我对Android中的这个片段编码很新，所以我希望这是一个简单的回答。
我有一个TextView对象，＆＃39; next＆＃39;，点击后，似乎没有响应。单击TextView文本时，我想做一些事情。首先，检查eventName微调器中的String值，然后Toast the eventID值，最后为下一部分用户交互启动一个新片段。
我还没有实现新片段或对片段的调用。我假设调用新片段的方法是使用以下代码：
NextFragment nextFrag= new NextFragment();
getActivity().getSupportFragmentManager().beginTransaction()
.replace(R.id.Layout_container, nextFrag,"findThisFragment")
.addToBackStack(null)
.commit();
我的问题是：
为什么Toast没有显示？好像OnCickListener或OnClick方法似乎没有触发Toast。
上面的代码是否需要做的就是调用新的片段并在当前的Activity中激活它还是需要在Activity代码中添加其他东西？
片段代码：
import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
/**
* A simple {@link Fragment} subclass.
* Activities that contain this fragment must implement the
* {@link FindEventFragment.OnFragmentInteractionListener} interface
* to handle interaction events.
* Use the {@link FindEventFragment#newInstance} factory method to
* create an instance of this fragment.
*/
public class FindEventFragment extends Fragment{
public static final String TAG = "FindEventFragment";
private VolleyHelper mInstance;
private ArrayList<String> eventList = new ArrayList<String>();
private JSONArray result;
private Spinner eventNameSpinner;
private TextView eventDate;
private String eventID;
private TextView next;
//TextView errorText;
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
public FindEventFragment() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment FindEventFragment.
*/
// TODO: Rename and change types and number of parameters
public static FindEventFragment newInstance(String param1, String param2) {
FindEventFragment fragment = new FindEventFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
public void onStart() {
super.onStart();
// Instantiate the RequestQueue from VolleyHelper
mInstance = VolleyHelper.getInstance(getActivity().getApplicationContext());
// API
connectApi();
}
@Override
public void onStop () {
super.onStop();
if (mInstance.getRequestQueue() != null) {
mInstance.getRequestQueue().cancelAll(TAG);
}
}
private void connectApi() {
String url = "http://gblakes.ddns.net/get_events.php";
StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
new Response.Listener<String>() {
@Override
public void onResponse(String ServerResponse) {
JSONObject j = null;
try {
result = new JSONArray(ServerResponse);
eventDetails(result);
} catch (JSONException e) {
e.printStackTrace();
}
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError volleyError) {
Toast.makeText(getActivity().getApplicationContext(), "Oops, something went wrong", Toast.LENGTH_LONG).show();
}
});
if (mInstance != null) {
// Add a request to your RequestQueue.
mInstance.addToRequestQueue(stringRequest);
// Start the queue
mInstance.getRequestQueue().start();
}
}
private void eventDetails(JSONArray j) {
eventList.add("Choose an event");
for (int i = 0; i < j.length(); i++) {
try {
JSONObject json = j.getJSONObject(i);
// eventList.add(json.getString("EventName") + json.getString("EventDate"));
eventList.add(json.getString("EventName"));
} catch (JSONException e) {
//e.printStackTrace();
Log.d(TAG, e.toString());
}
}
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_spinner_item, eventList);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
eventNameSpinner.setAdapter(dataAdapter);
eventNameSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View v, int position, long id) {
//Setting the value to textview for a selected item
eventDate.setText(getEventDate(position));
eventID = (getEventID(position));
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
eventDate.setText("test me");
}
});
next.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//Make sure the user has made a valid selection
//errorText.setError("");
if (eventNameSpinner.equals("Choose an event")){
//errorText.setError("");
Toast.makeText(getActivity().getApplicationContext(),"Choose an event first",Toast.LENGTH_LONG);
//errorText.setText("Choose an event first");
} else {
//if an event is selected then open the next fragment
Toast.makeText(getActivity().getApplicationContext(),eventID.toString(),Toast.LENGTH_LONG);
}
}
});
}
private String getEventID(int position) {
String eventID = "";
try {
//Getting object of given index
JSONObject json = result.getJSONObject(position);
//Fetching name from that object
eventID = json.getString("EventID");
} catch (JSONException e) {
e.printStackTrace();
}
//Returning the name
return eventID;
}
private String getEventDate(int position){
String eventDate="";
try {
JSONObject json = result.getJSONObject(position);
eventDate = json.getString("EventDate");
} catch (JSONException e) {
e.printStackTrace();
}
return eventDate;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.fragment_find_event,container,false);
eventNameSpinner = (Spinner) v.findViewById(R.id.spinEventPicker);
//eventNameSpinner = new Spinner(getActivity().getApplicationContext());
eventDate = (TextView) v.findViewById(R.id.textEventDate);
next = (TextView) v.findViewById(R.id.link_judgeToEvent);
eventDate.setText("test me");
// errorText = (TextView)eventNameSpinner.getSelectedView();
return v;
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(eventID);
}
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(String eventID);
}
}
和片段的XML
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:id="@+id/textEventName">
<Spinner
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/spinEventPicker"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:gravity="center"
android:layout_alignParentStart="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Large Text"
android:id="@+id/textEventDate"
android:layout_marginTop="49dp"
android:layout_below="@+id/spinEventPicker"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<TextView
android:id="@+id/link_judgeToEvent"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="24dp"
android:layout_below="@+id/textEventDate"
android:gravity="center"
android:text="Next"
android:textAlignment="center"
android:textSize="16dip" />
</RelativeLayout>
答案 0 :(得分：0)
将显示Toast，所以你必须改变以下代码行
Toast.makeText(getActivity().getApplicationContext(),"Choose an event first",Toast.LENGTH_LONG).show();
您可以使用以下代码示例代码从另一个片段
启动片段 Fragment2 fragment2 = new Fragment2();
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.fragment1, fragment2);
fragmentTransaction.commit();