowname + " VARCHAR," + KeyRowAge + " VARCHAR," + KeyRowClass + " VARCHAR," + KeyRowSchool + " VARCHAR);"; private static final String UpdateTableGradSql = "DROP TABLE IF EXISTS" + TableName; public sqldataHelper(Context context, int version) { super(context, Databasename, null, version); // TODO Auto-generated constructor stub } @Override public void onCreate(SQLiteDatabase db) { // TODO Auto-generated method stub db.execSQL(StudentTableSql); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { // TODO Auto-generated method stub db.execSQL(UpdateTableGradSql); onCreate(db); } }

页面代码：

package training.android.com; import android.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.content.DialogInterface.OnClickListener; import android.database.Cursor; import android.os.Bundle; import android.view.LayoutInflater; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.widget.AdapterView; import android.widget.EditText; import android.widget.ListView; import android.widget.SimpleCursorAdapter; import android.widget.Toast; import android.widget.AdapterView.OnItemClickListener; //创建人：周昕 //创建时间：2010-4-1 public class studentdatabase extends Activity { private MdbHelper mdbhelper; public static final String KeyRowID = "_id"; public static final String KeyRowname = "StudentName"; public static final String KeyRowAge = "StudentAge"; public static final String KeyRowClass = "StudentClass"; public static final String KeyRowSchool = "StudentSchool"; private EditText studentname; private EditText studentage; private EditText studentclass; private EditText studentschool; private String name; private String age; private String Class; private String School; private int Studentid; // private static final String TableName = "Student";// /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); Binddata(); } public boolean onCreateOptionsMenu(Menu menu) { super.onCreateOptionsMenu(menu); menu.add("新增"); return true; } public boolean onOptionsItemSelected(MenuItem items) { super.onOptionsItemSelected(items); switch (items.getItemId()) { case 0: // Toast.makeText(this, "新增", Toast.LENGTH_SHORT).show(); LayoutInflater factory = LayoutInflater.from(this); View myview = factory.inflate(R.layout.addstundet, null); studentname = (EditText) myview .findViewById(R.id.insertstudentname); studentage = (EditText) myview.findViewById(R.id.insertstudentage); studentclass = (EditText) myview .findViewById(R.id.insertstudentclass); studentschool = (EditText) myview .findViewById(R.id.insertstudentschool); OnClickListener click1 = new OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { // TODO Auto-generated method stub String name = studentname.getText().toString(); String age = studentage.getText().toString(); String sclass = studentclass.getText().toString(); String school = studentschool.getText().toString(); mdbhelper.open(); Cursor firstcurss = mdbhelper.QueryStudentALl(); int max; int temp = 0; while (firstcurss.moveToNext()) { max = firstcurss.getInt(0); if (temp < max) temp = max; } int maxIntID = temp; mdbhelper.InsertStudent(maxIntID + 1, name, age, sclass, school); Binddata(); } }; OnClickListener click2 = new OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { // TODO Auto-generated method stub } }; AlertDialog newstudentdialog = new AlertDialog.Builder(this) .create(); newstudentdialog.setView(myview); newstudentdialog.setButton("确定", click1); newstudentdialog.setButton2("取消", click2); newstudentdialog.show(); break; } return false; } public void Binddata() { mdbhelper = new MdbHelper(this); mdbhelper.open(); String[] student = new String[] { KeyRowID, KeyRowname, KeyRowAge, KeyRowClass, KeyRowSchool }; int[] arraystudent = new int[] { R.id.studentid, R.id.studentname, R.id.studentage, R.id.studentclass, R.id.studenschool }; Cursor curs = mdbhelper.QueryStudentALl(); startManagingCursor(curs); SimpleCursorAdapter ad = new SimpleCursorAdapter(this, R.layout.list_row, curs, student, arraystudent); // setListAdapter(ad);如果继承ListActivity ListView list = (ListView) findViewById(R.id.list); list.setAdapter(ad); OnItemClickListener clicklisterner = new OnItemClickListener() { @Override public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) { // TODO Auto-generated method stub Studentid= arg2 + 1; Cursor simplestuent = mdbhelper.fetchMyTableById(Studentid); while (simplestuent.moveToNext()) { name = simplestuent.getString(1); age = simplestuent.getString(2); Class = simplestuent.getString(3); School = simplestuent.getString(4); } LayoutInflater factory = LayoutInflater.from(studentdatabase.this); View myview = factory.inflate(R.layout.addstundet, null); studentname = (EditText) myview .findViewById(R.id.insertstudentname); studentage = (EditText) myview .findViewById(R.id.insertstudentage); studentclass = (EditText) myview .findViewById(R.id.insertstudentclass); studentschool = (EditText) myview .findViewById(R.id.insertstudentschool); studentname.setText(name); studentage.setText(age); studentclass.setText(Class); studentschool.setText(School); // Toast.makeText(studentdatabase.this, "您当前选择的编号为：" + Studentid, // Toast.LENGTH_SHORT).show(); OnClickListener click1 = new OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { // TODO Auto-generated method stub String name = studentname.getText().toString(); String age = studentage.getText().toString(); String sclass = studentclass.getText().toString(); String school = studentschool.getText().toString(); mdbhelper.open(); mdbhelper.UpdateStudent(Studentid, name, age, sclass, school); Binddata(); } }; OnClickListener click2 = new OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { // TODO Auto-generated method stub } }; OnClickListener click3=new OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { // TODO Auto-generated method stub mdbhelper.open(); if(mdbhelper.deletestudent(Studentid)) { Toast.makeText(studentdatabase.this, "编号为"+Studentid+"学生删除成功", Toast.LENGTH_SHORT).show(); Binddata(); } } }; AlertDialog newstudentdialog = new AlertDialog.Builder(studentdatabase.this) .create(); newstudentdialog.setView(myview); newstudentdialog.setButton("更新", click1); newstudentdialog.setButton2("取消", click2); newstudentdialog.setButton3("删除", click3); newstudentdialog.show(); } }; list.setOnItemClickListener(clicklisterner); // mdbhelper.close(); } }

mail.xml:

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <ListView android:id="@+id/list" android:layout_width="fill_parent" android:layout_height="wrap_content" /> </LinearLayout>

addstundet.xml:

<?xml version="1.0" encoding="UTF-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="wrap_content"> <TableLayout android:id="@+id/TableLayout01" android:layout_width="wrap_content" android:layout_height="wrap_content"> <TableRow android:id="@+id/TableRow01" android:orientation="horizontal" android:layout_width="wrap_content" android:layout_height="wrap_content"> <TextView android:id="@+id/txtname" android:layout_width="100px" android:layout_marginLeft="20px" android:layout_height="wrap_content" android:text="姓名"></TextView> <EditText android:id="@+id/insertstudentname" android:layout_width="150px" android:layout_height="wrap_content" android:text=""></EditText> </TableRow> <TableRow android:id="@+id/TableRow02" android:layout_width="wrap_content" android:layout_height="wrap_content"> <TextView android:id="@+id/txtage" android:layout_width="100px" android:layout_marginLeft="20px" android:layout_height="wrap_content" android:text="年龄"></TextView> <EditText android:id="@+id/insertstudentage" android:layout_width="150px" android:layout_height="wrap_content" android:text=""></EditText> </TableRow> <TableRow android:id="@+id/TableRow03" android:layout_width="wrap_content" android:layout_height="wrap_content"> <TextView android:id="@+id/txtclass" android:layout_width="100px" android:layout_marginLeft="20px" android:layout_height="wrap_content" android:text="班级"></TextView> <EditText android:id="@+id/insertstudentclass" android:layout_width="150px" android:layout_height="wrap_content" android:text=""></EditText> </TableRow> <TableRow android:id="@+id/TableRow03" android:layout_width="wrap_content" android:layout_height="wrap_content"> <TextView android:id="@+id/txtschool" android:layout_width="100px" android:layout_marginLeft="20px" android:layout_height="wrap_content" android:text="学校"></TextView> <EditText android:id="@+id/insertstudentschool" android:layout_width="150px" android:layout_height="wrap_content" android:text=""></EditText> </TableRow> <TableRow android:id="@+id/TableRow03" android:orientation="horizontal" android:layout_width="wrap_content" android:layout_height="wrap_content"> </TableRow> </TableLayout> </LinearLayout>

list_row.xml:

<?xml version="1.0" encoding="UTF-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="wrap_content"> <TextView android:text="学生编号" android:id="@+id/studentid" android:layout_width="fill_parent" android:layout_height="wrap_content"> </TextView> <LinearLayout xmlns="http://schemas.android.com/apk/res/android" android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="wrap_content" > <TextView android:id="@+id/studentname" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="学生姓名" android:layout_marginLeft="20px" > </TextView> <TextView android:id="@+id/studentage" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="学生年纪" android:layout_marginLeft="20px" ></TextView> <TextView android:id="@+id/studentclass" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="学生班级" android:layout_marginLeft="20px" > </TextView> <TextView android:id="@+id/studenschool" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="学生学校" android:layout_marginLeft="20px" ></TextView> </LinearLayout> </LinearLayout>