UITextFeild默认选中文本

方法1:selectAll:

[textFeild selectAll:nil]; //全选
[textFeild selectAll:self];//全选并弹出UIMenuController菜单

方法2:setSelectedTextRange

//利用`selectedTextRange`
//@property (nullable, readwrite, copy) UITextRange *selectedTextRange;
[textFeild setSelectedTextRange:[textFeild textRangeFromPosition:textFeild.beginningOfDocument toPosition:textFeild.endOfDocument]];

使用举例

- (void)showWCPlaceNameInputView{

    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"请输入名称" message:nil preferredStyle:UIAlertControllerStyleAlert];
    
    WS(weakSelf);
    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {
    }];
    
    UIAlertAction *otherAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
    }];
    
    [alertController addTextFieldWithConfigurationHandler:^(UITextField *textField) {
        
        textField.text = weakSelf.userInputLocationDescription;
        textField.textAlignment = NSTextAlignmentCenter;
        [textField addTarget:self action:@selector(handleTextFieldTextDidChange:) forControlEvents:UIControlEventEditingChanged];
        [textField addTarget:self action:@selector(handleTextFieldTextDidBegin:) forControlEvents:UIControlEventEditingDidBegin];
    }];
    // Add the actions.
    [alertController addAction:cancelAction];
    [alertController addAction:otherAction];
    [self presentViewController:alertController animated:YES completion:nil];
}

- (void)handleTextFieldTextDidBegin:(UITextField *)textFeild{
    
 
    dispatch_async(dispatch_get_main_queue(), ^{
        
        [textFeild selectAll:nil];    //直接选中
        //[textFeild selectAll:self]; 默认选中切会弹出UIMenuController
        //[textFeild setSelectedTextRange:[textFeild textRangeFromPosition:textFeild.beginningOfDocument toPosition:textFeild.endOfDocument]];
    });
}

- (void)handleTextFieldTextDidChange:(UITextField *)textFeild{
    self.userInputLocationDescription = textFeild.text.trimed;
}

##参考链接

https://stackoverflow.com/questions/1689911/programmatically-select-all-text-in-uitextfield