Drag and Drop - در برنامه نویسی اندروید

کدهای فایل MainActivity.java

package com.seven.cloner.articleslib;

import androidx.appcompat.app.AppCompatActivity;

import android.content.ClipData;
import android.content.ClipDescription;
import android.os.Bundle;
import android.util.Log;
import android.view.DragEvent;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
import android.widget.RelativeLayout;

public class MainActivity extends AppCompatActivity {

    private final String msg = "7CLONER:";
    private ImageView img;
    private android.widget.RelativeLayout.LayoutParams layoutParams;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        img= findViewById(R.id.imageView);

        img.setOnLongClickListener(v -> {
            ClipData.Item item = new ClipData.Item((CharSequence)v.getTag());
            String[] mimeTypes = {ClipDescription.MIMETYPE_TEXT_PLAIN};

            ClipData dragData = new ClipData(v.getTag().toString(),mimeTypes, item);
            View.DragShadowBuilder myShadow = new View.DragShadowBuilder(img);

            v.startDrag(dragData,myShadow,null,0);
            return true;
        });

        img.setOnDragListener((v, event) -> {
            switch(event.getAction()) {
                case DragEvent.ACTION_DRAG_STARTED:
                    layoutParams = (RelativeLayout.LayoutParams)v.getLayoutParams();
                    Log.d(msg, "Action => DragEvent.ACTION_DRAG_STARTED");

                    // Do nothing
                    break;

                case DragEvent.ACTION_DRAG_ENTERED:
                    Log.d(msg, "Action => DragEvent.ACTION_DRAG_ENTERED");
                    int x_cord = (int) event.getX();
                    int y_cord = (int) event.getY();
                    break;

                case DragEvent.ACTION_DRAG_EXITED :
                    Log.d(msg, "Action => DragEvent.ACTION_DRAG_EXITED");
                    x_cord = (int) event.getX();
                    y_cord = (int) event.getY();
                    layoutParams.leftMargin = x_cord;
                    layoutParams.topMargin = y_cord;
                    v.setLayoutParams(layoutParams);
                    break;

                case DragEvent.ACTION_DRAG_LOCATION  :
                    Log.d(msg, "Action => DragEvent.ACTION_DRAG_LOCATION");
                    x_cord = (int) event.getX();
                    y_cord = (int) event.getY();
                    break;

                case DragEvent.ACTION_DRAG_ENDED   :
                    Log.d(msg, "Action => DragEvent.ACTION_DRAG_ENDED");

                    // Do nothing
                    break;

                case DragEvent.ACTION_DROP:
                    Log.d(msg, "ACTION_DROP event");

                    // Do nothing
                    break;
                default: break;
            }
            return true;
        });

        img.setOnTouchListener((v, event) -> {
            if (event.getAction() == MotionEvent.ACTION_DOWN) {
                ClipData data = ClipData.newPlainText("", "");
                View.DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(img);

                img.startDrag(data, shadowBuilder, img, 0);
                img.setVisibility(View.INVISIBLE);
                return true;
            } else {
                return false;
            }
        });
    }

}

فایل activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:text="Drag and Drop مثال"
        android:textSize="30dp" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/textView"
        android:layout_centerHorizontal="true"
        android:text="7Cloner.com"
        android:textColor="#009688"
        android:textSize="30dp" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/textView2"
        android:layout_alignStart="@+id/textView2"
        android:layout_alignEnd="@+id/textView2"
        android:contentDescription="@string/empty"
        android:src="@drawable/abc" />

</RelativeLayout>

اکنون روی لوگوی 7CLONER کلیک کنید و آن را رها نکنید. خواهید دید که تصویر لوگو کمی بعد از یک کلیک طولانی از جای خود حرکت می کند و حالا میتوانید آنرا جابجا کنید. می توانید آن را در اطراف صفحه بکشید و در مکانی جدید رها کنید.