listview
时间: 2023-07-24 10:11:47 浏览: 66
ListView是Android中常用的控件,它可以展示一列数据,并且支持滑动、点击等交互操作。使用ListView需要自定义Adapter来管理数据和界面的显示。
以下是一个简单的ListView使用示例:
1. 定义ListView布局文件,例如listview_layout.xml:
```
<ListView
android:id="@+id/list_view"
android:layout_width="match_parent"
android:layout_height="match_parent" />
```
2. 定义ListView的每一个item布局文件,例如list_item_layout.xml:
```
<TextView
android:id="@+id/item_text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="16sp"
android:padding="16dp" />
```
3. 定义Adapter,例如MyAdapter.java:
```
public class MyAdapter extends BaseAdapter {
private List<String> mDataList;
public MyAdapter(List<String> dataList) {
mDataList = dataList;
}
@Override
public int getCount() {
return mDataList.size();
}
@Override
public Object getItem(int position) {
return mDataList.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_layout, parent, false);
holder = new ViewHolder();
holder.text = convertView.findViewById(R.id.item_text);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
String data = mDataList.get(position);
holder.text.setText(data);
return convertView;
}
private static class ViewHolder {
TextView text;
}
}
```
4. 在Activity中使用ListView:
```
public class MainActivity extends AppCompatActivity {
private ListView mListView;
private MyAdapter mAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mListView = findViewById(R.id.list_view);
List<String> dataList = new ArrayList<>();
for (int i = 0; i < 20; i++) {
dataList.add("Item " + i);
}
mAdapter = new MyAdapter(dataList);
mListView.setAdapter(mAdapter);
}
}
```
这样就完成了一个简单的ListView展示。当数据量较大时,可以使用RecyclerView来优化性能。