写入字符串文本文件 [英] Writing String to Text File

问题描述

我保存日志.txt文件的SD卡，但一旦有救两条线，它会覆盖它，并重新开始？

I am saving a log to a .txt file on the sdcard but once there is two lines saved, it overwrites it and starts over?

下面是我的code：

public static String getTimestamp() {
    try {

        SimpleDateFormat dateFormat = new SimpleDateFormat("MMMdd HH:mm:ss", Locale.getDefault());
        String currentTimeStamp = dateFormat.format(new Date()); // Find todays date

        return currentTimeStamp;
    } catch (Exception e) {
        e.printStackTrace();

        return null;
    }
}

public static void writeToLog(Context context, String string) {
    String text = getTimestamp() + " " + string;
    // ONLY SAVES TWO LINES
    try {
        PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(logFile, true)));
        out.println(text);
        out.close();
    } catch (IOException e) {
        Log.d(Constants.APP_NAME, e.toString());
    }
}

只要你安装在恢复/数据，在/ SD卡和放大器的日志文件; /数据/媒体/ 0显示完整的日志历史，但不能当设备上电

As soon as you mount /data in recovery, the log files in /sdcard & /data/media/0 show the full log history but not when the device is powered on

推荐答案

这是它做的方式。下面的示例code后点击提交按钮保存信息到一个文件：

This is the way it is done. The following sample code saves the details to a file upon clicking of the submit button:

Submit = (Button) findViewById(R.id.btnSubmit); //Instantiates the button in the onCreate method 
        Submit.setOnClickListener(new OnClickListener(){  //Called when the user clicks on the Submit button

            @Override
            public void onClick(View v) {
            // In this case the text to be written is the selected text in a radio button from radioGroup
                int Selection = AttendanceGroup.getCheckedRadioButtonId();

                // find the radiobutton by returned id 
                RadioButton radiobutton = (RadioButton) findViewById(Selection); 

                    // write on SD card file data in the text box
                    try {

                        //gets the current date since this is an attendance app.
                        Calendar c = Calendar.getInstance();
                        //Formats the date a desired
                        SimpleDateFormat date = new SimpleDateFormat("dd-MM-yy");
                        String getDate = date.format(c.getTime());

                        //writes the text to the file named attendance.txt which is created in the phone.
                        File myFile = new File("/sdcard/Albanapp/Attendance.txt");
                        FileWriter fOut = new FileWriter(myFile, true);
                        fOut.append(getDate + "\t" + getSelectedName.getSelectedItem().toString() + "\t" + radiobutton.getText().toString() + "\n");
                        fOut.flush();
                        fOut.close();

                        //Returns a statment to the user showing if the editing of the attendance.txt file was successful or not.  
                        Toast.makeText(getBaseContext(),"Status Saved", Toast.LENGTH_SHORT).show();
                    } catch (Exception e) {
                        Toast.makeText(getBaseContext(), "Attendance cannot be saved",
                                Toast.LENGTH_SHORT).show();
                    }
            }
        });

希望这有助于：）

Hope this helps :)

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