如何从资产文件夹db获取数据？我的资产文件夹中有一个.db文件。这就是我在做的事情。
DBHelper2.class
package com.example.testapp;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class DataBaseHelper2 extends SQLiteOpenHelper{
private static String DB_PATH = "/data/data/com.example.testapp/databases/";
private static String DB_NAME = "birthdate_details.db";
private SQLiteDatabase myDataBase;
private final Context myContext;
public DataBaseHelper2(Context context)
{
super(context, DB_NAME, null, 1);
this.myContext = context;
}
public void createDataBase() throws IOException{
boolean dbExist = checkDataBase();
if(dbExist)
{
Log.i("DB....", "database available...."+DB_NAME);
}
else
{
this.getWritableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
Log.i("DB..", "database created.....");
}
}
public boolean checkDataBase(){
SQLiteDatabase checkDB = null;
try{
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
}catch(SQLiteException e){
Log.e("CheckDb","DB not found");
//database does't exist yet.
if(checkDB != null){
checkDB.close();
}
}
finally
{
if(checkDB != null){
checkDB.close();
}
this.close();
}
return checkDB != null ? true : false;
}
private void copyDataBase() throws IOException{
InputStream myInput = myContext.getAssets().open(DB_NAME);
String outFileName = DB_PATH + DB_NAME;
OutputStream myOutput = new FileOutputStream(outFileName);
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
myOutput.flush();
myOutput.close();
myInput.close();
}
public SQLiteDatabase openDataBase() throws SQLException{
String myPath = DB_PATH + DB_NAME;
return myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
}
@Override
public synchronized void close() {
if(myDataBase != null)
myDataBase.close();
super.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
public Cursor getData()
{
SQLiteDatabase myDB ;
Cursor cursor ;
myDB=this.openDataBase();
cursor=myDB.rawQuery("SELECT * FROM bdatedetails",null);
return cursor;
}
}
MainActivity.class
public class MainActivity extends Activity {
ArrayList<String> AllAssociatedData;
ListView list;
DataBaseHelper2 myDbHelper;
int pos;
Cursor c;
ArrayAdapter<String> ad;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
list = (ListView) findViewById(R.id.listView1);
AllAssociatedData = new ArrayList<String>();
ad = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, AllAssociatedData);
list.setAdapter(ad);
myDbHelper = new DataBaseHelper2(this);
try
{
myDbHelper.createDataBase();
c = myDbHelper.getData();
c.moveToPosition(0);
AllAssociatedData.add(c.getString(3));
System.out.println(c.getString(3));
Toast.makeText(getApplicationContext(), c.getString(3), 0).show();
//ad.notifyDataSetChanged();
}catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally
{
myDbHelper.close();
}
}
}
但数据还没有到来。
此外，内部数据库表中的另一个问题。
Login.java
public class Login extends Activity {
EditText et1,et2;
Button b;
TextView tv1,tv2,tv3;
MyDatabase mdb;
int count=1;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
et1=(EditText) findViewById(R.id.editText1);
et2=(EditText) findViewById(R.id.editText2);
tv1=(TextView) findViewById(R.id.textView1);
tv2=(TextView) findViewById(R.id.textView2);
tv3=(TextView) findViewById(R.id.textView3);
b=(Button) findViewById(R.id.button1);
mdb = new MyDatabase(this);
mdb.open();
b.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
String username=et1.getText().toString();
String password=et2.getText().toString();
Cursor c = mdb.getAllUser();
if(c != null){
while(c.moveToNext()==true)
{ int id=c.getInt(0);
String uname = c.getString(1);
String pwd = c.getString(2);
long mob=c.getLong(3);
String email = c.getString(4);
Toast.makeText(getApplicationContext(),""+id+","+uname+","+pwd+","+mob+","+email,0).show();
if(count<=3)
{
if(username.equals(uname)&&password.equals(pwd))
{
Intent in=new Intent(getApplicationContext(),Welcome.class);
in.putExtra("key",uname);
mdb.close();
c.close();
startActivity(in);
return;
}
else
{
}
}
else
{
Toast.makeText(getApplicationContext(), "Account Blocked",0).show();
}
}
tv3.setText("No of tries "+count);
count++;
c.close();
Toast.makeText(getApplicationContext(), "Username/password is incorrect",0).show();
}
}
});
mydatabase.java
public class MyDatabase
{
private MyHelper mh;
private SQLiteDatabase sdb;
public MyDatabase(Context con)
{
mh=new MyHelper(con,"UserDetails",null,1);
}
public void open()
{ try{
sdb=mh.getWritableDatabase();
}
catch(Exception e)
{
}
}
public void insertRegiserUser(String Username,String password,long mobile,String e_mail)
{
ContentValues cv=new ContentValues();
cv.put("uname",Username);
cv.put("pwd",password);
cv.put("mob", mobile);
cv.put("email",e_mail);
sdb.insert("login", null,cv);
}
public void updatePwd(String old_pwd,String username,String new_pwd)
{
ContentValues cv=new ContentValues();
cv.put("pwd",new_pwd);
sdb.update("login", cv,"pwd=? AND uname=?",new String[]{old_pwd,username});
}
public Cursor getAllUser()
{ Cursor c=sdb.query("login",null,null,null,null,null,null);
return c;
}
class MyHelper extends SQLiteOpenHelper
{
public MyHelper(Context context, String name, CursorFactory factory,
int version) {
super(context, name, factory, version);
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("Create table login(_id integer primary key, uname text unique, pwd text, mob long, email text);");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
}
public void close(){
sdb.close();
}
}