java - 如何使用 arraylist 制作可扩展列表？

Question

我需要制作一个可扩展的 ListView ，但对于父级我必须传递 arraylist 并且我在 getGroupView 中遇到类转换异常。请帮助我编写以下适配器:

PhraseModel.java:

package in.abc.pdfsearchapp;

import android.os.Parcel;
import android.os.Parcelable;
import java.util.ArrayList;

public class PhraseModel implements Parcelable {

    private ArrayList<PhraseList> phraseList;

    // constructor

    public PhraseModel(ArrayList<PhraseList> phraseList) {
        this.phraseList = phraseList;
    }

    //---------------------------Getter-Setter--------------------------------------------------------------------------------
    public ArrayList<PhraseList> getPhraseList() {
        return phraseList;
    }

    public void setPhraseList(ArrayList<PhraseList> phraseList) {
        this.phraseList = phraseList;
    }

    // Parcelling

    protected PhraseModel(Parcel in) {
        phraseList=in.createTypedArrayList(PhraseList.CREATOR);
    }

    public static final Creator<PhraseModel> CREATOR = new Creator<PhraseModel>() {
        @Override
        public PhraseModel createFromParcel(Parcel in) {
            return new PhraseModel(in);
        }

        @Override
        public PhraseModel[] newArray(int size) {
            return new PhraseModel[size];
        }
    };

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeTypedList(phraseList);
    }


    //-----------------------------------   //PhraseList // ------------------------------------------------------------------------

    public static class PhraseList implements Parcelable {

        public int documentId,noOfOccurences;
        public String documentName,phrase;
        public ArrayList<OccurenceDetails> occurenceDetails;

        //constructor

        public PhraseList(int documentId, String documentName,String phrase, int noOfOccurences,  ArrayList<OccurenceDetails> occurenceDetails) {
            this.documentId = documentId;
            this.documentName = documentName;
            this.phrase = phrase;
            this.noOfOccurences = noOfOccurences;
            this.occurenceDetails = occurenceDetails;
        }
        //------------------------------Getter-Setter--------------------------------------------------------------------------------------

        public int getDocumentId() {
            return documentId;
        }

        public void setDocumentId(int documentId) {
            this.documentId = documentId;
        }

        public int getNoOfOccurences() {
            return noOfOccurences;
        }

        public void setNoOfOccurences(int noOfOccurences) {
            this.noOfOccurences = noOfOccurences;
        }

        public String getDocumentName() {
            return documentName;
        }

        public void setDocumentName(String documentName) {
            this.documentName = documentName;
        }

        public String getPhrase() {
            return phrase;
        }

        public void setPhrase(String phrase) {
            this.phrase = phrase;
        }

        public ArrayList<OccurenceDetails> getOccurenceDetails() {
            return occurenceDetails;
        }

        public void setOccurenceDetails(ArrayList<OccurenceDetails> occurenceDetails) {
            this.occurenceDetails = occurenceDetails;
        }

        //Parcelling

        protected PhraseList(Parcel in) {
            documentId = in.readInt();
            noOfOccurences = in.readInt();
            documentName = in.readString();
            phrase = in.readString();
        }

        public static final Creator<PhraseList> CREATOR = new Creator<PhraseList>() {
            @Override
            public PhraseList createFromParcel(Parcel in) {
                return new PhraseList(in);
            }

            @Override
            public PhraseList[] newArray(int size) {
                return new PhraseList[size];
            }
        };

        @Override
        public int describeContents() {
            return 0;
        }

        @Override
        public void writeToParcel(Parcel dest, int flags) {
            dest.writeInt(documentId);
            dest.writeString(documentName);
            dest.writeInt(noOfOccurences);
            dest.writeString(phrase);
        }
    }


//---------------------------------    //OccurrenceDetails // --------------------------------------------------------------------

    public static class OccurenceDetails implements Parcelable {

        int occurenceId,pageNo;
        String fullPhrase;

        //constructor

        public OccurenceDetails(int occurenceId, int pageNo, String fullPhrase) {
            this.occurenceId = occurenceId;
            this.pageNo = pageNo;
            this.fullPhrase = fullPhrase;
        }
//-------------------------------Getter-Setter----------------------------------------------------------------------------------

        public int getOccurenceId() {
            return occurenceId;
        }

        public void setOccurenceId(int occurenceId) {
            this.occurenceId = occurenceId;
        }

        public int getPageNo() {
            return pageNo;
        }

        public void setPageNo(int pageNo) {
            this.pageNo = pageNo;
        }

        public String getFullPhrase() {
            return fullPhrase;
        }

        public void setFullPhrase(String fullPhrase) {
            this.fullPhrase = fullPhrase;
        }


        //Parcelling

        protected OccurenceDetails(Parcel in) {
            occurenceId = in.readInt();
            pageNo = in.readInt();
            fullPhrase = in.readString();
        }

        public static final Creator<OccurenceDetails> CREATOR = new Creator<OccurenceDetails>() {
            @Override
            public OccurenceDetails createFromParcel(Parcel in) {
                return new OccurenceDetails(in);
            }

            @Override
            public OccurenceDetails[] newArray(int size) {
                return new OccurenceDetails[size];
            }
        };

        @Override
        public int describeContents() {
            return 0;
        }

        @Override
        public void writeToParcel(Parcel dest, int flags) {
            dest.writeInt(occurenceId);
            dest.writeInt(pageNo);
            dest.writeString(fullPhrase);
        }
    }
}

ExpandableListAdapter.java:

package in.abc.pdfsearchapp;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.HashMap;

/**
 * Created by Android on 22-Nov-17.
 */

public class ExpandableListAdapter extends BaseExpandableListAdapter {

    Context context;
    public ArrayList<PhraseModel.PhraseList> mPhraseList;
    private HashMap<Integer,ArrayList<PhraseModel.OccurenceDetails>> occurenceList;

    public ExpandableListAdapter(Context context, ArrayList<PhraseModel.PhraseList> mPhraseList, HashMap<Integer, ArrayList<PhraseModel.OccurenceDetails>> occurenceList) {
        this.context = context;
        this.mPhraseList = mPhraseList;
        this.occurenceList = occurenceList;
    }

    public Object getChild(int groupPosition, int childPosition){
        return this.occurenceList.get(this.mPhraseList.get(groupPosition)).get(childPosition);
    }


    public long getChildId(int groupPosition, int childPosition) {
        return childPosition;
    }


    public View getChildView(int groupPosition, final int childPosition,
                        boolean isLastChild, View convertView, ViewGroup parent) {

        final ArrayList<PhraseModel.OccurenceDetails> childList = (ArrayList<PhraseModel.OccurenceDetails>) getChild(groupPosition, childPosition);
        if(convertView==null){
            LayoutInflater infalInflater = (LayoutInflater) this.context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = infalInflater.inflate(R.layout.list_item, null);
        }

        TextView occurenceId,fullPhrase,pageNo;
        occurenceId=(TextView)convertView.findViewById(R.id.occurenceId);
        fullPhrase=(TextView)convertView.findViewById(R.id.fullPhrase);
        pageNo=(TextView)convertView.findViewById(R.id.pageNo);

        occurenceId.setText(childList.get(groupPosition).getOccurenceId());
        fullPhrase.setText(childList.get(groupPosition).getFullPhrase());
        pageNo.setText(childList.get(groupPosition).getPageNo());

        return convertView;
    }

    public int getChildrenCount(int groupPosition) {
        return this.occurenceList.get(this.mPhraseList.get(groupPosition))
                .size();
    }

    public Object getGroup(int groupPosition) {
        return this.mPhraseList.get(groupPosition);
    }

    public int getGroupCount() {
        return this.mPhraseList.size();
    }

    public long getGroupId(int groupPosition) {
        return groupPosition;
    }

    public View getGroupView(int groupPosition, boolean isExpanded,
                             View convertView, ViewGroup parent) {
        ArrayList<PhraseModel.PhraseList> parentList = (ArrayList<PhraseModel.PhraseList>) getGroup(groupPosition);
        if (convertView == null) {
            LayoutInflater infalInflater = (LayoutInflater) this.context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = infalInflater.inflate(R.layout.list_group, null);
        }

        TextView docName,totalOccurences;
        docName=(TextView)convertView.findViewById(R.id.docName);
        totalOccurences=(TextView)convertView.findViewById(R.id.totalOccurences);
        docName.setText(parentList.get(groupPosition).getDocumentName());
        totalOccurences.setText(parentList.get(groupPosition).getNoOfOccurences());
        return convertView;
    }

    public boolean hasStableIds() {
        return false;
    }

    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }
}

LandingActivity.java:

    package in.abc.pdfsearchapp;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ExpandableListView;
import android.widget.Toast;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;

public class LandingActivity extends AppCompatActivity {

    ExpandableListAdapter listAdapter;
    ExpandableListView expListView;
    ArrayList<PhraseModel.PhraseList> phraseLists;
    HashMap<Integer, ArrayList<PhraseModel.OccurenceDetails>> occurenceList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_landing);

        expListView = (ExpandableListView) findViewById(R.id.phraseList);

        // preparing list data
        phraseLists=new ArrayList<PhraseModel.PhraseList>();
        occurenceList=new HashMap<Integer,ArrayList<PhraseModel.OccurenceDetails>>();
        phraseLists.addAll(getmphraseset());

        for (PhraseModel.PhraseList pl: phraseLists){
            ArrayList<PhraseModel.OccurenceDetails>occurenceDetailses=pl.getOccurenceDetails();
            occurenceList.put(pl.getDocumentId(),occurenceDetailses);
        }

        listAdapter = new ExpandableListAdapter(this, phraseLists,occurenceList);

        // setting list adapter
        expListView.setAdapter(listAdapter);

        // Listview Group click listener
        expListView.setOnGroupClickListener(new ExpandableListView.OnGroupClickListener() {

            @Override
            public boolean onGroupClick(ExpandableListView parent, View v,
                                        int groupPosition, long id) {
                // Toast.makeText(getApplicationContext(),
                // "Group Clicked " + listDataHeader.get(groupPosition),
                // Toast.LENGTH_SHORT).show();
                return false;
            }
        });

        // Listview Group expanded listener
        expListView.setOnGroupExpandListener(new ExpandableListView.OnGroupExpandListener() {

            @Override
            public void onGroupExpand(int groupPosition) {
                Toast.makeText(getApplicationContext(),
                        phraseLists.get(groupPosition) + " Expanded",
                        Toast.LENGTH_SHORT).show();
            }
        });

        // Listview Group collasped listener
        expListView.setOnGroupCollapseListener(new ExpandableListView.OnGroupCollapseListener() {

            @Override
            public void onGroupCollapse(int groupPosition) {
                Toast.makeText(getApplicationContext(),
                        phraseLists.get(groupPosition) + " Collapsed",
                        Toast.LENGTH_SHORT).show();

            }
        });

        // Listview on child click listener
        expListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {

            @Override
            public boolean onChildClick(ExpandableListView parent, View v,
                                        int groupPosition, int childPosition, long id) {
                // TODO Auto-generated method stub
                Toast.makeText(
                        getApplicationContext(),
                        phraseLists.get(groupPosition)
                                + " : "
                                + occurenceList.get(
                                phraseLists.get(groupPosition)).get(
                                childPosition), Toast.LENGTH_SHORT)
                        .show();
                return false;
            }
        });

    }

    private ArrayList<PhraseModel.PhraseList> getmphraseset() {
        try{
            ArrayList<PhraseModel.PhraseList>phrase_Lists = new ArrayList<PhraseModel.PhraseList>();
            ArrayList<PhraseModel.OccurenceDetails>occurenceDetailsArrayList=new ArrayList<PhraseModel.OccurenceDetails>();
            JSONObject jsonObject = new JSONObject(readJSONFromAsset());

            JSONArray phraseArray = jsonObject.getJSONArray("phraseList");
            Log.d("getmphraseset", "phrase count: "+phraseArray.length());
            for (int i = 0; i < phraseArray.length(); i++)
            {
                JSONObject job = phraseArray.getJSONObject(i);

                int documentId =job.getInt("documentId");
                int noOfOccurences=job.getInt("noOfOccurences");

                String documentName=job.getString("documentName");
                String phrase=job.getString("phrase");

                //This i for Occurences array
                ArrayList<PhraseModel.OccurenceDetails> occurencesList = new ArrayList<>();
                JSONArray occurencesArray = job.getJSONArray("occurenceDetails");
                for (int j = 0; j < occurencesArray.length(); j++) {
                    JSONObject jobIn = occurencesArray.getJSONObject(j);

                    int occurenceId=jobIn.getInt("occurenceId");
                    int pageNo=jobIn.getInt("pageNo");
                    String fullPhrase=jobIn.getString("fullPhrase");

                    occurencesList.add(new PhraseModel.OccurenceDetails(occurenceId, pageNo, fullPhrase));

                }

                //here your Phrase[] value store in pdfArrayList
                phrase_Lists.add(new PhraseModel.PhraseList(documentId,documentName,phrase,noOfOccurences,occurencesList));

                Log.i("phraseList size = ", ""+phraseArray.length());
            }

            if (phrase_Lists != null)
            {
                Log.i("phraseList size = ", ""+phraseArray.length());
            }
            return phrase_Lists;
        }catch (JSONException e){
            e.printStackTrace();
            return null;
        }
    }

    @Override
    protected void onResume() {
        super.onResume();
    }

    public String readJSONFromAsset() {
        String json = null;
        try {
            InputStream is = getAssets().open("hipaJson.json");
            int size = is.available();
            byte[] buffer = new byte[size];
            is.read(buffer);
            is.close();
            json = new String(buffer, "UTF-8");
        } catch (IOException ex) {
            ex.printStackTrace();
            return null;
        }
        return json;
    }
}

Logcat:

11-23 15:52:06.428 1519-2794/? E/ActivityManager: applyOptionsLocked: Unknown animationType=0
11-23 15:52:06.428 459-2412/? E/ANDR-PERF-MPCTL: Invalid profile no. 0, total profiles 0 only
11-23 15:52:07.059 29210-29210/? E/HAL: PATH3 /odm/lib64/hw/gralloc.qcom.so
11-23 15:52:07.059 29210-29210/? E/HAL: PATH2 /vendor/lib64/hw/gralloc.qcom.so
11-23 15:52:07.059 29210-29210/? E/HAL: PATH1 /system/lib64/hw/gralloc.qcom.so
11-23 15:52:07.059 29210-29210/? E/HAL: PATH3 /odm/lib64/hw/gralloc.msm8953.so
11-23 15:52:07.059 29210-29210/? E/HAL: PATH2 /vendor/lib64/hw/gralloc.msm8953.so
11-23 15:52:07.059 29210-29210/? E/HAL: PATH1 /system/lib64/hw/gralloc.msm8953.so
11-23 15:52:11.066 459-2412/? E/ANDR-PERF-MPCTL: Invalid profile no. 0, total profiles 0 only
11-23 15:52:11.152 29210-29210/? E/AndroidRuntime: FATAL EXCEPTION: main
                                                   Process: in.hkcl.pdfsearchapp, PID: 29210
                                                   java.lang.ClassCastException: in.hkcl.pdfsearchapp.PhraseModel$PhraseList cannot be cast to java.util.ArrayList
                                                       at in.hkcl.pdfsearchapp.ExpandableListAdapter.getGroupView(ExpandableListAdapter.java:81)
                                                       at android.widget.ExpandableListConnector.getView(ExpandableListConnector.java:446)
                                                       at android.widget.AbsListView.obtainView(AbsListView.java:2367)
                                                       at android.widget.ListView.makeAndAddView(ListView.java:1972)
                                                       at android.widget.ListView.fillDown(ListView.java:704)
                                                       at android.widget.ListView.fillFromTop(ListView.java:765)
                                                       at android.widget.ListView.layoutChildren(ListView.java:1744)
                                                       at android.widget.AbsListView.onLayout(AbsListView.java:2161)
                                                       at android.view.View.layout(View.java:17548)
                                                       at android.view.ViewGroup.layout(ViewGroup.java:5614)

请解释并帮助，我做错了什么？该应用程序具有闪屏>landingActivity，其中包含可扩展列表，因为应用程序崩溃，在 getGroupView 方法中给出了类 cat 异常，因此我无法显示该列表。

list_group.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:app="http://schemas.android.com/apk/res-auto">

<android.support.v7.widget.CardView
    android:id="@+id/parent_phraseList_card"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="#BDBDBD"
    app:cardElevation="4dp"
    android:padding="8dp">
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#FFFFFF"
        android:padding="5dp">

    <TextView
        android:id="@+id/docNameLabel"
        android:layout_width="120dp"
        android:layout_height="wrap_content"
        android:text="Doc Name : "
        android:textStyle="bold"/>
    <TextView
        android:id="@+id/docName"
        android:layout_toRightOf="@id/docNameLabel"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
    <TextView
        android:id="@+id/totalOccurencesLabel"
        android:layout_below="@id/docNameLabel"
        android:layout_width="120dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="5dp"
        android:text="Total Occurences : "
        android:textStyle="bold"/>
    <TextView
        android:id="@+id/totalOccurences"
        android:layout_toRightOf="@id/totalOccurencesLabel"
        android:layout_below="@id/docNameLabel"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="5dp"/>

    <ImageButton
        android:id="@+id/linkToDirectOpenDoc_btn"
        android:layout_below="@id/totalOccurencesLabel"
        android:layout_centerHorizontal="true"
        android:layout_width="40dp"
        android:layout_height="40dp"
        android:src="@drawable/link"
        android:elevation="6dp"
        android:layout_marginTop="5dp"/>

    <ImageButton
        android:id="@+id/expandCard_btn"
        android:layout_below="@id/totalOccurencesLabel"
        android:layout_toRightOf="@id/linkToDirectOpenDoc_btn"
        android:layout_width="40dp"
        android:layout_height="40dp"
        android:src="@drawable/expand"
        android:elevation="6dp"
        android:layout_marginTop="5dp"/>
    </RelativeLayout>
</android.support.v7.widget.CardView>

</RelativeLayout>

list_item.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <android.support.v7.widget.CardView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:elevation="4dp"
        android:padding="8dp">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="5dp"
            android:background="#FFFFFF">

            <TextView
                android:id="@+id/occurenceId_label"
                android:layout_width="120dp"
                android:layout_height="wrap_content"
                android:text="Occurence : "
                android:textStyle="bold"/>
            <TextView
                android:id="@+id/occurenceId"
                android:layout_toRightOf="@id/occurenceId_label"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"/>
            <TextView
                android:id="@+id/fullPhrase_label"
                android:layout_below="@id/occurenceId_label"
                android:layout_width="120dp"
                android:layout_height="wrap_content"
                android:text="Full Phrase : "
                android:textStyle="bold"
                android:layout_marginTop="5dp"/>
            <TextView
                android:id="@+id/fullPhrase"
                android:layout_below="@id/occurenceId_label"
                android:layout_toRightOf="@id/fullPhrase_label"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="5dp"/>

            <TextView
                android:id="@+id/pageNo_label"
                android:layout_below="@id/fullPhrase_label"
                android:layout_width="120dp"
                android:layout_height="wrap_content"
                android:text="Full Phrase : "
                android:textStyle="bold"
                android:layout_marginTop="5dp"/>
            <TextView
                android:id="@+id/pageNo"
                android:layout_below="@id/fullPhrase_label"
                android:layout_toRightOf="@id/pageNo_label"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="5dp"/>

        </RelativeLayout>

    </android.support.v7.widget.CardView>

</RelativeLayout>

Answer 1

尝试更换

ArrayList<PhraseModel.PhraseList> parentList = (ArrayList<PhraseModel.PhraseList>) getGroup(groupPosition);

由

PhraseList parentList = (PhraseList) getGroup(groupPosition);