我正在嘗試創(chuàng)建一個(gè)介紹洛杉磯景點(diǎn)和洛杉磯餐廳的應(yīng)用程序。主頁(yè)是景點(diǎn)和餐廳的圖片，當(dāng)您單擊其中一個(gè)時(shí)，它會(huì)打開(kāi)更多景點(diǎn)或餐廳供人們閱讀詳細(xì)信息。我正在實(shí)施列表視圖，但是我的 setadapter 不起作用。請(qǐng)看看我的代碼并幫助新手！謝謝！錯(cuò)誤代碼如下，之后是我的程序代碼。Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object referenceMainActivity.java:        package com.example.android.tourguide;    import android.content.Context;    import android.content.Intent;    import android.media.Image;    import android.support.v7.app.AppCompatActivity;    import android.os.Bundle;    import android.view.View;    import android.widget.ImageView;    import android.widget.Toast;    public class MainActivity extends AppCompatActivity {        @Override        protected void onCreate(Bundle savedInstanceState) {            super.onCreate(savedInstanceState);            setContentView(R.layout.activity_main);        }        public void attractionList(View v) {            Intent intent = new Intent(this, attractionList.class);            startActivity(intent);        }    }attractionList.java:    package com.example.android.tourguide;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.widget.ListView;import java.util.ArrayList;public class attractionList extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_attraction_list);        ArrayList<Attraction> attractionArrayList = new ArrayList<>();        attractionArrayList.add(new Attraction(R.drawable.griffith, R.raw.attraction, "Griffith Observatory"));        AttractionAdapter attractionAdapter = new AttractionAdapter(this, attractionArrayList);        ListView listView = (ListView) findViewById(R.id.list);        listView.setAdapter(attractionAdapter);    }}