iOS中UITextView随键盘上升，随字数增多，TextView增加行数
1、创建一个继承UIView的类
CommentTextView.h
@interface CommentTextView : UIView<UITextViewDelegate>
@property(nonatomic,strong) UITextView *textView;
@property (nonatomic,assign) CGFloat keyHight;
CommentTextView.m
#import "CommentTextView.h"
#define SCREEN_HEIGHT [[UIScreen mainScreen] bounds].size.height //获得屏幕高度
#define SCREEN_WIDTH [[UIScreen mainScreen] bounds].size.width //获得屏幕宽度
@implementation CommentTextView
{
float heightText;//文字高度
}
-(id)initWithFrame:(CGRect)frame
{
self=[super initWithFrame:frame];
if (self) {
self.backgroundColor=[UIColor blueColor];
[self initTextView:frame];
}
return self;
}
-(void)initTextView:(CGRect)frame
{
self.textView=[[UITextView alloc]initWithFrame:CGRectMake(10, 5, SCREEN_WIDTH-60, frame.size.height-10)];
self.textView.backgroundColor=[UIColor colorWithRed:233.0/255 green:232.0/255 blue:250.0/255 alpha:1.0];
self.textView.delegate=self;
self.textView.returnKeyType=UIReturnKeyNext;
self.textView.font=[UIFont systemFontOfSize:16];
[self addSubview:self.textView];
[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(getKeyBoardHeight:) name:@"keyHeight" object:nil];
}
-(void)getKeyBoardHeight:(NSNotification *)notification
{
NSString *name=[notification.userInfo objectForKey:@"keyHeight"];
self.keyHight=[name doubleValue];
}
-(void)textViewDidChange:(UITextView *)textView
{
float currentLineNum=1;//默认文本框显示一行文字
float textViewWidth=self.textView.frame.size.width;//取得文本框高度
NSString *content=textView.text;
NSDictionary *dict=@{NSFontAttributeName:[UIFont systemFontOfSize:16.0]};
CGSize contentSize=[content sizeWithAttributes:dict];//计算文字长度
float numLine=ceilf(contentSize.width/textViewWidth); //计算当前文字长度对应的行数
heightText=contentSize.height;
NSLog(@"%f,%f",numLine,currentLineNum);
if(numLine>currentLineNum ){
//如果发现当前文字长度对应的行数超过。 文本框高度，则先调整当前view的高度和位置，然后调整输入框的高度，最后修改currentLineNum的值.行数大于3行时，不再增加行数
if(numLine<3)
{
self.frame=CGRectMake(self.frame.origin.x,SCREEN_HEIGHT-self.keyHight-50-heightText*(numLine-currentLineNum), self.frame.size.width, 50+heightText*(numLine-currentLineNum));
textView.frame=CGRectMake(textView.frame.origin.x,5, textView.frame.size.width, 40+heightText*(numLine-currentLineNum));
}
else
{
self.frame=CGRectMake(self.frame.origin.x,SCREEN_HEIGHT-self.keyHight-50-heightText*2, self.frame.size.width, 50+heightText*2);
textView.frame=CGRectMake(textView.frame.origin.x,5, textView.frame.size.width, 40+heightText*2);
}
currentLineNum=numLine;
}else if (numLine<currentLineNum ){
//次数为删除的时候检测文字行数减少的时候
self.frame=CGRectMake(self.frame.origin.x, SCREEN_HEIGHT-self.keyHight-50, self.frame.size.width, 50);
textView.frame=CGRectMake(textView.frame.origin.x, 5, textView.frame.size.width, 40);
currentLineNum=numLine;
}
}
在ViewController中引用
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
self.textView=[[CommentTextView alloc]initWithFrame:CGRectMake(0, SCREEN_HEIGHT-50, SCREEN_WIDTH, 50)];
self.textView.backgroundColor = [UIColor redColor];
[self.textView.layer setBorderWidth:0.5];
[self.textView.layer setBorderColor:[UIColor colorWithRed:188/255.0 green:188/255.0 blue:188/255.0 alpha:1.0].CGColor];
[self.view addSubview:self.textView];
UIButton *btn=[UIButton buttonWithType:UIButtonTypeCustom];
btn.frame=CGRectMake(SCREEN_WIDTH-45, 5, 40, 40);
btn.titleLabel.textAlignment=NSTextAlignmentCenter;
[btn setTitle:@"发送" forState:UIControlStateNormal];
[btn addTarget:self action:@selector(submit) forControlEvents:UIControlEventTouchUpInside];
[self.textView addSubview:btn];
}
-(void)submit
{
[self.textView.textView resignFirstResponder];
}
-(void)keyboardWillShow:(NSNotification *)notification
{
CGRect keyBoardRect=[notification.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];
CGFloat deltaY=keyBoardRect.size.height;
//获取到键盘高度，并且要返回给CommentText,键盘的高度以计算当前的高度
NSMutableDictionary *dict=[[NSMutableDictionary alloc]init];
[dict setValue:[NSString stringWithFormat:@"%f",deltaY] forKey:@"keyHeight"];
[[NSNotificationCenter defaultCenter]postNotificationName:@"keyHeight" object:nil userInfo:dict];
[UIView animateWithDuration:[notification.userInfo[UIKeyboardAnimationDurationUserInfoKey] floatValue] animations:^{
self.textView.transform=CGAffineTransformMakeTranslation(0, -deltaY);
}];
}
-(void)keyboardWillHide:(NSNotification *)notification
{
[UIView animateWithDuration:[notification.userInfo[UIKeyboardAnimationDurationUserInfoKey] floatValue] animations:^{
self.textView.transform=CGAffineTransformIdentity;
} completion:^(BOOL finished) {
}];
}
运行效果如下
