我正在使用一个片段来显示我发现的所有同伴，它成功地到达片段但在尝试显示对等体时崩溃。
片段
public class peerItemFragment extends ListFragment {
private List<WifiP2pDevice> peers = new ArrayList<>();
ProgressDialog progressDialog = null;
View mContentView = null;
private WifiP2pDevice device;
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
this.setListAdapter(new WiFiPeerListAdapter(getActivity(), R.layout.row_devices, peers));
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
mContentView = inflater.inflate(R.layout.fragment_item_grid, null);
return mContentView;
}
/**
* @return this device
*/
public WifiP2pDevice getDevice() {
return device;
}
private static String getDeviceStatus(int deviceStatus) {
Log.d(sendActivity.TAG, "Peer status :" + deviceStatus);
switch (deviceStatus) {
case WifiP2pDevice.AVAILABLE:
return "Available";
case WifiP2pDevice.INVITED:
return "Invited";
case WifiP2pDevice.CONNECTED:
return "Connected";
case WifiP2pDevice.FAILED:
return "Failed";
case WifiP2pDevice.UNAVAILABLE:
return "Unavailable";
default:
return "Unknown";
}
}
/**
* Initiate a connection with the peer.
*/
@Override
public void onListItemClick(ListView l, View v, int position, long id) {
WifiP2pDevice device = (WifiP2pDevice) getListAdapter().getItem(position);
((DeviceActionListener) getActivity()).showDetails(device);
}
/**
* Array adapter for ListFragment that maintains WifiP2pDevice list.
*/
private class WiFiPeerListAdapter extends ArrayAdapter<WifiP2pDevice> {
private List<WifiP2pDevice> items;
/**
* @param context
* @param textViewResourceId
* @param objects
*/
public WiFiPeerListAdapter(Context context, int textViewResourceId,
List<WifiP2pDevice> objects) {
super(context, textViewResourceId, objects);
items = objects;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if (v == null) {
LayoutInflater vi = (LayoutInflater) getActivity().getSystemService(
Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.row_devices, parent, false);
}
WifiP2pDevice device = items.get(position);
if (device != null) {
TextView top = (TextView) v.findViewById(R.id.device_name);
TextView bottom = (TextView) v.findViewById(R.id.device_details);
if (top != null) {
top.setText(device.deviceName);
}
if (bottom != null) {
bottom.setText(getDeviceStatus(device.status));
}
}
return v;
}
}
/**
* Update UI for this device.
*
* @param device WifiP2pDevice object
*/
public void updateThisDevice(WifiP2pDevice device) {
this.device = device;
TextView view = (TextView) mContentView.findViewById(R.id.tvMyName);
view.setText(device.deviceName);
view = (TextView) mContentView.findViewById(R.id.tvMyStatus);
view.setText(getDeviceStatus(device.status));
}
public void addPeers(WifiP2pDeviceList peerList) {
if (progressDialog != null && progressDialog.isShowing()) {
progressDialog.dismiss();
}
peers.clear();
peers.addAll(peerList.getDeviceList());
((WiFiPeerListAdapter) getListAdapter()).notifyDataSetChanged();
if (peers.size() == 0) {
Log.d(sendActivity.TAG, "No devices found");
return;
}
}
public void clearPeers() {
peers.clear();
((WiFiPeerListAdapter) getListAdapter()).notifyDataSetChanged();
}
问题atm是当我从主类调用时使用以下代码调用它...
peerItemFragment peerFragment = new peerItemFragment();
FragmentManager managerAuthenticate = getFragmentManager();
FragmentTransaction transactionAuthen = managerAuthenticate.beginTransaction();
// Replace whatever is in the fragment_container view with this fragment,
// and add the transaction to the back stack so the user can navigate back
transactionAuthen.replace(R.id.fragment_container, peerFragment);
transactionAuthen.addToBackStack(null);
//***************************************************
Bundle bundle = new Bundle();
bundle.putParcelableArrayList("list", mService.peerList);
peerFragment.setArguments(bundle);
// Commit the transaction
transactionAuthen.commit();
一步一步地查看并运行它，我发现它出现以下问题？
((WiFiPeerListAdapter) getListAdapter()).notifyDataSetChanged();
真的很奇怪，因为这一切都来自谷歌样本，不知道为什么它会崩溃..
请注意，该片段有一个listView命名列表，如谷歌建议的那样（没有问题）。
发现很难看出它出了什么问题？可能是适配器不存在吗？
编辑------------------------------------------- ---------------------------
调用活动中的片段
peerItemFragment peerFragment = new peerItemFragment();
FragmentManager managerAuthenticate = getFragmentManager();
Bundle bundle = new Bundle();
ArrayList<WifiP2pDevice> list = new ArrayList<>(mService.peerList.getDeviceList());
bundle.putParcelableArrayList("list", list);
peerFragment.setArguments(bundle);
FragmentTransaction transactionAuthen = managerAuthenticate.beginTransaction();
// Replace whatever is in the fragment_container view with this fragment,
// and add the transaction to the back stack so the user can navigate back
transactionAuthen.replace(R.id.fragment_container, peerFragment);
transactionAuthen.addToBackStack(null);
// Commit the transaction
transactionAuthen.commit();
//pass peer list to fragment to display
//peerFragment.addPeers(mService.peerList);
}
编辑后的碎片
public class peerItemFragment extends ListFragment {
private List<WifiP2pDevice> peers = new ArrayList<>();
ProgressDialog progressDialog = null;
View mContentView = null;
private WifiP2pDevice device;
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
this.setListAdapter(new WiFiPeerListAdapter(getActivity(), R.layout.row_devices, peers));
Bundle bundle = getArguments();
peers = bundle.getParcelableArrayList("list");
((WiFiPeerListAdapter) getListAdapter()).notifyDataSetChanged();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
mContentView = inflater.inflate(R.layout.fragment_item_grid, null);
return mContentView;
}
/**
* @return this device
*/
public WifiP2pDevice getDevice() {
return device;
}
private static String getDeviceStatus(int deviceStatus) {
Log.d(sendActivity.TAG, "Peer status :" + deviceStatus);
switch (deviceStatus) {
case WifiP2pDevice.AVAILABLE:
return "Available";
case WifiP2pDevice.INVITED:
return "Invited";
case WifiP2pDevice.CONNECTED:
return "Connected";
case WifiP2pDevice.FAILED:
return "Failed";
case WifiP2pDevice.UNAVAILABLE:
return "Unavailable";
default:
return "Unknown";
}
}
/**
* Initiate a connection with the peer.
*/
@Override
public void onListItemClick(ListView l, View v, int position, long id) {
WifiP2pDevice device = (WifiP2pDevice) getListAdapter().getItem(position);
((DeviceActionListener) getActivity()).showDetails(device);
}
/**
* Array adapter for ListFragment that maintains WifiP2pDevice list.
*/
private class WiFiPeerListAdapter extends ArrayAdapter<WifiP2pDevice> {
private List<WifiP2pDevice> items;
/**
* @param context
* @param textViewResourceId
* @param objects
*/
public WiFiPeerListAdapter(Context context, int textViewResourceId,
List<WifiP2pDevice> objects) {
super(context, textViewResourceId, objects);
items = objects;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if (v == null) {
LayoutInflater vi = (LayoutInflater) getActivity().getSystemService(
Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.row_devices, parent, false);
}
WifiP2pDevice device = items.get(position);
if (device != null) {
TextView top = (TextView) v.findViewById(R.id.device_name);
TextView bottom = (TextView) v.findViewById(R.id.device_details);
if (top != null) {
top.setText(device.deviceName);
}
if (bottom != null) {
bottom.setText(getDeviceStatus(device.status));
}
}
return v;
}
}
答案 0 :(得分：1)
代码的问题在于，当您调用addPears时，onActivityCreated尚未调用（事务未以同步方式执行），导致getListAdapter返回{ {1}}。要解决此问题，您可以在null，（peerList为bundle）中添加WifiP2pDevice，并为parcelable设置arguments Fragment 1}}
Bundle bundle = new Bundle();
ArrayList<WifiP2pDevice> list = new ArrayList<>(mService.peerList.getDeviceList());
bundle.putParcelableArrayList("list", list);
peerFragmet.setArguments(bundle);
并摆脱
peerFragment.addPeers(mService.peerList);
当调用onActivityCreated时，您可以使用getArguments读回包，检索您的peerList对象并实例化您的adpater
答案 1 :(得分：0)
你的catlog说：
at com.haswell.phoneduplicator.peerItemFragment.addPeers(peerItemFragment.java:137)
该行的内容是什么？