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。
我在Android m中写了一个权限请求的简写,这段代码还处理了对旧Android版本的向后兼容性。
所有丑陋的代码都被提取到一个片段中,该片段将自己附加到请求权限的活动上。PermissionRequestManager的使用方法如下:
new PermissionRequestManager()
// We need a AppCompatActivity here, if you are not using support libraries you will have to slightly change
// the PermissionReuqestManager class
.withActivity(this)
// List all permissions you need
.withPermissions(android.Manifest.permission.CALL_PHONE, android.Manifest.permission.READ_CALENDAR)
// This Runnable is called whenever the request was successfull
.withSuccessHandler(new Runnable() {
@Override
public void run() {
// Do something with your permissions!
// This is called after the user has granted all
// permissions, we are one a older platform where
// the user does not need to grant permissions
// manually, or all permissions are already granted
}
})
// Optional, called when the user did not grant all permissions
.withFailureHandler(new Runnable() {
@Override
public void run() {
// This is called if the user has rejected one or all of the requested permissions
L.e(this.getClass().getSimpleName(), "Unable to request permission");
}
})
// After calling this, the user is prompted to grant the rights
.request();
来看看:https://gist.github.com/crysxd/385b57d74045a8bd67c4110c34ab74aa
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()
}
}
}
一个有用的函数来确定任意权限是否被阻止请求(在Kotlin中):
private fun isPermissionBlockedFromAsking(activity: Activity, permission: String): Boolean {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
return ContextCompat.checkSelfPermission(activity, permission) != PackageManager.PERMISSION_GRANTED
&& !activity.shouldShowRequestPermissionRationale(permission)
&& PreferenceManager.getDefaultSharedPreferences(activity).getBoolean(permission, false)
}
return false
}
当你第一次请求一个权限时,需要设置一个共享首选项布尔值为true,其中包含你想要的权限名称(例如android.Manifest.permission.READ_PHONE_STATE)。
解释:
Build.VERSION。SDK_INT >= Build.VERSION_CODES。因为有些代码只能在API级别23+上运行。
ContextCompat。checkSelfPermission(activity, permission) != PackageManager。permission_granting检查我们还没有权限。
activity.shouldShowRequestPermissionRationale(permission)来检查用户是否再次拒绝了应用程序的请求。由于这个函数的特性,还需要下面这行代码。
PreferenceManager.getDefaultSharedPreferences(活动)。getBoolean(permission, false)用于区分“Never asked”和“Never ask again”状态(以及在第一次权限请求时将值设置为true),因为前一行不会返回此信息。
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)
}