任何人都可以帮我解决如何为可能在屏幕上拖动的图像编写程序的问题吗？你能给我一个示例代码吗？非常感谢。我怎么能为它做一个游戏得分。我将非常感谢您的回复。
答案 0 :(得分：4)
imageView.setOnLongClickListener(new OnLongClickListener() {
public boolean onLongClick(View v) {
modeEdit = false;
ClipData.Item item = new ClipData.Item((CharSequence) v.getTag());
String[] mimeTypes = {ClipDescription.MIMETYPE_TEXT_PLAIN};
ClipData dragData = new ClipData(v.getTag().toString(), mimeTypes, item);
// Instantiates the drag shadow builder.
DragShadowBuilder myShadow = new MyDragShadowBuilder(treeBitmap);
v.startDrag(dragData, // the data to be dragged
myShadow, // the drag shadow builder
treeBitmap, // no need to use local data
0 // flags (not currently used, set to 0)
);
return true;
}
});
以下代码用于设置拖动侦听器
MyDragEventListener mDragListen = new MyDragEventListener();
这是拖动侦听器
protected class MyDragEventListener implements OnDragListener {
public boolean onDrag(View v, DragEvent event) {
final int action = event.getAction();
switch(action) {
case DragEvent.ACTION_DRAG_STARTED:
Log.d(TAG, "FIELD ACTION_DRAG_STARTED");
if (event.getClipDescription().hasMimeType(ClipDescription.MIMETYPE_TEXT_PLAIN)) {
v.invalidate();
return(true);
}
else {
return(false);
}
case DragEvent.ACTION_DRAG_ENTERED:
Log.d(TAG, "FIELD ACTION_DRAG_ENTERED");
treePresentInMyView = true;
//Toast.makeText(getApplicationContext(), "Dragged data entered", Toast.LENGTH_LONG).show();
v.invalidate();
return(true);
case DragEvent.ACTION_DRAG_LOCATION:
Log.d(TAG, "FIELD ACTION_DRAG_LOCATION");
positionX = event.getX();
positionY = event.getY();
layoutParams = v.getLayoutParams();
return(true);
case DragEvent.ACTION_DRAG_EXITED:
Log.d(TAG, "FIELD ACTION_DRAG_EXITED");
modeEdit = false;
treePresentInMyView = false;
//Toast.makeText(getApplicationContext(), "Dragged data exited", Toast.LENGTH_LONG).show();
v.invalidate();
return(true);
case DragEvent.ACTION_DROP:
Log.d(TAG, "FIELD ACTION_DROP");
keyOfTree = event.getClipDescription().getLabel().toString();
Log.d(TAG, "KEY VALUE = "+keyOfTree);
final ImageView view = new ImageView(getApplicationContext());
String treeWidth = getResources().getString(R.string.treeWidth);
String treeHeight = getResources().getString(R.string.treeHeight);
RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(Integer.parseInt(treeWidth), Integer.parseInt(treeHeight));
view.setLayoutParams(params);
view.setImageResource(R.drawable.tree1);
//to get image width and height:
BitmapFactory.Options o = new BitmapFactory.Options();
o.inTargetDensity = DisplayMetrics.DENSITY_DEFAULT;
Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.tree1, o);
int w = bmp.getWidth();
int h = bmp.getHeight();
Log.d(TAG, "width = " + w + " height = " +h);
params.leftMargin = (int) positionX - w;//-w and -h so dragged image placed not at mouse
params.topMargin = (int) positionY - h;// but where actual image is on map
view.setVisibility(View.VISIBLE);
openField.addView(view);
LinearLayout.LayoutParams paramsOpenField = new LinearLayout.LayoutParams(openFieldWidth, openFieldHeight);
openField.setLayoutParams(paramsOpenField);
try {
Thread.sleep(1000);
}
catch (InterruptedException e) {
e.printStackTrace();
}
v.invalidate();
return true;
case DragEvent.ACTION_DRAG_ENDED:
Log.d(TAG, "FIELD ACTION_DRAG_ENDED");
v.invalidate();
if (event.getResult() & treePresentInMyView) {
Log.d(TAG, "(x,y) = ("+positionX+", "+positionY+")");
int subSubPlot = 0;
if (positionX > openField.measuredWidth/2) { //3 and 4
if (positionY > openField.measuredHeight/2) {
subSubPlot = 4;
}
else {
subSubPlot = 3;
}
}
else {
if (positionY > openField.measuredHeight/2) {
subSubPlot = 1;
}
else {
subSubPlot = 2;
}
}
double latitudeOfTree = mValues[0] + (Math.abs(mValues[0] - mValues[2]) / openField.measuredWidth) * positionX;
double longitudeOfTree = mValues[1] + (Math.abs(mValues[1] - mValues[3])/ openField.measuredHeight) * positionY;
// openField.drawTreeCoordinated(latitudeOfTree, longitudeOfTree, positionX, positionY);
return true;
}
else {
return false;
}
default:
Log.e(TAG,"Unknown action type received by OnDragListener.");
break;
};
return false;
}
};