DragnDropActivity.java

package net.vvakame.dragndrop;

import java.util.ArrayList;
import java.util.Arrays;

import net.vvakame.android.widget.DragnDropListView;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Toast;

public class DragnDropActivity extends Activity {
	private static String[] items = { "Alpha", "Bravo", "Charlie", "Delta",
			"Echo", "Foxtrot", "Golf", "Hotel", "India", "Juliet", "Kilo",
			"Lima", "Mike" };
	private ArrayList<String> array = new ArrayList<String>(Arrays
			.asList(items));
	private ArrayAdapter<String> adapter = null;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		adapter = new ArrayAdapter<String>(this,
				android.R.layout.simple_list_item_1, array);

		final DragnDropListView ddlist = (DragnDropListView) findViewById(R.id.list);
		ddlist.setAdapter(adapter);
		ddlist.setRemoveTile(findViewById(R.id.remove_tile));

		findViewById(R.id.sort).setOnClickListener(new View.OnClickListener() {
			@Override
			public void onClick(View v) {
				ddlist.setSortMode(!ddlist.isSortMode());
				Toast.makeText(DragnDropActivity.this,
						"SortMode=" + String.valueOf(ddlist.isSortMode()),
						Toast.LENGTH_SHORT).show();
			}
		});
	}
}

DragnDropListView.java

package net.vvakame.android.widget;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.util.Log;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;
import android.widget.Adapter;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.ListView;

public class DragnDropListView extends ListView {
	private static final String TAG = DragnDropListView.class.getSimpleName();
	private static final boolean DEBUG = false;

	private static final int SCROLL_SPEED_FAST = 25;
	private static final int SCROLL_SPEED_SLOW = 8;

	private boolean sortMode = false;
	private DragListener mDrag = new DragListenerImpl();
	private DropListener mDrop = new DropListenerImpl();
	private RemoveListener mRemove = new RemoveListenerImpl();

	public DragnDropListView(Context context, AttributeSet attrs) {
		this(context, attrs, 0);
	}

	public DragnDropListView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
	}

	private Bitmap mDragBitmap = null;
	private ImageView mDragView = null;
	private WindowManager.LayoutParams mWindowParams = null;
	private int mFrom = -1;

	private View mRemoveTile = null;
	private Rect mRemoveHit = null;

	@Override
	public boolean onTouchEvent(MotionEvent ev) {
		if (!sortMode) {
			return super.onTouchEvent(ev);
		}

		WindowManager wm = null;
		int index = -1;
		final int x = (int) ev.getX();
		final int y = (int) ev.getY();

		switch (ev.getAction()) {

		case MotionEvent.ACTION_DOWN:
			index = pointToIndex(ev);

			if (index < 0) {
				return false;
			}

			mFrom = index;
			startDrag(ev);

			// fall through

		case MotionEvent.ACTION_MOVE:

			final int height = getHeight();
			final int fastBound = height / 9;
			final int slowBound = height / 4;
			final int center = height / 2;

			int speed = 0;
			if (ev.getEventTime() - ev.getDownTime() < 500) {
				// 500ミリ秒間はスクロールなし
			} else if (y < slowBound) {
				speed = y < fastBound ? -SCROLL_SPEED_FAST : -SCROLL_SPEED_SLOW;
			} else if (y > height - slowBound) {
				speed = y > height - fastBound ? SCROLL_SPEED_FAST
						: SCROLL_SPEED_SLOW;
			}

			if (DEBUG) {
				Log
						.d(TAG, "ACTION_MOVE y=" + y + ", height=" + height
								+ ", fastBound=" + fastBound + ", slowBound="
								+ slowBound + ", center=" + center + ", speed="
								+ speed);
			}

			View v = null;
			if (speed != 0) {
				// 横方向はとりあえず考えない
				int centerPosition = pointToPosition(0, center);
				if (centerPosition == AdapterView.INVALID_POSITION) {
					centerPosition = pointToPosition(0, center
							+ getDividerHeight() + 64);
				}
				v = getChildByIndex(centerPosition);
				if (v != null) {
					int pos = v.getTop();
					setSelectionFromTop(centerPosition, pos - speed);
				}
			}

			if (mDragView != null) {
				if (mDragView.getHeight() < 0) {
					mDragView.setVisibility(View.INVISIBLE);
				} else {
					mDragView.setVisibility(View.VISIBLE);
				}
				mWindowParams.x = getLeft() + x - 130;
				mWindowParams.y = getTop() + y - 32;
				wm = (WindowManager) getContext().getSystemService("window");
				wm.updateViewLayout(mDragView, mWindowParams);

				if (mDrag != null) {
					index = pointToIndex(ev);
					mDrag.drag(mFrom, index);
				}

				return true;
			}

			break;

		case MotionEvent.ACTION_UP:

			if (mRemove != null && mRemoveTile != null
					|| mRemoveTile.getVisibility() == View.VISIBLE) {
				if (mRemoveHit == null) {
					mRemoveHit = new Rect();
				}
				mRemoveTile.getHitRect(mRemoveHit);
				if (mRemoveHit.contains(x + getLeft(), y + getTop())) {
					mRemove.remove(mFrom);
				}
			}
			if (mDrop != null) {
				index = pointToIndex(ev);
				mDrop.drop(mFrom, index);
			}

			// fall through

		case MotionEvent.ACTION_CANCEL:
		case MotionEvent.ACTION_OUTSIDE:

			if (mDragView != null) {
				wm = (WindowManager) getContext().getSystemService("window");
				wm.removeView(mDragView);
				mDragView = null;
				// リサイクルするとたまに死ぬけどタイミング分からない
				// mDragBitmap.recycle();
				mDragBitmap = null;

				return true;
			}

			break;

		default:
			Log.d(TAG, "Unknown event action=" + ev.getAction());

			break;
		}

		return super.onTouchEvent(ev);
	}

	private void startDrag(MotionEvent ev) {
		WindowManager wm;
		View view = getChildByIndex(mFrom);

		final Bitmap.Config c = Bitmap.Config.ARGB_8888;
		mDragBitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(), c);
		Canvas canvas = new Canvas();
		canvas.setBitmap(mDragBitmap);
		view.draw(canvas);

		if (mWindowParams == null) {
			mWindowParams = new WindowManager.LayoutParams();
			mWindowParams.gravity = Gravity.TOP | Gravity.LEFT;

			mWindowParams.height = WindowManager.LayoutParams.WRAP_CONTENT;
			mWindowParams.width = WindowManager.LayoutParams.WRAP_CONTENT;
			mWindowParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
					| WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
					| WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
					| WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS;
			mWindowParams.format = PixelFormat.TRANSLUCENT;
			mWindowParams.windowAnimations = 0;
			mWindowParams.x = 0;
			mWindowParams.y = 0;
		}

		ImageView v = new ImageView(getContext());
		v.setBackgroundColor(Color.argb(128, 0, 0, 0));
		v.setImageBitmap(mDragBitmap);

		wm = (WindowManager) getContext().getSystemService("window");
		if (mDragView != null) {
			wm.removeView(mDragView);
		}
		wm.addView(v, mWindowParams);
		mDragView = v;
	}

	private View getChildByIndex(int index) {
		return getChildAt(index - getFirstVisiblePosition());
	}

	private int pointToIndex(MotionEvent ev) {
		return pointToIndex((int) ev.getX(), (int) ev.getY());
	}

	private int pointToIndex(int x, int y) {
		return (int) pointToPosition(x, y);
	}

	public void setRemoveTile(View v) {
		mRemoveTile = v;
	}

	public void setOnDragListener(DragListener listener) {
		mDrag = listener;
	}

	public void setOnDropListener(DragListener listener) {
		mDrag = listener;
	}

	public void setOnRemoveListener(RemoveListener listener) {
		mRemove = listener;
	}

	public interface DragListener {
		public void drag(int from, int to);
	}

	public interface DropListener {
		public void drop(int from, int to);
	}

	public interface RemoveListener {
		public void remove(int which);
	}

	class DragListenerImpl implements DragListener {
		public void drag(int from, int to) {
			if (DEBUG) {
				Log.d(TAG, "DragListenerImpl drag event. from=" + from
						+ ", to=" + to);
			}
		}
	}

	public class DropListenerImpl implements DropListener {
		@SuppressWarnings("unchecked")
		public void drop(int from, int to) {
			if (DEBUG) {
				Log.d(TAG, "DropListenerImpl drop event. from=" + from
						+ ", to=" + to);
			}

			if (from == to || from < 0 || to < 0) {
				return;
			}

			Adapter adapter = getAdapter();
			if (adapter != null && adapter instanceof ArrayAdapter) {
				ArrayAdapter arrayAdapter = (ArrayAdapter) adapter;
				Object item = adapter.getItem(from);

				arrayAdapter.remove(item);
				arrayAdapter.insert(item, to);
			}
		}
	}

	public class RemoveListenerImpl implements RemoveListener {
		@SuppressWarnings("unchecked")
		public void remove(int which) {
			if (DEBUG) {
				Log.d(TAG, "RemoveListenerImpl remove event. which=" + which);
			}

			if (which < 0) {
				return;
			}

			Adapter adapter = getAdapter();
			if (adapter != null && adapter instanceof ArrayAdapter) {
				ArrayAdapter arrayAdapter = (ArrayAdapter) adapter;
				Object item = adapter.getItem(which);

				arrayAdapter.remove(item);
			}
		}
	}

	public void setSortMode(boolean sortMode) {
		this.sortMode = sortMode;
	}

	public boolean isSortMode() {
		return sortMode;
	}
}

main.xml

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

<LinearLayout android:layout_width="fill_parent"
	android:layout_height="fill_parent" xmlns:android="http://schemas.android.com/apk/res/android"
	android:orientation="vertical">

	<Button android:text="sort toggle" android:id="@+id/sort"
		android:layout_width="wrap_content" android:layout_height="wrap_content" />
	<ImageView android:layout_width="wrap_content"
		android:layout_height="wrap_content" android:id="@+id/remove_tile"
		android:src="@drawable/icon" />
	<net.vvakame.android.widget.DragnDropListView
		android:id="@+id/list" android:layout_width="fill_parent"
		android:layout_height="fill_parent" android:drawSelectorOnTop="false"
		normal_height="64dip" grabber="@+id/icon" remove_mode="slideRight"
		xmlns:android="http://schemas.android.com/apk/res/android" />

</LinearLayout>