嘗試使用SQLite數據庫時，Android應用程序會凍結

Question

我正在對'Flash Talk'應用程序進行討論，讓您在EditText上插入問題並返回String作爲答案。我已經創建了一個數據庫，將問題和答案存儲在同一個表上，但在不同的列上，其中每個問題及其相應答案位於同一行。

我的問題是，當我嘗試運行應用程序時，它凍結，當我按下按鈕，開始尋找輸入問題的答案（通過使用answerToQuestion方法，將該問題作爲參數傳遞）

我試過尋找一個解決方案，但沒有找到（這種做，但不明白它的意思）。

這是我的數據庫處理類（裏面複製的所有內容）：

package com.beacon.talktotheflash; 

import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteOpenHelper; 
import android.database.Cursor; 
oimport android.content.Context; 

public class MyDBHandler extends SQLiteOpenHelper{ 

private static final int DATABASE_VERSION = 1; 
private static final String DATABASE_NAME = "flash.db"; 
private static final String TABLE_QANDA = "questions_and_answers"; 
private static final String COLUMN_ID = "id"; 
private static final String COLUMN_QUESTIONS = "questions"; 
private static final String COLUMN_ANSWERS = "answers"; 

public MyDBHandler(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) { 
super(context, DATABASE_NAME, factory, DATABASE_VERSION); 
} 

// Initializes the database 
@Override 
public void onCreate(SQLiteDatabase db) { 
String query = "CREATE TABLE " + TABLE_QANDA + "(" + 
COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + 
COLUMN_QUESTIONS + " TEXT, " + 
COLUMN_ANSWERS + " TEXT);"; 
db.execSQL(query); 
listOfQandA(db); 
} 

@Override 
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
db.execSQL("DROP TABLE IF EXISTS " + TABLE_QANDA); 
onCreate(db); 
} 

// List of the questions and answers 
public void listOfQandA(SQLiteDatabase db){ 
String query = "INSERT INTO " + TABLE_QANDA + " (" + COLUMN_QUESTIONS + ", " + COLUMN_ANSWERS + ") " 
+ " VALUES(\"hello\", \"Hi says the Flash!\")"; 

db.execSQL(query); 
} 

// Get the answer for the provided question 
public String answerToQuestion(String question){ 
// Check if the question and the answer are in the same row 
// by using a cursor 
SQLiteDatabase db = getWritableDatabase(); 
String final_answer = ""; 
String query1 = "SELECT " + COLUMN_QUESTIONS + " FROM " + TABLE_QANDA + " WHERE 1"; 
String query2 = "SELECT " + COLUMN_ANSWERS + " FROM " + TABLE_QANDA + " WHERE 1"; 

// Cursor point to a location in a column 
Cursor c1 = db.rawQuery(query1, null); 
Cursor c2 = db.rawQuery(query2, null); 

// Move to the first row in column_questions 
c1.moveToFirst(); 

while(!c1.isAfterLast()){ 
if (c1.getString(c1.getColumnIndex("questions")).equals(question)){ 
int c1_position = c1.getPosition(); 
c2.moveToPosition(c1_position); 
final_answer = c2.getString(c2.getColumnIndex("answers")); 
} 
} 

c1.close(); 
c2.close(); 

return final_answer; 
} 
} 

Answer 1

你無限循環。您在c1上moveToFirst，但您從不moveToNext。所以你永遠不會在後。