手机号码保存在一个文件中android

Question

我开发了一个android应用程序，使用户可以通过他/她的手机号码进行注册。我希望我的应用程序保存电话号码，以便下次用户打开应用程序时，不需要再次输入电话号码，类似于Whatsapp .. 这是我的代码，但它不起作用，我每次打开应用程序时都必须输入电话号码，此外，在将此代码添加到我的应用程序后，应用程序变得如此沉重而缓慢。

if (android.os.Build.VERSION.SDK_INT > 9) 
    { 
     StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder() 
       .permitAll().build(); 
     StrictMode.setThreadPolicy(policy); 
    } 
    try { 
     TelephonyManager tMgr = (TelephonyManager) getApplicationContext() 
       .getSystemService(Context.TELEPHONY_SERVICE); 
     mPhoneNumber = tMgr.getLine1Number().toString(); 
    } catch (Exception e) { 
     String EE = e.getMessage(); 
    } 
    if (mPhoneNumber == null) { 
    try { 
     fOut = openFileOutput("textfile.txt", MODE_WORLD_READABLE); 

     fIn = openFileInput("textfile.txt"); 
     InputStreamReader isr = new InputStreamReader(fIn); 
     char[] inputBuffer = new char[50]; 
     if (isr.read(inputBuffer) == 0) { 

     } 

    } catch (IOException ioe) { 
     ioe.printStackTrace(); 
    } 

    AlertDialog.Builder alert = new AlertDialog.Builder(this); 
    alert.setTitle("Warrning"); 
    alert.setMessage("Please Set Your Phone number"); 
    final EditText input = new EditText(this); 
    alert.setView(input); 
    alert.setPositiveButton("Ok", new DialogInterface.OnClickListener() { 
     public void onClick(DialogInterface dialog, int whichButton) { 
      mPhoneNumber = input.getText().toString(); 
      try { 
       fIn = openFileInput("textfile.txt"); 
       InputStreamReader isr = new InputStreamReader(fIn); 
       char[] inputBuffer = new char[50]; 
       if (isr.read(inputBuffer) == 0) { 
        OutputStreamWriter osw = new OutputStreamWriter(fOut); 
        // ---write the string to the file--- 
        osw.write(mPhoneNumber); 
        osw.flush(); 
        osw.close(); 
        // ---display file saved message--- 
        Toast.makeText(getBaseContext(), 
          "Phone number saved successfully!", 
          Toast.LENGTH_SHORT).show(); 
        // ---clears the EditText--- 
        input.setText(""); 
       } else { 
        int charRead; 
        while ((charRead = isr.read(inputBuffer)) > 0) { 
         // ---convert the chars to a String--- 
         String readString = String.copyValueOf(inputBuffer, 
           0, charRead); 
         mPhoneNumber = readString; 
         inputBuffer = new char[50]; 
        } 
        // ---set the EditText to the text that has been 
        // read--- 

        Toast.makeText(getBaseContext(), 
          "Phone number read successfully!", 
          Toast.LENGTH_SHORT).show(); 
       } 

      } catch (IOException ioe) { 
       ioe.printStackTrace(); 
      } 
      int UserServiceId = CallLogin(mPhoneNumber); 
      if (UserServiceId > 0) { 
       Intent Service = new Intent(MainScreeen.this, 
         RecipeService.class); 
       Service.putExtra("UserId", UserServiceId); 
       startService(Service); 
      } else { 
       Intent Reg = new Intent(MainScreeen.this, 
         Regsteration.class); 
       Reg.putExtra("PhoneNumber", mPhoneNumber); 
       startActivity(Reg); 
      } 
     } 
    }); 
    alert.show(); 
    } else { 

     int UserServiceId = CallLogin(mPhoneNumber); 
     if (UserServiceId > 0) { 
      Intent Service = new Intent(MainScreeen.this, 
        RecipeService.class); 
      Service.putExtra("UserId", UserServiceId); 
      startService(Service); 
     } else { 
      Intent Reg = new Intent(MainScreeen.this, Regsteration.class); 
      Reg.putExtra("PhoneNumber", mPhoneNumber); 
      startActivity(Reg); 
     } 
    } 

请帮我弄明白了！

Answer 1

那么，在这个代码块：

if (mPhoneNumber == null) { 
try { 
    fOut = openFileOutput("textfile.txt", MODE_WORLD_READABLE); 
    fIn = openFileInput("textfile.txt"); 

打开输出文件，这会破坏你已经写入任何东西。后来，当你试图从这个文件中读取时，一切都为时已晚。

另外，你在这里的代码太多了。不要重新发明轮子。您不需要一次读取一个角色的文件。如果您只想将字符串写入文件并稍后再读取它，请使用DataInputStream和DataOutputStream，您可以直接使用readUTF()和writeUTF()读取/写入字符串。这里有一个简单的例子与R EAD文件：

DataInputStream in = new DataInputStream(openFileInput("textfile.txt")); 
    String contents = in.readUTF(); 

写入文件时使用：

DataOuputStream out = new DataOutputStream(openFileOutput("textfile.txt", 0)); 
    out.writeUTF(phoneNumber); 

显然，你需要添加try/catch块，并处理异常，并确保您关闭流在finally块中，但如果你这样做，你会得到更少的代码。

Answer 2

为了帮助你，我给你要想在一个文件中读取和写入数据我的活动例如：

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.util.Log; 

public class StoreDataActivity extends Activity { 

    private static final String TAG = "ExerciceActivity"; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     // TODO Auto-generated method stub 
     super.onCreate(savedInstanceState); 
     this.setContentView(R.layout.main); 

     writeFileOnDisk("toto.txt", "Bienvenue chez Android"); 

     String content = readFileOnDisk("toto.txt"); 
     Log.v(TAG, "content=" + content); 
    } 

    private void writeFileOnDisk(String filename, String data) { 

     try { 
      FileOutputStream fos = openFileOutput(filename, this.MODE_PRIVATE); 
      fos.write(data.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 readFileOnDisk(String filename) { 

     int inChar; 
     StringBuffer buffer = new StringBuffer(); 

     try { 
      FileInputStream fis = this.openFileInput(filename); 
      while ((inChar = fis.read()) != -1) { 
       buffer.append((char) inChar); 
      } 
      fis.close(); 

      String content = buffer.toString(); 

      return content; 

     } catch (FileNotFoundException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } catch (IOException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 

     return null; 
    }