Question

我有一个列表视图，其中包含每个项目旁边的复选框。我想通过选中或取消选中项目将项目移动到列表的顶部或底部。如果我检查该项目，请移至顶部并取消选中，移至底部。

我尝试过实现不同的代码集，包括setSelection(int position)。我一直专注于适配器上的if和else语句，因为它们与您选中和取消选中复选框时会发生的情况有关。当我尝试实现setSelection(int position)方法时，我收到错误消息。有没有办法修复代码，以便setSelection(int position)与我的代码兼容？

MainActivity.java

public class MainActivity extends AppCompatActivity {

    ArrayList<String> selectedItems;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        selectedItems = new ArrayList<String>();
        ListView chl = (ListView) findViewById(R.id.cityselector);
        chl.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
        String[] items = {"Berlin", "New York", "Paris", "Mexico City", "Asana", "Tangier"};
        Adapter adapter=new Adapter(this,items);
        chl.setAdapter(adapter);

        chl.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {

                int item_position=i;



            }
        });

    }

Adapter.java

public class Adapter extends BaseAdapter {

    String[] items;
    LayoutInflater inflater;
   ArrayList selectedItems;
    Activity activity;
    Adapter(Activity activity, String[] items){

        this.items=items;
        inflater=activity.getLayoutInflater();
        selectedItems = new ArrayList<String>();
        this.activity=activity;
    }

    @Override
    public int getCount() {
        return items.length;
    }

    @Override
    public String getItem(int i) {
        return items[i];
    }

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

    @Override
    public View getView(final int i, View view, ViewGroup viewGroup) {

        View v = view;
        if(v == null){
            v = inflater.inflate(R.layout.checkboxlayout,null);
        }

        TextView textview_Cities=(TextView)v.findViewById(R.id.Textview_Cities);
        textview_Cities.setText(items[i]);

        final CheckedTextView  checkedTextView=(CheckedTextView)v.findViewById(R.id.checkbox);
        checkedTextView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                if (!checkedTextView.isChecked()){
                    checkedTextView.setChecked(true);
                    selectedItems.add(items[i]);
                    //This is where I put the setSelection(int position) method////         


                }
                else {
                    checkedTextView.setChecked(false);
                    selectedItems.remove(items[i]);
                }


            }
        });



        return v;
    }
}

Answer 1

你可以试试这个

 checkBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
                @Override
                public void onCheckedChanged(CompoundButton compoundButton, boolean isChecked) {
                    int finalPosition = isChecked ? 0 : list.size() - 1;
                    int currentPosition = getAdapterPosition();
                    moveItem(currentPosition, finalPosition);
                }
            });



   void moveItem(int currentPosition, int finalPosition) {
            if (currentPosition < finalPosition) {
                for (int i = currentPosition; i < finalPosition; i++) {
                    Collections.swap(list, i, i + 1);
                }
            } else {
                for (int i = currentPosition; i > finalPosition; i--) {
                    Collections.swap(list, i, i - 1);
                }
            }
            notifyItemMoved(currentPosition, finalPosition);
        }

此处OnCheckedChangeListener位于ViewHolder的{{1}}内。

选中或取消选中复选框可将项目从列表视图移动到顶部或底部

1 个答案: