android - 如何在android中拖动多个图像

Question

我可以在 Canvas 上拖动一张图片。现在我想拖动多张图片。有没有可能这样做？

Answer 1

使用此代码对您很有帮助，如果有帮助请点击右边。

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 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);
}
  }

而Xml是……

 <?xml version="1.0" encoding="utf-8"?>
 <AbsoluteLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent"  
    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>