android - .renameTo() 的结果被忽略

Question

我正在尝试通过 FTP 上传文件，但在上传之前必须将其重命名为 2 个 editText 的输入。为此，我使用以下代码:

public FTPClient client = new FTPClient();

    public void upload_klik (View view) {
        EditText week_text = (EditText) findViewById(R.id.week_edit);
        EditText pagina_text = (EditText) findViewById(R.id.pagina_edit);
        String w_val = week_text.getText().toString();
        String p_val = pagina_text.getText().toString();
        upload_task up = new upload_task();
        up.execute(w_val, p_val);
    }

    protected class upload_task extends AsyncTask<String, Object, String> {

        @Override
        protected String doInBackground(String... params) {

            String w = params[0];
            String p = params[1];

            Intent intent = getIntent();
            Bundle bundle = intent.getExtras();
            String ret = "Done!";
            if(!bundle.isEmpty()) {
                String afdeling_url = bundle.getString("afdeling_url", "DKW/");
                String afdeling_preFix = bundle.getString("afdeling_preFix", "dkw");
                String locatie_url = bundle.getString("locatie_url", "/delf_wend/");

                String new_fileName = afdeling_preFix +"_" + "w" + w + "_" + "p" + p + ".jpg";

                System.out.println(new_fileName);

                File f = new File(foto_path);
                File sdcard = Environment.getExternalStorageDirectory();
                File to = new File(sdcard, new_fileName);
                f.renameTo(to);

                if(f != null) {

                    try{
                        client.setPassive(true);
                        client.setAutoNoopTimeout(30000);
                        client.connect(FTP_HOST, 21);
                        client.login(FTP_USER, FTP_PASS);
                        client.setType(FTPClient.TYPE_BINARY);
                        System.out.println(locatie_url + afdeling_url);
                        client.changeDirectory(locatie_url + afdeling_url);
                        client.upload(to);

                        restart();

                    }
                    catch (Exception e){
                        e.printStackTrace();
                        try {
                            client.disconnect(true);
                        }
                        catch (Exception e2) {
                            e2.printStackTrace();
                        }
                    }
                }

            }
            return ret;
        }
    }

但是当我尝试上传它时，Logcat 给了我这个:

09-09 16:33:17.794  23674-25966/nl.knapper_development.jrw_uploader I/System.out﹕ slag_w11_p222.jpg
09-09 16:33:17.994  23674-25966/nl.knapper_development.jrw_uploader I/System.out﹕ /delf_wend/SLAG/
09-09 16:33:18.024  23674-25966/nl.knapper_development.jrw_uploader W/System.err﹕ java.io.FileNotFoundException: /slag_w11_p222.jpg
09-09 16:33:18.024  23674-25966/nl.knapper_development.jrw_uploader W/System.err﹕ at it.sauronsoftware.ftp4j.FTPClient.upload(FTPClient.java:2577)
09-09 16:33:18.024  23674-25966/nl.knapper_development.jrw_uploader W/System.err﹕ at it.sauronsoftware.ftp4j.FTPClient.upload(FTPClient.java:2457)
09-09 16:33:18.024  23674-25966/nl.knapper_development.jrw_uploader W/System.err﹕ at nl.knapper_development.jrw_uploader.upload$upload_task.doInBackground(upload.java:154)
09-09 16:33:18.024  23674-25966/nl.knapper_development.jrw_uploader W/System.err﹕ at nl.knapper_development.jrw_uploader.upload$upload_task.doInBackground(upload.java:119)
09-09 16:33:18.024  23674-25966/nl.knapper_development.jrw_uploader W/System.err﹕ at android.os.AsyncTask$2.call(AsyncTask.java:288)
09-09 16:33:18.024  23674-25966/nl.knapper_development.jrw_uploader W/System.err﹕ at java.util.concurrent.FutureTask.run(FutureTask.java:237)
09-09 16:33:18.024  23674-25966/nl.knapper_development.jrw_uploader W/System.err﹕ at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
09-09 16:33:18.024  23674-25966/nl.knapper_development.jrw_uploader W/System.err﹕ at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
09-09 16:33:18.024  23674-25966/nl.knapper_development.jrw_uploader W/System.err﹕ at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
09-09 16:33:18.024  23674-25966/nl.knapper_development.jrw_uploader W/System.err﹕ at java.lang.Thread.run(Thread.java:818)

我将问题缩小到函数 f.renameTo(new_fileName)，它说调用此方法的结果被忽略。但是为什么会被忽略呢？有办法解决这个问题吗？

提前谢谢你:)

Answer 1

错误是非常直接的，因为它都记录在案了:

https://developer.android.com/reference/java/io/File.html#renameTo(java.io.File)

Many failures are possible. Some of the more likely failures include:

• Write permission is required on the directories containing both the source and destination paths.
• Search permission is required for all parents of both paths.
• Both paths be on the same mount point. On Android, applications are most likely to hit this restriction when attempting to copy between internal storage and an SD card.

https://developer.android.com/reference/java/io/FileNotFoundException.html

Thrown when a file specified by a program cannot be found

我敢打赌，如果您检查文件是否存在代码:

if(f.exists()){

你会发现 foto_path不是现有文件，或者您应该检查 foto_path也在Environment.getExternalStorageDirectory()里面.

如果它不在同一个挂载点中，您必须将文件复制过来(使用新名称)而不是仅仅重命名。