Question

在mainFest中有

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

对于较新的操作系统，它会检查权限

ContextCompat.checkSelfPermission(context, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED;

如果它没有返回true，它将请求许可

ActivityCompat.requestPermissions(activity, new String[] { Manifest.permission.WRITE_EXTERNAL_STORAGE }, 5);

只有拥有权限时才会尝试创建文件

File directory = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);

String sysDownloadPath = directory.getPath();


                try {
                    if (!directory.exists() && !directory.mkdirs()) {
                        //shouldn't happen in here
                        /* Checks if external storage is available for read and write */
                        String state = Environment.getExternalStorageState();
                        String externalStorageAvailable = (Environment.MEDIA_MOUNTED.equals(state)) ?
                                "ext-ST available" :
                                "ext-ST NOT available";                        }
                } catch (Exception e) {  //<=== did not caught exception here
                }

                String fileName = ‘SD_20170404.pdf’;

                String newFilePath = (sysDownloadPath + "/" + fileName);
                File newFile = new File(newFilePath);

                try {
                    newFile.createNewFile();// <=== throws at this one
                } catch (Exception e) {


fatal Exception: java.lang.Exception: open failed: EACCES (Permission    denied), newFile.getPath():/storage/emulated/0/Download/SD_20170404.pdf

OS 5,6和7会发生（并非总是如此）任何建议？谢谢！

在获得许可后仍然可以获得权限拒绝例外

0 个答案: