Android BaseAdapter基本使用及数据刷新
16lz
2021-01-23
Android BaseAdapter基本使用及数据刷新
1. 首先是Adapter适配器类：
MyListAdapter.java
public abstract class MyListAdapter extends BaseAdapter { private Context context; private int listItemId = 0; public MyListAdapter(Context context, int listItemId) { super(); this.context = context; this.listItemId = listItemId; } public Context getContext() { return context; } private List list = new ArrayList(); public void add(T item) { list.add(item); notifyDataSetChanged(); } public void remove(int position) { list.remove(position); notifyDataSetChanged(); } public void removeLast() { remove(getCount() - 1); } @Override public int getCount() { return list.size(); } @Override public T getItem(int position) { return list.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { if(convertView == null) { convertView = LayoutInflater.from(getContext()).inflate(listItemId, null); System.out.println("convertView=null"); } initListItem(position, convertView, parent); return convertView; } protected abstract void initListItem(int position, View listItem, ViewGroup parent);} 主界面布局文件：
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" 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=".MainActivity" > <ListView android:id="@android:id/list" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_weight="1" /> <LinearLayout android:orientation="horizontal" android:layout_width="match_parent" android:layout_height="wrap_content" > <Button android:id="@+id/btn_add" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_weight="1" android:text="add" /> <Button android:id="@+id/btn_remove" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="remove" android:layout_weight="1" /> LinearLayout>LinearLayout>然后是业务代码实现：
MainActivity.java
public class MainActivity extends ListActivity implements OnClickListener{ private MyListAdapter adapter; private int index = 0; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); adapter = new MyListAdapter(MainActivity.this, android.R.layout.simple_list_item_1) { @Override protected void initListItem(int position, View listItem, ViewGroup parent) { ((TextView)listItem).setText(getItem(position)); System.out.println(getItem(position)); } }; setListAdapter(adapter); for (index = 0; index < 5; index++) { adapter.add("eoe" + index); } findViewById(R.id.btn_add).setOnClickListener(this); findViewById(R.id.btn_remove).setOnClickListener(this); } @Override public void onClick(View v) { switch (v.getId()) { case R.id.btn_add: index ++; adapter.add("eoe" + index); break; case R.id.btn_remove: adapter.removeLast(); break; } }} 更多相关文章
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