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
对每一种许可情况的完整解释
/**
* Case 1: User doesn't have permission
* Case 2: User has permission
*
* Case 3: User has never seen the permission Dialog
* Case 4: User has denied permission once but he din't clicked on "Never Show again" check box
* Case 5: User denied the permission and also clicked on the "Never Show again" check box.
* Case 6: User has allowed the permission
*
*/
public void handlePermission() {
if (ContextCompat.checkSelfPermission(MainActivity.this,
Manifest.permission.WRITE_EXTERNAL_STORAGE)
!= PackageManager.PERMISSION_GRANTED) {
// This is Case 1. Now we need to check further if permission was shown before or not
if (ActivityCompat.shouldShowRequestPermissionRationale(MainActivity.this,
Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
// This is Case 4.
} else {
// This is Case 3. Request for permission here
}
} else {
// This is Case 2. You have permission now you can do anything related to it
}
}
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// This is Case 2 (Permission is now granted)
} else {
// This is Case 1 again as Permission is not granted by user
//Now further we check if used denied permanently or not
if (ActivityCompat.shouldShowRequestPermissionRationale(MainActivity.this,
Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
// case 4 User has denied permission but not permanently
} else {
// case 5. Permission denied permanently.
// You can open Permission setting's page from here now.
}
}
}
其他回答
你可以在onRequestPermissionsResult()中检查shouldShowRequestPermissionRationale()。
https://youtu.be/C8lUdPVSzDk?t=2m23s
在onRequestPermissionsResult()中检查权限是否被授予。如果不是，检查shouldShowRequestPermissionRationale()。
如果此方法返回true，则说明为什么需要此特定权限。然后根据用户的选择再次请求permissions()。 如果它返回false，则显示一个错误消息，权限未授予，应用程序不能继续前进或特定功能被禁用。
下面是示例代码。
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
switch (requestCode) {
case STORAGE_PERMISSION_REQUEST:
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// permission was granted :)
downloadFile();
} else {
// permission was not granted
if (getActivity() == null) {
return;
}
if (ActivityCompat.shouldShowRequestPermissionRationale(getActivity(), Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
showStoragePermissionRationale();
} else {
Snackbar snackbar = Snackbar.make(getView(), getResources().getString(R.string.message_no_storage_permission_snackbar), Snackbar.LENGTH_LONG);
snackbar.setAction(getResources().getString(R.string.settings), new View.OnClickListener() {
@Override
public void onClick(View v) {
if (getActivity() == null) {
return;
}
Intent intent = new Intent();
intent.setAction(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
Uri uri = Uri.fromParts("package", getActivity().getPackageName(), null);
intent.setData(uri);
OrderDetailFragment.this.startActivity(intent);
}
});
snackbar.show();
}
}
break;
}
}
显然，谷歌maps对位置许可正是这样做的。
shouldShowRequestPermissionRationale()方法可以用来检查用户是否选择了“never asked again”选项并拒绝了权限。 有很多代码示例，所以我宁愿解释如何将它用于这样的目的，因为我认为它的名称和实现使它比实际情况更加复杂。
正如在运行时请求权限中解释的那样，如果选项“never ask again”可见，该方法返回true，否则返回false;因此，它在第一次显示对话框时返回false，然后从第二次开始返回true，只有当用户拒绝选择该选项的权限时，它才会再次返回false。
要检测这种情况，您可以检测序列false-true-false，或者(更简单)您可以使用一个标记来跟踪对话框显示的初始时间。在此之后，该方法返回true或false，其中false将允许您检测何时选择该选项。
试试这个简单的权限库。它将在3个简单的步骤中处理与权限相关的所有操作。这节省了我的时间。您可以在15分钟内完成所有权限相关的工作。
它可以处理拒绝，它可以处理永不再请求，它可以调用应用程序设置的权限，它可以给出一个Rational消息，它可以给出一个拒绝消息，它可以给出一个接受的权限列表，它可以给出一个拒绝的权限列表，等等。
https://github.com/ParkSangGwon/TedPermission
步骤1:添加依赖项
dependencies {
compile 'gun0912.ted:tedpermission:2.1.1'
//check the above link for latest libraries
}
步骤2:征求许可
TedPermission.with(this)
.setPermissionListener(permissionlistener)
.setDeniedMessage("If you reject permission,you can not use this service\n\nPlease turn on permissions at [Setting] > [Permission]")
.setPermissions(Manifest.permission.READ_CONTACTS, Manifest.permission.ACCESS_FINE_LOCATION)
.check();
步骤3:处理权限响应
PermissionListener permissionlistener = new PermissionListener() {
@Override
public void onPermissionGranted() {
Toast.makeText(MainActivity.this, "Permission Granted", Toast.LENGTH_SHORT).show();
}
@Override
public void onPermissionDenied(ArrayList<String> deniedPermissions) {
Toast.makeText(MainActivity.this, "Permission Denied\n" + deniedPermissions.toString(), Toast.LENGTH_SHORT).show();
}
};
对每一种许可情况的完整解释
/**
* Case 1: User doesn't have permission
* Case 2: User has permission
*
* Case 3: User has never seen the permission Dialog
* Case 4: User has denied permission once but he din't clicked on "Never Show again" check box
* Case 5: User denied the permission and also clicked on the "Never Show again" check box.
* Case 6: User has allowed the permission
*
*/
public void handlePermission() {
if (ContextCompat.checkSelfPermission(MainActivity.this,
Manifest.permission.WRITE_EXTERNAL_STORAGE)
!= PackageManager.PERMISSION_GRANTED) {
// This is Case 1. Now we need to check further if permission was shown before or not
if (ActivityCompat.shouldShowRequestPermissionRationale(MainActivity.this,
Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
// This is Case 4.
} else {
// This is Case 3. Request for permission here
}
} else {
// This is Case 2. You have permission now you can do anything related to it
}
}
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// This is Case 2 (Permission is now granted)
} else {
// This is Case 1 again as Permission is not granted by user
//Now further we check if used denied permanently or not
if (ActivityCompat.shouldShowRequestPermissionRationale(MainActivity.this,
Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
// case 4 User has denied permission but not permanently
} else {
// case 5. Permission denied permanently.
// You can open Permission setting's page from here now.
}
}
}
一旦用户标记了“不要再问”，该问题就不能再次显示。 但是可以向用户解释，他之前拒绝了权限，必须在设置中授予权限。并参考他的设置，使用以下代码:
@Override
public void onRequestPermissionsResult(int permsRequestCode, String[] permissions, int[] grantResults) {
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// now, you have permission go ahead
// TODO: something
} else {
if (ActivityCompat.shouldShowRequestPermissionRationale(MainActivity.this,
Manifest.permission.READ_CALL_LOG)) {
// now, user has denied permission (but not permanently!)
} else {
// now, user has denied permission permanently!
Snackbar snackbar = Snackbar.make(findViewById(android.R.id.content), "You have previously declined this permission.\n" +
"You must approve this permission in \"Permissions\" in the app settings on your device.", Snackbar.LENGTH_LONG).setAction("Settings", new View.OnClickListener() {
@Override
public void onClick(View view) {
startActivity(new Intent(android.provider.Settings.ACTION_APPLICATION_DETAILS_SETTINGS, Uri.parse("package:" + BuildConfig.APPLICATION_ID)));
}
});
View snackbarView = snackbar.getView();
TextView textView = (TextView) snackbarView.findViewById(android.support.design.R.id.snackbar_text);
textView.setMaxLines(5); //Or as much as you need
snackbar.show();
}
}
return;
}
