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....
