我在listview项目中使用触摸侦听器进行imageview。当我像样例应用程序那样执行时，它正常工作（我的意思是我将Listview项目作为样本项目）。但是当我把它放在列表视图中时，它实际上变得非常慢。
我只是想在水平方向上拖动图像，为此我使用了从Github获得的ConstrainedDragandDrop View类。
在我的示例应用程序中：
public class HorizontalScroll extends Activity {
ImageView full_left,heart;
RelativeLayout rlMainLayout,rlImages,Cartoon_image,half_left,play_btn,centre,centre_leftanimate;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.inflated_bloops);
half_left=(RelativeLayout)findViewById(R.id.half_left);
Cartoon_image=(RelativeLayout)findViewById(R.id.cartoon_image);
play_btn=(RelativeLayout)findViewById(R.id.play_btn);
heart=(ImageView)findViewById(R.id.ivheart);
ConstrainedDragAndDropView dndView = (ConstrainedDragAndDropView) findViewById(R.id.dndView);
dndView.setDragHandle(findViewById(R.id.cartoon_image),findViewById(R.id.half_left),heart);
dndView.setAllowVerticalDrag(false,HorizontalScroll.this);
}
}
当我在Listview中使用时：
public class Cars extends BaseAdapter
{
public View getView(int position, View convertView, ViewGroup parent)
{
View v = convertView;
LayoutInflater inflator = getLayoutInflater();
v= inflator.inflate(R.layout.inflated_bloops, null);
ConstrainedDragAndDropView dndView = (ConstrainedDragAndDropView) v.findViewById(R.id.dndView);
dndView.setDragHandle(v.findViewById(R.id.cartoon_image),v.findViewById(R.id.half_left),heart);
dndView.setAllowVerticalDrag(false,FeedModeActivity.this);
RelativeLayout Cartoon_image=(RelativeLayout)v.findViewById(R.id.cartoon_image);
ImageView ivDummy =(ImageView)v.findViewById(R.id.dummy);
try{
loader.DisplayImageRelative( al_new.get(position).replace(" ", "%20"),ivDummy, Cartoon_image);
}
catch(Exception e){
e.printStackTrace();
}
return v;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return al_new.size();
}
@Override
public Object getItem(int arg0) {
// TODO Auto-generated method stub
return null;
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
}
}
这是我的自定义dragDrop视图：
public class ConstrainedDragAndDropView extends LinearLayout {
Activity main;
protected View dragHandle,half,heart;
protected List<View> dropTargets = new ArrayList<View>();
protected boolean dragging = false;
protected int pointerId;
protected int selectedDropTargetIndex = -1;
protected int lastSelectedDropTargetIndex = -1;
protected int lastDroppedIndex = -1;
protected boolean allowHorizontalDrag = true;
protected boolean allowVerticalDrag = true;
protected DropListener dropListener;
public interface DropListener {
public void onDrop(final int dropIndex, final View dropTarget);
}
public ConstrainedDragAndDropView(Context context) {
super(context);
}
public ConstrainedDragAndDropView(Context context, AttributeSet attrs) {
super(context, attrs);
applyAttrs(context, attrs);
}
@SuppressLint("NewApi")
public ConstrainedDragAndDropView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
applyAttrs(context, attrs);
}
public DropListener getDropListener() {
return dropListener;
}
public void setDropListener(DropListener dropListener) {
this.dropListener = dropListener;
}
public View getDragHandle() {
return dragHandle;
}
public void setDragHandle(View dragHandle,View half_left,View heart) {
this.dragHandle = dragHandle;
this.half=half_left;
this.heart=heart;
setupDragHandle();
}
public List<View> getDropTargets() {
return dropTargets;
}
public void setDropTargets(List<View> dropTargets) {
this.dropTargets = dropTargets;
}
public void addDropTarget(View target) {
if (dropTargets == null) {
dropTargets = new ArrayList<View>();
}
dropTargets.add(target);
}
public boolean isAllowHorizontalDrag() {
return allowHorizontalDrag;
}
public void setAllowHorizontalDrag(boolean allowHorizontalDrag) {
this.allowHorizontalDrag = allowHorizontalDrag;
}
public boolean isAllowVerticalDrag() {
return allowVerticalDrag;
}
public void setAllowVerticalDrag(boolean allowVerticalDrag,Activity c) {
this.allowVerticalDrag = allowVerticalDrag;
this.main=c;
}
protected void applyAttrs(Context context, AttributeSet attrs) {
TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.ConstrainedDragAndDropView, 0, 0);
try {
/*
layoutId = a.getResourceId(R.styleable.ConstrainedDragAndDropView_layoutId, 0);
if (layoutId > 0) {
LayoutInflater.from(context).inflate(layoutId, this, true);
}
*/
} finally {
a.recycle();
}
}
protected void setupDragHandle() {
this.setOnTouchListener(new DragAreaTouchListener());
}
protected class DragAreaTouchListener implements OnTouchListener {
public boolean onTouch(View view, MotionEvent motionEvent) {
switch (motionEvent.getAction()) {
case MotionEvent.ACTION_DOWN:
Log.d("Action down", "action down in listener");
onActionDown(view, motionEvent);
break;
case MotionEvent.ACTION_UP:
Log.d("Action up", "action up in listener");
onActionUp(view, motionEvent);
break;
case MotionEvent.ACTION_MOVE:
Log.d("Action move", "action move in listener");
onActionMove(view, motionEvent);
break;
default:
break;
}
return true;
}
}
public static int param;
protected void onActionDown(View view, MotionEvent motionEvent) {
// if we're not already dragging, and the touch position is on the drag handle,
// then start dragging
if(!dragging && isDragHandleTouch(motionEvent)) {
pointerId = motionEvent.getPointerId(0);
Float s1= dragHandle.getX();
param=Integer.valueOf(s1.intValue());
Log.e("param",""+param);
// updateDragPosition(motionEvent);
dragging = true;
Log.d("drag", "drag start");
}
}
protected void onActionUp(View view, MotionEvent motionEvent) {
Log.d("Action up", "action up");
// if we're dragging, then stop dragging
if (dragging && motionEvent.getPointerId(0) == pointerId) {
Log.e("condition","satisfied");
Log.e("x val"+(int)motionEvent.getX(),"y val"+(int)motionEvent.getY());
Log.e("x1"+half.getLeft(),"y1"+half.getTop());
Log.e("x4"+half.getRight(),"y4"+half.getBottom());
Float s1=motionEvent.getX();
Float s2=motionEvent.getY();
int x=Integer.valueOf(s1.intValue());
dragging = false;
int y=Integer.valueOf(s2.intValue());
if((half.getLeft()<x)&&(x<half.getRight())&&((half.getTop()<y)&&(y<half.getBottom())))
{
Log.e("drop","on target");
try {
Thread.sleep(1000);
dragHandle.setX(param);
heart.setVisibility(View.VISIBLE);
Animation pulse = AnimationUtils.loadAnimation(main, R.anim.pulse);
heart.startAnimation(pulse);
// heart.setVisibility(View.GONE);
pulse.setAnimationListener(new AnimationListener() {
public void onAnimationStart(Animation animation) {
// TODO Auto-generated method stub
Log.e("animation","start");
}
public void onAnimationRepeat(Animation animation) {
// TODO Auto-generated method stub
}
public void onAnimationEnd(Animation animation) {
// TODO Auto-generated method stub
Log.e("animation","end");
heart.setVisibility(View.GONE);
}
});
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// class SimpleThread extends Thread {
//
// public void run() {
//
// try {
// sleep(1000);
// runOnUiThread(new Runnable() {
// public void run() {
// dragHandle.setX(param);
// heart.setVisibility(View.VISIBLE);
//
// Animation pulse = AnimationUtils.loadAnimation(main, R.anim.pulse);
// heart.startAnimation(pulse);
// }
// });
//
// }
// catch (InterruptedException e) {
// // TODO Auto-generated catch block
// e.printStackTrace();
// }
//
// }
// }
//
// new SimpleThread().start();
}
else{
Log.e("drop",""+"outside target");
dragHandle.setX(param);
// TranslateAnimation transAnimation= new TranslateAnimation(x, 300, y, 300);
// transAnimation.setDuration(1000);//set duration
// view.startAnimation(transAnimation);
}
// if()
// updateDragPosition(motionEvent);
Log.d("drag", "drag end");
// find out what drop target, if any, the drag handle was dropped on
int dropTargetIndex = findDropTargetIndexUnderDragHandle();
if(dropTargetIndex >= 0) { // if drop was on a target, select the target
Log.d("drag", "drop on target " + dropTargetIndex);
// selectDropTarget(dropTargetIndex);
// snapDragHandleToDropTarget(dropTargetIndex);
// lastDroppedIndex = dropTargetIndex;
if(dropListener != null) {
dropListener.onDrop(dropTargetIndex, dropTargets.get(dropTargetIndex));
}
} else { // if drop was not on a target, re-select the last selected target
// deselectDropTarget();
// snapDragHandleToDropTarget(lastDroppedIndex);
}
}
else{
Log.e("condition not","satisfied");
}
}
protected void onActionMove(View view, MotionEvent motionEvent) {
Log.d("Action move", "action move");
if (dragging && motionEvent.getPointerId(0) == pointerId) {
updateDragPosition(motionEvent);
int dropTargetIndex = findDropTargetIndexUnderDragHandle();
if(dropTargetIndex >= 0) {
Log.d("drag", "hover on target " + dropTargetIndex);
// selectDropTarget(dropTargetIndex);
} else {
// deselectDropTarget();
}
}
}
@SuppressLint("NewApi")
protected void updateDragPosition(MotionEvent motionEvent) {
// this is where we constrain the movement of the dragHandle
if(allowHorizontalDrag) {
float candidateX = motionEvent.getX() - dragHandle.getWidth() / 2;
if(candidateX > 0 && candidateX + dragHandle.getWidth() < this.getWidth()) {
dragHandle.setX(candidateX);
}
}
if(allowVerticalDrag) {
float candidateY = motionEvent.getY() - dragHandle.getHeight() / 2;
if(candidateY > 0 && candidateY + dragHandle.getHeight() < this.getHeight()) {
dragHandle.setY(candidateY);
}
}
}
@SuppressLint("NewApi")
protected void snapDragHandleToDropTarget(int dropTargetIndex) {
if(dropTargetIndex > -1) {
View dropTarget = dropTargets.get(dropTargetIndex);
float xCenter = dropTarget.getX() + dropTarget.getWidth() / 2;
float yCenter = dropTarget.getY() + dropTarget.getHeight() / 2;
float xOffset = dragHandle.getWidth() / 2;
float yOffset = dragHandle.getHeight() / 2;
float x = xCenter - xOffset;
float y = yCenter - yOffset;
dragHandle.setX(x);
dragHandle.setY(y);
}
}
protected boolean isDragHandleTouch(MotionEvent motionEvent) {
Point point = new Point(
new Float(motionEvent.getRawX()).intValue(),
new Float(motionEvent.getRawY()).intValue()
);
return isPointInView(point, dragHandle);
}
protected int findDropTargetIndexUnderDragHandle() {
int dropTargetIndex = -1;
for(int i = 0; i < dropTargets.size(); i++) {
if(isCollision(dragHandle, dropTargets.get(i))) {
dropTargetIndex = i;
break;
}
}
return dropTargetIndex;
}
/**
* Determines whether a raw screen coordinate is within the bounds of the specified view
* @param point - Point containing screen coordinates
* @param view - View to test
* @return true if the point is in the view, else false
*/
protected boolean isPointInView(Point point, View view) {
int[] viewPosition = new int[2];
view.getLocationOnScreen(viewPosition);
int left = viewPosition[0];
int right = left + view.getWidth();
int top = viewPosition[1];
int bottom = top + view.getHeight();
return point.x >= left && point.x <= right && point.y >= top && point.y <= bottom;
}
@SuppressLint("NewApi")
protected boolean isCollision(View view1, View view2) {
boolean collision = false;
do {
if(view1.getY() + view1.getHeight() < view2.getY()) {
break;
}
if(view1.getY() > view2.getY() + view2.getHeight()) {
break;
}
if(view1.getX() > view2.getX() + view2.getWidth()) {
break;
}
if(view1.getX() + view1.getWidth() < view2.getX()) {
break;
}
collision = true;
} while(false);
return collision;
}
protected void selectDropTarget(int index) {
if(index > -1) {
deselectDropTarget();
selectedDropTargetIndex = index;
dropTargets.get(selectedDropTargetIndex).setSelected(true);
}
}
protected void deselectDropTarget() {
if(selectedDropTargetIndex > -1) {
dropTargets.get(selectedDropTargetIndex).setSelected(false);
lastSelectedDropTargetIndex = selectedDropTargetIndex;
selectedDropTargetIndex = -1;
}
}
}