Android数据库

1. 数据库DBAdapter类

import android.content.*;import android.database.*;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteException;import android.database.sqlite.SQLiteDatabase.CursorFactory;import android.database.sqlite.SQLiteOpenHelper;public class DBAdapter{    public static final String DB_NAME = "student.db";    public static final String DB_TABLE = "studentinfo";    public static final int DB_VERSION = 1;        public static final String KEY_NAME = "name";    public static final String KEY_CLASS = "class";    public static final String KEY_NO = "no";        public SQLiteDatabase db;    public final Context context;    public DBOpenHelper dbOpenHelper;            public DBAdapter(Context _context)    {       context = _context;    }        public void close()    {    if(db != null)    {    db.close();    db = null;    }    }  /** Open the database */  public void open() throws SQLiteException {    dbOpenHelper = new DBOpenHelper(context, DB_NAME, null, DB_VERSION);  try {  db = dbOpenHelper.getWritableDatabase();  }  catch (SQLiteException ex) {  db = dbOpenHelper.getReadableDatabase();  }  }    public long insert(People people) {    ContentValues newValues = new ContentValues();      newValues.put(KEY_NAME, people.Name);    newValues.put(KEY_CLASS, people.Class);    newValues.put(KEY_NO, people.No);        return db.insert(DB_TABLE, null, newValues);  }  public People[] queryAllData() {    Cursor results =  db.query(DB_TABLE, new String[] { KEY_NAME, KEY_CLASS, KEY_NO},   null, null, null, null, null);  return ConvertToPeople(results);     }    public People[] queryOneData(long id) {    Cursor results =  db.query(DB_TABLE, new String[] { KEY_NAME, KEY_CLASS, KEY_NO},   KEY_NO + "=" + id, null, null, null, null);  return ConvertToPeople(results);     }    private People[] ConvertToPeople(Cursor cursor){  int resultCounts = cursor.getCount();  if (resultCounts == 0 || !cursor.moveToFirst()){  return null;  }  People[] peoples = new People[resultCounts];  for (int i = 0 ; i<resultCounts; i++){  peoples[i] = new People();  peoples[i].Name = cursor.getString(cursor.getColumnIndex(KEY_NAME));  peoples[i].Class = cursor.getInt(cursor.getColumnIndex(KEY_CLASS));  peoples[i].No = cursor.getInt(cursor.getColumnIndex(KEY_NO));    cursor.moveToNext();  }    return peoples;   }    public long deleteAllData() {  return db.delete(DB_TABLE, null, null);  }  public long deleteOneData(long id) {  return db.delete(DB_TABLE,  KEY_NO + "=" + id, null);  }  public long updateOneData(long id , People people){  ContentValues updateValues = new ContentValues();    updateValues.put(KEY_NAME, people.Name);  updateValues.put(KEY_CLASS, people.Class);  updateValues.put(KEY_NO, people.No);    return db.update(DB_TABLE, updateValues,  KEY_NO + "=" + id, null);  }    private static class DBOpenHelper extends SQLiteOpenHelper{        public DBOpenHelper(Context context,String name,CursorFactory factory,int version)    {    super(context,name,factory,version);    }        private static final String DB_CREATE = "create table "+ DB_TABLE + " (" + KEY_NAME + " text not null, " + KEY_CLASS + " integer," + KEY_NO + " integer primary key autoincrement)";@Overridepublic void onCreate(SQLiteDatabase db){// TODO 自动生成的方法存根db.execSQL(DB_CREATE);}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion){// TODO 自动生成的方法存根db.execSQL("DROP TABLE IF EXIST " + DB_TABLE);onCreate(db);}        }}

2.  People类

public class People {public String Name;public int Class;public int No;@Overridepublic String toString(){String result = "";result += "姓名： " + this.Name + "  ";result += "班级： " + this.Class + "  ";result += "学号： " + this.No + "  ";return result;}}

3. MainActivity

import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.widget.*;public class MainActivity extends Activity{Button input;Button output;Button delete;//public static final int SUBACTIVITY1 = 1;//public static final int SUBACTIVITY2 = 2;@Overrideprotected void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);    input = (Button)findViewById(R.id.button1);    output = (Button)findViewById(R.id.button2);    delete = (Button)findViewById(R.id.button3);        Button.OnClickListener btnListener = new Button.OnClickListener(){@Overridepublic void onClick(View v){// TODO 自动生成的方法存根switch(v.getId()){case R.id.button1:Intent intent1 = new Intent(MainActivity.this,SubActivity1.class);//startActivityForResult(intent,SUBACTIVITY1);startActivity(intent1);return;case R.id.button2:Intent intent2 = new Intent(MainActivity.this,SubActivity2.class);startActivity(intent2);return;case R.id.button3:Intent intent3 = new Intent(MainActivity.this,SubActivity3.class);startActivity(intent3);return;}}        };    input.setOnClickListener(btnListener);    output.setOnClickListener(btnListener);    delete.setOnClickListener(btnListener);    }@Overridepublic boolean onCreateOptionsMenu(Menu menu){// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.main, menu);return true;}@Overridepublic boolean onOptionsItemSelected(MenuItem item){// Handle action bar item clicks here. The action bar will// automatically handle clicks on the Home/Up button, so long// as you specify a parent activity in AndroidManifest.xml.int id = item.getItemId();if (id == R.id.action_settings){return true;}return super.onOptionsItemSelected(item);}}

4.  SubActivity1

import android.app.Activity;import android.os.Bundle;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.view.View.OnClickListener;import android.widget.*;public class SubActivity1 extends Activity{EditText line_name,line_class,line_no;    Button btn_submit,btn_back;    TextView labelView;DBAdapter dba;@Overrideprotected void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_sub_activity1);dba = new DBAdapter(this);dba.open();line_name = (EditText)findViewById(R.id.editText1);line_class = (EditText)findViewById(R.id.editText2);line_no = (EditText)findViewById(R.id.editText3);btn_back = (Button)findViewById(R.id.button1);btn_submit = (Button)findViewById(R.id.button2);labelView = (TextView)findViewById(R.id.textView4);Button.OnClickListener btnListener = new Button.OnClickListener(){@Overridepublic void onClick(View v){// TODO 自动生成的方法存根switch(v.getId()){case R.id.button1://line_name.setText("返回");finish();return;case R.id.button2:People people = new People();    people.Name = line_name.getText().toString();people.Class = Integer.parseInt(line_class.getText().toString());    people.No = Integer.parseInt(line_no.getText().toString());long colunm = dba.insert(people);if (colunm == -1 ){labelView.setText("提交失败");} else {labelView.setText("提交成功"+String.valueOf(colunm));}return;}}};btn_submit.setOnClickListener(btnListener);btn_back.setOnClickListener(btnListener);}@Overridepublic boolean onCreateOptionsMenu(Menu menu){// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.sub_activity1, menu);return true;}@Overridepublic boolean onOptionsItemSelected(MenuItem item){// Handle action bar item clicks here. The action bar will// automatically handle clicks on the Home/Up button, so long// as you specify a parent activity in AndroidManifest.xml.int id = item.getItemId();if (id == R.id.action_settings){return true;}return super.onOptionsItemSelected(item);}}

5. SubActivity2

import android.app.Activity;import android.os.Bundle;import android.util.Log;import android.view.Menu;import android.view.MenuItem;import android.widget.*;public class SubActivity2 extends Activity{TextView textshow;DBAdapter db;@Overrideprotected void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_sub_activity2);textshow = (TextView)findViewById(R.id.textView4);db = new DBAdapter(this);db.open();People people[] = db.queryAllData();int num = people.length;    Log.e("msg",String.valueOf(num));for(int i=0; i<num; i++){String str = " 姓名： " + people[i].Name + " 班级： " + people[i].Class + " 学号： " + people[i].No;Log.e("msg", str);textshow.append(str+"\n");}}@Overridepublic boolean onCreateOptionsMenu(Menu menu){// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.sub_activity2, menu);return true;}@Overridepublic boolean onOptionsItemSelected(MenuItem item){// Handle action bar item clicks here. The action bar will// automatically handle clicks on the Home/Up button, so long// as you specify a parent activity in AndroidManifest.xml.int id = item.getItemId();if (id == R.id.action_settings){return true;}return super.onOptionsItemSelected(item);}}

6. SubActivity3

import android.app.Activity;import android.os.Bundle;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.widget.*;public class SubActivity3 extends Activity{TextView show;EditText edit;DBAdapter da;Button button_back,button_confirm,button_deleteAll;@Overrideprotected void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_sub_activity3);show = (TextView)findViewById(R.id.textView5);edit = (EditText)findViewById(R.id.editText_delete);button_back = (Button)findViewById(R.id.button_3back);button_confirm = (Button)findViewById(R.id.button_3confirm);button_deleteAll = (Button)findViewById(R.id.button_deleteAll);da = new DBAdapter(this);da.open();Button.OnClickListener btnListener = new Button.OnClickListener(){@Overridepublic void onClick(View v){// TODO 自动生成的方法存根switch(v.getId()){case R.id.button_3back:finish();return;case R.id.button_3confirm:int num = Integer.parseInt(edit.getText().toString());            long result = da.deleteOneData(num);            if(result > 0)            show.setText("删除成功！！！");             else show.setText("删除失败！！！");return;case R.id.button_deleteAll:da.deleteAllData();show.setText("全部清空！");return;}}};button_back.setOnClickListener(btnListener);button_confirm.setOnClickListener(btnListener);button_deleteAll.setOnClickListener(btnListener);}@Overridepublic boolean onCreateOptionsMenu(Menu menu){// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.sub_activity3, menu);return true;}@Overridepublic boolean onOptionsItemSelected(MenuItem item){// Handle action bar item clicks here. The action bar will// automatically handle clicks on the Home/Up button, so long// as you specify a parent activity in AndroidManifest.xml.int id = item.getItemId();if (id == R.id.action_settings){return true;}return super.onOptionsItemSelected(item);}}