Android:返回null的视图
我正在尝试获取联系人并将其显示在列表中。我正在使用RxPermissions。这里的问题是,当我第一次允许权限时,视图返回null并显示空列表,即使列表中有项目。但是,当我回到上一个活动并回来时,它工作得很好 ContactsFragment.ktAndroid:返回null的视图,android,android-fragments,kotlin,mvp,rxpermissions,Android,Android Fragments,Kotlin,Mvp,Rxpermissions,我正在尝试获取联系人并将其显示在列表中。我正在使用RxPermissions。这里的问题是,当我第一次允许权限时,视图返回null并显示空列表,即使列表中有项目。但是,当我回到上一个活动并回来时,它工作得很好 ContactsFragment.kt override fun onResume() { super.onResume() if (isPermissionGranted) { Timber.d("Permission is gra
override fun onResume() {
super.onResume()
if (isPermissionGranted) {
Timber.d("Permission is granted")
contactsPresenter.fetchContacts(context)
noPermissionsWarning.visibility = View.GONE
} else {
noPermissionsWarning.visibility = View.VISIBLE
showContactList(ArrayList()) // Show empty list when permissions not granted
}
}
private fun askPermissions() {
rxPermissions
.request(android.Manifest.permission.GET_ACCOUNTS,
android.Manifest.permission.READ_CONTACTS,
android.Manifest.permission.WRITE_CONTACTS)
.subscribe { permissionGranted ->
isPermissionGranted = permissionGranted
}
}
override fun showContactList(selectedContacts: ArrayList<Contact>) {
contactAdapter = ContactListAdapter(selectedContacts, this, context)
val layoutManager = LinearLayoutManager(this.context)
contactsRecyclerView?.layoutManager = layoutManager
contactsRecyclerView?.addItemDecoration(DividerItemDecoration(
contactsRecyclerView?.context,
DividerItemDecoration.VERTICAL
))
contactsRecyclerView?.adapter = contactAdapter
}
我会错过什么呢
谢谢你看来你应该在这一行之后马上取你的联系人:
isPermissionGranted = permissionGranted
我通过在
onResume()
和onViewCreated()
中附加视图解决了这个问题。谢谢大家的帮助
- 过了很长一段时间后,我发现我正在清除
上的一次性磁盘,在我的情况下,这应该在onPause()
onDestroy()中完成。我写了这个解决方案,以防对别人有所帮助
if (ContextCompat.checkSelfPermission(MainActivity.this,
Manifest.permission.WRITE_EXTERNAL_STORAGE) ==
PackageManager.PERMISSION_GRANTED) {
Filtering filtering=new Filtering();
//contactFetch method here
} else {
Permission.requestStoragePermission(MainActivity.this,
STORAGE_PERMISSION_CODE);
}
之后,当你请求许可时
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
if (requestCode == STORAGE_PERMISSION_CODE) {
if (grantResults.length > 0 && grantResults[0] ==
PackageManager.PERMISSION_GRANTED) {
Filtering filtering=new Filtering();
//Again your fetching method
} else {
Toast.makeText(this, "Permission DENIED", Toast.LENGTH_SHORT).show();
Permission.requestStoragePermission(MainActivity.this,
STORAGE_PERMISSION_CODE);
}
}
}
试试这个,我不确定,但我认为它会帮助你它一开始确实存在,但没有成功。我用java对此有一个答案,但问题是你必须在这两个地方调用contactFetching方法。。。。。1.当您检查是否已授予权限时,如果未授予调用该方法以获取权限的权限,并将您的获取方法放在此处,则可能您不了解这一点,因此请再次询问我,然后检查答案。。。。
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
if (requestCode == STORAGE_PERMISSION_CODE) {
if (grantResults.length > 0 && grantResults[0] ==
PackageManager.PERMISSION_GRANTED) {
Filtering filtering=new Filtering();
//Again your fetching method
} else {
Toast.makeText(this, "Permission DENIED", Toast.LENGTH_SHORT).show();
Permission.requestStoragePermission(MainActivity.this,
STORAGE_PERMISSION_CODE);
}
}
}