[TQC+ Android] 2-7 密碼鎖

設計密碼鎖 , 可自行設定密碼進行比對並更新 , 以下是程式碼。

package COM.TQC.GDD02;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class GDD02 extends Activity
{
 
 private String btnAdd = "Add";
 private String btnLogin = "Login";
 private String btnUpdate = "Update";
 private String FileName = "MY_PASSWORD";
 private FileInputStream fileInputStream = null; 
 private Button Button01;
 private EditText EditText01;
    
 /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        EditText01 = (EditText) findViewById(R.id.EditText01);
        Button01 = (Button) findViewById(R.id.Button01);
        
  try 
  {
   fileInputStream = openFileInput(FileName+".txt");
   //如果檔案不存在的話及會發生 FileNotFoundException 
   Button01.setText(btnLogin);
   
   fileInputStream.close();
   //已經確定檔案存在了, Closes this stream
   
  }catch (FileNotFoundException e)
  {
   // TODO Auto-generated catch block
   if(fileInputStream==null)
   {
    Button01.setText(btnAdd);
   }
   e.printStackTrace();
  } catch (IOException e)
  {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  
  Button01.setOnClickListener(new View.OnClickListener()
  {
   @Override
   public void onClick(View arg0)
   {
    // TODO Auto-generated method stub
    if(Button01.getText().equals(btnAdd))
    {
     String text = ""+EditText01.getText();
     if(!text.equals(""))     
     {
      writeFile(text);      
      showToast("新增成功！請重新登入！"); 
      Button01.setText(btnLogin);
      EditText01.setText("");
     }
     else showToast("請輸入密碼！");      
    }
    else if(Button01.getText().equals(btnLogin))
    {
     String text = EditText01.getText().toString();
     
     if(text.equals(readFile()))
     {
      showToast("登入成功！");
      Button01.setText(btnUpdate);
      EditText01.setText("");
     }
     else
     {
      showToast("登入失敗！");
      EditText01.setText("");
     }     
    }
    else if(Button01.getText().equals(btnUpdate))
    {
     String text = ""+EditText01.getText();
     if(!text.equals(""))
     {
      writeFile(text);
      showToast("修改成功！請重新登入！");
      Button01.setText(btnLogin);
      EditText01.setText("");
     }
     else showToast("請輸入密碼！");     
    }
   }});
    }
    
    private void writeFile(String data)
    {   
  try
  {
   StringBuffer SBuffer = new StringBuffer(data);
   SBuffer.append('\n');
   //使用\n字元做為字串結尾
   FileOutputStream fos = openFileOutput(FileName+".txt", MODE_PRIVATE);
      fos.write(SBuffer.toString().getBytes());
      fos.close();
  }catch (FileNotFoundException e)
  {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
    }
    
    private String readFile()
    {    
     byte[] byteArray = new byte[1024];
     
  try
  {
   fileInputStream = this.openFileInput(FileName+".txt");
   fileInputStream.read(byteArray);
   fileInputStream.close();   
   
  } catch (FileNotFoundException e)
  {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } 
  String data = new String(byteArray);
  int index = data.indexOf("\n");
  return data.substring(0, index);
  /*
          由於byteArray長度為1024 , 將byteArray轉為字串後長度為1024
          因為字串補了空白字元所以長度才會到1024 , 所以當初在writeFile的時候
          才會在最後面補上\n作為結尾 , 現在取開頭到\n中間的部分做為回傳的字串 
   */
  
    }
    
    private void showToast(String message)
    {
     Toast t = Toast.makeText(this, message, Toast.LENGTH_LONG);
        t.show();
    }
}

以及簡單的 Layout檔

                                   

檔案儲存的地方在/data/data/PackageName/FileName.txt

P.S. 題目中所要求的Variable和Method皆會保留 , 也會根據題目所要求的流程去實作 , 縱使題目要求繞遠路....