Android 将字符串写入文件

我想把一些东西写入文件。我发现这个代码：

private void writeToFile(String data) {
    try {
        OutputStreamWriter outputStreamWriter = new OutputStreamWriter(context.openFileOutput("config.txt", Context.MODE_PRIVATE));
        outputStreamWriter.write(data);
        outputStreamWriter.close();
    }
    catch (IOException e) {
        Log.e("Exception", "File write failed: " + e.toString());
    } 
}

代码似乎非常合理，但我在手机中找不到config.txt文件。

---

如何检索包含字符串的文件？

没有指定路径，您的文件将保存在应用程序空间中（

/data/data/your.app.name/

）

因此，您最好将文件保存到外部存储器（不一定是SD卡，它可以是默认存储器）

你可能想通过阅读

综合而言：

将此权限添加到您的清单：

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

[编辑]确定按如下方式尝试（不同路径-外部存储器上的文件夹）：

---

此方法将文件名和数据字符串作为输入，并将其转储到SD卡上的文件夹中。 如果需要，可以更改文件夹的名称

根据文件操作的成功或失败，返回类型为布尔值

重要提示：尝试在异步任务中执行此操作，因为文件IO使主线程上出现ANR。

 public boolean writeToFile(String dataToWrite, String fileName) {

            String directoryPath =
                    Environment.getExternalStorageDirectory()
                            + File.separator
                            + "LOGS"
                            + File.separator;

            Log.d(TAG, "Dumping " + fileName +" At : "+directoryPath);

            // Create the fileDirectory.
            File fileDirectory = new File(directoryPath);

            // Make sure the directoryPath directory exists.
            if (!fileDirectory.exists()) {

                // Make it, if it doesn't exist
                if (fileDirectory.mkdirs()) {
                    // Created DIR
                    Log.i(TAG, "Log Directory Created Trying to Dump Logs");
                } else {
                    // FAILED
                    Log.e(TAG, "Error: Failed to Create Log Directory");
                    return false;
                }
            } else {
                Log.i(TAG, "Log Directory Exist Trying to Dump Logs");
            }

            try {
                // Create FIle Objec which I need to write
                File fileToWrite = new File(directoryPath, fileName + ".txt");

                // ry to create FIle on card
                if (fileToWrite.createNewFile()) {
                    //Create a stream to file path
                    FileOutputStream outPutStream = new FileOutputStream(fileToWrite);
                    //Create Writer to write STream to file Path
                    OutputStreamWriter outPutStreamWriter = new OutputStreamWriter(outPutStream);
                    // Stream Byte Data to the file
                    outPutStreamWriter.append(dataToWrite);
                    //Close Writer
                    outPutStreamWriter.close();
                    //Clear Stream
                    outPutStream.flush();
                    //Terminate STream
                    outPutStream.close();
                    return true;
                } else {
                    Log.e(TAG, "Error: Failed to Create Log File");
                    return false;
                }

            } catch (IOException e) {
                Log.e("Exception", "Error: File write failed: " + e.toString());
                e.fillInStackTrace();
                return false;
            }
        }

---

编写一个简化的文本文件：

private void writeToFile(String content) {
    try {
        File file = new File(Environment.getExternalStorageDirectory() + "/test.txt");

        if (!file.exists()) {
            file.createNewFile();
        }
        FileWriter writer = new FileWriter(file);
        writer.append(content);
        writer.flush();
        writer.close();
    } catch (IOException e) {
    }
}

---

您可以在文件的logData中写入完整的数据

该文件将在Downlaods目录中创建

这仅适用于Api 28及更低版本

这在Api 29和更高版本上不起作用

---

我在data/datait下找不到我的应用程序它是

/data/data/…

不是

data/data/…

，如果你没有root访问权限，文件浏览器也看不到它。我正在整个手机中搜索config.txt，它找不到任何东西。你有root访问权限吗？如果没有，你就找不到它。但是你可以重新阅读我更新的答案，按照提供的链接将文件保存到你决定保存它的地方。答案很好，但让我惊讶的是，每个答案都使用

缓冲区跳过。考虑到效率，考虑用<代码> BuffReDeDebug < /COD>包装<代码> OutPutsDraveScript < /代码>。是否真的需要在TXT文件中写入一些东西？如果不考虑使用SyrdPoopy。
 public boolean writeToFile(String dataToWrite, String fileName) {

            String directoryPath =
                    Environment.getExternalStorageDirectory()
                            + File.separator
                            + "LOGS"
                            + File.separator;

            Log.d(TAG, "Dumping " + fileName +" At : "+directoryPath);

            // Create the fileDirectory.
            File fileDirectory = new File(directoryPath);

            // Make sure the directoryPath directory exists.
            if (!fileDirectory.exists()) {

                // Make it, if it doesn't exist
                if (fileDirectory.mkdirs()) {
                    // Created DIR
                    Log.i(TAG, "Log Directory Created Trying to Dump Logs");
                } else {
                    // FAILED
                    Log.e(TAG, "Error: Failed to Create Log Directory");
                    return false;
                }
            } else {
                Log.i(TAG, "Log Directory Exist Trying to Dump Logs");
            }

            try {
                // Create FIle Objec which I need to write
                File fileToWrite = new File(directoryPath, fileName + ".txt");

                // ry to create FIle on card
                if (fileToWrite.createNewFile()) {
                    //Create a stream to file path
                    FileOutputStream outPutStream = new FileOutputStream(fileToWrite);
                    //Create Writer to write STream to file Path
                    OutputStreamWriter outPutStreamWriter = new OutputStreamWriter(outPutStream);
                    // Stream Byte Data to the file
                    outPutStreamWriter.append(dataToWrite);
                    //Close Writer
                    outPutStreamWriter.close();
                    //Clear Stream
                    outPutStream.flush();
                    //Terminate STream
                    outPutStream.close();
                    return true;
                } else {
                    Log.e(TAG, "Error: Failed to Create Log File");
                    return false;
                }

            } catch (IOException e) {
                Log.e("Exception", "Error: File write failed: " + e.toString());
                e.fillInStackTrace();
                return false;
            }
        }

private void writeToFile(String content) {
    try {
        File file = new File(Environment.getExternalStorageDirectory() + "/test.txt");

        if (!file.exists()) {
            file.createNewFile();
        }
        FileWriter writer = new FileWriter(file);
        writer.append(content);
        writer.flush();
        writer.close();
    } catch (IOException e) {
    }
}

@TargetApi(Build.VERSION_CODES.P)
public static File createPrivateFile(String logData) {
    String fileName = "/Abc.txt";
    File directory = new File(Environment.getExternalStorageDirectory() + "/" + Environment.DIRECTORY_DOWNLOADS + "/");
    directory.mkdir();
    File file = new File(directory + fileName);
    FileOutputStream fos = null;
    try {
        if (file.exists()) {
            file.delete();
        }
        file = new File(getAppDir() + fileName);
        file.createNewFile();
        fos = new FileOutputStream(file);
        fos.write(logData.getBytes());
        fos.flush();
        fos.close();
        return file;
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return null;
}