用Java写入文本文件

Question

我有一个应用程序需要一位经验丰富的 Java 专业人士（可能是一目了然）。引擎运行良好，但我无法将数据保存到文本文件；而且，每次调试文件操作时，我都必须绑定我的平板电脑，卸载旧应用程序，复制apk并重新安装，因为我无法在模拟器中写入磁盘。

我补充说：

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

到应用程序标签之外的清单，并尝试了许多写入文件的方法。例外是（取决于当前尝试）eacces 或文件不存在。我也整天在谷歌上寻找解决方案。有人知道吗？

// this is a canned method that should presumably work
 private void writeStringToTextFile(String s, String f){
File sdCard = Environment.getExternalStorageDirectory();
File dir = new File (sdCard.getAbsolutePath());
dir.mkdirs();
File file = new File(dir, f);
try{
    FileOutputStream f1 = new FileOutputStream(file,false); //True = Append to file, false = Overwrite
    PrintStream p = new PrintStream(f1);
    p.print(s);
    p.close();
    f1.close();
} catch (FileNotFoundException e) {
} catch (IOException e) {
}   }


// this is the save method
// it has been modified a little less than a million times today
// some lines may be unnecessary because I have tried several approaches
  public void saveSystem(View view){
          String s="";
          String FILENAME = "data/data/TopExpertAndroid/" + fileName;
          FileOutputStream f;
          File file = new File(FILENAME);
          if(!(file.exists())){
             try{
                 file.createNewFile();} 
             catch(Exception e){
                showSplash(e.getMessage() + e.getCause(), "OK");
                return;}}
          try{
              getFile();
              if(fileName.equals("")){}
              else{
                   f = openFileOutput(FILENAME, Context.MODE_PRIVATE);
                   for(int temp=0; temp<50; temp++){
                       for(int loop=0; loop<50; loop++){
                           s += topExpert.nodeBank[temp][loop].activationResponse + "\n";
                           s += topExpert.nodeBank[temp][loop].display + "\n";
                           s += topExpert.nodeBank[temp][loop].falseLink + "\n";
                           s += topExpert.nodeBank[temp][loop].identifier + "\n";
                           if(topExpert.nodeBank[temp][loop].isTop){
                              s += "true";}
                           else{
                                s += "false";}
                           s += "\n" + topExpert.nodeBank[temp][loop].trueLink + "\n";}}
                           writeStringToTextFile(s,FILENAME);
              }}
          catch(Exception e){
                showSplash(e.getMessage() + e.getCause(), "OK");}}

Answer 1

FILENAME 变量可能在开头缺少/：

String FILENAME = "/data/data/TopExpertAndroid/" + fileName;

您可能应该改用getDataDirectory 或getExternalStorageDirectory...

但是你所说的无法写入模拟器的磁盘似乎很奇怪......？