我正在尝试检索存储在Android设备内部存储中的文件，但找不到

Question

I have written a file to internal storage. It shows up in my "data/data/package-name/file folder. It exists when I check in this directory. But in the code below, when I type File file = new File(fileName), file.exists() comes up false. Can anyone tell me why?

fileName = "match." + mMatchID + ".json";

Log.d(TAG1, "Filename: " + fileName);   // the file name is ok


File file = new File(fileName);

Log.d(TAG1, "Does File Exist: " + file.exists());

Gson gson = new Gson();


if (file.exists()) {
    // read file into memory and assign the string to matchString
    BufferedReader reader = null;
    try {
        reader = new BufferedReader(new FileReader(fileName));
        matchString = reader.readLine();

        Log.d(TAG1, "When you read the match back into memory: " + matchString);


    } catch (IOException e) {
        e.printStackTrace();

        Log.d(TAG1, "an error occured:" );
    } finally{
        try {
            assert reader != null;
            reader.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    match = gson.fromJson(matchString, Match.class);
}


match.setMatchName(mMatchNameEditText.getText().toString());
match.setMatchLevel(mSpinner.getSelectedItem().toString());

// convert match back to JSON
matchString = new Gson().toJson(match);

FileOutputStream fos = null;

try {
    fos = openFileOutput(fileName, MODE_PRIVATE);
    fos.write(matchString.getBytes());
} catch (IOException e) {
    e.printStackTrace();
} finally {
    try {
        assert fos != null;
        fos.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

Toast.makeText(EditMatchActivity.this, "Match Updated", Toast.LENGTH_SHORT).show();
}

SharedPreferences.Editor editor = getSharedPreferences(MY_GLOBAL_PREFS, MODE_PRIVATE).edit();
editor.putString(CURRENT_MATCH_NAME, mMatchNameEditText.getText().toString());
String level = mSpinner.getSelectedItem().toString();
editor.putString(CURRENT_MATCH_LEVEL, level);
editor.apply();

Here is the evidence in the stack trace:

08-22 14:17:50.674 2883-2883/com.checkinsystems.ez_score D/EditMatchActivity: Filename: match.08222017PGA5614023.json
08-22 14:17:50.674 2883-2883/com.checkinsystems.ez_score D/EditMatchActivity: Does File Exist: false
08-22 14:17:50.703 2883-3109/com.checkinsystems.ez_score D/EGL_emulation: eglMakeCurrent: 0x7f92842e1d20: ver 2 0 (tinfo 0x7f92842c2f00)
08-22 14:17:50.710 2883-3109/com.checkinsystems.ez_score D/EGL_emulation: eglMakeCurrent: 0x7f92842e1d20: ver 2 0 (tinfo 0x7f92842c2f00)
08-22 14:17:52.684 2883-3109/com.checkinsystems.ez_score E/Surface: getSlotFromBufferLocked: unknown buffer: 0x7f92842e25e0

Answer 1

"match." + mMatchID + ".json" "match." + mMatchID + ".json" is a simple filename. It is not a fully-qualified path to a file.

You need to check a File using code that matches how you created that file in the first place. If you used getFilesDir() or openInputStream() to create that file, then use new File(getFilesDir(), "match." + mMatchID + ".json") to create the corresponding File .