我已经构建了一个可以在listview中插入和检索数据的应用程序。我使用了放在assets文件夹中的数据库。当我通过usb调试在设备（xiaomi redmi note4）上运行我的应用程序但是当我点击注册按钮时我无法注册用户。如果我删除了＆＃34; /data/data/com.example.ibtb.bmkg/databases /＆＃34;中的数据库文件，这也会发生在模拟器上。像这样的logcat
04-12 12:09:27.789 16299-16299/? E/SQLiteLog: (1) no such table: tb_user
04-12 12:09:27.794 16299-16299/? E/SQLiteDatabase: Error inserting email=t password=t nip=t username=t nama=t
android.database.sqlite.SQLiteException: no such table: tb_user (code 1): , while compiling: INSERT INTO tb_user(email,password,nip,username,nama) VALUES (?,?,?,?,?)
at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:889)
at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:500)
at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
at android.database.sqlite.SQLiteStatement.<init>(SQLiteStatement.java:31)
at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1470)
at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1343)
at com.example.ibtb.bmkg.database.DatabaseHelper.insertUser(DatabaseHelper.java:73)
at com.example.ibtb.bmkg.SignUp$1.onClick(SignUp.java:68)
at android.view.View.performClick(View.java:5619)
at android.view.View$PerformClick.run(View.java:22295)
at android.os.Handler.handleCallback(Handler.java:754)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:163)
at android.app.ActivityThread.main(ActivityThread.java:6342)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:880)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:770)
这是我的数据库代码
package com.example.ibtb.bmkg.database;
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import com.example.ibtb.bmkg.model.Instrumen;
import com.example.ibtb.bmkg.model.User;
import com.example.ibtb.bmkg.model.Pengecekan;
import java.util.ArrayList;
import java.util.List;
/**
* Created by IBTB on 08/02/2018.
*/
public class DatabaseHelper extends SQLiteOpenHelper {
public static String DB_PATH = "/data/data/com.example.ibtb.bmkg/databases/";
public static String DB_NAME = "bmkgdb.db";
SQLiteDatabase myDataBase;
private final Context myContext;
public DatabaseHelper(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
public void openDataBase() {
String dbPath = myContext.getDatabasePath(DB_NAME).getPath();
if (myDataBase != null && myDataBase.isOpen()) {
return;
}
myDataBase = SQLiteDatabase.openDatabase(dbPath, null, SQLiteDatabase.OPEN_READWRITE);
}
public void closeDatabase() {
if (myDataBase != null) {
myDataBase.close();
}
}
public long insertUser(User c){
myDataBase = this.getWritableDatabase();
ContentValues values = new ContentValues();
/*String query = "select * from tb_user";
Cursor cursor = myDataBase.rawQuery(query,null);
int count = cursor.getCount();
values.put("id_user", count); */
values.put("nama", c.getName());
values.put("nip", c.getNip());
values.put("email", c.getEmail());
values.put("username", c.getUname());
values.put("password", c.getPass());
openDataBase();
long returnValue = myDataBase.insert("tb_user", null, values);
closeDatabase();
return returnValue;}
public String searchPass(String uname) {
myDataBase = this.getReadableDatabase();
String query = "select username, password from tb_user";
Cursor cursor = myDataBase.rawQuery(query, null);
String a, b;
b = "not found";
if (cursor.moveToFirst()) {
do {
a = cursor.getString(0);
//b= cursor.getString(1);
if (a.equals(uname)) {
b = cursor.getString(1);
break;
}
}
while (cursor.moveToNext());
}
return b;
}
public List<Pengecekan> getListPengecekan() {
// String[] whereargs = new String[]{String.valueOf(id)};
Pengecekan pengecekan = null;
List<Pengecekan> PengecekanList = new ArrayList<>();
openDataBase();
Cursor cursor = myDataBase.rawQuery("SELECT A.id_pengecekan, A.pengecekan, A.normal, B.nama_alat FROM tb_pengecekan A, tb_alat B, tb_instrumen C " +
"WHERE C.id_instrumen = B.id_instrumen AND A.id_alat = B.id_alat AND C.id_instrumen = '9' ", null);
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
pengecekan = new Pengecekan(cursor.getInt(0), cursor.getString(1), cursor.getString(2), cursor.getString(3));
PengecekanList.add(pengecekan);
/* if (cursor.moveToFirst()) {
pengecekan = new Pengecekan(cursor.getInt(0), cursor.getString(1), cursor.getString(2), cursor.getString(3));
PengecekanList.add(pengecekan);*/
cursor.moveToNext();}
cursor.close();
close();
return PengecekanList;
}
public Pengecekan getPengecekanId(int id) {
Pengecekan pengecekan = null;
openDataBase();
Cursor cursor = myDataBase.rawQuery("SELECT A.id_pengecekan, A.pengecekan, A.normal, B.nama_alat FROM tb_pengecekan A, tb_alat B, tb_instrumen C " +
"WHERE A.id_pengecekan = ?", new String[]{String.valueOf(id)});
cursor.moveToFirst();
pengecekan = new Pengecekan(cursor.getInt(0), cursor.getString(1), cursor.getString(2), cursor.getString(3));
//Only 1 resul
cursor.close();
closeDatabase();
return pengecekan;
}
public long updatePengecekan(Pengecekan pengecekan) {
ContentValues contentValues = new ContentValues();
contentValues.put("pengecekan", pengecekan.getPengecekan());
contentValues.put("normal", pengecekan.getNormal());
contentValues.put("nama_alat", pengecekan.getNama_alat());
String[] whereArgs = {Integer.toString(pengecekan.getId_pengecekan())};
openDataBase();
long returnValue = myDataBase.update("tb_pengecekan",contentValues, "id_pengecekan=?", whereArgs);
closeDatabase();
return returnValue;
}
public long addPengecekan(Pengecekan pengecekan) {
ContentValues contentValues = new ContentValues();
contentValues.put("ID", pengecekan.getId_pengecekan());
contentValues.put("pengecekan", pengecekan.getPengecekan());
contentValues.put("normal", pengecekan.getNormal());
contentValues.put("nama_alat", pengecekan.getNama_alat());
openDataBase();
long returnValue = myDataBase.insert("tb_pengecekan", null, contentValues);
closeDatabase();
return returnValue;
}
public boolean deletePengecekanById(int id) {
openDataBase();
int result = myDataBase.delete("tb_pengecekan", "id_pengecekan =?", new String[]{String.valueOf(id)});
closeDatabase();
return result !=0;
}
public List<Instrumen> getListInstrumen() {
Instrumen instrumen = null;
List<Instrumen> InstrumenList = new ArrayList<>();
openDataBase();
Cursor cursor = myDataBase.rawQuery("SELECT * FROM tb_instrumen ", null);
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
instrumen = new Instrumen(cursor.getInt(0), cursor.getString(1));
InstrumenList.add(instrumen);
cursor.moveToNext();
}
cursor.close();
close();
return InstrumenList;
}
public Instrumen geInstrumenId(int id) {
Instrumen instrumen = null;
openDataBase();
Cursor cursor = myDataBase.rawQuery("SELECT * FROM tb_instrumen WHERE id_instrumen = ?", new String[]{String.valueOf(id)});
cursor.moveToFirst();
instrumen = new Instrumen(cursor.getInt(0), cursor.getString(1));
//Only 1 resul
cursor.close();
closeDatabase();
return instrumen;
}
}
复制数据库
File database = getApplicationContext().getDatabasePath(DatabaseHelper.DB_NAME);
if(false == database.exists()) {
myDbHelper.getReadableDatabase();
//Copy db
if(copyDatabase(this)) {
Toast.makeText(this, "Copy database succes", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(this, "Copy data error", Toast.LENGTH_SHORT).show();
return;
}
}
SignUp.Java
package com.example.ibtb.bmkg;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Message;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import com.example.ibtb.bmkg.database.DatabaseHelper;
import com.example.ibtb.bmkg.model.User;
/**
* Created by IBTB on 08/02/2018.
*/
public class SignUp extends Activity {
private Button reg;
private DatabaseHelper dbHelper;
private EditText name, nip, email, uname, pass1, pass2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.signup);
dbHelper = new DatabaseHelper(getApplicationContext());
reg = (Button)findViewById(R.id.Bsignupbutton);
reg.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
name = (EditText) findViewById(R.id.Tfname);
nip = (EditText) findViewById(R.id.Tfnip);
email = (EditText) findViewById(R.id.Tfemail);
uname = (EditText) findViewById(R.id.Tfuname);
pass1 = (EditText) findViewById(R.id.Tfpass1);
pass2 = (EditText) findViewById(R.id.Tfpass2);
String namestr = name.getText().toString();
String nipstr = nip.getText().toString();
String emailstr = email.getText().toString();
String unamestr = uname.getText().toString();
String pass1str = pass1.getText().toString();
String pass2str = pass2.getText().toString();
User c = new User(namestr, nipstr, emailstr, unamestr, pass1str);
if (namestr.isEmpty() || nipstr.isEmpty() || emailstr.isEmpty() || unamestr.isEmpty() || pass1str.isEmpty() || pass2str.isEmpty()) {
Toast full = Toast.makeText(SignUp.this, "Please fill all the coloumn", Toast.LENGTH_SHORT);
full.show();
} else if (!pass1str.equals(pass2str)) {
Toast pass = Toast.makeText(SignUp.this, "Password dont match", Toast.LENGTH_SHORT);
pass.show();
} else {
/*c.setName(namestr);
c.setNip(nipstr);
c.setEmail(emailstr);
c.setUname(unamestr);
c.setPass(pass1str);*/
long result = dbHelper.insertUser(c);
Intent j = new Intent(SignUp.this, MainActivity.class);
startActivity(j);
if (result > 0) {
Toast.makeText(getApplicationContext(), "Added", Toast.LENGTH_SHORT).show();
//back to main activity
finish();
} else {
Toast.makeText(getApplicationContext(), "Add failed", Toast.LENGTH_SHORT).show();
}
}
}
});
}
}
MainActivity.Java
package com.example.ibtb.bmkg;
import android.content.Intent;
import android.app.Activity;
//import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import com.example.ibtb.bmkg.database.DatabaseHelper;
public class MainActivity extends Activity {
private Session session;
//private Button button;
DatabaseHelper myDbHelper = new DatabaseHelper(this);
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
session = new Session(this);
// button = (Button)findViewById(R.id.button);
if(session.loggedin()){
startActivity(new Intent(MainActivity.this,Home.class));
finish();
}
}
public void onButtonClick(View v)
{
if(v.getId()==R.id.Blogin)
{
EditText a = (EditText)findViewById(R.id.Tfusername);
String str = a.getText().toString();
EditText b = (EditText)findViewById(R.id.Tfpassword);
String pass = b.getText().toString();
String password = myDbHelper.searchPass(str);
if (pass.isEmpty() || str.isEmpty()) {
Toast full = Toast.makeText(MainActivity.this, "Please enter username and password", Toast.LENGTH_SHORT);
full.show();
}
else if(pass.equals(password))
{
session.setLoggedin(true);
Intent i = new Intent (MainActivity.this, Home.class);
i.putExtra("Username",str);
startActivity(i);
finish();
}
else
{
Toast temp = Toast.makeText(MainActivity.this, "Username and Password dont match", Toast.LENGTH_SHORT);
temp.show();
}
}
if (v.getId()==R.id.Bsignup)
{
Intent i = new Intent (MainActivity.this, SignUp.class);
startActivity(i);
}
}
/*
public void press (View v){
Intent i = new Intent (MainActivity.this, ListPengecekan2.class);
startActivity(i);
}*/
}
Session.java
package com.example.ibtb.bmkg;
import android.content.Context;
import android.content.SharedPreferences;
/**
* Created by IBTB on 06/04/2018.
*/
public class Session {
SharedPreferences prefs;
SharedPreferences.Editor editor;
Context ctx;
public Session(Context ctx){
this.ctx = ctx;
prefs = ctx.getSharedPreferences("myapp", Context.MODE_PRIVATE);
editor = prefs.edit();
}
public void setLoggedin(boolean logggedin){
editor.putBoolean("loggedInmode",logggedin);
editor.commit();
}
public boolean loggedin(){
return prefs.getBoolean("loggedInmode", false);
}
}
ListPengecekan.java
package com.example.ibtb.bmkg;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.RadioButton;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
import com.example.ibtb.bmkg.adapter.ListPengecekanAdapter;
import com.example.ibtb.bmkg.database.DatabaseHelper;
import com.example.ibtb.bmkg.model.Pengecekan;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.List;
public class ListPengecekan extends AppCompatActivity {
private ListView lvPengecekan;
private TextView instrumen;
private ListPengecekanAdapter adapter;
private List<Pengecekan> mPengecekanList;
private Button btnAdd;
private DatabaseHelper myDbHelper;
//Cursor c = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_pengecekan);
lvPengecekan = (ListView) findViewById(R.id.listview_pengecekan);
btnAdd = (Button)findViewById(R.id.Badd);
myDbHelper = new DatabaseHelper(this);
String instrumen = getIntent().getStringExtra("ins");
TextView tv = (TextView) findViewById(R.id.tv_instrumen);
tv.setText(instrumen);
File database = getApplicationContext().getDatabasePath(DatabaseHelper.DB_NAME);
if(false == database.exists()) {
myDbHelper.getReadableDatabase();
//Copy db
if(copyDatabase(this)) {
Toast.makeText(this, "Copy database succes", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(this, "Copy data error", Toast.LENGTH_SHORT).show();
return;
}
}
//String id = getIntent().getStringExtra("id");
mPengecekanList = myDbHelper.getListPengecekan();
adapter = new ListPengecekanAdapter (this, mPengecekanList);
lvPengecekan.setAdapter(adapter);
}
@Override
protected void onResume() {
super.onResume();
mPengecekanList = myDbHelper.getListPengecekan();
//Init adapter
adapter.updateList(mPengecekanList);
}
private boolean copyDatabase(Context context) {
try {
InputStream inputStream = context.getAssets().open(DatabaseHelper.DB_NAME);
String outFileName = DatabaseHelper.DB_PATH + DatabaseHelper.DB_NAME;
OutputStream outputStream = new FileOutputStream(outFileName);
byte[] buff = new byte[1024];
int length = 0;
while ((length = inputStream.read(buff)) > 0) {
outputStream.write(buff, 0, length);
}
outputStream.flush();
outputStream.close();
Log.v("ListPengecekan", "DB copied");
return true;
} catch (IOException e) {
e.printStackTrace();
return false;
}
// });
}
public void onRadioButtonClicked(View view) {
String kondisi="";
boolean checked = ((RadioButton) view).isChecked();
switch(view.getId()) {
case R.id.B:
if (checked)
kondisi = "Baik";
break;
case R.id.RR:
if (checked)
kondisi = "Rusak ringan";
AlertDialog.Builder mBuilder = new AlertDialog.Builder(ListPengecekan.this);
View mView = getLayoutInflater().inflate(R.layout.dialogrusak, null);
mBuilder.setTitle("Keterangan kerusakan");
final Spinner mSpinner = (Spinner) mView.findViewById(R.id.Spenanganan);
final Spinner mSpinner1 = (Spinner) mView.findViewById(R.id.Shasil);
final EditText kronologi = (EditText) mView.findViewById(R.id.ekro);
final EditText lapor = (EditText) mView.findViewById(R.id.elapor);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(ListPengecekan.this, android.R.layout.simple_spinner_item, getResources().getStringArray(R.array.penaganan));
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
mSpinner.setAdapter(adapter);
ArrayAdapter<String> adapter1 = new ArrayAdapter<String>(ListPengecekan.this, android.R.layout.simple_spinner_item, getResources().getStringArray(R.array.hasil));
adapter1.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
mSpinner1.setAdapter(adapter1);
mBuilder.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
String Kronologi = kronologi.getText().toString();
Toast.makeText(ListPengecekan.this, Kronologi, Toast.LENGTH_SHORT).show();
if (!mSpinner.getSelectedItem().toString().equalsIgnoreCase("Pilih penanganan…")) {
Toast.makeText(ListPengecekan.this, mSpinner.getSelectedItem().toString(), Toast.LENGTH_SHORT).show();
dialogInterface.dismiss();
}
if (!mSpinner.getSelectedItem().toString().equalsIgnoreCase("Pilih hasil…")) {
Toast.makeText(ListPengecekan.this, mSpinner1.getSelectedItem().toString(), Toast.LENGTH_SHORT).show();
dialogInterface.dismiss();
}
String Lapor = lapor.getText().toString();
Toast.makeText(ListPengecekan.this, Lapor, Toast.LENGTH_SHORT).show();
}
});
mBuilder.setNegativeButton("Batal", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
dialogInterface.dismiss();
}
});
mBuilder.setView(mView);
AlertDialog dialog = mBuilder.create();
dialog.show();
break;
case R.id.RB:
if (checked)
kondisi = "Rusak berat";
AlertDialog.Builder mBuilder1 = new AlertDialog.Builder(ListPengecekan.this);
View mView1 = getLayoutInflater().inflate(R.layout.dialogrusak, null);
mBuilder1.setTitle("Keterangan kerusakan");
final Spinner mSpinner2 = (Spinner) mView1.findViewById(R.id.Spenanganan);
final Spinner mSpinner3 = (Spinner) mView1.findViewById(R.id.Shasil);
final EditText kronologi1 = (EditText) mView1.findViewById(R.id.ekro);
final EditText lapor1 = (EditText) mView1.findViewById(R.id.elapor);
ArrayAdapter<String> adapter2 = new ArrayAdapter<String>(ListPengecekan.this, android.R.layout.simple_spinner_item, getResources().getStringArray(R.array.penaganan));
adapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
mSpinner2.setAdapter(adapter2);
ArrayAdapter<String> adapter3 = new ArrayAdapter<String>(ListPengecekan.this, android.R.layout.simple_spinner_item, getResources().getStringArray(R.array.hasil));
adapter3.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
mSpinner3.setAdapter(adapter3);
mBuilder1.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
String Kronologi = kronologi1.getText().toString();
Toast.makeText(ListPengecekan.this, Kronologi, Toast.LENGTH_SHORT).show();
if (!mSpinner2.getSelectedItem().toString().equalsIgnoreCase("Pilih penanganan…")) {
Toast.makeText(ListPengecekan.this, mSpinner2.getSelectedItem().toString(), Toast.LENGTH_SHORT).show();
dialogInterface.dismiss();
}
if (!mSpinner3.getSelectedItem().toString().equalsIgnoreCase("Pilih hasil…")) {
Toast.makeText(ListPengecekan.this, mSpinner3.getSelectedItem().toString(), Toast.LENGTH_SHORT).show();
dialogInterface.dismiss();
}
String Lapor = lapor1.getText().toString();
Toast.makeText(ListPengecekan.this, Lapor, Toast.LENGTH_SHORT).show();
}
});
mBuilder1.setNegativeButton("Batal", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
dialogInterface.dismiss();
}
});
mBuilder1.setView(mView1);
AlertDialog dialog1 = mBuilder1.create();
dialog1.show();
break;
}
//myDbHelper.execSQl
}
}
答案 0 :(得分：0)
好的，您的问题可能是onCreate方法无效。如果删除现有/可用数据库，则表示没有创建表。
您需要在db.execSql(a_string_with_the_sql_to_create_your_tables);方法中使用onCreate。
类似的东西： -
@Override
public void onCreate(SQLiteDatabase db) {
crtsql = "CREATE TABLE IF NOT EXISTS tb_user (id INTEGER PRIMARY KEY,nama TEXT,nip TEXT, email TEXT, password TEXT)";
db.execSQL(crtsql);
}
如果您有其他代码从assets文件夹复制数据库，则会出现异常。如果是这样，包括那将是相关的，就像这样，这不起作用可能是问题。
已经确定问题很可能是没有调用assets资源文件夹中的数据库副本。
为了简化修复，建议使用以下内容（而不是编辑代码）： -
CopyDBFromAssets的Java类，即文件 CopyDBFromAssets.java ，并将以下内容纳入该类： -
public class CopyDBFromAssets {
private static final String TAG = "DBASSETCOPY";
String mDBPath, mDatabasename;
CopyDBFromAssets(Context context, String databasename) {
mDatabasename = databasename;
mDBPath = context.getDatabasePath(mDatabasename).getPath();
if(!ifDatabaseExists(mDBPath)) {
Log.d(TAG,
"Attempting to copy database " +
mDatabasename +
" from assets folder."
);
if (copyDatabase(context)) {
Log.d(TAG,"Database " +
mDatabasename + " successfully copied.");
} else {
Log.e(TAG,"Database " + mDatabasename + " NOT COPIED!!!");
}
}
}
private boolean copyDatabase(Context context) {
try {
InputStream inputStream = context.getAssets().open(mDatabasename);
String outFileName = mDBPath;
OutputStream outputStream = new FileOutputStream(outFileName);
byte[] buff = new byte[1024];
int length = 0;
while ((length = inputStream.read(buff)) > 0) {
outputStream.write(buff, 0, length);
}
outputStream.flush();
outputStream.close();
Log.v(TAG, "DB copied");
return true;
} catch (IOException e) {
e.printStackTrace();
return false;
}
}
private boolean ifDatabaseExists(String dbpath) {
File db = new File(dbpath);
if(db.exists()) return true;
File dir = new File(db.getParent());
if (!dir.exists()) {
dir.mkdirs();
}
return false;
}
}
： -
公共类MainActivity扩展了Activity {
private Session session;
//private Button button;
//DatabaseHelper myDbHelper = new DatabaseHelper(this); //<<<< COMMENTED OUT
DatabaseHelper myDbHelper; //<<<< ADDED
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
CopyDBFromAssets cdbfa = new CopyDBFromAssets(this,DatabaseHelper.DB_NAME); //<<<< ADDED LINE
myDbHelper = new DatabaseHelper(this); //<<<< ADDED LINE
session = new Session(this);
// button = (Button)findViewById(R.id.button);
if(session.loggedin()){
startActivity(new Intent(MainActivity.this,Home.class));
finish();
}
}
........ the rest of MainActivity.Java
DatabaseHelper myDbHelper = new DatabaseHelper(this);已被注释掉并分为声明和实例化（设置）使用//＆lt;＆lt;＆lt;＆lt;＆lt;
检查所有行： -
04-12 12:39:31.672 1568-1568/soanswers.soanswers D/DBASSETCOPY: Attempting to copy database mydb from assets folder.
04-12 12:39:31.672 1568-1568/soanswers.soanswers V/DBASSETCOPY: DB copied
04-12 12:39:31.672 1568-1568/soanswers.soanswers D/DBASSETCOPY: Database mydb successfully copied.
答案 1 :(得分：-1)
您正在将记录插入到不存在的表中。在执行插入操作之前创建表。