android-adapter小结

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adapter即适配器，功能就是把数据加载到界面上，通常是加载到listview上

例如：网易新闻列表，如下图

案例一：显示文字

main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="vertical" ></LinearLayout>

MainActivity.java

public class MainActivity extends Activity {
private static final String TAG = "MYDAPTER";
private ListView lv;

private List<String> data;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

LinearLayout ll_root = (LinearLayout) findViewById(R.id.ll_root);
lv = (ListView) findViewById(R.id.lv);

data = new ArrayList<String>();

for(int i = 0; i < 50; i++){

data.add("第" + i + "个view");

}
}

private class MyAdapter extends BaseAdapter{

/**
* 控制listview里面总共有多少个条目
*/
@Override
public int getCount() {
// TODO Auto-generated method stub
return data.size();
}

@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return null;
}

@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
Log.i(TAG, "返回VIEW对象，位置：" + position);
TextView tv = new TextView(getApplicationContext());
tv.setTextSize(20);
tv.setTextColor(Color.BLACK);

String info= data.get(position);
tv.setText(info);
return tv;

}

}
}

案例二：组合view，SimpleAdapter使用

实现效果：

activity_main.xml

list_item.xml

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

<ImageView
android:id="@+id/iv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:id="@+id/tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</LinearLayout>

MainActivity.java

public class MainActivity extends Activity {

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

ListView lv = (ListView) findViewById(R.id.lv);

List<Map<String, Object>> data = new ArrayList<Map<String,Object>>();

Map<String, Object> map1 = new HashMap<String, Object>();
map1.put("nameText", "我是第一个功能");
map1.put("iconId", R.drawable.sym_call_incoming);
data.add(map1);

Map<String, Object> map2 = new HashMap<String, Object>();
map2.put("nameText", "我是第二个功能");
map2.put("iconId", R.drawable.sym_call_missed);
data.add(map2);

Map<String, Object> map3 = new HashMap<String, Object>();
map3.put("nameText", "我是第三个功能");
map3.put("iconId", R.drawable.sym_call_incoming);
data.add(map3);

Map<String, Object> map4 = new HashMap<String, Object>();
map4.put("nameText", "我是第四个功能");
map4.put("iconId", R.drawable.sym_call_outgoing);
data.add(map4);

Map<String, Object> map5 = new HashMap<String, Object>();
map5.put("nameText", "我是第五个功能");
map5.put("iconId", R.drawable.sym_contact_card);
data.add(map5);


//data 绑定数据 list集合
//R.layout.list_item 数据显示对应的布局
//要让数据跟view对象建立一个映射关系
//from [] map集合里面数据的key
//to [] 布局文件里面的 id
lv.setAdapter(new SimpleAdapter(this, data, R.layout.list_item, new String[]{"nameText", "iconId"}, new int[]{R.id.tv, R.id.iv}));
}

}

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