objective-c - iPhone - 程序接收信号 : 0 - on device but not on simulator ( Memory MAnagement Issue)

Question

我正在经历一个严格的基于内存的问题，同时迭代一个在 SQLite 数据库中执行批量插入的循环。

我很确定这是内存问题，我无法指出导致问题的变量。据我所知，我已经释放了所有分配的东西。

到目前为止，通过仪器分析没有内存泄漏。代码片段如下:

int m=0;

while ([arrData count]!=0) {

if (newQuery) {

    exeQuery = query;
    newQuery = false;

}
else 
{
    exeQuery=[exeQuery stringByAppendingFormat:@" UNION"];
}

NSMutableDictionary *data = [[NSMutableDictionary alloc] initWithDictionary:[arrData objectAtIndex:0]];

[data removeObjectForKey:@"statement"];
[data removeObjectForKey:@"datetime_stamp"];

NSString *strVal=@"";
NSString *_value=@"";

int i=0;
    for(;i<[keys  count]-1;i++)
    {
        if(_value==nil || _value==NULL){
            _value=@"";
        }

        _value=[NSString stringWithFormat:@"%@",[data objectForKey:[keys objectAtIndex:i]]];
        _value=[_value stringByReplacingOccurrencesOfString:@"'" withString:@"''"];

        strVal=[strVal stringByAppendingFormat:@"'%@',",_value];

    }

if(_value==nil || _value==NULL){
    _value=@"";
}

_value=[NSString stringWithFormat:@"%@",[data objectForKey:[keys objectAtIndex:i]]];
_value=[_value stringByReplacingOccurrencesOfString:@"'" withString:@"''"];

strVal=[strVal stringByAppendingFormat:@"'%@'",_value];


exeQuery=[exeQuery stringByAppendingFormat:@" SELECT %@",strVal];


if (m!=0 && m%499==0) {

    [DataSource executeQuery:exeQuery];

    //db.execute(exeQuery);
    newQuery = true;
}

[data release];

[arrData removeObjectAtIndex:0];

m++;
}

for (;m<locations_length; m++) {

if (newQuery) {

    exeQuery = query;
    newQuery = false;

}
else 
{
    exeQuery=[exeQuery stringByAppendingFormat:@" UNION"];
}

NSMutableDictionary *data = [[NSMutableDictionary alloc] initWithDictionary:[arrData objectAtIndex:m]];

[data removeObjectForKey:@"statement"];
[data removeObjectForKey:@"datetime_stamp"];

NSString *strVal=@"";
NSString *_value=@"";

int i=0;
    for(;i<[keys  count]-1;i++)
    {
        if(_value==nil || _value==NULL){
            _value=@"";
        }

        _value=[NSString stringWithFormat:@"%@",[data objectForKey:[keys objectAtIndex:i]]];
        _value=[_value stringByReplacingOccurrencesOfString:@"'" withString:@"''"];

        strVal=[strVal stringByAppendingFormat:@"'%@',",_value];

    }

if(_value==nil || _value==NULL){
    _value=@"";
}

_value=[NSString stringWithFormat:@"%@",[data objectForKey:[keys objectAtIndex:i]]];
_value=[_value stringByReplacingOccurrencesOfString:@"'" withString:@"''"];

strVal=[strVal stringByAppendingFormat:@"'%@'",_value];


exeQuery=[exeQuery stringByAppendingFormat:@" SELECT %@",strVal];


if (m!=0 && m%499==0) {

    [DataSource executeQuery:exeQuery];

    //db.execute(exeQuery);
    newQuery = true;
}

[data release];
}

非常感谢任何帮助。请携手...!

提前致谢。

Answer 1

很明显，我们使用的字符串在每个实例中都会发生变异，因此 nsmutablestring 是优化的解决方案。此外，在分析函数时:

[NSMutableString replaceOccurrencesOfString:@"'" withString:@"''"]
[NSMutableString  appendString:]

在仪器中，与您以前使用过的仪器相比，它们留下的内存足迹更少。