android开发在adapter中使用反射添加元素

android开发中最常用的控件之一就是listview,伴随listview还要有adapter和放入适配器的item.然后假设其中有一部分item的生成符合一定规律,Item item = new Item(jsonObject);那么就该考虑下用反射来生成这些元素了.

首先是item的代码

public class TestItem {
public int id;
public String image;

public TestItem(JSONObject json) {
try {
id = json.getInt("id");
} catch (JSONException e1) {
e1.printStackTrace();
}
try {
image = json.getString("image");
} catch (JSONException e) {
e.printStackTrace();
}
}

}

然后是生成一个item对象的代码

Object object = TestItem.class.getConstructors()[0].newInstance(json);

放入adapter之后就是

/**
* 适配器的抽象类
*
* @author oldfeel
*/
public abstract class BaseBaseAdapter extends BaseAdapter {
private List<Object> list = new LinkedList<Object>();
/** 适配器中元素的类 */
private Class<?> classItem;

/**
*
* @param context
* @param classItem
*            适配器中元素的类
*/
public BaseBaseAdapter(Class<?> classItem) {
this.classItem = classItem;
}

/**
* 预处理清除列表数据和获取jsonarray
*
* @param page
*            页码
* @param json
*            json对象
* @throws JSONException
*/
public void putJSON(JSONObject json, int page) {
if (page == 1) {
list.clear();
}
try {
JSONArray array = json.getJSONArray("adimage");
for (int i = 0; i < array.length(); i++) {
try {
Object object = classItem.getConstructors()[0]
.newInstance(array.getJSONObject(i));
addItem(object);
} catch (Exception e) {
e.printStackTrace();
}
}
} catch (JSONException e1) {
e1.printStackTrace();
}
}

/**
* 清除list
*/
public void clear() {
list.clear();
notifyDataSetChanged();
}

/**
* 添加元素
*
* @param object
*/
public void addItem(Object object) {
list.add(object);
notifyDataSetChanged();
}

@Override
public int getCount() {
return list.size();
}

@Override
public Object getItem(int position) {
if (position > list.size() - 1) {
return null;
}
return list.get(position);
}

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

@Override
public View getView(int position, View convertView, ViewGroup parent) {
return getExView(position, convertView, parent);
}

public abstract View getExView(int position, View convertView,
ViewGroup parent);

}

在使用adapter的时候继承BaseBaseAdapter并输入item的类和布局文件就可以了

例如

BaseBaseAdapter adapter = new BaseBaseAdapter(
TestItem.class) {

@Override
public View getExView(int position, View convertView,
ViewGroup parent) {
TestItem item = (TestItem) getItem(position);
TextView textView = new TextView(MainActivity.this);
textView.setText(item.image);
return textView;
}
};