Android HorizontalScrollView内子控件横向拖拽实例代码

前言

        网上listview上下拖动的例子有，效果也很好，但是项目要横着拖的，只要硬着头皮自己写（主要是没找到合适的），参考文章1修改而来，分享一下。

正文

截图

实现代码：

public class hodragactivity extends activity {

 private linearlayout main;

 private gesturedetector mgesturedetector;

 @override
 public void oncreate(bundle savedinstancestate) {
  super.oncreate(savedinstancestate);
  setcontentview(r.layout.main_cc);

  main = (linearlayout) findviewbyid(r.id.main);

  binddraplistener(r.id.myimage1);
  binddraplistener(r.id.myimage2);
  binddraplistener(r.id.myimage3);
  binddraplistener(r.id.myimage4);
  binddraplistener(r.id.myimage5);
  binddraplistener(r.id.myimage6);
  binddraplistener(r.id.myimage7);
  binddraplistener(r.id.myimage8);
  binddraplistener(r.id.myimage9);
  binddraplistener(r.id.myimage10);
  binddraplistener(r.id.myimage11);
  binddraplistener(r.id.myimage12);

  mgesturedetector = new gesturedetector(this, new drapgesturelistener());
 }

 private view mdrapview;

 private void binddraplistener(int id) {
  view v = findviewbyid(id);
  v.setontouchlistener(montouchlistener);
  v.setondraglistener(mondraglistener);
 }

 private ontouchlistener montouchlistener = new ontouchlistener() {

  @override
  public boolean ontouch(view v, motionevent event) {
   mdrapview = v;

   if (mgesturedetector.ontouchevent(event))
    return true;

   switch (event.getaction() & motionevent.action_mask) {
   case motionevent.action_up:

    break;
   }

   return false;
  }
 };

 private ondraglistener mondraglistener = new ondraglistener() {

  @override
  public boolean ondrag(view v, dragevent event) {
   switch (event.getaction()) {
   case dragevent.action_drag_started:
    // do nothing
    break;
   case dragevent.action_drag_entered:
    v.setalpha(0.5f);
    break;
   case dragevent.action_drag_exited:
    v.setalpha(1f);
    break;
   case dragevent.action_drop:
    view view = (view) event.getlocalstate();
    for (int i = 0, j = main.getchildcount(); i < j; i++) {
     if (main.getchildat(i) == v) {
      // 当前位置
      main.removeview(view);
      main.addview(view, i);
      break;
     }
    }
    break;
   case dragevent.action_drag_ended:
    v.setalpha(1f);
   default:
    break;
   }
   return true;
  }
 };

 private class drapgesturelistener extends simpleongesturelistener {
  @override
  public boolean onsingletapconfirmed(motionevent e) {
   return super.onsingletapconfirmed(e);
  }

  @override
  public void onlongpress(motionevent e) {
   super.onlongpress(e);
   clipdata data = clipdata.newplaintext("", "");
   mydragshadowbuilder shadowbuilder = new mydragshadowbuilder(
     mdrapview);
   mdrapview.startdrag(data, shadowbuilder, mdrapview, 0);
  }

  @override
  public boolean ondown(motionevent e) {
   return true;
  }
 }

 private class mydragshadowbuilder extends view.dragshadowbuilder {

  private final weakreference<view> mview;

  public mydragshadowbuilder(view view) {
   super(view);
   mview = new weakreference<view>(view);
  }

  @override
  public void ondrawshadow(canvas canvas) {
   canvas.scale(1.5f, 1.5f);
   super.ondrawshadow(canvas);
  }

  @override
  public void onprovideshadowmetrics(point shadowsize,
    point shadowtouchpoint) {
   // super.onprovideshadowmetrics(shadowsize, shadowtouchpoint);

   final view view = mview.get();
   if (view != null) {
    shadowsize.set((int) (view.getwidth() * 1.5f),
      (int) (view.getheight() * 1.5f));
    shadowtouchpoint.set(shadowsize.x / 2, shadowsize.y / 2);
   } else {
    // log.e(view.view_log_tag,
    // "asked for drag thumb metrics but no view");
   }
  }
 }
｝

代码说明

   1、 mydragshadowbuilder主要用于缩放拖拽的imageview，这里放大了1.5倍，而又不至于影响原控件，这里是放大两倍

   2、这里是通过长按来唤起拖拽操作，所以监听了onlongpress。

   3、注意拖拽ondraglistener是android 3.0才新增的api。

 以上就是android horizontalscrollview内子控件横向拖拽实例，欢迎交流，有需要参考下。