问如何在Android中创建文件？

EN

//Writing a file...  



try { 
       // catches IOException below
       final String TESTSTRING = new String("Hello Android");
      
       /* We have to use the openFileOutput()-method
       * the ActivityContext provides, to
       * protect your file from others and
       * This is done for security-reasons.
       * We chose MODE_WORLD_READABLE, because
       *  we have nothing to hide in our file */             
       FileOutputStream fOut = openFileOutput("samplefile.txt",
                                                            MODE_PRIVATE);
       OutputStreamWriter osw = new OutputStreamWriter(fOut); 

       // Write the string to the file
       osw.write(TESTSTRING);

       /* ensure that everything is
        * really written out and close */
       osw.flush();
       osw.close();

//Reading the file back...

       /* We have to use the openFileInput()-method
        * the ActivityContext provides.
        * Again for security reasons with
        * openFileInput(...) */
       
        FileInputStream fIn = openFileInput("samplefile.txt");
        InputStreamReader isr = new InputStreamReader(fIn);
        
        /* Prepare a char-Array that will
         * hold the chars we read back in. */
        char[] inputBuffer = new char[TESTSTRING.length()];

        // Fill the Buffer with data from the file
        isr.read(inputBuffer);

        // Transform the chars to a String
        String readString = new String(inputBuffer);
                   
        // Check if we read back the same chars that we had written out
        boolean isTheSame = TESTSTRING.equals(readString);

        Log.i("File Reading stuff", "success = " + isTheSame);

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

File file = new File(Environment.getExternalStorageDirectory() + "/" + File.separator + "test.txt");
file.createNewFile();
byte[] data1={1,1,0,0};
//write the bytes in file
if(file.exists())
{
     OutputStream fo = new FileOutputStream(file);              
     fo.write(data1);
     fo.close();
     System.out.println("file created: "+file);
}               

//deleting the file             
file.delete();
System.out.println("file deleted");

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

import android.content.Context;

public class AndroidFileFunctions {

    public static String getFileValue(String fileName, Context context) {
        try {
            StringBuffer outStringBuf = new StringBuffer();
            String inputLine = "";
            /*
             * We have to use the openFileInput()-method the ActivityContext
             * provides. Again for security reasons with openFileInput(...)
             */
            FileInputStream fIn = context.openFileInput(fileName);
            InputStreamReader isr = new InputStreamReader(fIn);
            BufferedReader inBuff = new BufferedReader(isr);
            while ((inputLine = inBuff.readLine()) != null) {
                outStringBuf.append(inputLine);
                outStringBuf.append("\n");
            }
            inBuff.close();
            return outStringBuf.toString();
        } catch (IOException e) {
            return null;
        }
    }

    public static boolean appendFileValue(String fileName, String value,
            Context context) {
        return writeToFile(fileName, value, context, Context.MODE_APPEND);
    }

    public static boolean setFileValue(String fileName, String value,
            Context context) {
        return writeToFile(fileName, value, context,
                Context.MODE_WORLD_READABLE);
    }

    public static boolean writeToFile(String fileName, String value,
            Context context, int writeOrAppendMode) {
        // just make sure it's one of the modes we support
        if (writeOrAppendMode != Context.MODE_WORLD_READABLE
                && writeOrAppendMode != Context.MODE_WORLD_WRITEABLE
                && writeOrAppendMode != Context.MODE_APPEND) {
            return false;
        }
        try {
            /*
             * We have to use the openFileOutput()-method the ActivityContext
             * provides, to protect your file from others and This is done for
             * security-reasons. We chose MODE_WORLD_READABLE, because we have
             * nothing to hide in our file
             */
            FileOutputStream fOut = context.openFileOutput(fileName,
                    writeOrAppendMode);
            OutputStreamWriter osw = new OutputStreamWriter(fOut);
            // Write the string to the file
            osw.write(value);
            // save and close
            osw.flush();
            osw.close();
        } catch (IOException e) {
            return false;
        }
        return true;
    }

    public static void deleteFile(String fileName, Context context) {
        context.deleteFile(fileName);
    }
}