正在下載apk，沒有此類文件或目錄錯誤。

Question

我正在創建一個從網絡服務器下載apk文件然后安裝的應用程序，但是我遇到了問題，當我單擊“下載”時，進度條會比較，但不會更改，在Android Monitor中會比較：

我正在Android 7.1.1上使用avd，然后嘗試使用棉花糖。 這是代碼：

    try {
    if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
   String sdPath = Environment.getExternalStorageDirectory() + "/";

                    mSavePath = sdPath + "updateDownload";
                    File dir = new File(mSavePath);

                    if (!dir.exists())
                        if (dir.mkdir())
                            Log.d(TAG, "mkdir success");
                        else
                            Log.d(TAG, "mkdir failed!");

                    HttpURLConnection conn = (HttpURLConnection) new URL(path).openConnection();
                    conn.connect();

                    InputStream is = conn.getInputStream();

                    int length = conn.getContentLength();

                    File apkFile = new File(mSavePath, version_name);

                    FileOutputStream fos = new FileOutputStream(apkFile);

                    int count = 0;
                    byte[] buffer = new byte[1024];
                    while (!isCancel) {
                        int numread = is.read(buffer);
                        count += numread;
                        mProgress = (int) ((float) (count / length) * 100);

                        mUpdateProgressHandler.sendEmptyMessage(DOWNLOADING);
                        if (numread < 0) {
                            mUpdateProgressHandler.sendEmptyMessage(DOWNDLOAD_FINISHED);
                            break;
                        }
                        fos.write(buffer, 0, numread);

                    }
                    fos.close();
                    is.close();

                } else {
                    Log.d(TAG, " Media not mounted");
                }


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

Answer 1

Android 6.0之后的Android Need運行時權限請參閱https://developer.android.com/training/permissions/requesting.html