在Android IO中创建文本文件

我试图在android手机上制作一个文本文件，并在需要时填充它。很明显，我遇到了一些问题，我想看看是否有人能看看我目前的情况

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;

public class ViewLog extends Activity {

    private TextView tv;
    private static final String TAG = "MEDIA";

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        tv = (TextView) findViewById(R.id.TextView01);

        CreateExternalLogFile("I am adding something into the text file!");
    }

private void CreateExternalLogFile(String s){
    File root = android.os.Environment.getExternalStorageDirectory(); 
    tv.append("\nExternal file system root: "+root);
    File dir = new File (root.getAbsolutePath() + "/logs");
    dir.mkdirs(); 
    File file = new File(dir,"log.txt");
    try {
        FileOutputStream f = new FileOutputStream(file,true); //True = Append to file, false = Overwrite
        PrintWriter pw = new PrintWriter(f);
        System.out.println(s);
        pw.println(s);
        pw.flush();
        pw.close();
        f.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
        Log.i(TAG, "******* File not found. Did you" +
                        " add a WRITE_EXTERNAL_STORAGE permission to the manifest?");
    } catch (IOException e) {
        e.printStackTrace();
    }   
    tv.append("\nFile written to \n"+file);


}
}

---

任何帮助都将不胜感激。我使用adb查找该文件，但该文件未被创建。

编辑：该功能正常-刚刚测试过

确保清单中也有：

 package com.example.fileio;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintStream;

import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.widget.TextView;

public class FilioActivity extends Activity {

    private TextView tv;
    private static final String TAG = "MEDIA";

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        tv = (TextView) findViewById(R.id.TextView01);

        CreateExternalLogFile("I am adding something into the text file!");
    }

private void CreateExternalLogFile(String s){
    File sdCard = Environment.getExternalStorageDirectory();
    File dir = new File (sdCard.getAbsolutePath());
    dir.mkdirs();
    File file = new File(dir, "filename.txt");
    tv.append("\nExternal file system root: "+ dir);
    try {
        FileOutputStream f = new FileOutputStream(file,false); //True = Append to file, false = Overwrite
        PrintStream p = new PrintStream(f);
        p.print(s);
        p.close();
        f.close();


    } catch (FileNotFoundException e) {
        e.printStackTrace();
        Log.i(TAG, "******* File not found. Did you" +
                        " add a WRITE_EXTERNAL_STORAGE permission to the manifest?");
    } catch (IOException e) {
        e.printStackTrace();
    }   
    tv.append("\nFile written to \n"+file);


}
}

我想将文件存储在SD卡上，这就是我选择.getExternalStorageDirectory（）的原因；当使用adb（通过仿真器查看）访问文件路径时，它应该位于“/mnt/sdcard/nullwall_logs/log.txt”目录中没有任何内容。此外，代码通过try块，没有输入任何异常。刚刚编辑了我的帖子，测试以确保代码正常工作。祝你好运，如果你需要更多的帮助，请告诉我：）非常感谢！我错过了什么？你还说确保你的舱单上有。吃什么？：]谢谢Woops，编辑它-现在应该包括权限：）别忘了选择我的答案；）我不完全确定我更改了什么，我认为只是环境.getExternalStorageDirectory（）以及清单更改。这是我看到的屏幕。希望这有帮助！非常感谢你的帮助。我所看到的是：确保你的舱单上也有。