我必须实现相机的动态权限。有三种可能的情况:允许2。否认,3。别再问了。

 @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {

    for (String permission : permissions) {
        if (ActivityCompat.shouldShowRequestPermissionRationale(getActivity(), permission)) {
            //denied
            Log.e("denied", permission);
        } else {
            if (ActivityCompat.checkSelfPermission(getActivity(), permission) == PackageManager.PERMISSION_GRANTED) {
                //allowed
                Log.e("allowed", permission);
            } else {
                //set to never ask again
                Log.e("set to never ask again", permission);
                //do something here.
            }
        }
    }
    if (requestCode != MaterialBarcodeScanner.RC_HANDLE_CAMERA_PERM) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        return;
    }
    if (grantResults.length != 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
        mScannerView.setResultHandler(this);
        mScannerView.startCamera(mCameraId);
        mScannerView.setFlash(mFlash);
        mScannerView.setAutoFocus(mAutoFocus);
        return;
    } else {
        //set to never ask again
        Log.e("set to never ask again", permissions[0]);
    }
    DialogInterface.OnClickListener listener = new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int id) {
            dialog.cancel();
        }
    };
    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    builder.setTitle("Error")
            .setMessage(R.string.no_camera_permission)
            .setPositiveButton(android.R.string.ok, listener)
            .show();


}

private void insertDummyContactWrapper() {
        int hasWriteContactsPermission = checkSelfPermission(Manifest.permission.CAMERA);
        if (hasWriteContactsPermission != PackageManager.PERMISSION_GRANTED) {
            requestPermissions(new String[]{Manifest.permission.CAMERA},
                    REQUEST_CODE_ASK_PERMISSIONS);
            return;
        }
        mScannerView.setResultHandler(this);
        mScannerView.startCamera(mCameraId);
        mScannerView.setFlash(mFlash);
        mScannerView.setAutoFocus(mAutoFocus);
    }

private int checkSelfPermission(String camera) {
    if (ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.CAMERA)
            != PackageManager.PERMISSION_GRANTED) {
        return REQUEST_CODE_ASK_PERMISSIONS;
    } else {
        return REQUEST_NOT_CODE_ASK_PERMISSIONS;
    }
}

我有点晚了，我也遇到过类似的问题。解决此问题如下

假设您需要位置权限

请求权限启动器

private final ActivityResultLauncher<String> requestPermissionLauncher =
      registerForActivityResult(
          new RequestPermission(),
          isGranted -> {
            if (isGranted) {
              // Permission is granted go ahead
            } else {
              shouldShowRequestPermissionRationale();
            }
          });

权限检查

  private boolean hasPermissions() {
        if (checkSelfPermission(requireActivity(), ACCESS_FINE_LOCATION) == PERMISSION_GRANTED) {
          // Permission is granted go ahead
        } else {
          requestPermissionLauncher.launch(ACCESS_FINE_LOCATION);
        }
      }

检查是否需要显示权限理性/自定义对话来教育用户

private void shouldShowRequestPermissionRationale() {
        if (!shouldShowRequestPermissionRationale(ACCESS_FINE_LOCATION)) {
          // need to show permission rational custom dialog.
        } 
    }

你可以使用

shouldShowRequestPermissionRationale()

内部

onRequestPermissionsResult()

请看下面的例子:

当用户点击按钮时检查是否有权限:

@Override
public void onClick(View v) {
    if (v.getId() == R.id.appCompatBtn_changeProfileCoverPhoto) {
        if (Build.VERSION.SDK_INT < 23) { // API < 23 don't need to ask permission
            navigateTo(MainActivity.class); // Navigate to activity to change photos
        } else {
            if (ContextCompat.checkSelfPermission(SettingsActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
                    != PackageManager.PERMISSION_GRANTED) {
                // Permission is not granted yet. Ask for permission...
                requestWriteExternalPermission();
            } else {
                // Permission is already granted, good to go :)
                navigateTo(MainActivity.class);
            }
        } 
    }
}

当用户回答权限对话框时，我们将进入onRequestPermissionResult:

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);

    if (requestCode == WRITE_EXTERNAL_PERMISSION_REQUEST_CODE) {
        // Case 1. Permission is granted.  
        if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {  
            if (ContextCompat.checkSelfPermission(SettingsActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
                    == PackageManager.PERMISSION_GRANTED) {
                // Before navigating, I still check one more time the permission for good practice.
                navigateTo(MainActivity.class);
            }
        } else { // Case 2. Permission was refused
            if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
                // Case 2.1. shouldShowRequest... returns true because the
                // permission was denied before. If it is the first time the app is running we will 
                // end up in this part of the code. Because he need to deny at least once to get 
                // to onRequestPermissionsResult. 
                Snackbar snackbar = Snackbar.make(findViewById(R.id.relLayout_container), R.string.you_must_verify_permissions_to_send_media, Snackbar.LENGTH_LONG);
                snackbar.setAction("VERIFY", new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        ActivityCompat.requestPermissions(SettingsActivity.this
                                , new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}
                                , WRITE_EXTERNAL_PERMISSION_REQUEST_CODE);
                    }
                });
                snackbar.show();
            } else {
                // Case 2.2. Permission was already denied and the user checked "Never ask again". 
                // Navigate user to settings if he choose to allow this time.
                AlertDialog.Builder builder = new AlertDialog.Builder(this);
                builder.setMessage(R.string.instructions_to_turn_on_storage_permission)
                        .setPositiveButton(getString(R.string.settings), new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                Intent settingsIntent = new Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
                                Uri uri = Uri.fromParts("package", getPackageName(), null);
                                settingsIntent.setData(uri);
                                startActivityForResult(settingsIntent, 7);
                            }
                        })
                        .setNegativeButton(getString(R.string.not_now), null);
                Dialog dialog = builder.create();
                dialog.show();
            }
        }
    }

}

你可以听漂亮。

侦听器

interface PermissionListener {
    fun onNeedPermission()
    fun onPermissionPreviouslyDenied(numberDenyPermission: Int)
    fun onPermissionDisabledPermanently(numberDenyPermission: Int)
    fun onPermissionGranted()
}

MainClass的权限

class PermissionUtil {

    private val PREFS_FILENAME = "permission"
    private val TAG = "PermissionUtil"

    private fun shouldAskPermission(context: Context, permission: String): Boolean {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            val permissionResult = ActivityCompat.checkSelfPermission(context, permission)
            if (permissionResult != PackageManager.PERMISSION_GRANTED) {
                return true
            }
        }
        return false
    }

    fun checkPermission(context: Context, permission: String, listener: PermissionListener) {

        Log.i(TAG, "CheckPermission for $permission")

        if (shouldAskPermission(context, permission)) {

            // Load history permission
            val sharedPreference = context.getSharedPreferences(PREFS_FILENAME, 0)
            val numberShowPermissionDialog = sharedPreference.getInt(permission, 0)

            if (numberShowPermissionDialog == 0) {

                (context as? Activity)?.let {
                    if (ActivityCompat.shouldShowRequestPermissionRationale(it, permission)) {
                        Log.e(TAG, "User has denied permission but not permanently")
                        listener.onPermissionPreviouslyDenied(numberShowPermissionDialog)
                    } else {
                        Log.e(TAG, "Permission denied permanently.")
                        listener.onPermissionDisabledPermanently(numberShowPermissionDialog)
                    }
                } ?: kotlin.run {
                    listener.onNeedPermission()
                }

            } else {
                // Is FirstTime
                listener.onNeedPermission()
            }


            // Save history permission
            sharedPreference.edit().putInt(permission, numberShowPermissionDialog + 1).apply()


        } else {
            listener.onPermissionGranted()
        }

    }
}

以这种方式使用

      PermissionUtil().checkPermission(this, Manifest.permission.ACCESS_FINE_LOCATION,
                object : PermissionListener {
                    override fun onNeedPermission() {
                        log("---------------------->onNeedPermission")

//                            ActivityCompat.requestPermissions(this@SplashActivity,
//                                    Array(1) { Manifest.permission.ACCESS_FINE_LOCATION },
//                                    118)

                    }

                    override fun onPermissionPreviouslyDenied(numberDenyPermission: Int) {
                        log("---------------------->onPermissionPreviouslyDenied")
                    }

                    override fun onPermissionDisabledPermanently(numberDenyPermission: Int) {
                        log("---------------------->onPermissionDisabled")
                    }

                    override fun onPermissionGranted() {
                        log("---------------------->onPermissionGranted")
                    }

                })

在activity或fragmnet中覆盖onRequestPermissionsResult

override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
 if (requestCode == 118) {
        if (permissions[0] == Manifest.permission.ACCESS_FINE_LOCATION && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            getLastLocationInMap()
        }
        }
    }

在阅读了一些答案后，我发现了许多冗长而令人困惑的答案 我的结论是

if (!ActivityCompat.shouldShowRequestPermissionRationale(this,Manifest.permission.READ_EXTERNAL_STORAGE))
                Toast.makeText(this, "permanently denied", Toast.LENGTH_SHORT).show();

为了准确地回答这个问题，当用户按下“永不再问”时会发生什么?

重写的方法/函数

onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray)

grantResult数组显示为空，你可以在这里做些什么?但不是最好的做法。

如何处理“永不再问”?

我正在使用Fragment，它需要READ_EXTERNAL_STORAGE权限。

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        when {
            isReadPermissionsGranted() -> {

                /**
                 * Permissions has been Granted
                 */

                getDirectories()
            }

            isPermissionDeniedBefore() -> {

                /**
                 * User has denied before, explain why we need the permission and ask again
                 */

                updateUIForDeniedPermissions()
                checkIfPermissionIsGrantedNow()

            }
            else -> {

                /**
                 * Need to ask For Permissions, First Time
                 */

                checkIfPermissionIsGrantedNow()

                /**
                 * If user selects, "Dont Ask Again" it will never ask again! so just update the UI for Denied Permissions
                 */

                updateUIForDeniedPermissions()

            }
        }
    }

其他的函数是微不足道的。

// Is Read Write Permissions Granted
fun isReadWritePermissionGranted(context: Context): Boolean {
    return (ContextCompat.checkSelfPermission(
        context as Activity,
        Manifest.permission.READ_EXTERNAL_STORAGE
    ) == PackageManager.PERMISSION_GRANTED) and
            (ContextCompat.checkSelfPermission(
                context,
                Manifest.permission.WRITE_EXTERNAL_STORAGE
            ) == PackageManager.PERMISSION_GRANTED)
}

fun isReadPermissionDenied(context: Context) : Boolean {
    return ActivityCompat.shouldShowRequestPermissionRationale(
        context as Activity,
        PermissionsUtils.READ_EXTERNAL_STORAGE_PERMISSIONS)
}