Q:Get rows count by indexPath of tableView comes `Trying to put the stack in unreadable memory at:` error

aircraft Published at Dev

aircraft

In my tableView delegate methods:

I get numberOfRows and numberOfSections in my tableView delegate methods:

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

and

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath  ,

but in the - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section method, I tried this method:

NSString *key = [NSString stringWithFormat:@"%ld", section];

In this line , it shows the error:Thread 1：EXC_BAD_ACCESS(code=2,address=0x) and I taken the (lldb):

(lldb) po [NSString stringWithFormat:@"%ld", section]
error: Trying to put the stack in unreadable memory at: 0x7fff50739eb0.

If I don't get numberOfRows and numberOfSections in my tableView delegate methods: the error will not appear.

The below is my code:

- (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];
    }

    NSInteger numberOfRows = [tableView numberOfRowsInSection:[indexPath section]];

    NSInteger numberOfSections = [tableView numberOfSections];

    if (indexPath.row == 0 && numberOfRows != 1) {

        cell.textLabel.text = [_arr objectAtIndex:indexPath.row];
    }



    return cell;
}

    - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {

        NSInteger numberOfRows = [tableView numberOfRowsInSection:[indexPath section]];

        NSInteger numberOfSections = [tableView numberOfSections];

        if (indexPath.row == 0 && numberOfRows != 1) {

             return 40;
        }else {
            return 5;
        }

    }

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {

    //NSString *key = [NSString stringWithFormat:@"%d", (int)section];

    NSString *key = [NSString stringWithFormat:@"%ld", section];  // this line shows the error.


    BOOL folded = [[_foldInfoDic objectForKey:key] boolValue];

    if (section == 0) {
        return folded?_arr.count:1;
    } else if (section == 1) {
        return folded?_arr.count:1;
    } else if (section == 2) {
        return folded?_arr.count:1;
    } else {
        return folded?_arr.count:0;
    }
}

zylenv

This is not a error caused by this code:

NSString *key = [NSString stringWithFormat:@"%ld", section];

Your code is run in an endless loop and end by the system. Look at the below:

When you call:

 NSInteger numberOfRows = [tableView numberOfRowsInSection:[indexPath section]];
 NSInteger numberOfSections = [tableView numberOfSections];

in - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath, this will case an endless loop.

For Example(call either of them will cause an endless loop):

- (void)func1 {
    // Code
    [self func2];
}
- (void)func2 {
    // Code
    [self func1];
}

The Simplest solution is implement you code as below:

   - (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];
    }

    NSInteger numberOfRows = [tableView numberOfRowsInSection:[indexPath section]];

    NSInteger numberOfSections = [self numberOfSectionsInTableView:tableView];

    if (indexPath.row == 0 && numberOfRows != 1) {

        cell.textLabel.text = [_arr objectAtIndex:indexPath.row];
    }



    return cell;
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {

    NSInteger numberOfRows = [self tableView:self numberOfRowsInSection:[indexPath section]];

    NSInteger numberOfSections = [self numberOfSectionsInTableView:tableView];

    if (indexPath.row == 0 && numberOfRows != 1) {

        return 40;
    }else {
        return 5;
    }

}

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

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    //NSString *key = [NSString stringWithFormat:@"%d", (int)section];

    NSString *key = [NSString stringWithFormat:@"%ld", section];  // this line shows the error.


    BOOL folded = [[_foldInfoDic objectForKey:key] boolValue];

    if (section == 0) {
        return folded?_arr.count:1;
    } else if (section == 1) {
        return folded?_arr.count:1;
    } else if (section == 2) {
        return folded?_arr.count:1;
    } else {
        return folded?_arr.count:0;
    }
}

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