【Android】HorizontalScrollView内子控件横向拖拽

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。

声明

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正文

截图



代码

java

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

文章

Android Drag and Drop - Tutorial

Android开发者指南-用户界面-拖放-Drag and Drop

下载

VogellaDraganddrop.zip

结束

欢迎交流！想做成拖动插入时自动两边挤开的效果，没弄出来，出来是抖动的效果。