Android ListView的子項的隨意拖動效果
阿新 • • 發佈:2019-01-27
自定義ListView:
呼叫自定義view:package com.miao.listview; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Bitmap; import android.graphics.PixelFormat; import android.graphics.Rect; import android.util.AttributeSet; import android.view.GestureDetector; import android.view.Gravity; import android.view.MotionEvent; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewGroup; import android.view.WindowManager; import android.view.GestureDetector.SimpleOnGestureListener; import android.widget.AdapterView; import android.widget.ImageView; import android.widget.ListView; import com.miao.listview.R; public class DraggableListView extends ListView { private ImageView mDragView; private WindowManager mWindowManager; private WindowManager.LayoutParams mWindowParams; private int mDragPos; // which item is being dragged private int mFirstDragPos; // where was the dragged item originally private int mDragPoint; // at what offset inside the item did the user grab // it private int mCoordOffset; // the difference between screen coordinates and // coordinates in this view private DragListener mDragListener; private DropListener mDropListener; private RemoveListener mRemoveListener; private int mUpperBound; private int mLowerBound; private int mHeight; private GestureDetector mGestureDetector; public static final int FLING = 0; public static final int SLIDE_RIGHT = 1; public static final int SLIDE_LEFT = 2; private int mRemoveMode = -1; private Rect mTempRect = new Rect(); private Bitmap mDragBitmap; private final int mTouchSlop; private int mItemHeightNormal = -1; private int mItemHeightExpanded = -1; private int grabberId = -1; private int dragndropBackgroundColor = 0x00000000; public DraggableListView(Context context, AttributeSet attrs) { this(context, attrs, 0); } public DraggableListView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop(); if (attrs != null) { TypedArray a = getContext().obtainStyledAttributes(attrs, R.styleable.TouchListView, 0, 0); mItemHeightNormal = a.getDimensionPixelSize( R.styleable.TouchListView_normal_height, 0); mItemHeightExpanded = a.getDimensionPixelSize( R.styleable.TouchListView_expanded_height, mItemHeightNormal); grabberId = a.getResourceId(R.styleable.TouchListView_grabber, -1); dragndropBackgroundColor = a.getColor( R.styleable.TouchListView_dragndrop_background, 0x00000000); mRemoveMode = a.getInt(R.styleable.TouchListView_remove_mode, -1); a.recycle(); } } @Override public boolean onInterceptTouchEvent(MotionEvent ev) { if (mRemoveListener != null && mGestureDetector == null) { if (mRemoveMode == FLING) { mGestureDetector = new GestureDetector(getContext(), new SimpleOnGestureListener() { @Override public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) { if (mDragView != null) { if (velocityX > 1000) { Rect r = mTempRect; mDragView.getDrawingRect(r); if (e2.getX() > r.right * 2 / 3) { // fast fling right with release // near the right edge of the screen stopDragging(); mRemoveListener .remove(mFirstDragPos); unExpandViews(true); } } // flinging while dragging should have no // effect return true; } return false; } }); } } if (mDragListener != null || mDropListener != null) { switch (ev.getAction()) { case MotionEvent.ACTION_DOWN: int x = (int) ev.getX(); int y = (int) ev.getY(); int itemnum = pointToPosition(x, y); if (itemnum == AdapterView.INVALID_POSITION) { break; } ViewGroup item = (ViewGroup) getChildAt(itemnum - getFirstVisiblePosition()); mDragPoint = y - item.getTop(); mCoordOffset = ((int) ev.getRawY()) - y; View dragger = item.findViewById(grabberId); Rect r = mTempRect; // dragger.getDrawingRect(r); r.left = dragger.getLeft(); r.right = dragger.getRight(); r.top = dragger.getTop(); r.bottom = dragger.getBottom(); if ((r.left < x) && (x < r.right)) { item.setDrawingCacheEnabled(true); // Create a copy of the drawing cache so that it does not // get recycled // by the framework when the list tries to clean up memory Bitmap bitmap = Bitmap.createBitmap(item.getDrawingCache()); startDragging(bitmap, y); mDragPos = itemnum; mFirstDragPos = mDragPos; mHeight = getHeight(); int touchSlop = mTouchSlop; mUpperBound = Math.min(y - touchSlop, mHeight / 3); mLowerBound = Math.max(y + touchSlop, mHeight * 2 / 3); return false; } mDragView = null; break; } } return super.onInterceptTouchEvent(ev); } /* * pointToPosition() doesn't consider invisible views, but we need to, so * implement a slightly different version. */ private int myPointToPosition(int x, int y) { Rect frame = mTempRect; final int count = getChildCount(); for (int i = count - 1; i >= 0; i--) { final View child = getChildAt(i); child.getHitRect(frame); if (frame.contains(x, y)) { return getFirstVisiblePosition() + i; } } return INVALID_POSITION; } private int getItemForPosition(int y) { int adjustedy = y - mDragPoint - 32; int pos = myPointToPosition(0, adjustedy); if (pos >= 0) { if (pos <= mFirstDragPos) { pos += 1; } } else if (adjustedy < 0) { pos = 0; } return pos; } private void adjustScrollBounds(int y) { if (y >= mHeight / 3) { mUpperBound = mHeight / 3; } if (y <= mHeight * 2 / 3) { mLowerBound = mHeight * 2 / 3; } } /* * Restore size and visibility for all listitems */ private void unExpandViews(boolean deletion) { for (int i = 0;; i++) { View v = getChildAt(i); if (v == null) { if (deletion) { // HACK force update of mItemCount int position = getFirstVisiblePosition(); int y = getChildAt(0).getTop(); setAdapter(getAdapter()); setSelectionFromTop(position, y); // end hack } layoutChildren(); // force children to be recreated where needed v = getChildAt(i); if (v == null) { break; } } ViewGroup.LayoutParams params = v.getLayoutParams(); params.height = mItemHeightNormal; v.setLayoutParams(params); v.setVisibility(View.VISIBLE); } } /* * Adjust visibility and size to make it appear as though an item is being * dragged around and other items are making room for it: If dropping the * item would result in it still being in the same place, then make the * dragged listitem's size normal, but make the item invisible. Otherwise, * if the dragged listitem is still on screen, make it as small as possible * and expand the item below the insert point. If the dragged item is not on * screen, only expand the item below the current insertpoint. */ private void doExpansion() { int childnum = mDragPos - getFirstVisiblePosition(); if (mDragPos > mFirstDragPos) { childnum++; } View first = getChildAt(mFirstDragPos - getFirstVisiblePosition()); for (int i = 0;; i++) { View vv = getChildAt(i); if (vv == null) { break; } int height = mItemHeightNormal; int visibility = View.VISIBLE; if (vv.equals(first)) { // processing the item that is being dragged if (mDragPos == mFirstDragPos) { // hovering over the original location visibility = View.INVISIBLE; } else { // not hovering over it height = 1; } } else if (i == childnum) { if (mDragPos < getCount() - 1) { height = mItemHeightExpanded; } } ViewGroup.LayoutParams params = vv.getLayoutParams(); params.height = height; vv.setLayoutParams(params); vv.setVisibility(visibility); } } @Override public boolean onTouchEvent(MotionEvent ev) { if (mGestureDetector != null) { mGestureDetector.onTouchEvent(ev); } if ((mDragListener != null || mDropListener != null) && mDragView != null) { int action = ev.getAction(); switch (action) { case MotionEvent.ACTION_UP: case MotionEvent.ACTION_CANCEL: Rect r = mTempRect; mDragView.getDrawingRect(r); stopDragging(); if (mDropListener != null && mDragPos >= 0 && mDragPos < getCount()) { mDropListener.drop(mFirstDragPos, mDragPos); } unExpandViews(false); break; case MotionEvent.ACTION_DOWN: case MotionEvent.ACTION_MOVE: int x = (int) ev.getX(); int y = (int) ev.getY(); dragView(x, y); int itemnum = getItemForPosition(y); if (itemnum >= 0) { if (action == MotionEvent.ACTION_DOWN || itemnum != mDragPos) { if (mDragListener != null) { mDragListener.drag(mDragPos, itemnum); } mDragPos = itemnum; doExpansion(); } int speed = 0; adjustScrollBounds(y); if (y > mLowerBound) { // scroll the list up a bit speed = y > (mHeight + mLowerBound) / 2 ? 16 : 4; } else if (y < mUpperBound) { // scroll the list down a bit speed = y < mUpperBound / 2 ? -16 : -4; } if (speed != 0) { int ref = pointToPosition(0, mHeight / 2); if (ref == AdapterView.INVALID_POSITION) { // we hit a divider or an invisible view, check // somewhere else ref = pointToPosition(0, mHeight / 2 + getDividerHeight() + 64); } View v = getChildAt(ref - getFirstVisiblePosition()); if (v != null) { int pos = v.getTop(); setSelectionFromTop(ref, pos - speed); } } } break; } return true; } return super.onTouchEvent(ev); } private void startDragging(Bitmap bm, int y) { stopDragging(); mWindowParams = new WindowManager.LayoutParams(); mWindowParams.gravity = Gravity.TOP; mWindowParams.x = 0; mWindowParams.y = y - mDragPoint + mCoordOffset; 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_IN_SCREEN; mWindowParams.format = PixelFormat.TRANSLUCENT; mWindowParams.windowAnimations = 0; ImageView v = new ImageView(getContext()); // int backGroundColor = // getContext().getResources().getColor(R.color.dragndrop_background); v.setBackgroundColor(dragndropBackgroundColor); v.setImageBitmap(bm); mDragBitmap = bm; mWindowManager = (WindowManager) getContext() .getSystemService("window"); mWindowManager.addView(v, mWindowParams); mDragView = v; } private void dragView(int x, int y) { float alpha = 1.0f; int width = mDragView.getWidth(); if (mRemoveMode == SLIDE_RIGHT) { if (x > width / 2) { alpha = ((float) (width - x)) / (width / 2); } mWindowParams.alpha = alpha; } else if (mRemoveMode == SLIDE_LEFT) { if (x < width / 2) { alpha = ((float) x) / (width / 2); } mWindowParams.alpha = alpha; } mWindowParams.y = y - mDragPoint + mCoordOffset; mWindowManager.updateViewLayout(mDragView, mWindowParams); } private void stopDragging() { if (mDragView != null) { WindowManager wm = (WindowManager) getContext().getSystemService( "window"); wm.removeView(mDragView); mDragView.setImageDrawable(null); mDragView = null; } if (mDragBitmap != null) { mDragBitmap.recycle(); mDragBitmap = null; } } public void setDragListener(DragListener l) { mDragListener = l; } public void setDropListener(DropListener l) { mDropListener = l; } public void setRemoveListener(RemoveListener l) { mRemoveListener = l; } public interface DragListener { void drag(int from, int to); } public interface DropListener { void drop(int from, int to); } public interface RemoveListener { void remove(int which); } }
package com.miao.listview; import android.os.Bundle; import android.app.ListActivity; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ArrayAdapter; import android.widget.TextView; import android.widget.Toast; import com.miao.listview.R; import java.util.ArrayList; import java.util.Arrays; public class DragDemo extends ListActivity { private static String[] items = { "浙江", "江蘇", "廣東", "上海", "北京", "新疆" }; private IconicAdapter adapter = null; private ArrayList<String> array = new ArrayList<String>( Arrays.asList(items)); @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); setContentView(R.layout.main); adapter = new IconicAdapter(); setListAdapter(adapter); DraggableListView tlv = (DraggableListView) getListView(); tlv.setDropListener(onDrop); tlv.setRemoveListener(onRemove); tlv.getAdapter(); } private DraggableListView.DropListener onDrop = new DraggableListView.DropListener() { @Override public void drop(int from, int to) { String item = adapter.getItem(from); adapter.remove(item); adapter.insert(item, to); Toast.makeText(DragDemo.this, adapter.getList().toString(), Toast.LENGTH_SHORT).show(); } }; private DraggableListView.RemoveListener onRemove = new DraggableListView.RemoveListener() { @Override public void remove(int which) { adapter.remove(adapter.getItem(which)); } }; class IconicAdapter extends ArrayAdapter<String> { IconicAdapter() { super(DragDemo.this, R.layout.row, array); } public ArrayList<String> getList() { return array; } public View getView(int position, View convertView, ViewGroup parent) { View row = convertView; if (row == null) { LayoutInflater inflater = getLayoutInflater(); row = inflater.inflate(R.layout.row, parent, false); } TextView label = (TextView) row.findViewById(R.id.label); label.setText(array.get(position)); return (row); } } }
main.xml:
<?xml version="1.0" encoding="utf-8"?> <com.miao.listview.DraggableListView xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tlv="http://schemas.android.com/apk/res/com.miao.listview" android:id="@android:id/list" android:layout_width="fill_parent" android:layout_height="fill_parent" android:drawSelectorOnTop="false" tlv:normal_height="64dip" tlv:grabber="@+id/icon" tlv:remove_mode="slideLeft" />
row.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="64dip"
android:gravity="center_vertical"
android:ignoreGravity="@+id/icon">
<ImageView android:id="@+id/icon"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:layout_alignParentBottom="true"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/grabber"
/>
<TextView android:id="@+id/label"
android:textAppearance="?android:attr/textAppearanceMedium"
android:layout_width="wrap_content"
android:paddingLeft="9dip"
android:paddingRight="9dip"
android:layout_height="wrap_content"
android:layout_alignWithParentIfMissing="true"
android:layout_alignParentLeft="true"
android:layout_toLeftOf="@id/icon"
android:layout_centerVertical="true"
android:ellipsize="marquee"
android:singleLine="true"
/>
</RelativeLayout>
素材圖片:
效果圖: