Question

我正在尝试实现android的拖放示例。经过长时间按下一个项目后，我将其拖动到目标水平并放在那里。我在某种程度上是成功的。但我想要一些不同的东西。我做过这样的事...... enter image description here

但是我想将所有项目添加到listView中，并且在长按listview后我将拍摄一个项目，然后我将项目拖动到目标级别并将其放在那里。我想要这样的东西.. enter image description here

我的代码如下......

public class MainActivity extends Activity {



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






    findViewById(R.id.mango).setOnLongClickListener(longListen);
    findViewById(R.id.orange).setOnLongClickListener(longListen);
    findViewById(R.id.apple).setOnLongClickListener(longListen);
    findViewById(R.id.banana).setOnLongClickListener(longListen);

    findViewById(R.id.drop_here).setOnDragListener(DropListener);

    listview.setOnItemLongClickListener(new OnItemLongClickListener() {

        public boolean onItemLongClick(AdapterView<?> arg0, View arg1,
                int pos, long id) {
            // TODO Auto-generated method stub

            Log.i("long clicked","pos"+" "+pos);

            return true;
        }
    }); 
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

OnLongClickListener longListen = new OnLongClickListener() {

    @Override
    public boolean onLongClick(View v) {

        DragShadow dragShadow = new DragShadow(v);

        ClipData data = ClipData.newPlainText("", "");

        v.startDrag(data, dragShadow, v, 0);

        return false;
    }
};

private class DragShadow extends View.DragShadowBuilder {

    ColorDrawable greyBox;

    public DragShadow(View view) {
        super(view);
        // TODO Auto-generated constructor stub
        greyBox = new ColorDrawable(Color.LTGRAY);
    }

    @Override
    public void onDrawShadow(Canvas canvas) {
        // TODO Auto-generated method stub
        // super.onDrawShadow(canvas);

        greyBox.draw(canvas);
    }

    @Override
    public void onProvideShadowMetrics(Point shadowSize,
            Point shadowTouchPoint) {
        // TODO Auto-generated method stub
        // super.onProvideShadowMetrics(shadowSize, shadowTouchPoint);
        View v = getView();

        int height = (int) v.getHeight() / 2;
        int width = (int) v.getWidth() / 2;

        greyBox.setBounds(0, 0, width, height);
        shadowSize.set(width, height);

        shadowTouchPoint.set(width / 2, height / 2);

    }


}

OnDragListener DropListener = new View.OnDragListener() {

    @Override
    public boolean onDrag(View v, DragEvent event) {
        // TODO Auto-generated method stub

        int dragEvent = event.getAction();

        switch (dragEvent) {
        case DragEvent.ACTION_DRAG_ENTERED:
            Log.i("Drag ", "Entered");
            break;
        case DragEvent.ACTION_DRAG_EXITED:
            Log.i("Drag ", "Exit");
            break;
        case DragEvent.ACTION_DROP:
            Log.i("Drag ", "Drop");

            TextView target = (TextView) v;
            TextView dragg = (TextView) event.getLocalState();
            target.setText(dragg.getText());
            break;
        default:
            break;
        }

        return true;
    }
};

}

我已经尝试了一些教程，但我无法从那里获得解决方案。 Android List View Drag and Drop sort

Answer 1

我找到了解决方案。这很简单，只需在setOnItemClickListener中调用startDrag方法即可。

listview.setOnItemLongClickListener(new OnItemLongClickListener() {

        public boolean onItemLongClick(AdapterView<?> arg0, View v,
                int pos, long id) {
            // TODO Auto-generated method stub


            v.startDrag(data, dragShadow, v, 0);
            return true;
        }
    });

Answer 2

这里有很好的教程http://www.vogella.com/articles/AndroidDragAndDrop/article.html 作者：Lars Vogel。但它只适用于Android 4及更高版本（ICS之后）。

如果这没有给你一个解决方案，请尝试添加一个简单的onTouchListener来拖动一个对象，看看拖动时的对象是否落入你想要拖入的视图范围内（在你的情况下为textview）

可以在此处找到一个简单的Drag ontouchlistener实现：https://stackoverflow.com/a/9398861/2138983

如何从列表视图中拖动项目并将其放在外部textView上？

2 个答案: