将图像从 NSOutputStream 保存到库的正确方法是什么答案

【问题标题】：What is correct way to save image from NSOutputStream to library将图像从 NSOutputStream 保存到库的正确方法是什么
【发布时间】：2014-11-28 02:43:05
【问题描述】：

如何编写 UIImage 并将数据发送到接收服务器。我尝试过，但 NSOutputStream 只能在流中写入最多 136768 个字节，而且我只保存一小部分图像。非常感谢您的帮助。这是我的代码：

来自 UIImage 选择器

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    UIImage *image = info[UIImagePickerControllerOriginalImage];
    NSData *imgData = UIImageJPEGRepresentation(image,1.0f);
    NSLog(@"%d",imgData.length);
    NSMutableData *completeData = [[NSMutableData alloc]init];
    [completeData appendData:imgData];

    NSInteger bytesWritten = 0;
    while ( completeData.length > bytesWritten )
    {


        //sending NSData over to server
        NSInteger writeResult = [outputStream write:[completeData bytes]+bytesWritten maxLength:[completeData length]-bytesWritten];
        if ( writeResult == -1 )
            NSLog(@"error code here");

        else
            bytesWritten += writeResult;

        if (bytesWritten == writeResult) {
                        [self dismissViewControllerAnimated:YES completion:nil];
        }
    }

}

流代理

- (void)stream:(NSStream *)aStream handleEvent:(NSStreamEvent)eventCode
// An NSStream delegate callback that's called when events happen on our 
// network stream.
{
#pragma unused(aStream)
    assert(aStream == self.networkStream);

    switch (eventCode) {
        case NSStreamEventOpenCompleted: {
            [self _updateStatus:@"Opened connection"];
        } break;
        case NSStreamEventHasBytesAvailable: {


            if (aStream == self.networkStream) {

                uint8_t buffer[5000];
                int len;

                while ([self.networkStream hasBytesAvailable]) {

                    len = [self.networkStream read:buffer maxLength:sizeof(buffer)];
                    NSLog(@"len=%d", len);

                    if (len > 0) {

                        NSData *pictureData = [NSData dataWithBytes:buffer length:len];

                        [sharedManager.pictureMutableData appendData:pictureData];

                        NSLog(@"%d",sharedManager.pictureMutableData.length);



                    }

                }
            }
        case NSStreamEventHasSpaceAvailable: {

            [self _didReceiveDataImage:sharedManager.pictureMutableData];

            NSLog(@"%d",sharedManager.pictureMutableData.length);
                   } break;
        case NSStreamEventErrorOccurred: {
            [self _stopReceiveWithStatus:@"Stream open error"];
        } break;
        case NSStreamEventEndEncountered: {
            // ignore
        } break;
        default: {
            assert(NO);
        } break;
    }
}

【问题讨论】：

标签： ios objective-c

【解决方案1】：

你的代码很奇怪：

您为 input 流 (NSStreamEventHasBytesAvailable) 实现事件。
数据不是一部分写的，而是要一部分一部分的发送。部件的大小由操作系统决定。如果数据较大，则必须在事件NSStreamEventHasSpaceAvailable 的委托方法中编写下一部分。但你不在那里写。相反，您设置收到数据！？

看看这里：

https://developer.apple.com/library/IOs/documentation/Cocoa/Conceptual/Streams/Articles/WritingOutputStreams.html#//apple_ref/doc/uid/20002274-1002233

【讨论】：