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。
OnRequestPermissionResult-free和shouldshowrequestpermissionrationalfree方法:
public static void requestDangerousPermission(AppCompatActivity activity, String permission) {
if (hasPermission(activity, permission)) return;
requestPermission();
new Handler().postDelayed(() -> {
if (activity.getLifecycle().getCurrentState() == Lifecycle.State.RESUMED) {
Intent intent = new Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
intent.setData(Uri.parse("package:" + context.getPackageName()));
context.startActivity(intent);
}
}, 250);
}
如果没有权限弹出,250ms后打开设备设置(如果选择了“Never ask again”,就是这种情况)。
如果你想检测所有的“状态”(第一次被拒绝,刚刚被拒绝,刚刚被“Never Ask Again”拒绝或永久拒绝),你可以做以下事情:
创建2个布尔值:
private boolean beforeClickPermissionRat;
private boolean afterClickPermissionRat;
在请求允许之前设置第一个:
beforeClickPermissionRat = shouldShowRequestPermissionRationale(Manifest.permission.READ_EXTERNAL_STORAGE);
在你的onRequestPermissionsResult方法中设置第二个:
afterClickPermissionRat = shouldShowRequestPermissionRationale(Manifest.permission.READ_EXTERNAL_STORAGE);
使用下面的“真值表”在onRequestPermissionsResult()中做任何你需要的事情(在检查你仍然没有权限之后):
// before after
// FALSE FALSE = Was denied permanently, still denied permanently --> App Settings
// FALSE TRUE = First time deny, not denied permanently yet --> Nothing
// TRUE FALSE = Just been permanently denied --> Changing my caption to "Go to app settings to edit permissions"
// TRUE TRUE = Wasn't denied permanently, still not denied permanently --> Nothing
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。