根据这个:http://developer.android.com/preview/features/runtime-permissions.html#coding一个应用程序可以检查运行时权限和请求权限，如果它还没有被授予。弹出如下对话框:
如果用户拒绝一个重要的权限，在我看来，应用程序应该显示一个解释为什么需要权限和什么影响拒绝。该对话框有两个选项:
重试(再次请求许可) 拒绝(应用程序将工作没有该许可)。
但是，如果用户选中“Never ask again”，则不应该显示带有解释的第二个对话框，特别是如果用户之前已经拒绝了一次。 现在的问题是:我的应用程序如何知道用户是否选中了Never ask again?IMO onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults)没有给我这个信息。
第二个问题是:谷歌是否计划在权限对话框中包含一个自定义消息，以解释为什么应用程序需要权限?这样就不会出现第二个对话框，这肯定会带来更好的用户体验。
当前回答
扩展上面mVck的答案，下面的逻辑确定是否“Never ask again”已经为给定的权限请求进行了检查:
bool bStorage = grantResults[0] == Permission.Granted;
bool bNeverAskForStorage =
!bStorage && (
_bStorageRationaleBefore == true && _bStorageRationaleAfter == false ||
_bStorageRationaleBefore == false && _bStorageRationaleAfter == false
);
摘自下面(完整的例子见这个答案)
private bool _bStorageRationaleBefore;
private bool _bStorageRationaleAfter;
private const int ANDROID_PERMISSION_REQUEST_CODE__SDCARD = 2;
//private const int ANDROID_PERMISSION_REQUEST_CODE__CAMERA = 1;
private const int ANDROID_PERMISSION_REQUEST_CODE__NONE = 0;
public override void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Permission[] grantResults)
{
base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
switch (requestCode)
{
case ANDROID_PERMISSION_REQUEST_CODE__SDCARD:
_bStorageRationaleAfter = ShouldShowRequestPermissionRationale(Android.Manifest.Permission.WriteExternalStorage);
bool bStorage = grantResults[0] == Permission.Granted;
bool bNeverAskForStorage =
!bStorage && (
_bStorageRationaleBefore == true && _bStorageRationaleAfter == false ||
_bStorageRationaleBefore == false && _bStorageRationaleAfter == false
);
break;
}
}
private List<string> GetRequiredPermissions(out int requestCode)
{
// Android v6 requires explicit permission granting from user at runtime for security reasons
requestCode = ANDROID_PERMISSION_REQUEST_CODE__NONE; // 0
List<string> requiredPermissions = new List<string>();
_bStorageRationaleBefore = ShouldShowRequestPermissionRationale(Android.Manifest.Permission.WriteExternalStorage);
Permission writeExternalStoragePerm = ApplicationContext.CheckSelfPermission(Android.Manifest.Permission.WriteExternalStorage);
//if(extStoragePerm == Permission.Denied)
if (writeExternalStoragePerm != Permission.Granted)
{
requestCode |= ANDROID_PERMISSION_REQUEST_CODE__SDCARD;
requiredPermissions.Add(Android.Manifest.Permission.WriteExternalStorage);
}
return requiredPermissions;
}
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
// Android v6 requires explicit permission granting from user at runtime for security reasons
int requestCode;
List<string> requiredPermissions = GetRequiredPermissions(out requestCode);
if (requiredPermissions != null && requiredPermissions.Count > 0)
{
if (requestCode >= ANDROID_PERMISSION_REQUEST_CODE__SDCARD)
{
_savedInstanceState = savedInstanceState;
RequestPermissions(requiredPermissions.ToArray(), requestCode);
return;
}
}
}
OnCreate2(savedInstanceState);
}
其他回答
扩展上面mVck的答案，下面的逻辑确定是否“Never ask again”已经为给定的权限请求进行了检查:
bool bStorage = grantResults[0] == Permission.Granted;
bool bNeverAskForStorage =
!bStorage && (
_bStorageRationaleBefore == true && _bStorageRationaleAfter == false ||
_bStorageRationaleBefore == false && _bStorageRationaleAfter == false
);
摘自下面(完整的例子见这个答案)
private bool _bStorageRationaleBefore;
private bool _bStorageRationaleAfter;
private const int ANDROID_PERMISSION_REQUEST_CODE__SDCARD = 2;
//private const int ANDROID_PERMISSION_REQUEST_CODE__CAMERA = 1;
private const int ANDROID_PERMISSION_REQUEST_CODE__NONE = 0;
public override void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Permission[] grantResults)
{
base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
switch (requestCode)
{
case ANDROID_PERMISSION_REQUEST_CODE__SDCARD:
_bStorageRationaleAfter = ShouldShowRequestPermissionRationale(Android.Manifest.Permission.WriteExternalStorage);
bool bStorage = grantResults[0] == Permission.Granted;
bool bNeverAskForStorage =
!bStorage && (
_bStorageRationaleBefore == true && _bStorageRationaleAfter == false ||
_bStorageRationaleBefore == false && _bStorageRationaleAfter == false
);
break;
}
}
private List<string> GetRequiredPermissions(out int requestCode)
{
// Android v6 requires explicit permission granting from user at runtime for security reasons
requestCode = ANDROID_PERMISSION_REQUEST_CODE__NONE; // 0
List<string> requiredPermissions = new List<string>();
_bStorageRationaleBefore = ShouldShowRequestPermissionRationale(Android.Manifest.Permission.WriteExternalStorage);
Permission writeExternalStoragePerm = ApplicationContext.CheckSelfPermission(Android.Manifest.Permission.WriteExternalStorage);
//if(extStoragePerm == Permission.Denied)
if (writeExternalStoragePerm != Permission.Granted)
{
requestCode |= ANDROID_PERMISSION_REQUEST_CODE__SDCARD;
requiredPermissions.Add(Android.Manifest.Permission.WriteExternalStorage);
}
return requiredPermissions;
}
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
// Android v6 requires explicit permission granting from user at runtime for security reasons
int requestCode;
List<string> requiredPermissions = GetRequiredPermissions(out requestCode);
if (requiredPermissions != null && requiredPermissions.Count > 0)
{
if (requestCode >= ANDROID_PERMISSION_REQUEST_CODE__SDCARD)
{
_savedInstanceState = savedInstanceState;
RequestPermissions(requiredPermissions.ToArray(), requestCode);
return;
}
}
}
OnCreate2(savedInstanceState);
}
这个示例演示了当用户选择“拒绝&不要再次询问”时如何处理
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
registerStoragePermission()
registerGalleryLauncher()
registerCameraPermission()
registerCameraLauncher()
}
private fun registerCameraPermission() {
requestCameraPermissionLauncher =
registerForActivityResult(ActivityResultContracts.RequestPermission()) { granted ->
if (granted) {
Log.d(TAG, "registerCameraPermission - Camera Permission Granted")
openCamera()
} else {
Log.d(TAG, "registerCameraPermission - Camera Permission NOT Granted")
requestCameraPermission()
}
}
}
private fun registerStoragePermission() {
requestStoragePermissionLauncher =
registerForActivityResult(ActivityResultContracts.RequestPermission()) { granted ->
if (granted) {
Log.d(TAG, "registerStoragePermission - Storage Permission Granted")
viewGallery()
} else {
Log.d(TAG, "registerStoragePermission - Storage Permission NOT Granted")
requestStoragePermission()
}
}
}
private fun registerCameraLauncher() {
cameraLauncher =
registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
if (result.resultCode == Activity.RESULT_OK) {
val data: Intent? = result.data
if (data == null) {
return@registerForActivityResult
}
val extras = data.extras
imageBitmap = extras!!["data"] as Bitmap
file = FileUtils.createFile(requireContext(),
getString(R.string.app_name),
"my_profile_image.png"
)
//FileUtils.saveBitmap(imageBitmap, file);
val imageLocalPath = FileUtils.saveImageToInternalStorage(file, imageBitmap)
SharedPreferencesUtils.setProfilePath(requireActivity(), imageLocalPath)
profileFragmentBinding.imageViewCircleNoStroke.setImageBitmap(imageBitmap)
profileFragmentBinding.imageViewCircleNoStroke.setScaleType(ImageView.ScaleType.CENTER_CROP)
}
}
}
private fun registerGalleryLauncher() {
galleryLauncher =
registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
if (result.resultCode == Activity.RESULT_OK) {
val data: Intent? = result.data
if (data == null) {
return@registerForActivityResult
}
val uri = data.data
var imageLocalPath = File(FileUtils.getPathReal(requireActivity(), uri!!))
file = imageLocalPath.absoluteFile
SharedPreferencesUtils.setProfilePath(requireActivity(), imageLocalPath.absolutePath)
Glide.with(requireActivity()).load(uri)
.into(profileFragmentBinding.imageViewCircleNoStroke)
profileFragmentBinding.imageViewCircleNoStroke.setScaleType(ImageView.ScaleType.CENTER_CROP)
}
}
}
private fun showImageUploadOptions() {
val mDialog = activity.let { Dialog(it!!) }
mDialog.requestWindowFeature(Window.FEATURE_NO_TITLE)
mDialog.setContentView(R.layout.dialog_profile_image_option)
mDialog.window!!.setBackgroundDrawable(ColorDrawable(Color.TRANSPARENT))
//val mAlertMessageTv = mDialog.findViewById<View>(R.id.id_alert_tv) as TextView
//mAlertMessageTv.text = message
galleryLl = mDialog.findViewById<View>(R.id.id_gallery_ll) as LinearLayout
cameraLl = mDialog.findViewById<View>(R.id.id_camera_ll) as LinearLayout
removePhotoLl = mDialog.findViewById<View>(R.id.id_remove_photo_ll) as LinearLayout
galleryLl.setOnClickListener {
CallStoragePermission()
mDialog.dismiss()
}
cameraLl.setOnClickListener {
CallCameraPermission()
mDialog.dismiss()
}
removePhotoLl.setOnClickListener {
CallRemovePhoto()
mDialog.dismiss()
}
mDialog.setCancelable(true)
mDialog.show()
val metrics = resources.displayMetrics
val width = metrics.widthPixels
val height = metrics.heightPixels
mDialog.window!!.setLayout(
width,
LinearLayout.LayoutParams.WRAP_CONTENT
)
}
fun CallStoragePermission() {
if (!Status_checkReadExternalStoragePermission()) {
requestStoragePermissionLauncher.launch(Manifest.permission.READ_EXTERNAL_STORAGE)
} else {
viewGallery()
}
}
private fun Status_checkReadExternalStoragePermission(): Boolean {
val permissionState = ActivityCompat.checkSelfPermission(
requireActivity(),
Manifest.permission.READ_EXTERNAL_STORAGE
)
return permissionState == PackageManager.PERMISSION_GRANTED
}
private fun requestCameraPermission() {
when {
ContextCompat.checkSelfPermission(
requireContext(),
Manifest.permission.CAMERA
) == PackageManager.PERMISSION_GRANTED -> {
Log.d(TAG, "requestCameraPermission - Camera Permission Granted")
openCamera()
// The permission is granted
// you can go with the flow that requires permission here
}
shouldShowRequestPermissionRationale(Manifest.permission.CAMERA) -> {
// This case means user previously denied the permission
// So here we can display an explanation to the user
// That why exactly we need this permission
Log.d(TAG, "requestCameraPermission - Camera Permission NOT Granted")
showPermissionAlert(
getString(R.string.camera_permission),
getString(R.string.camera_permission_denied),
getString(R.string.ok_caps),
getString(R.string.cancel_caps)
) { requestCameraPermissionLauncher.launch(Manifest.permission.CAMERA) }
}
else -> {
// Everything is fine you can simply request the permission
showPermissionAlert(
getString(R.string.camera_permission),
getString(R.string.camera_permission_denied),
getString(R.string.settings_caps),
getString(R.string.cancel_caps)
) {
val intent = Intent()
intent.action = Settings.ACTION_APPLICATION_DETAILS_SETTINGS
val uri = Uri.fromParts(
"package",
BuildConfig.APPLICATION_ID, null
)
intent.data = uri
intent.flags = Intent.FLAG_ACTIVITY_NEW_TASK
startActivity(intent)
}
}
}
}
private fun requestStoragePermission() {
when {
ContextCompat.checkSelfPermission(
requireContext(),
Manifest.permission.READ_EXTERNAL_STORAGE
) == PackageManager.PERMISSION_GRANTED -> {
Log.d(TAG, "requestStoragePermission - Storage Permission Granted")
viewGallery()
// The permission is granted
// you can go with the flow that requires permission here
}
shouldShowRequestPermissionRationale(Manifest.permission.READ_EXTERNAL_STORAGE) -> {
// This case means user previously denied the permission
// So here we can display an explanation to the user
// That why exactly we need this permission
Log.d(TAG, "requestStoragePermission - Storage Permission NOT Granted")
showPermissionAlert(
getString(R.string.read_storage_permission_required),
getString(R.string.storage_permission_denied),
getString(R.string.ok_caps),
getString(R.string.cancel_caps)
) { requestStoragePermissionLauncher.launch(Manifest.permission.READ_EXTERNAL_STORAGE) }
}
else -> {
// Everything is fine you can simply request the permission
showPermissionAlert(
getString(R.string.read_storage_permission_required),
getString(R.string.storage_permission_denied),
getString(R.string.settings_caps),
getString(R.string.cancel_caps)
) {
val intent = Intent()
intent.action = Settings.ACTION_APPLICATION_DETAILS_SETTINGS
val uri = Uri.fromParts(
"package",
BuildConfig.APPLICATION_ID, null
)
intent.data = uri
intent.flags = Intent.FLAG_ACTIVITY_NEW_TASK
startActivity(intent)
}
}
}
}
private fun showPermissionAlert(
title: String,
message: String,
ok: String,
cancel: String,
function: () -> Unit
) {
val mDialog = requireActivity().let { Dialog(it) }
mDialog.requestWindowFeature(Window.FEATURE_NO_TITLE)
mDialog.setContentView(R.layout.dialog_permission_alert)
mDialog.window!!.setBackgroundDrawable(ColorDrawable(Color.TRANSPARENT))
val mTitleTv = mDialog.findViewById<View>(R.id.id_title_tv) as AppCompatTextView
mTitleTv.text = title
val mMessageTv = mDialog.findViewById<View>(R.id.id_message_tv) as AppCompatTextView
mMessageTv.text = message
val mNoBtn = mDialog.findViewById<View>(R.id.no_btn) as AppCompatTextView
mNoBtn.text = cancel
val mYesBtn = mDialog.findViewById<View>(R.id.yes_btn) as AppCompatTextView
mYesBtn.text = ok
mYesBtn.setOnClickListener {
function.invoke()
mDialog.dismiss()
}
mNoBtn.setOnClickListener { mDialog.dismiss() }
mDialog.setCancelable(true)
mDialog.show()
val metrics = resources.displayMetrics
val width = metrics.widthPixels
val height = metrics.heightPixels
mDialog.window!!.setLayout(
width,
LinearLayout.LayoutParams.WRAP_CONTENT
)
}
fun viewGallery() {
val intentDocument = Intent(Intent.ACTION_GET_CONTENT)
intentDocument.type = "image/*"
intentDocument.putExtra(
Constants.REQUEST_CODE,
Constants.REQUEST_PHOTO_FROM_GALLERY
)
galleryLauncher.launch(intentDocument)
}
fun openCamera() {
val takePictureIntent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
takePictureIntent.putExtra(
Constants.REQUEST_CODE,
Constants.REQUEST_PERMISSIONS_REQUEST_CODE_CAMERA
)
cameraLauncher.launch(takePictureIntent)
}
fun CallCameraPermission() {
if (!Status_checkCameraPermission()) {
requestCameraPermissionLauncher.launch(Manifest.permission.CAMERA)
} else {
openCamera()
}
}
private fun Status_checkCameraPermission(): Boolean {
val camera = ActivityCompat.checkSelfPermission(
requireActivity(),
Manifest.permission.CAMERA
)
return camera == PackageManager.PERMISSION_GRANTED
}
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()
}
}
}
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)
}
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();
}
}
}
}
