【发布时间】：2013-06-25 00:28:49
【问题描述】：
我已经给出了我所拥有的完整代码。
下面的代码可以非常流畅地拖放，但它不像下面描述的那样工作。
- 拖动数据是（Apple、Orage、Ball）
- 放置目标位置是（A 代表，O 代表，B 代表）
因此，如果将“Apple”拖放到“A for”，它将是正确的并将文本更新为“A for Apple”，并且拖动时的文本“Apple”将被隐藏......但是如果我们拖动“Apple”拖放到“O for”或“B for”将失败，因为“O for Orange”和“B for Ball”。
根据下面的代码，我应该添加什么。
布局：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="10dp"
android:paddingLeft="50dp"
android:paddingRight="50dp" >
<TextView
android:id="@+id/option_1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:background="@drawable/option"
android:gravity="center"
android:text="Apple"
android:textStyle="bold" />
<TextView
android:id="@+id/option_2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:background="@drawable/option"
android:gravity="center"
android:text="Orange"
android:textStyle="bold" />
<TextView
android:id="@+id/option_3"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:background="@drawable/option"
android:gravity="center"
android:text="Ball"
android:textStyle="bold" />
<TextView
android:id="@+id/choice_1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:background="@drawable/choice"
android:gravity="center"
android:text="A for " />
<TextView
android:id="@+id/choice_2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:background="@drawable/choice"
android:gravity="center"
android:text="O for" />
<TextView
android:id="@+id/choice_3"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:background="@drawable/choice"
android:gravity="center"
android:text="B for " />
</LinearLayout>
活动：
public class picture_to_word_24_color extends Activity {
//text views being dragged and dropped onto
private TextView option1, option2, option3, choice1, choice2, choice3;
public CharSequence dragData;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.picture_to_word_24_color);
//get both sets of text views
//views to drag
option1 = (TextView)findViewById(R.id.option_1);
option2 = (TextView)findViewById(R.id.option_2);
option3 = (TextView)findViewById(R.id.option_3);
//views to drop onto
choice1 = (TextView)findViewById(R.id.choice_1);
choice2 = (TextView)findViewById(R.id.choice_2);
choice3 = (TextView)findViewById(R.id.choice_3);
//set touch listeners
option1.setOnTouchListener(new ChoiceTouchListener());
option2.setOnTouchListener(new ChoiceTouchListener());
option3.setOnTouchListener(new ChoiceTouchListener());
//set drag listeners
choice1.setOnDragListener(new ChoiceDragListener());
choice2.setOnDragListener(new ChoiceDragListener());
choice3.setOnDragListener(new ChoiceDragListener());
}
/**
* ChoiceTouchListener will handle touch events on draggable views
*
*/
private final class ChoiceTouchListener implements OnTouchListener {
@SuppressLint("NewApi")
public boolean onTouch(View view, MotionEvent motionEvent) {
if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) {
/*
* Drag details: we only need default behavior
* - clip data could be set to pass data as part of drag
* - shadow can be tailored
*/
ClipData data = ClipData.newPlainText("", "");
DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view);
//start dragging the item touched
view.startDrag(data, shadowBuilder, view, 0);
return true;
} else {
return false;
}
}
}
/**
* DragListener will handle dragged views being dropped on the drop area
* - only the drop action will have processing added to it as we are not
* - amending the default behavior for other parts of the drag process
*
*/
@SuppressLint("NewApi")
private class ChoiceDragListener implements OnDragListener {
@Override
public boolean onDrag(View v, DragEvent event) {
switch (event.getAction()) {
case DragEvent.ACTION_DRAG_STARTED:
//no action necessary
break;
case DragEvent.ACTION_DRAG_ENTERED:
//no action necessary
Toast.makeText(picture_to_word_24_color.this, "ACTION_DRAG_ENTERED", Toast.LENGTH_SHORT).show();
break;
case DragEvent.ACTION_DRAG_EXITED:
//no action necessary
Toast.makeText(picture_to_word_24_color.this, "ACTION_DRAG_EXITED", Toast.LENGTH_SHORT).show();
break;
case DragEvent.ACTION_DROP:
Toast.makeText(picture_to_word_24_color.this, "ACTION_DROP", Toast.LENGTH_SHORT).show();
//handle the dragged view being dropped over a drop view
View view = (View) event.getLocalState();
//stop displaying the view where it was before it was dragged
view.setVisibility(View.INVISIBLE);
//view dragged item is being dropped on
TextView dropTarget = (TextView) v;
//view being dragged and dropped
TextView dropped = (TextView) view;
//update the text in the target view to reflect the data being dropped
dropTarget.setText(dropped.getText());
//make it bold to highlight the fact that an item has been dropped
dropTarget.setTypeface(Typeface.DEFAULT_BOLD);
//if an item has already been dropped here, there will be a tag
Object tag = dropTarget.getTag();
//if there is already an item here, set it back visible in its original place
if(tag!=null)
{
//the tag is the view id already dropped here
int existingID = (Integer)tag;
//set the original view visible again
findViewById(existingID).setVisibility(View.VISIBLE);
}
//set the tag in the target view being dropped on - to the ID of the view being dropped
dropTarget.setTag(dropped.getId());
break;
case DragEvent.ACTION_DRAG_ENDED:
//no action necessary
Toast.makeText(picture_to_word_24_color.this, "ACTION_DRAG_ENDED", Toast.LENGTH_SHORT).show();
break;
default:
break;
}
return true;
}
}
}
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标签： android drag-and-drop