在 android 项目中为 EditText 创建“密码检测器”答案

【问题标题】：Creating "Password detector" for EditText in android project在 android 项目中为 EditText 创建“密码检测器”
【发布时间】：2016-04-10 11:33:28
【问题描述】：

我正在尝试使用字符串密码创建一个应用程序，它所做的就是遍历字符和数字的所有可能组合，直到找到正确的组合，类似这样：

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();
            }
        }
    });


}
}

我应该如何处理它？

【问题讨论】：

标签： java android

【解决方案1】：

这类问题最常见的方法是重复排列。

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]);
        }
    }
}

String[] elements 是密码中使用的字符数组。
int lenghtOflist 是密码长度。

Check this answer

【讨论】：