Question

如何检索drop target的id（调用ChoiceDragListener（）类的按钮）
如何指定拖放限制，即。可以完成“拖放”多少次

这是我的代码

设计activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:background="@drawable/g"
android:paddingTop="@dimen/activity_vertical_margin"
android:orientation="vertical"
tools:context=".MainActivity" >

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/hello_world" />

  <TableLayout 
     android:id="@+id/table"
     android:paddingTop="50dp"
    android:layout_width="wrap_content"    
           android:layout_height="wrap_content">


    <TableRow >
        <Button android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b1"          
           android:layout_margin="5dp"
          android:background="@android:color/transparent"
          android:textSize="26sp" 

              android:text="a"/>
         <Button android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b2"          
           android:layout_margin="5dp"
          android:background="@android:color/transparent"
          android:textSize="26sp" 

              android:text="b"/>


        </TableRow>
         <TableRow >
        <Button android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b3"          
           android:layout_margin="5dp"
          android:background="@android:color/transparent"
          android:textSize="26sp" 
              android:text="1"/>
          <Button android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b4"          
           android:layout_margin="5dp"
          android:background="@android:color/transparent"
          android:textSize="26sp" 

              android:text="2"/>

        </TableRow> <TableRow >
          <Button android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b5"          
           android:layout_margin="5dp"
          android:background="@android:color/transparent"
          android:textSize="26sp" 

              android:text="A"/>
          <Button android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b6"          
           android:layout_margin="5dp"
          android:background="@android:color/transparent"
          android:textSize="26sp" 

              android:text="B"/>

        </TableRow>
</TableLayout>

MainActivity.java

          package com.example.in;

                  import android.os.Build;

                 import android.os.Bundle;

            import android.annotation.SuppressLint;

          import android.annotation.TargetApi;
        import android.app.Activity;
          import android.content.ClipData;
           import android.graphics.Color;
      import android.graphics.Typeface;
       import android.view.DragEvent;
         import android.view.Menu;
        import android.view.MotionEvent;
         import android.view.View;
        import android.view.View.DragShadowBuilder;
        import android.view.View.OnDragListener;
       import android.view.View.OnTouchListener;
        import android.widget.Button;
      import android.widget.TextView;
     import android.widget.Toast;

  public class MainActivity extends Activity {
Button b1,b2,b3,b4,b5,b6;

@TargetApi(Build.VERSION_CODES.HONEYCOMB)
@SuppressLint("NewApi")
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    final String BTN_TAG ="BUTTON";
    setContentView(R.layout.activity_main);



     Button b1=(Button) findViewById(R.id.b1);

    Button b2=(Button) findViewById(R.id.b2);

    Button b3=(Button) findViewById(R.id.b3);

    Button b4=(Button) findViewById(R.id.b4);

    Button b5=(Button) findViewById(R.id.b5);

    Button b6=(Button) findViewById(R.id.b6);


    //b1.setTag(BTN_TAG);


    b1.setOnTouchListener(new ChoiceTouchListener());
    b2.setOnTouchListener(new ChoiceTouchListener());
    b3.setOnTouchListener(new ChoiceTouchListener());


    b4.setOnDragListener(new ChoiceDragListener());
    b5.setOnDragListener(new ChoiceDragListener());
    b6.setOnDragListener(new ChoiceDragListener());

}
@SuppressWarnings("unused")
private final class ChoiceTouchListener implements OnTouchListener {
    @SuppressLint("NewApi")
    @Override
    public boolean onTouch(View view, MotionEvent motionEvent) {
        if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) {

            ClipData data = ClipData.newPlainText("", "");
            DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view);

            view.startDrag(data, shadowBuilder, view, 0);
            return true;
        } else {
            return false;
        }
    }
} 

@SuppressLint("NewApi")
private class ChoiceDragListener implements OnDragListener {

    @Override
    public boolean onDrag(View v, DragEvent event) {
        switch (event.getAction()) {
        case DragEvent.ACTION_DRAG_STARTED:

            break;
        case DragEvent.ACTION_DRAG_ENTERED:


            break;
        case DragEvent.ACTION_DRAG_EXITED:    

            //no action necessary
            break;
        case DragEvent.ACTION_DROP:


            View view = (View) event.getLocalState();

            Button dropTarget = (Button) v;

            Button dropped = (Button) view;
            dropTarget.setText(dropTarget.getText().toString() + dropped.getText().toString());
        case DragEvent.ACTION_DRAG_ENDED:
            //no action necessary
            break;
        default:
            break;
        }
        return true;
    }
} 

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

}

Answer 1

您可以使用本地计数变量来计算拖放次数。
您可以在切换案例陈述中使用v.getId();来获取拖放视图的ID ...

Answer 2

使用地图跟踪每个项目被拖动的次数

Map<Integer, Integer> dragMap = new HashMap<Integer, Integer>();

在onDrag()方法中，您可以向dragMap添加新项目或增加与现有项目相关的计数

if (dragMap.get(dragTarget.getId() == null) {
    dragMap.put(dragTarget.getId(), 1);
}
else {
    dragMap.put(dragTarget.getId(), 
                dragMap.get(dragTarget.getId()++);
}

您需要一些额外的代码来检查项目被拖动的次数，如果超过某个数字，则阻止拖动操作。此代码将放在DragEvent.ACTION_DRAG_STARTED:块中。

如何限制拖放次数

2 个答案: