我正在开发Android，我使用教程中的代码来编写我的应用， 我的应用程序是一个聊天机器人，它从用户那里获取输入（字符串）并给出合适的答案： 例如用户类型“hi”和chatbot回答“hi there”
我的应用程序工作正常，但我试图添加一个方法来处理如果用户在输入中再次输入last inputSentence，我只是添加简单的if（）来检查重复，但现在问题面临新问题。 当用户和聊天机器人与eahother聊天，然后用户按下手机上的后退按钮，然后再回到应用程序并尝试再次聊天，当用户输入内容时，然后当聊天机器人尝试从数据库中找到合适的答案时，程序崩溃了“强制”停止“错误，
我刚刚在这里添加了代码并制作了新方法BOLD：它有点长......
package com.color.speechbubble;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Random;
import android.app.ListActivity;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.hardware.Camera.Size;
import android.os.AsyncTask;
import android.os.Bundle;
import android.text.InputFilter.LengthFilter;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
/**
* MessageActivity is a main Activity to show a ListView containing Message
* items
*
* @author Adil Soomro
* @author Mehrdad4all
*
*/
public class MessageActivity extends ListActivity {
/** Called when the activity is first created. */
// Variables,Constants and Objects $$$$$$$$$$$$$$$$$$
// DATABASE VARIABLES
private String USER = "user";
private String SHOMPET = "shompet";
Utility utility_obj = new Utility();
private static String newMessage = "null in sql";
ir.mehrdadsalimi.ShompetBot.DataBaseHelper myDbHelper = new ir.mehrdadsalimi.ShompetBot.DataBaseHelper(
this);
ArrayList<Message> messages;
AwesomeAdapter adapter;
EditText text;
static Random rand = new Random();
static String sender;
// to save USER chat Log and check repeatation
ArrayList<String> userChatLogArray = new ArrayList<String>();
// to check whether this is user's first input
public static Boolean firstInput = true;
// $$$$$$$$$$$$$$$$$$$
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
text = (EditText) this.findViewById(R.id.text);
sender = utility_obj.sender[rand.nextInt(utility_obj.sender.length - 1)];
this.setTitle("ShompetBot(" + sender + ")");
messages = new ArrayList<Message>();
// here we choose between two method, user starts chat or ShompetBot
// starts it!
// we use random method to choose,
// it makes ShompetBot more Real!
// we have 7 condition 4 for user starts which is nothing
// and 4 which ShompetBot choose one of this sentences randomly
switch (rand.nextInt(7)) {
case 0:
messages.add(new Message("Welcome here!", false));
break;
case 1:
messages.add(new Message("user, how are you doing today??!", false));
break;
case 2:
messages.add(new Message("What's up?", false));
break;
case 3:
messages.add(new Message("Hey, How can i help you?", false));
break;
default:
break;
}
// messages.add(new Message("Hello", false));
// messages.add(new Message("Hi!", true));
// messages.add(new Message("Wassup??", false));
// messages.add(new
// Message("nothing much, working on speech bubbles.",true));
// messages.add(new Message("you say!", true));
// messages.add(new Message("oh thats great. how are you showing them",
// false));
adapter = new AwesomeAdapter(this, messages);
setListAdapter(adapter);
// addNewMessage(new
// Message("mmm, well, using 9 patches png to show them.", true));
}
public void sendMessage(View v) {
String newMessage = text.getText().toString().trim();
userChatLogArray.add(newMessage);
this.newMessage = newMessage;
if (newMessage.length() > 0) {
text.setText("");
addNewMessage(new Message(newMessage, true));
new SendMessage().execute();
}
}
private class SendMessage extends AsyncTask<Void, String, String> {
@Override
protected String doInBackground(Void... params) {
try {
Thread.sleep(2000); // simulate a network call
} catch (InterruptedException e) {
e.printStackTrace();
}
this.publishProgress(String.format("%s started writing", sender));
try {
Thread.sleep(2000); // simulate a network call
} catch (InterruptedException e) {
e.printStackTrace();
}
this.publishProgress(String.format("%s has entered text", sender));
try {
Thread.sleep(3000);// simulate a network call
} catch (InterruptedException e) {
e.printStackTrace();
}
// **************************************************
try { // here
myDbHelper.createDataBase(); // we
} catch (IOException ioe) { // create
throw new Error("Unable to create database"); // and
} // open
try { // DB
myDbHelper.openDataBase(); //
} catch (SQLException sqle) { //
throw sqle; //
} //
SQLiteDatabase db = myDbHelper.getReadableDatabase();// make an
// readable
// database
// from
// existing
// one
String shompetAnswer = "";// shompet final answer
**if (checkRepeatation(firstInput)) {
shompetAnswer = " rep test";
} else {**
// here we first edit userInput to make it easier to search
// for suitable answer in DB
editEndOfNewMessage();
Cursor cursor = db.rawQuery(
"SELECT shompet FROM exact_sentence WHERE " + USER
+ " = '" + newMessage + "'", null);// query
// exact_sentence
// table
ArrayList<String> stringArrayList = new ArrayList<String>();
String shompetAnswersSet[] = null;
String tempString = "";
// check if got answer from exact_sentence table(first engine)
if (cursor.moveToFirst()) {
do {
// add to arraylist
tempString = cursor.getString(cursor
.getColumnIndex("shompet"));
stringArrayList.add(tempString);
} while (cursor.moveToNext());
shompetAnswersSet = stringArrayList
.toArray(new String[stringArrayList.size()]);
shompetAnswer = shompetAnswersSet[rand
.nextInt(shompetAnswersSet.length)];
cursor.close();
}
// Here we will use second engine to search DB with 40% accuracy
else {
cursor = db.rawQuery("SELECT shompet FROM sentence "
+ "WHERE LENGTH(user) = ( "
+ " SELECT MAX(LENGTH(user)) FROM sentence "
+ " WHERE ? LIKE '%' || " + USER + " || '%' "
+ ") AND ? LIKE '%' || " + USER + " || '%' ",
new String[] { newMessage, newMessage });
// check if find answer from second engine
if (cursor.moveToFirst()) {
do {
// add to arraylist
tempString = cursor.getString(cursor
.getColumnIndex("shompet"));
stringArrayList.add(tempString);
} while (cursor.moveToNext());
shompetAnswersSet = stringArrayList
.toArray(new String[stringArrayList.size()]);
shompetAnswer = shompetAnswersSet[rand
.nextInt(shompetAnswersSet.length)];
}
cursor.close();
}
// ***************************************************
}
// to prevent from onPause and onResume errors
myDbHelper.close();
return shompetAnswer;
}
@Override
public void onProgressUpdate(String... v) {
if (messages.get(messages.size() - 1).isStatusMessage)// check
// wether we
// have
// already
// added a
// status
// message
{
messages.get(messages.size() - 1).setMessage(v[0]); // update
// the
// status
// for that
adapter.notifyDataSetChanged();
getListView().setSelection(messages.size() - 1);
} else {
addNewMessage(new Message(true, v[0])); // add new message, if
// there I'm fine,
// thanks, what about
// you?is no existing
// status message
}
}
@Override
protected void onPostExecute(String text) {
if (messages.get(messages.size() - 1).isStatusMessage)// check if
// there is
// any
// status
// message,
// now
// remove
// it.
{
messages.remove(messages.size() - 1);
}
addNewMessage(new Message(text, false)); // add the original message
// from server.
}
}
void addNewMessage(Message m) {
messages.add(m);
adapter.notifyDataSetChanged();
getListView().setSelection(messages.size() - 1);
}
void editEndOfNewMessage() {
// here we edit userinput from useless sign at the end of the statement
while (newMessage.charAt(newMessage.length() - 1) == '!'
|| newMessage.charAt(newMessage.length() - 1) == '.'
|| newMessage.charAt(newMessage.length() - 1) == '?') {
newMessage = newMessage.substring(0, newMessage.length() - 1);
} //
newMessage = newMessage.trim();// delete whitespace from end of
// statement
newMessage = newMessage.toLowerCase();// clear!
}
**public Boolean checkRepeatation(Boolean input)// check equality of user
// //
// input with last user
{ // input for repeatation
if (input) {
firstInput = false;
return false;
} else {
String userChatLog[] = userChatLogArray
.toArray(new String[userChatLogArray.size()]);
if (userChatLog[userChatLog.length - 2].equals(newMessage)) {
return true;
}
return false;
}
}**
}
和扩展SQLiteOpenHelper类的类：
package ir.mehrdadsalimi.ShompetBot;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Environment;
public class DataBaseHelper extends SQLiteOpenHelper{
//The Android's default system path of your application database.
private static String DB_PATH = "/data/data/com.color.speechbubble/databases/";
private static String DB_NAME = "ShompetBot_DBTest";
private SQLiteDatabase myDataBase;
private final Context myContext;
/**
* Constructor
* Takes and keeps a reference of the passed context in order to access to the application assets and resources.
* @param context
*/
public DataBaseHelper(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
}
/**
* Creates a empty database on the system and rewrites it with your own database.
* */
public void createDataBase() throws IOException{
boolean dbExist = checkDataBase();
if(dbExist){
//do nothing - database already exist
}else{
//By calling this method and empty database will be created into the default system path
//of your application so we are gonna be able to overwrite that database with our database.
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
/**
* Check if the database already exist to avoid re-copying the file each time you open the application.
* @return true if it exists, false if it doesn't
*/
private boolean checkDataBase(){
SQLiteDatabase checkDB = null;
try{
String myPath = Environment.getExternalStorageDirectory() + "/" + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}catch(SQLiteException e){
//database does't exist yet.
}
if(checkDB != null){
checkDB.close();
}
return checkDB != null ? true : false;
}
/**
* Copies your database from your local assets-folder to the just created empty database in the
* system folder, from where it can be accessed and handled.
* This is done by transfering bytestream.
* */
private void copyDataBase() throws IOException{
//Open your local db as the input stream
InputStream myInput = myContext.getAssets().open(DB_NAME);
// Path to the just created empty db
String outFileName = DB_PATH + DB_NAME;
//Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
//transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException{
//Open the database
String myPath = DB_PATH + DB_NAME;
myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}
@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) {
}
// Add your public helper methods to access and get content from the database.
// You could return cursors by doing "return myDataBase.query(....)" so it'd be easy
// to you to create adapters for your views.
}
答案 0 :(得分：0)
经过一天我终于得到了重点：问题是因为这一行：
public static Boolean firstInput = true;
我刚刚将这一行添加到onCtreate方法的第一个：
firstInput = true;
在程序中，我们在用户第一次输入后创建此变量false，然后当用户按下后退按钮时，它仍为false，并且程序运行到此条件并执行if()中的任何内容，这是不正确的因为这一行：
if (userChatLog[userChatLog.length - 2].equals(newMessage))
长度为1，索引为-1！