试图制作自定义适配器

时间：2017-03-12 23:49:05

标签： android listview indexoutofboundsexception

我开始学习Android开发课程，同时我正在学习自定义适配器 执行此代码后，应用程序崩溃

这是我的全部代码

customlistview.java 

package com.example.vamsi.customadapter;

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

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

/**
 * Created by vamsi on 3/12/2017.
 */

public class customlistviewadadapter extends BaseAdapter {
    private Context mcontext;
    private ArrayList<HashMap<String,String>> books;
    private static LayoutInflater inflater=null;

    public customlistviewadadapter(Context context, ArrayList<HashMap<String,String>> data){
        mcontext=context;
        books=data;
        inflater=(LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }
    @Override
    public int getCount() {
        return books.size();
    }

    @Override
    public Object getItem(int position) {
        return position;
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View view =convertView;
        if(convertView==null){
            view=inflater.inflate(R.layout.list_row,null);
            TextView title = (TextView)view.findViewById(R.id.title);
            TextView author=(TextView)view.findViewById(R.id.author);
            TextView pages=(TextView)view.findViewById(R.id.pages);
            ImageView image=(ImageView)view.findViewById(R.id.listimg);

            HashMap<String,String> mbook=new HashMap<>();
            mbook = books.get(position);
            title.setText(mbook.get("title"));
            author.setText(mbook.get("author"));
            pages.setText(mbook.get("pages"));



        }

        return view;
    }
}

MainActivity.java 

package com.example.vamsi.customadapter;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.Toast;

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

public class MainActivity extends AppCompatActivity {
    private ListView listview;
    private customlistviewadadapter custlistadapter;


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

        final String[] bookTitles=new String[]{
                "alchemist",
                "gulivers trvvels",
                "brief history of time",
                "get away with murder",
                "god thank you",
                "books books books"
        };
        final String[] pages=new String[]{
                "100 pages",
                "120 pages",
                "111 pages",
                "121 pages",
                "123 pages"
        };
        final String[] authors=new String[]{
                "lol",
                "donno",
                "stephen",
                "boom",
                "god",
                "books again"
        };
        ArrayList<HashMap<String,String>> authorlist=new ArrayList<>();
        for (int i=0;i<6;i++){
            HashMap<String,String> data=new HashMap<>();
            data.put("title",bookTitles[i]);
            data.put("pages",pages[i]);
            data.put("author",authors[i]);

            authorlist.add(data);

        }
        listview=(ListView)findViewById(R.id.listview1);
        custlistadapter=new customlistviewadadapter(getApplicationContext(),authorlist);
        listview.setAdapter(custlistadapter);
        listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                int mypos=position;
                String itemclicked=listview.getItemAtPosition(mypos).toString();
                Toast.makeText(getApplicationContext(),"id cliccked"+itemclicked,Toast.LENGTH_SHORT).show();

            }
        });
    }
}

list_row.xml 

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:background="@drawable/listselector"
    android:orientation="horizontal"
    android:layout_height="wrap_content"
    >
    <LinearLayout
        android:id="@+id/thumbnail"
        android:padding="3dp"
        android:layout_alignParentLeft="true"
        android:background="#ffeeeade"
        android:layout_marginRight="5dp"
        android:orientation="vertical"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">
        <ImageView
            android:id="@+id/listimg"
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:src="@mipmap/ic_launcher"/>
    </LinearLayout>
    <TextView
        android:id="@+id/title"
        android:layout_alignTop="@+id/thumbnail"
        android:layout_width="wrap_content"
        android:text="the alchemist"
        android:textSize="14sp"
        android:textColor="#040404"
        android:layout_toRightOf="@+id/thumbnail"
        android:layout_height="wrap_content" />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/author"
        android:layout_below="@+id/title"
        android:text="paulo"
        android:layout_toRightOf="@+id/thumbnail"
        android:textColor="#ffde3a3d"
        android:layout_marginTop="2dp"
        />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="234 pages"
        android:id="@+id/pages"
        android:layout_alignParentRight="true"
        android:layout_alignTop="@+id/title"
        android:layout_marginRight="10dp"
        android:textColor="#10bcc9"
        android:gravity="right"
        />
    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@android:drawable/ic_media_play"
        android:layout_alignParentRight="true"
        android:layout_centerVertical="true"/>
</RelativeLayout>

activity_main.xml中

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    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"
    tools:context="com.example.vamsi.customadapter.MainActivity">

    <ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:id="@+id/listview1"
        android:listSelector="@drawable/listselector"
        android:divider="@color/colorAccent"
        android:dividerHeight="1dp" />
</RelativeLayout>

我尝试启用调试，这是控制台输出。

V/BoostFramework: mIOPStart method = public int com.qualcomm.qti.Performance.perfIOPrefetchStart(int,java.lang.String)
V/BoostFramework: mIOPStop method = public int com.qualcomm.qti.Performance.perfIOPrefetchStop()
V/BoostFramework: BoostFramework() : mPerf = com.qualcomm.qti.Performance@28f08ea
V/BoostFramework: BoostFramework() : mPerf = com.qualcomm.qti.Performance@a9a47db
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.example.vamsi.customadapter, PID: 6371
                  java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.vamsi.customadapter/com.example.vamsi.customadapter.MainActivity}: java.lang.ArrayIndexOutOfBoundsException: length=5; index=5
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2728)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2814)
                      at android.app.ActivityThread.-wrap12(ActivityThread.java)
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1527)
                      at android.os.Handler.dispatchMessage(Handler.java:102)
                      at android.os.Looper.loop(Looper.java:154)
                      at android.app.ActivityThread.main(ActivityThread.java:6290)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
                   Caused by: java.lang.ArrayIndexOutOfBoundsException: length=5; index=5
                      at com.example.vamsi.customadapter.MainActivity.onCreate(MainActivity.java:51)
                      at android.app.Activity.performCreate(Activity.java:6760)
                      at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1134)
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2681)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2814) 
                      at android.app.ActivityThread.-wrap12(ActivityThread.java) 
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1527) 
                      at android.os.Handler.dispatchMessage(Handler.java:102) 
                      at android.os.Looper.loop(Looper.java:154) 
                      at android.app.ActivityThread.main(ActivityThread.java:6290) 
                      at java.lang.reflect.Method.invoke(Native Method) 
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) 
D/AppTracker: App Event: crash
I/Process: Sending signal. PID: 6371 SIG: 9
Disconnected from the target VM, address: 'localhost:8612', transport: 'socket'

我正在使用API​​级别25 任何帮助将不胜感激

1 个答案:

答案 0 :(得分：1)

pages有5个值，而不是其他6个值。

除此之外，您还对数组的长度进行了硬编码。 

for (int i=0; i < 6; i++){ // Here
    // Code removed
}

所以，不要这样做。将6替换为5，或者最好是bookTitles.length ...

甚至更好。了解对象

public static class BookData {
    public String title, author, pages;
}

并制作ArrayList<BookData>

参考：CodePath | Using a Custom ArrayAdapter

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