• android ListView列表显示数据


    item.xml

    <?xml version="1.0" encoding="utf-8"?>
    <LinearLayout
      xmlns:android="http://schemas.android.com/apk/res/android"
      android:orientation="horizontal"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent">
      
      <TextView
      android:layout_width="120dp"
      android:textSize="22sp"
      android:layout_height="wrap_content"
      android:id="@+id/name"
      />
      
       <TextView
      android:layout_width="150dp"
       android:textSize="22sp"
      android:layout_height="wrap_content"
      android:id="@+id/phone"
      />
      
      <TextView
      android:layout_width="fill_parent"
       android:textSize="22sp"
      android:layout_height="wrap_content"
      android:id="@+id/amount"
      />
    </LinearLayout>

    MainActivity.java

    public class MainActivity extends Activity {
        private ListView listView;
        private PersonService personService;
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
            personService = new PersonService(this);
            
            listView = (ListView) this.findViewById(R.id.listView);
            listView.setOnItemClickListener(new ItemClickListener());
            show2();
        }
        
        private final class ItemClickListener implements OnItemClickListener{
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                ListView lView = (ListView)parent;
                /* 自定义适配器
                Person person = (Person) lView.getItemAtPosition(position);
                Toast.makeText(getApplicationContext(), person.getId().toString(), 1).show();*/
                
                Cursor cursor = (Cursor) lView.getItemAtPosition(position);
                int personid = cursor.getInt(cursor.getColumnIndex("_id"));
                Toast.makeText(getApplicationContext(), personid+ "", 1).show();
            }
        }
        
        
        //自定义适配器
    
        private void show3() {
            List<Person> persons = personService.getScrollData(0, 20);
            PersonAdapter adapter = new PersonAdapter(this, persons, R.layout.item);
            listView.setAdapter(adapter);
        }
    
        private void show2() {
            //此适配器要求有一个字段为_id,不然会报错,解决方法两种,1、增加_id的字段 2、为字段指定别名
            Cursor cursor = personService.getCursorScrollData(0, 20);
            SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, R.layout.item, cursor,
                    new String[]{"name", "phone", "amount"}, new int[]{R.id.name, R.id.phone, R.id.amount});
            listView.setAdapter(adapter);
        }
    
        private void show() {
            List<Person> persons = personService.getScrollData(0, 20);
            List<HashMap<String, Object>> data = new ArrayList<HashMap<String,Object>>();
            for(Person person : persons){
                HashMap<String, Object> item = new HashMap<String, Object>();
                item.put("name", person.getName());
                item.put("phone", person.getPhone());
                item.put("amount", person.getAmount());
                item.put("id", person.getId());
                data.add(item);
            }
            SimpleAdapter adapter = new SimpleAdapter(this, data, R.layout.item,
                    new String[]{"name", "phone", "amount"}, new int[]{R.id.name, R.id.phone, R.id.amount});
            
            listView.setAdapter(adapter);
            
        }
    }

    自定义适配器:

    public class PersonAdapter extends BaseAdapter {
        private List<Person> persons;//在绑定的数据
        private int resource;//绑定的条目界面,item.xml
        private LayoutInflater inflater; //布局填充器,通过上下文得到
        
        public PersonAdapter(Context context, List<Person> persons, int resource) {
            this.persons = persons;
            this.resource = resource;
            inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        }
    
        @Override
    
        public int getCount() {
            return persons.size();//数据总数
        }
    
        @Override
        public Object getItem(int position) {
            return persons.get(position);
        }
    
        @Override
        public long getItemId(int position) {
            return position;
        }
    
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            TextView nameView = null;
            TextView phoneView = null;
            TextView amountView = null;
            //利用View的缓存
            if(convertView==null){
                convertView = inflater.inflate(resource, null);//生成条目界面对象
                nameView = (TextView) convertView.findViewById(R.id.name);
                phoneView = (TextView) convertView.findViewById(R.id.phone);
                amountView = (TextView) convertView.findViewById(R.id.amount);
                
                ViewCache cache = new ViewCache();
                cache.nameView = nameView;
                cache.phoneView = phoneView;
                cache.amountView = amountView;            
                convertView.setTag(cache);
            }else{
                ViewCache cache = (ViewCache) convertView.getTag();
                nameView = cache.nameView;
                phoneView = cache.phoneView;
                amountView = cache.amountView;
            }
            Person person = persons.get(position);
            //下面代码实现数据绑定
            nameView.setText(person.getName());
            phoneView.setText(person.getPhone());
            amountView.setText(person.getAmount().toString());
            
            return convertView;
        }
        
        private final class ViewCache{
            public TextView nameView;
            public TextView phoneView;
            public TextView amountView;
        }
    
    }
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  • 原文地址:https://www.cnblogs.com/heml/p/3509459.html
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