ipad：从一个UITableViewController拖动一个UITableViewCell并将其放入另一个 [英] ipad: Drag a UITableViewCell from one UITableViewController and drop it into another
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问题描述
我的问题是，这是否可能，如果是这样，你将如何处理这个任务？
my question is, wether or not this is possible, and if so, how would you approach this task?
有没有人知道一个应用程序已经在使用这个功能，或在哪里获取一些示例代码？
Does anybody know of an app already using this functionality, or where to get some sample code?
另外，如果我自己实现这个，而不是太多的知识，那么你对需要花费很长时间才能完成？
Also, if i'm to implement this on my own without too much knowledge of the topic what would be your estimation on how long it would take to get it done?
另外还有一件事，因为它可以使事情变得更复杂：目标表在默认情况下是编辑模式，所以用户可以重新排列单元格（使用附件视图中的标准重新排序控件），这些单元格已经被删除。
One other thing to mention, since it could make things more complicated: The destination table is in editmode per default, so that the user can rearrange the cells (using the standard reordering control in accessory view), which have already been dropped there.
编辑：
我刚刚尝试在我的帖子中添加一个概念图像的屏幕截图。图像显示左侧的一个表格，右侧显示一个灰色的下降区域。我的客户说，他也在其他应用程序上看到这个，所以我必须有一些我不知道的ui元素。
I just tried to include a screenshot of a concept image in my post. The image shows one table on the left and a grayish drop area on the right. My customer says that he saw this on other apps, too, so there has to be some kind of ui element that I am not aware of.
我还没有找到开发人员库中有关于这样一个放置区域的任何内容，希望你们中的一个可以给我指示或清楚一些。
I haven't found anything in the developer library about such a drop area, so hopefully one of you can give me directions or clear things up.
推荐答案
好的，我自己实现了这一点，我对结果很满意。您可以将单元格从左侧（源表）拖动到右侧（目标表），还可以拖动目标表中的单元格以进行重新编制。如果您尝试从右向左拖动单元格，将重新插入到您开始拖动的相同位置（因此没有任何反应）。目的地表还支持删除单元格，源表不支持。所以这里是完整的代码：
Ok, I managed to implement this myself and I'm quite happy with the result. You can drag cells from left (source table) to right (destination table) and also drag cells within the destination table for reodering. If you try to drag a cell from right to left it will be reinserted at the same position where you started dragging (so nothing happens). The destination table also supports deletion of cells, the source table doesn't. So here's the complete code:
UIDropTableViewController.h
UIDropTableViewController.h
#import <UIKit/UIKit.h>
@interface UIDropTableViewController : UIViewController <UITableViewDelegate, UITableViewDataSource, UIGestureRecognizerDelegate>
{
UINavigationItem* srcTableNavItem;
UINavigationItem* dstTableNavItem;
UITableView* srcTableView;
UITableView* dstTableView;
UITableViewCell* draggedCell;
UIView* dropArea;
NSMutableArray* srcData;
NSMutableArray* dstData;
id draggedData;
BOOL dragFromSource; // used for reodering
NSIndexPath* pathFromDstTable; // used to reinsert data when reodering fails
}
@property (nonatomic, readonly) NSArray* srcData;
@property (nonatomic, readonly) NSArray* dstData;
- (id)initWithFrame:(CGRect)frame SourceData:(NSArray*)sourceData DestinationData:(NSArray*)destinationData;
- (void)setSrcTableTitle:(NSString*)title;
- (void)setDstTableTitle:(NSString*)title;
@end
UIDropTableViewController.m
UIDropTableViewController.m
#import "UIDropTableViewController.h"
#define kCellIdentifier @"DropTableCell"
#define kCellHeight 44
#define kNavBarHeight 30
// forward declaration of private helper methods
@interface UIDropTableViewController()
- (void)setupSourceTableWithFrame:(CGRect)frame;
- (void)setupDestinationTableWithFrame:(CGRect)frame;
- (void)initDraggedCellWithCell:(UITableViewCell*)cell AtPoint:(CGPoint)point;
- (void)startDragging:(UIPanGestureRecognizer *)gestureRecognizer;
- (void)startDraggingFromSrcAtPoint:(CGPoint)point;
- (void)startDraggingFromDstAtPoint:(CGPoint)point;
- (void)doDrag:(UIPanGestureRecognizer *)gestureRecognizer;
- (void)stopDragging:(UIPanGestureRecognizer *)gestureRecognizer;
- (UITableViewCell*)srcTableCellForRowAtIndexPath:(NSIndexPath*)indexPath;
- (UITableViewCell*)dstTableCellForRowAtIndexPath:(NSIndexPath*)indexPath;
@end
@implementation UIDropTableViewController
@synthesize srcData, dstData;
#pragma mark -
#pragma mark Public Methods
- (void)setSrcTableTitle:(NSString*)title
{
srcTableNavItem.title = title;
}
- (void)setDstTableTitle:(NSString*)title
{
dstTableNavItem.title = title;
}
#pragma mark -
#pragma mark UIViewController
- (id)initWithFrame:(CGRect)frame SourceData:(NSArray*)sourceData DestinationData:(NSArray*)destinationData
{
self = [super init];
if (self)
{
self.view.clipsToBounds = YES;
self.view.frame = frame;
int width = frame.size.width;
int height = frame.size.height;
// set up data
srcData = [[NSMutableArray alloc] initWithArray:sourceData];
dstData = [[NSMutableArray alloc] initWithArray:destinationData];
draggedCell = nil;
draggedData = nil;
pathFromDstTable = nil;
// set up views
[self setupSourceTableWithFrame:CGRectMake(0, 0, width / 2, height)];
[self setupDestinationTableWithFrame:CGRectMake(width / 2, 0, width / 2, height)];
UIView* separator = [[UIView alloc] initWithFrame:CGRectMake(width / 2, 0, 1, height)];
separator.backgroundColor = [UIColor blackColor];
[self.view addSubview:separator];
[separator release];
// set up gestures
UIPanGestureRecognizer* panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePanning:)];
[self.view addGestureRecognizer:panGesture];
[panGesture release];
}
return self;
}
- (void)dealloc
{
[srcTableNavItem release];
[dstTableNavItem release];
[srcTableView release];
[dstTableView release];
[dropArea release];
[srcData release];
[dstData release];
if(draggedCell != nil)
[draggedCell release];
if(draggedData != nil)
[draggedData release];
if(pathFromDstTable != nil)
[pathFromDstTable release];
[super dealloc];
}
- (void)viewWillAppear:(BOOL)animated
{
[srcTableView reloadData];
[dstTableView reloadData];
[UIView animateWithDuration:0.2 animations:^
{
CGRect frame = dstTableView.frame;
frame.size.height = kCellHeight * [dstData count];
dstTableView.frame = frame;
}];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
return UIInterfaceOrientationIsLandscape(interfaceOrientation);
}
#pragma mark -
#pragma mark Helper methods for initialization
- (void)setupSourceTableWithFrame:(CGRect)frame
{
srcTableNavItem = [[UINavigationItem alloc] init];
srcTableNavItem.title = @"Source Table";
CGRect navBarFrame = frame;
navBarFrame.size.height = kNavBarHeight;
UINavigationBar* navigationBar = [[UINavigationBar alloc] initWithFrame:navBarFrame];
[navigationBar pushNavigationItem:srcTableNavItem animated:false];
[navigationBar setTintColor:[UIColor lightGrayColor]];
[self.view addSubview:navigationBar];
[navigationBar release];
CGRect tableFrame = frame;
tableFrame.origin.y = kNavBarHeight;
tableFrame.size.height -= kNavBarHeight;
srcTableView = [[UITableView alloc] initWithFrame:tableFrame];
[srcTableView setDelegate:self];
[srcTableView setDataSource:self];
[self.view addSubview:srcTableView];
}
- (void)setupDestinationTableWithFrame:(CGRect)frame
{
dstTableNavItem = [[UINavigationItem alloc] init];
dstTableNavItem.title = @"Destination Table";
CGRect navBarFrame = frame;
navBarFrame.size.height = kNavBarHeight;
UINavigationBar* navigationBar = [[UINavigationBar alloc] initWithFrame:navBarFrame];
[navigationBar pushNavigationItem:dstTableNavItem animated:false];
[navigationBar setTintColor:[UIColor lightGrayColor]];
[self.view addSubview:navigationBar];
[navigationBar release];
CGRect dropAreaFrame = frame;
dropAreaFrame.origin.y = kNavBarHeight;
dropAreaFrame.size.height -= kNavBarHeight;
dropArea = [[UIView alloc] initWithFrame:dropAreaFrame];
[dropArea setBackgroundColor:[UIColor grayColor]];
[self.view addSubview:dropArea];
CGRect contentFrame = dropAreaFrame;
contentFrame.origin = CGPointMake(0, 0);
UILabel* dropAreaLabel = [[UILabel alloc] initWithFrame:contentFrame];
dropAreaLabel.backgroundColor = [UIColor clearColor];
dropAreaLabel.font = [UIFont boldSystemFontOfSize:12];
dropAreaLabel.textAlignment = UITextAlignmentCenter;
dropAreaLabel.textColor = [UIColor whiteColor];
dropAreaLabel.text = @"Drop items here...";
[dropArea addSubview:dropAreaLabel];
[dropAreaLabel release];
CGRect tableFrame = contentFrame;
tableFrame.size.height = kCellHeight * [dstData count];
dstTableView = [[UITableView alloc] initWithFrame:tableFrame];
[dstTableView setEditing:YES];
[dstTableView setDelegate:self];
[dstTableView setDataSource:self];
[dropArea addSubview:dstTableView];
}
- (void)initDraggedCellWithCell:(UITableViewCell*)cell AtPoint:(CGPoint)point
{
// get rid of old cell, if it wasn't disposed already
if(draggedCell != nil)
{
[draggedCell removeFromSuperview];
[draggedCell release];
draggedCell = nil;
}
CGRect frame = CGRectMake(point.x, point.y, cell.frame.size.width, cell.frame.size.height);
draggedCell = [[UITableViewCell alloc] init];
draggedCell.selectionStyle = UITableViewCellSelectionStyleGray;
draggedCell.textLabel.text = cell.textLabel.text;
draggedCell.textLabel.textColor = cell.textLabel.textColor;
draggedCell.highlighted = YES;
draggedCell.frame = frame;
draggedCell.alpha = 0.8;
[self.view addSubview:draggedCell];
}
#pragma mark -
#pragma mark UIGestureRecognizer
- (void)handlePanning:(UIPanGestureRecognizer *)gestureRecognizer
{
switch ([gestureRecognizer state]) {
case UIGestureRecognizerStateBegan:
[self startDragging:gestureRecognizer];
break;
case UIGestureRecognizerStateChanged:
[self doDrag:gestureRecognizer];
break;
case UIGestureRecognizerStateEnded:
case UIGestureRecognizerStateCancelled:
case UIGestureRecognizerStateFailed:
[self stopDragging:gestureRecognizer];
break;
default:
break;
}
}
#pragma mark -
#pragma mark Helper methods for dragging
- (void)startDragging:(UIPanGestureRecognizer *)gestureRecognizer
{
CGPoint pointInSrc = [gestureRecognizer locationInView:srcTableView];
CGPoint pointInDst = [gestureRecognizer locationInView:dstTableView];
if([srcTableView pointInside:pointInSrc withEvent:nil])
{
[self startDraggingFromSrcAtPoint:pointInSrc];
dragFromSource = YES;
}
else if([dstTableView pointInside:pointInDst withEvent:nil])
{
[self startDraggingFromDstAtPoint:pointInDst];
dragFromSource = NO;
}
}
- (void)startDraggingFromSrcAtPoint:(CGPoint)point
{
NSIndexPath* indexPath = [srcTableView indexPathForRowAtPoint:point];
UITableViewCell* cell = [srcTableView cellForRowAtIndexPath:indexPath];
if(cell != nil)
{
CGPoint origin = cell.frame.origin;
origin.x += srcTableView.frame.origin.x;
origin.y += srcTableView.frame.origin.y;
[self initDraggedCellWithCell:cell AtPoint:origin];
cell.highlighted = NO;
if(draggedData != nil)
{
[draggedData release];
draggedData = nil;
}
draggedData = [[srcData objectAtIndex:indexPath.row] retain];
}
}
- (void)startDraggingFromDstAtPoint:(CGPoint)point
{
NSIndexPath* indexPath = [dstTableView indexPathForRowAtPoint:point];
UITableViewCell* cell = [dstTableView cellForRowAtIndexPath:indexPath];
if(cell != nil)
{
CGPoint origin = cell.frame.origin;
origin.x += dropArea.frame.origin.x;
origin.y += dropArea.frame.origin.y;
[self initDraggedCellWithCell:cell AtPoint:origin];
cell.highlighted = NO;
if(draggedData != nil)
{
[draggedData release];
draggedData = nil;
}
draggedData = [[dstData objectAtIndex:indexPath.row] retain];
// remove old cell
[dstData removeObjectAtIndex:indexPath.row];
[dstTableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationMiddle];
pathFromDstTable = [indexPath retain];
[UIView animateWithDuration:0.2 animations:^
{
CGRect frame = dstTableView.frame;
frame.size.height = kCellHeight * [dstData count];
dstTableView.frame = frame;
}];
}
}
- (void)doDrag:(UIPanGestureRecognizer *)gestureRecognizer
{
if(draggedCell != nil && draggedData != nil)
{
CGPoint translation = [gestureRecognizer translationInView:[draggedCell superview]];
[draggedCell setCenter:CGPointMake([draggedCell center].x + translation.x,
[draggedCell center].y + translation.y)];
[gestureRecognizer setTranslation:CGPointZero inView:[draggedCell superview]];
}
}
- (void)stopDragging:(UIPanGestureRecognizer *)gestureRecognizer
{
if(draggedCell != nil && draggedData != nil)
{
if([gestureRecognizer state] == UIGestureRecognizerStateEnded
&& [dropArea pointInside:[gestureRecognizer locationInView:dropArea] withEvent:nil])
{
NSIndexPath* indexPath = [dstTableView indexPathForRowAtPoint:[gestureRecognizer locationInView:dstTableView]];
if(indexPath != nil)
{
[dstData insertObject:draggedData atIndex:indexPath.row];
[dstTableView insertRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationMiddle];
}
else
{
[dstData addObject:draggedData];
[dstTableView reloadData];
}
}
else if(!dragFromSource && pathFromDstTable != nil)
{
// insert cell back where it came from
[dstData insertObject:draggedData atIndex:pathFromDstTable.row];
[dstTableView insertRowsAtIndexPaths:[NSArray arrayWithObject:pathFromDstTable] withRowAnimation:UITableViewRowAnimationMiddle];
[pathFromDstTable release];
pathFromDstTable = nil;
}
[UIView animateWithDuration:0.3 animations:^
{
CGRect frame = dstTableView.frame;
frame.size.height = kCellHeight * [dstData count];
dstTableView.frame = frame;
}];
[draggedCell removeFromSuperview];
[draggedCell release];
draggedCell = nil;
[draggedData release];
draggedData = nil;
}
}
#pragma mark -
#pragma mark UITableViewDataSource
- (BOOL)tableView:(UITableView*)tableView canMoveRowAtIndexPath:(NSIndexPath*)indexPath
{
// disable build in reodering functionality
return NO;
}
- (void)tableView:(UITableView*)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
// enable cell deletion for destination table
if([tableView isEqual:dstTableView] && editingStyle == UITableViewCellEditingStyleDelete)
{
[dstData removeObjectAtIndex:indexPath.row];
[dstTableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
[UIView animateWithDuration:0.2 animations:^
{
CGRect frame = dstTableView.frame;
frame.size.height = kCellHeight * [dstData count];
dstTableView.frame = frame;
}];
}
}
- (NSInteger)tableView:(UITableView*)tableView numberOfRowsInSection:(NSInteger)section
{
// tell our tables how many rows they will have
int count = 0;
if([tableView isEqual:srcTableView])
{
count = [srcData count];
}
else if([tableView isEqual:dstTableView])
{
count = [dstData count];
}
return count;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return kCellHeight;
}
- (UITableViewCell*)tableView:(UITableView*)tableView cellForRowAtIndexPath:(NSIndexPath*)indexPath
{
UITableViewCell* result = nil;
if([tableView isEqual:srcTableView])
{
result = [self srcTableCellForRowAtIndexPath:indexPath];
}
else if([tableView isEqual:dstTableView])
{
result = [self dstTableCellForRowAtIndexPath:indexPath];
}
return result;
}
#pragma mark -
#pragma mark Helper methods for table stuff
- (UITableViewCell*)srcTableCellForRowAtIndexPath:(NSIndexPath*)indexPath
{
// tell our source table what kind of cell to use and its title for the given row
UITableViewCell *cell = [srcTableView dequeueReusableCellWithIdentifier:kCellIdentifier];
if (cell == nil)
{
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:kCellIdentifier] autorelease];
cell.selectionStyle = UITableViewCellSelectionStyleNone;
cell.textLabel.textColor = [UIColor darkGrayColor];
}
cell.textLabel.text = [[srcData objectAtIndex:indexPath.row] description];
return cell;
}
- (UITableViewCell*)dstTableCellForRowAtIndexPath:(NSIndexPath*)indexPath
{
// tell our destination table what kind of cell to use and its title for the given row
UITableViewCell *cell = [dstTableView dequeueReusableCellWithIdentifier:kCellIdentifier];
if (cell == nil)
{
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:kCellIdentifier] autorelease];
cell.selectionStyle = UITableViewCellSelectionStyleNone;
cell.textLabel.textColor = [UIColor darkGrayColor];
}
cell.textLabel.text = [[dstData objectAtIndex:indexPath.row] description];
return cell;
}
@end
这是一个例子使用它：
NSArray* srcData = [NSArray arrayWithObjects:@"item0", @"item1", @"item2", @"item3", @"item4", nil];
NSArray* dstData = [NSArray arrayWithObjects:@"item5", @"item6", nil];
dropTable = [[UIDropTableViewController alloc] initWithFrame:CGRectMake(100, 100, 600, 500) SourceData:srcData DestinationData:dstData];
[dropTable setSrcTableTitle:@"Bla"];
[dropTable setDstTableTitle:@"Blub"];
[[dropTable.view layer] setBorderColor:[[UIColor darkGrayColor] CGColor]];
[[dropTable.view layer] setBorderWidth:1];
[[dropTable.view layer] setCornerRadius:2];
[self.view addSubview:dropTable.view];
然后，完成编辑后，您只需阅读 dropTable.dstData 并继续使用它为您想做什么。
Then, after you are done editing you just read dropTable.dstData and continue using it for what ever you want to do.
在 UIDropTableViewController.m 你可能需要调整 initDraggedCellWithCell ， srcTableCellForRowAtIndexPath 和 dstTableCellForRowAtIndexPath 自己的需求就像单元格表示一样。
In UIDropTableViewController.m you might want to adjust initDraggedCellWithCell, srcTableCellForRowAtIndexPath and dstTableCellForRowAtIndexPath for your own needs as far as cell representation goes.
这篇关于ipad：从一个UITableViewController拖动一个UITableViewCell并将其放入另一个的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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