Question

用户可以将视图从ListView拖到onItemLongClick ListView上的布局。根据一些客户的反馈，我想使用onItemClick来拖动视图onItemLongClick。使用onitemClick时startDrag()无效。请在下面找到我的代码。可能是什么问题？如果我们使用onItemLongClick

，则相同的代码正在运行

OnItemClickListener onItemClick = new OnItemClickListener() 
{
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position,long id)
    {   
        ClipData clipData = ClipData.newPlainText("", "");
        DragShadowBuilder shadowBuilder = new CustomDragShadowBuilder(getActivity());
        view.startDrag(clipData, shadowBuilder,null, 0);
    }
}
};

Answer 1

首先看一下：http://www.vogella.com/tutorials/AndroidDragAndDrop/article.html

你使用startDrag的地方是错误的尝试在touchlistener中使用它。您可以在适配器的getview方法中向行添加触摸侦听器。我写的一个小例子在listview中显示动物图像，你可以将这些图像拖放到容器（布局）中

主要活动中的

公共类MainActivity扩展了Activity {

public static final String TAG="Drag-Drog";

ListView list;
Integer[] imageId = { R.drawable.image1, R.drawable.image2,
        R.drawable.image3, R.drawable.image4, R.drawable.image5,
        R.drawable.image6,

};

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

    CustomList adapter = new CustomList(MainActivity.this,
            R.layout.list_row, imageId);
    list = (ListView) findViewById(R.id.listview1);

    list.setAdapter(adapter);

    list.setOnItemClickListener(new OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
            Toast.makeText(getApplicationContext(),
                    "Click ListItem Number " + position, Toast.LENGTH_LONG)
                    .show();
        }
    });

    findViewById(R.id.container1).setOnDragListener(new MyDragListener());

}

public class MyDragListener implements OnDragListener {

    Drawable enterShape = getResources().getDrawable(
            R.drawable.shape_droptarget);
    Drawable normalShape = getResources().getDrawable(R.drawable.shape);

    @Override
    public boolean onDrag(View v, DragEvent event) {

        int action = event.getAction();

        switch (action) {
        case DragEvent.ACTION_DRAG_STARTED:
            // do nothing
            Log.d(TAG,"on ACTION_DRAG_STARTED");
            break;

        case DragEvent.ACTION_DRAG_ENTERED:
            v.setBackground(enterShape);
            Log.d(TAG,"on ACTION_DRAG_ENTERED");
            break;

        case DragEvent.ACTION_DRAG_EXITED:
            v.setBackground(normalShape);
            Log.d(TAG,"on ACTION_DRAG_EXITED");
            break;

        case DragEvent.ACTION_DROP:
            // the view dropped
            // getlocatestate probably gets the reference of this view
            View view = (View) event.getLocalState(); // get the view which
                                                        // will be dropped
            ViewGroup owner = (ViewGroup) view.getParent();
            owner.removeView(view); // remove the view from the first
                                    // position

            LinearLayout container = (LinearLayout) v;
            container.addView(view);
            view.setVisibility(View.VISIBLE);
            Log.d(TAG,"on ACTION_DRAG_STARTED");
            break;

        case DragEvent.ACTION_DRAG_ENDED:
            v.setBackground(normalShape);
            Log.d(TAG,"onACTION_DRAG_ENDED");
            break;

        }
        return true;
    }

}

}

在自定义触控侦听器中

公共类MyTouchListener实现了OnTouchListener {

public static final String TAG="Drag-Drog";
@Override
public boolean onTouch(View v, MotionEvent event) {
    // when touch event occurs first check the document
    if (event.getAction() == MotionEvent.ACTION_DOWN) {
        ClipData data=ClipData.newPlainText("", "");
        //ClippedData is a complex type containing one or Item instances, 
        //each of which can hold one or more representations of an item of data

        DragShadowBuilder shadowBuilder=new View.DragShadowBuilder(v);
        v.startDrag(data, shadowBuilder,v, 0);
        v.setVisibility(View.VISIBLE);

        Log.d(TAG,"on Action Down");

        return true;
    } 
    /*
    if(event.getAction()==MotionEvent.)


    */
    else
        return false;

}

}

这是这里的自定义适配器

公共类CustomList扩展了ArrayAdapter {

private final Context context;
private final Integer[] imageId;

public CustomList(Context c, int resource, Integer[] imageId) {

    super(c, resource, imageId);

    this.context = c;
    this.imageId = imageId;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    ViewHolder viewHolder;

    if (convertView == null) {

        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = inflater.inflate(R.layout.list_row, null, false);
        viewHolder = new ViewHolder();
        viewHolder.img = (ImageView) convertView.findViewById(R.id.img);
        convertView.setTag(viewHolder);

    } else {
        // we call the view created before to not create a view in each time
        viewHolder = (ViewHolder) convertView.getTag();
    }

    int imgId = imageId[position];

    viewHolder.img.setImageResource(imgId);

    viewHolder.img.setOnTouchListener(new MyTouchListener());

    return convertView;
}

public class ViewHolder {

    ImageView img;

    public ImageView getImg() {
        return img;
    }

    public void setImg(ImageView img) {
        this.img = img;
    }

}

}

startDrag（）不能在listview onItemClick上工作

1 个答案: