Android运行时权限问题

Question

假设我试图将位图图像保存为png

public void save() {
  String filename = "file.png";
        File sd = Environment.getExternalStorageDirectory();
        File dest = new File(sd, filename);

        try {

            FileOutputStream out = new FileOutputStream(dest);
            fBitmap.compress(Bitmap.CompressFormat.PNG, 90, out);
            out.flush();
            out.close();

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

如果我使用Android 6.0及以上版本，我需要请求运行时权限

void validatePermissions() {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {

            if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {

            } else {

                ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);

            }

        }
  }

我有几个问题：

上面的代码成功地请求了权限，但是我不得不重新启动应用程序，我如何恰当地暂停代码直到权限被授予或未被授予？

在 Android 6.0 下方，权限由清单文件在安装时授予。Android 5 或更低版本如何处理运行时权限代码？

谢谢

Answer 1

您可以使用Dexter库以获得更好的性能。我在这里也分享了Dexter代码

使用Dexter，您需要在应用程序中添加＜code＞Dexterdependency＜code＞。构建gradle文件。

implementation 'com.karumi:dexter:6.2.2'

Single permission/////
Dexter.withContext(activity)
            .withPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE)
            .withListener(object : PermissionListener {
                override fun onPermissionGranted(p0: PermissionGrantedResponse?) {
                    downloadImage(url)
                }

                override fun onPermissionDenied(p0: PermissionDeniedResponse?) {
                    if (p0!!.isPermanentlyDenied) {
                        showSettingsDialog()
                    }
                }

                override fun onPermissionRationaleShouldBeShown(
                        p0: PermissionRequest?, p1: PermissionToken?
                ) {
                    p1!!.continuePermissionRequest()
                }

            })
            .onSameThread()
            .check()


Multiple Permission////

Dexter.withContext(requireContext())
            .withPermissions(Manifest.permission.RECORD_AUDIO,
                    Manifest.permission.WRITE_EXTERNAL_STORAGE,
                    Manifest.permission.READ_EXTERNAL_STORAGE)
            .withListener(object : MultiplePermissionsListener {
                override fun onPermissionsChecked(p0: MultiplePermissionsReport?) {
                    if (p0!!.areAllPermissionsGranted())
                    {
                        
                        
                    }else if (p0.isAnyPermissionPermanentlyDenied)
                    {
                        openSettings()
                    }
                }

                override fun onPermissionRationaleShouldBeShown(p0: MutableList<PermissionRequest>?, permissionToken: PermissionToken?) {
                    permissionToken?.continuePermissionRequest()
                }
            }).check()

Answer 2

上面的代码成功地请求了权限，但是我不得不重新启动应用程序，我如何恰当地暂停代码直到权限被授予或未被授予？

你可以利用这个空虚

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[], @NonNull int[] grantResults) {
    switch (requestCode) {
        case 1: {
            // If request is cancelled, the result arrays are empty.
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                // permission was granted, yay! Do the
                // contacts-related task you need to do.          
            } else {

                // permission denied, boo! Disable the
                // functionality that depends on this permission.
                Toast.makeText(MainActivity.this, "Permission denied to read your External storage", Toast.LENGTH_SHORT).show();
            }
        }

        // other 'case' lines to check for other
        // permissions this app might request
    }
}

从这个答案

在Android 6.0以下，清单文件在安装时授予权限。如何

Android 5或更低版本处理运行时权限代码？

代码将被跳过

Answer 3

你不应该重启应用程序。你应该改变你的应用程序的逻辑:当用户授予权限时等待，并尝试第二次运行一个操作。是的，你可以为此使用第三方库。比如我个人选择:权限调度员。