ios - 内存管理 iOS 开发应用程序在一些细节项目后不起作用

Question

我正在处理一个带有 tableView Controller 的项目，详细 View 包含 CMMotionManager。当我打开 5 或 6 个 detailViews 时一切顺利，但一段时间后应用程序变慢并最终崩溃。

在仪器上，唯一的泄漏是在 main.m 上，而且我必须说我正在使用 ARC，我无法释放或重新分配实例。

代码如下:首先是 TableView :

- (void)viewDidLoad
{
    [super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
    self.title = @"Movement";//Master View Controller title bar
    UIImage *image = [UIImage imageNamed:@"jg_navibar.png"];
    [self.navigationController.navigationBar setBackgroundImage:image      forBarMetrics:UIBarMetricsDefault];

    //Init the array with data
    bodypartsMutableArray = [NSMutableArray arrayWithCapacity:26];

BodypartData *part1 = [[BodypartData alloc] init];
part1.bodypartname = @"Shoulder";
    part1.movementname = @"Flexion";
    part1.fullimageStartingPosition=[UIImage imageNamed:@"2_shoulder_flexion_end_position.jpg"];
    part1.fullimageEndedPosition=[UIImage imageNamed:@"2_shoulder_flexion_end_position.jpg"];
    part1.thumbimage=[UIImage imageNamed:@"1_shoulder_flexion_landmarks_thumb.jpg"];
[bodypartsMutableArray addObject:part1];

.........
}

然后是单元格:

   - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"MyBasicCell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil){
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
    }
    else {
    BodypartData *part = [self.bodypartsMutableArray objectAtIndex:indexPath.row];
    cell.textLabel.text =[NSString stringWithFormat:part.movementname];
    cell.detailTextLabel.text =[NSString stringWithFormat:part.bodypartname];
    cell.imageView.image =part.thumbimage;
    }
    return cell;
}

和 detailViewdid 加载:

我没有收到任何错误或警告，什么都没有。就在我加载 6,7 个细节 View 时，motionManagers 似乎停止工作了......只是这个......我可以回到主视图并一次又一次地加载细节项目，但运动管理器不起作用。这是我的详细 View 的代码

@synthesize liveCounterLabel = _liveCounterLabel;
@synthesize resultLabel = _resultLabel;

@synthesize detailItem = _detailItem;
@synthesize imageView = _imageView;
@synthesize calculateButton = _calculateButton;
@synthesize motionManager =_motionManager;
@synthesize selectedImage=_selectedImage;
@synthesize unselectedImage=_unselectedImage;

@synthesize m11started=_m11started;
@synthesize m12started=_m12started;
@synthesize m13started=_m13started;
@synthesize m11ended=_m11ended;
@synthesize m12ended=_m12ended;
@synthesize m13ended=_m13ended;
@synthesize m11=_m11;
@synthesize m12=_m12;
@synthesize m13=_m13;
@synthesize queue=_queue;

@synthesize buttonCounter=_buttonCounter;



#pragma mark - Managing the detail item

- (void)setDetailItem:(id)newDetailItem
{
    if (_detailItem != newDetailItem) {
        _detailItem = newDetailItem;

        // Update the view.
        [self configureView];

    }
}

- (void)configureView
{
    // Update the user interface for the detail item.
    if (self.detailItem) {
        self.imageView.image = [self.detailItem fullimageStartingPosition];
        NSString* longString = [[self.detailItem bodypartname ] stringByAppendingString:    [@" " stringByAppendingString:[self.detailItem movementname]]];
        self.navigationItem.title = [NSString stringWithFormat:longString];
        //Backround Image code
        [[self view] setBackgroundColor:[UIColor colorWithPatternImage:[UIImage     imageNamed:@"background.jpg"]]];
    }
}
- (void)viewDidLoad
{
    [super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
    // Init motionManager object and set the Update Interval
    _buttonCounter=0;


    _motionManager = [[CMMotionManager alloc]init];
    _motionManager.deviceMotionUpdateInterval=1/60; //60 Hz
    [_motionManager startGyroUpdates];

    if (!_queue){
        _queue = [NSOperationQueue mainQueue];
    }

    if (_motionManager.gyroAvailable) {
        _motionManager.gyroUpdateInterval = 1.0/60.0;
        //[_motionManager startDeviceMotionUpdatesToQueue:[NSOperationQueue currentQueue]
         //                                  withHandler: ^(CMDeviceMotion *motion,    NSError *error)
        [_motionManager startDeviceMotionUpdatesToQueue:_queue
                                            withHandler: ^(CMDeviceMotion *motion, NSError *error)

         {
             CMAttitude *attitude = [[CMAttitude alloc] init];
             attitude=motion.attitude;

             //Calculation with rotationMatrix
             _m11 = [NSString stringWithFormat:@"%.02f", attitude.rotationMatrix.m11];
             _m12 = [NSString stringWithFormat:@"%.02f", attitude.rotationMatrix.m12];
             _m13 = [NSString stringWithFormat:@"%.02f", attitude.rotationMatrix.m13];

     }];

`

Answer 1

您应该检查 dequeueReusableCellWithIdentifier 的结果。如果它为 nil，则您可能在不属于您的内存部分中设置属性。

请引用这个doc (如果您想跳过章节，请搜索 dequeueReusableCellWithIdentifier)