IOS高访微信聊天对话界面(sizeWithFont:constrainedToSize和stretchableImageWithLeftCapWidth的使用)

背景图片的高度适应文本文字。

先看一下效果图：左图为截取微信的，右图是本demo的效果








再看一下主要代码实现：

源码打印？

@implementation ViewController

- (void)viewDidLoad
{
[super viewDidLoad];

NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:@"weixin",@"name",@"微信团队欢迎你。很高兴你开启了微信生活，期待能为你和朋友们带来愉快的沟通体检。",@"content", nil];
NSDictionary *dict1 = [NSDictionary dictionaryWithObjectsAndKeys:@"rhl",@"name",@"hello",@"content", nil];
NSDictionary *dict2 = [NSDictionary dictionaryWithObjectsAndKeys:@"rhl",@"name",@"0",@"content", nil];
NSDictionary *dict3 = [NSDictionary dictionaryWithObjectsAndKeys:@"weixin",@"name",@"谢谢反馈，已收录。",@"content", nil];
NSDictionary *dict4 = [NSDictionary dictionaryWithObjectsAndKeys:@"rhl",@"name",@"0",@"content", nil];
NSDictionary *dict5 = [NSDictionary dictionaryWithObjectsAndKeys:@"weixin",@"name",@"谢谢反馈，已收录。",@"content", nil];
NSDictionary *dict6 = [NSDictionary dictionaryWithObjectsAndKeys:@"rhl",@"name",@"大数据测试，长数据测试，大数据测试，长数据测试，大数据测试，长数据测试，大数据测试，长数据测试，大数据测试，长数据测试，大数据测试，长数据测试。",@"content", nil];

_resultArray = [NSMutableArray arrayWithObjects:dict,dict1,dict2,dict3,dict4,dict5,dict6, nil];

}

- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

//泡泡文本
- (UIView *)bubbleView:(NSString *)text from:(BOOL)fromSelf withPosition:(int)position{

//计算大小
UIFont *font = [UIFont systemFontOfSize:14];
CGSize size = [text sizeWithFont:font constrainedToSize:CGSizeMake(180.0f, 20000.0f) lineBreakMode:NSLineBreakByWordWrapping];

// build single chat bubble cell with given text
UIView *returnView = [[UIView alloc] initWithFrame:CGRectZero];
returnView.backgroundColor = [UIColor clearColor];

//背影图片
UIImage *bubble = [UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:fromSelf?@"SenderAppNodeBkg_HL":@"ReceiverTextNodeBkg" ofType:@"png"]];

UIImageView *bubbleImageView = [[UIImageView alloc] initWithImage:[bubble stretchableImageWithLeftCapWidth:floorf(bubble.size.width/2) topCapHeight:floorf(bubble.size.height/2)]];
NSLog(@"%f,%f",size.width,size.height);

//添加文本信息
UILabel *bubbleText = [[UILabel alloc] initWithFrame:CGRectMake(fromSelf?15.0f:22.0f, 20.0f, size.width+10, size.height+10)];
bubbleText.backgroundColor = [UIColor clearColor];
bubbleText.font = font;
bubbleText.numberOfLines = 0;
bubbleText.lineBreakMode = NSLineBreakByWordWrapping;
bubbleText.text = text;

bubbleImageView.frame = CGRectMake(0.0f, 14.0f, bubbleText.frame.size.width+30.0f, bubbleText.frame.size.height+20.0f);

if(fromSelf)
returnView.frame = CGRectMake(320-position-(bubbleText.frame.size.width+30.0f), 0.0f, bubbleText.frame.size.width+30.0f, bubbleText.frame.size.height+30.0f);
else
returnView.frame = CGRectMake(position, 0.0f, bubbleText.frame.size.width+30.0f, bubbleText.frame.size.height+30.0f);

[returnView addSubview:bubbleImageView];
[returnView addSubview:bubbleText];

return returnView;
}

//泡泡语音
- (UIView *)yuyinView:(NSInteger)logntime from:(BOOL)fromSelf withIndexRow:(NSInteger)indexRow withPosition:(int)position{

//根据语音长度
int yuyinwidth = 66+fromSelf;

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
button.tag = indexRow;
if(fromSelf)
button.frame =CGRectMake(320-position-yuyinwidth, 10, yuyinwidth, 54);
else
button.frame =CGRectMake(position, 10, yuyinwidth, 54);

//image偏移量
UIEdgeInsets imageInsert;
imageInsert.top = -10;
imageInsert.left = fromSelf?button.frame.size.width/3:-button.frame.size.width/3;
button.imageEdgeInsets = imageInsert;

[button setImage:[UIImage imageNamed:fromSelf?@"SenderVoiceNodePlaying":@"ReceiverVoiceNodePlaying"] forState:UIControlStateNormal];
UIImage *backgroundImage = [UIImage imageNamed:fromSelf?@"SenderVoiceNodeDownloading":@"ReceiverVoiceNodeDownloading"];
backgroundImage = [backgroundImage stretchableImageWithLeftCapWidth:20 topCapHeight:0];
[button setBackgroundImage:backgroundImage forState:UIControlStateNormal];

UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(fromSelf?-30:button.frame.size.width, 0, 30, button.frame.size.height)];
label.text = [NSString stringWithFormat:@"%d''",logntime];
label.textColor = [UIColor grayColor];
label.font = [UIFont systemFontOfSize:13];
label.textAlignment = NSTextAlignmentCenter;
label.backgroundColor = [UIColor clearColor];
[button addSubview:label];

return button;
}

#pragma UITableView

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return _resultArray.count;
}

-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSDictionary *dict = [_resultArray objectAtIndex:indexPath.row];
UIFont *font = [UIFont systemFontOfSize:14];
CGSize size = [[dict objectForKey:@"content"] sizeWithFont:font constrainedToSize:CGSizeMake(180.0f, 20000.0f) lineBreakMode:NSLineBreakByWordWrapping];

return size.height+44;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{

static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
cell.selectionStyle = UITableViewCellSelectionStyleNone;

}else{
for (UIView *cellView in cell.subviews){
[cellView removeFromSuperview];
}
}

NSDictionary *dict = [_resultArray objectAtIndex:indexPath.row];

//创建头像
UIImageView *photo ;
if ([[dict objectForKey:@"name"]isEqualToString:@"rhl"]) {
photo = [[UIImageView alloc]initWithFrame:CGRectMake(320-60, 10, 50, 50)];
[cell addSubview:photo];
photo.image = [UIImage imageNamed:@"photo1"];

if ([[dict objectForKey:@"content"] isEqualToString:@"0"]) {
[cell addSubview:[self yuyinView:1 from:YES withIndexRow:indexPath.row withPosition:65]];

}else{
[cell addSubview:[self bubbleView:[dict objectForKey:@"content"] from:YES withPosition:65]];
}

}else{
photo = [[UIImageView alloc]initWithFrame:CGRectMake(10, 10, 50, 50)];
[cell addSubview:photo];
photo.image = [UIImage imageNamed:@"photo"];

if ([[dict objectForKey:@"content"] isEqualToString:@"0"]) {
[cell addSubview:[self yuyinView:1 from:NO withIndexRow:indexPath.row withPosition:65]];
}else{
[cell addSubview:[self bubbleView:[dict objectForKey:@"content"] from:NO withPosition:65]];
}
}

return cell;

}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{

}

@end

其实很简单，主要说一下两个知识点，重要的两个知识点就能写出完美的泡泡对话聊天！
第一个是NSString中的一个方法：

- (CGSize)sizeWithFont:(UIFont *)font constrainedToSize:(CGSize)size lineBreakMode:(NSLineBreakMode)lineBreakMode;
根据文本内容，算出所需要的大小CGSize；
第二个是UIImage中的一个方法：

- (UIImage *)stretchableImageWithLeftCapWidth:(NSInteger)leftCapWidth topCapHeight:(NSInteger)topCapHeight;
这里有几遍文章供大家参考这个方法的使用：
http://blog.csdn.net/lixing333/article/details/7589281 http://blog.csdn.net/w122079514/article/details/7848980
http://www.cnblogs.com/bandy/archive/2012/04/25/2469369.html
ok！完美，perfect！