Question

我想阅读一个使用OutputStreamWriter在另一个活动中编写的文本文件。这是我在Sale.java中的readFromFile方法：

private int readFromFile(String request) {

        int res = 0;
        try {
            //InputStream inputStream = openFileInput("dalassnums.txt");
            File file=new File("dalassnums.txt");
            InputStream inputStream = new FileInputStream(file);

            if ( inputStream != null ) {
                InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
                BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
                String receiveString = "";

                while ( (receiveString = bufferedReader.readLine()) != null ) {
                    String s=bufferedReader.readLine();
                    if(receiveString==request)  {
                        res=Integer.valueOf(s);
                        break;
                    }
                }

                inputStream.close();

            }
        }
        catch (FileNotFoundException e) {
            Log.e("login activity", "File not found: " + e.toString());
            res=0;

        } catch (IOException e) {
            //Log.e("login activity", "Can not read file: " + e.toString());

        }

        return res;



    }

这是MainActivity.java中的writeToFile方法：

private void writeToFile2(String numchar) {
    try {
        //File file=new File("dalassnums.txt");
        //OutputStream outputStream=new FileOutputStream(file);
        OutputStreamWriter outputStreamWriter;
        if(numchar=="1") outputStreamWriter = new OutputStreamWriter(openFileOutput("dalassnums.txt", Context.MODE_PRIVATE));
        else  outputStreamWriter = new OutputStreamWriter(openFileOutput("dalassnums.txt", Context.MODE_APPEND));
        for(int k=0; k<imageNums.size();k+=2){
        outputStreamWriter.append(imageNums.get(k));
        outputStreamWriter.append("\n");
        outputStreamWriter.append(imageNums.get(k+1));
        outputStreamWriter.append("\n");
        }
        outputStreamWriter.close();
    }
    catch (IOException e) {
        Log.e("Exception", "File write failed: " + e.toString());
    } 
}

执行readFromFile时，返回0表示找不到文件; 我读过关于传递上下文但我不知道要传递什么上下文;并且想知道除了传递上下文之外是否还有其他方式。任何帮助将不胜感激。

Answer 1

使用openFileInput中的readFromFile，例如：

openFileInput() and/or openFileOutput() i/o streams silently failing

另一个问题是这是无效的：

if(numchar=="1")

你应该

if(numchar.equals("1"))

否则你比较参考值而不是字符串

的内容

从另一个活动中读取文件

1 个答案: