在android項目中爲EditText創建「密碼檢測器」

Question

我想創建一個帶有字符串密碼的應用程序，它所做的一切都是遍歷所有可能的字符和數字組合，直到找到正確的字符串，如下所示：

import android.os.Bundle; 
import android.support.v7.app.AppCompatActivity; 
import android.view.View; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.Toast; 

public class PasswordDetector extends AppCompatActivity { 
private static final String PASSWORD = "abc123"; 
private Button search; 
private EditText combination; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    search.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      //here I want the loop to run, untill it hits the PASSWORD 
      combination.setText("combinations"); 
      if (combination.getText().toString().equals(PASSWORD)) { 
       Toast.makeText(PasswordDetector.this, "Success", Toast.LENGTH_SHORT).show(); 
      } 
     } 
    }); 


} 
} 

我該如何處理它？

Answer 1

這種類型的問題最常見的方法是重複排列。

public static String[] getAllLists(String[] elements, int lengthOfList) 
{ 
    //initialize our returned list with the number of elements calculated above 
    String[] allLists = new String[(int)Math.pow(elements.length, lengthOfList)]; 

    //lists of length 1 are just the original elements 
    if(lengthOfList == 1) return elements; 
    else { 
     //the recursion--get all lists of length 3, length 2, all the way up to 1 
     String[] allSublists = getAllLists(elements, lengthOfList - 1); 

     //append the sublists to each element 
     int arrayIndex = 0; 

     for(int i = 0; i < elements.length; i++){ 
      for(int j = 0; j < allSublists.length; j++){ 
       //add the newly appended combination to the list 
       allLists[arrayIndex] = elements[i] + allSublists[j]; 
       arrayIndex++; 
      } 
     } 
     return allLists; 
    } 
} 

public static void main(String[] args){ 
    String[] database = {"a","b","c"}; 
    for(int i=1; i<=database.length; i++){ 
     String[] result = getAllLists(database, i); 
     for(int j=0; j<result.length; j++){ 
      System.out.println(result[j]); 
     } 
    } 
} 

1. String[] elements是在passwd中使用的字符陣列。
2. int lenghtOflist是密碼長度。

Check this answer