ListView控件拖放

ListView控件拖放：实现数据的自由移动

java
public class MainActivity extends AppCompatActivity {
    private ListView listView;
    private ArrayList dataList;
    private ArrayAdapter adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView = findViewById(R.id.listView);
        dataList = new ArrayList<>();
        dataList.add("数据项1");
        dataList.add("数据项2");
        dataList.add("数据项3");
        adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, dataList);
        listView.setAdapter(adapter);
        // 设置长按监听器，实现拖动功能
        listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView parent, View view, int position, long id) {
                ClipData data = ClipData.newPlainText("", "");
                View.DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view);
                view.startDragAndDrop(data, shadowBuilder, view, 0);
                return true;
            }
        });
        // 设置点击监听器，实现释放功能
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView parent, View view, int position, long id) {
                ClipData.Item item = new ClipData.Item(dataList.get(position));
                ClipData data = new ClipData("", new String[]{ClipDescription.MIMETYPE_TEXT_PLAIN}, item);
                View.DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view);
                view.startDragAndDrop(data, shadowBuilder, view, 0);
            }
        });
        // 设置拖放监听器，实现数据移动
        listView.setOnDragListener(new View.OnDragListener() {
            @Override
            public boolean onDrag(View v, DragEvent event) {
                switch (event.getAction()) {
                    case DragEvent.ACTION_DRAG_STARTED:
                        // 拖动开始
                        return true;
                    case DragEvent.ACTION_DRAG_ENTERED:
                        // 拖动进入
                        return true;
                    case DragEvent.ACTION_DRAG_EXITED:
                        // 拖动退出
                        return true;
                    case DragEvent.ACTION_DROP:
                        // 拖动释放
                        int position = listView.pointToPosition((int) event.getX(), (int) event.getY());
                        if (position != AdapterView.INVALID_POSITION) {
                            ClipData.Item item = event.getClipData().getItemAt(0);
                            String data = item.getText().toString();
                            dataList.remove(data);
                            dataList.add(position, data);
                            adapter.notifyDataSetChanged();
                            return true;
                        }
                    case DragEvent.ACTION_DRAG_ENDED:
                        // 拖动结束
                        return true;
                    default:
                        break;
                }
                return false;
            }
        });
    }
}