2

上一个问题我已经开始了，但是我想改变拖动的方法。

所以任务是，用户（孩子）学习如何做加法。所以有 2 个糖果和 1 个糖果罐。用户需要将糖果拖放到罐子中。怎么做？

这些是我的代码：

主要的 xml

<?xml version="1.0" encoding="utf-8"?>


<AbsoluteLayout android:layout_width="fill_parent" android:layout_height="fill_parent" xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/mainLayout">
<ImageView android:layout_height="wrap_content" android:layout_width="wrap_content" android:id="@+id/emptyLetterView" android:src="@drawable/r_empty" android:layout_x="200px" android:layout_y="300px"></ImageView>
<ImageView android:layout_height="wrap_content" android:layout_width="wrap_content" android:id="@+id/letterView" android:src="@drawable/r_filled" ></ImageView>
</AbsoluteLayout>

这是java文件包edu.sbcc.cs123.draganddropbasic；

import android.app.*;
import android.graphics.*;
import android.os.*;
import android.view.*;
import android.view.View.*;
import android.widget.*;

@SuppressWarnings("deprecation")
public class DragAndDropBasicActivity extends Activity implements OnTouchListener {
    private ImageView letterView;                       // The letter that the user drags.
    private ImageView emptyLetterView;              // The letter outline that the user is supposed to drag letterView to.
    private AbsoluteLayout mainLayout;


    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        mainLayout = (AbsoluteLayout) findViewById(R.id.mainLayout);
        mainLayout.setOnTouchListener(this);
        letterView = (ImageView) findViewById(R.id.letterView);
        letterView.setOnTouchListener(this);

        emptyLetterView = (ImageView) findViewById(R.id.emptyLetterView);
    }

    private boolean dragging = false;
    private Rect hitRect = new Rect();

    @Override
    /**
     * NOTE:  Had significant problems when I tried to react to ACTION_MOVE on letterView.   Kept getting alternating (X,Y) 
     * locations of the motion events, which caused the letter to flicker and move back and forth.  The only solution I could 
     * find was to determine when the user had touched down on the letter, then process moves in the ACTION_MOVE 
     * associated with the mainLayout.
     */
    public boolean onTouch(View v, MotionEvent event) {
        boolean eventConsumed = true;
        int x = (int)event.getX();
        int y = (int)event.getY();

        int action = event.getAction();
        if (action == MotionEvent.ACTION_DOWN) {
            if (v == letterView) {
                dragging = true;
                eventConsumed = false;
            }
        } else if (action == MotionEvent.ACTION_UP) {

            if (dragging) {
                emptyLetterView.getHitRect(hitRect);
                if (hitRect.contains(x, y))
                    setSameAbsoluteLocation(letterView, emptyLetterView);
            }
            dragging = false;
            eventConsumed = false;

        } else if (action == MotionEvent.ACTION_MOVE) {
            if (v != letterView) {
                if (dragging) {
                    setAbsoluteLocationCentered(letterView, x, y);
                }
            }
        }

        return eventConsumed;

    }


    private void setSameAbsoluteLocation(View v1, View v2) {
        AbsoluteLayout.LayoutParams alp2 = (AbsoluteLayout.LayoutParams) v2.getLayoutParams();
        setAbsoluteLocation(v1, alp2.x, alp2.y);
    }


    private void setAbsoluteLocationCentered(View v, int x, int y) {
        setAbsoluteLocation(v, x - v.getWidth() / 2, y - v.getHeight() / 2);
    }


    private void setAbsoluteLocation(View v, int x, int y) {
        AbsoluteLayout.LayoutParams alp = (AbsoluteLayout.LayoutParams) v.getLayoutParams();
        alp.x = x;
        alp.y = y;
        v.setLayoutParams(alp);
    }
}

这就是我已经实现了一段时间我只是添加新变量并将其更改为 letterView1 和 emptyLetterView1

Java 文件：

package edu.sbcc.cs123.draganddropbasic;

import android.app.*;
import android.graphics.*;
import android.os.*;
import android.view.*;
import android.view.View.*;
import android.widget.*;

@SuppressWarnings("deprecation")
public class DragAndDropBasicActivity extends Activity implements OnTouchListener {
    private ImageView letterView;                       // The letter that the user drags.
    private ImageView emptyLetterView;          // The letter outline that the user is supposed to drag letterView to.
    private ImageView letterView1;                      // The letter that the user drags.
    private ImageView emptyLetterView1; 
    private AbsoluteLayout mainLayout;


    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        mainLayout = (AbsoluteLayout) findViewById(R.id.mainLayout);
        mainLayout.setOnTouchListener(this);
        letterView = (ImageView) findViewById(R.id.letterView);
        letterView.setOnTouchListener(this);

        emptyLetterView = (ImageView) findViewById(R.id.emptyLetterView);

        letterView1 = (ImageView) findViewById(R.id.letterView1);
        letterView1.setOnTouchListener(this);

        emptyLetterView1 = (ImageView) findViewById(R.id.emptyLetterView1);
    }

    private boolean dragging = false;
    private Rect hitRect = new Rect();

    @Override
    /**
     * NOTE:  Had significant problems when I tried to react to ACTION_MOVE on letterView.   Kept getting alternating (X,Y) 
     * locations of the motion events, which caused the letter to flicker and move back and forth.  The only solution I could 
     * find was to determine when the user had touched down on the letter, then process moves in the ACTION_MOVE 
     * associated with the mainLayout.
     */
    public boolean onTouch(View v, MotionEvent event) {
        boolean eventConsumed = true;
        int x = (int)event.getX();
        int y = (int)event.getY();

        int action = event.getAction();
        if (action == MotionEvent.ACTION_DOWN) {
            if (v == letterView) {
                dragging = true;
                eventConsumed = false;
            }
            if (v == letterView1) {
                dragging = true;
                eventConsumed = false;
            }
        } else if (action == MotionEvent.ACTION_UP) {

            if (dragging) {
                emptyLetterView.getHitRect(hitRect);
                if (hitRect.contains(x, y))
                    setSameAbsoluteLocation(letterView, emptyLetterView);
            }

            if (dragging) {
                emptyLetterView1.getHitRect(hitRect);
                if (hitRect.contains(x, y))
                    setSameAbsoluteLocation1(letterView1, emptyLetterView1);
            }
            dragging = false;
            eventConsumed = true;

        } else if (action == MotionEvent.ACTION_MOVE) {
            if (v != letterView) {
                if (dragging) {
                    setAbsoluteLocationCentered(letterView, x, y);
                }
            }
            if (v != letterView1) {
                if (dragging) {
                    setAbsoluteLocationCentered1(letterView1, x, y);
                }
            }
        }

        return eventConsumed;

    }


    private void setSameAbsoluteLocation(View v1, View v2) {
        AbsoluteLayout.LayoutParams alp2 = (AbsoluteLayout.LayoutParams) v2.getLayoutParams();
        setAbsoluteLocation(v1, alp2.x, alp2.y);
    }


    private void setAbsoluteLocationCentered(View v, int x, int y) {
        setAbsoluteLocation(v, x - v.getWidth() / 2, y - v.getHeight() / 2);
    }


    private void setAbsoluteLocation(View v, int x, int y) {
        AbsoluteLayout.LayoutParams alp = (AbsoluteLayout.LayoutParams) v.getLayoutParams();
        alp.x = x;
        alp.y = y;
        v.setLayoutParams(alp);
    }




    private void setSameAbsoluteLocation1(View v1, View v2) {
        AbsoluteLayout.LayoutParams alp2 = (AbsoluteLayout.LayoutParams) v2.getLayoutParams();
        setAbsoluteLocation1(v1, alp2.x, alp2.y);
    }


    private void setAbsoluteLocationCentered1(View v, int x, int y) {
        setAbsoluteLocation1(v, x - v.getWidth() / 2, y - v.getHeight() / 2);
    }


    private void setAbsoluteLocation1(View v, int x, int y) {
        AbsoluteLayout.LayoutParams alp = (AbsoluteLayout.LayoutParams) v.getLayoutParams();
        alp.x = x;
        alp.y = y;
        v.setLayoutParams(alp);
    }
}

我已将图像文件添加到 xml 文件中，并将 id 更改为 letterView1 和 emptyLetterView1。

所以成功显示了另一张图片，但是，当我拖动其中一张时，另一张图片消失了。

请问我该如何实施？

4

2 回答 2

3

我会将您的解决方案基于以下代码/信息：

于 2013-01-12T10:04:05.120 回答
1

您的代码的问题在这里

else if (action == MotionEvent.ACTION_MOVE) {
        if (v != letterView) {
            if (dragging) {
                setAbsoluteLocationCentered(letterView, x, y);
            }
        }
        if (v != letterView1) {
            if (dragging) {
                setAbsoluteLocationCentered1(letterView1, x, y);
            }
        }
    }

现在在您之前的代码中有 2 个侦听器。

  1. 主要背景
  2. 这letterView

现在您有 3 个侦听器，if (v != letterView)如果用户在地面或字母上拖动，这将是真的。

例如，如果您开始在随机屏幕上拖动，v!=letterView然后v!=letterView1. 然后它们都将居中到同一点，因此一个会显得隐藏。

如果您拖动其中一个，同样适用。另一个将移动到该点并显示为隐藏。

而不是使用非方程，你可以尝试

else if (action == MotionEvent.ACTION_MOVE) {
        if (v == letterView) {
            if (dragging) {
                setAbsoluteLocationCentered(letterView, x, y);
            }
        }
        if (v == letterView1) {
            if (dragging) {
                setAbsoluteLocationCentered1(letterView1, x, y);
            }
        }
    }

或者你甚至可以做一个命中测试

   else if (action == MotionEvent.ACTION_MOVE) {
        letterView.getHitRect(hitRect);
        if (letterView.contains(x,y)) {
            if (dragging) {
                setAbsoluteLocationCentered(letterView, x, y);
            }
        }
        letterView1.getHitRect(hitRect);
        if (letterView1.contains(x,y)) {
            if (dragging) {
                setAbsoluteLocationCentered1(letterView1, x, y);
            }
        }
  }
于 2013-01-13T10:00:52.710 回答