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。