Iphone 我想在数组中存储单个字符串值，但只保存最后一个值并删除所有第一个值

将你的阵法的alloc移出“while”， 或者每次插入阵列时都要创建阵列2

-(void) getAllRowsFromTableNamed:(NSString *)  tableName
{   
AppDelegate *app =[[UIApplication sharedApplication]delegate];
strNam = app.strName;
NSString *qsql = [ NSString stringWithFormat:@"SELECT * FROM %@", tableName];
sqlite3_stmt  *statement;
if( sqlite3_prepare_v2(db2, [qsql UTF8String], -1, &statement, nil) == SQLITE_OK)
{    
while (sqlite3_step(statement)  ==  SQLITE_ROW)
{   
char *field1= (char *) sqlite3_column_text(statement, 0);
 NSString   *field1Str = [[NSString   alloc] initWithUTF8String:field1];
char *field2= (char *) sqlite3_column_text(statement, 1);
NSString   *field2Str = [[NSString   alloc] initWithUTF8String:field2];
 char *field3= (char *) sqlite3_column_text(statement, 2);
NSString   *field3Str = [[NSString   alloc] initWithUTF8String:field3];
char *field4= (char *) sqlite3_column_text(statement, 3);
 NSString   *field4Str = [[NSString   alloc] initWithUTF8String:field4];
NSString   *str =[[NSString alloc] initWithFormat:@"%@ - %@- %@- %@", field1Str, field2Str, field3Str, field4Str];
NSLog(@"%@",str);
 NSLog(@"%@",field1Str);

 self.strDat = field1Str;
 NSLog(@"%@", strDat);    
 array2 =[[NSMutableArray alloc]init];
 [self.array2 addObject:self.strDat]; 
 }
sqlite3_finalize(statement);
NSLog(@"%@",[array2 description]);
} 
}

---

像这样在循环之前初始化数组

if( sqlite3_prepare_v2(db2, [qsql UTF8String], -1, &statement, nil) == SQLITE_OK)

{

//here

    array2 =[[NSMutableArray alloc]init];

    while (sqlite3_step(statement) == SQLITE_ROW)

    {
        ....
        ....
        ....


        [array2 addObject:self.strDat];

    }
}

-(void) getAllRowsFromTableNamed:(NSString *)  tableName
{   
AppDelegate *app =[[UIApplication sharedApplication]delegate];
strNam = app.strName;
NSString *qsql = [ NSString stringWithFormat:@"SELECT * FROM %@", tableName];
sqlite3_stmt  *statement;
if( sqlite3_prepare_v2(db2, [qsql UTF8String], -1, &statement, nil) == SQLITE_OK)
{ 
 array2 =[[NSMutableArray alloc]init];

while (sqlite3_step(statement)  ==  SQLITE_ROW)
{   
char *field1= (char *) sqlite3_column_text(statement, 0);
 NSString   *field1Str = [[NSString   alloc] initWithUTF8String:field1];
char *field2= (char *) sqlite3_column_text(statement, 1);
NSString   *field2Str = [[NSString   alloc] initWithUTF8String:field2];
 char *field3= (char *) sqlite3_column_text(statement, 2);
NSString   *field3Str = [[NSString   alloc] initWithUTF8String:field3];
char *field4= (char *) sqlite3_column_text(statement, 3);
 NSString   *field4Str = [[NSString   alloc] initWithUTF8String:field4];
NSString   *str =[[NSString alloc] initWithFormat:@"%@ - %@- %@- %@", field1Str, field2Str, field3Str, field4Str];
NSLog(@"%@",str);
 NSLog(@"%@",field1Str);

 self.strDat = field1Str;
 NSLog(@"%@", strDat);    
 [self.array2 addObject:self.strDat]; 
 }
sqlite3_finalize(statement);
NSLog(@"%@",[array2 description]);
} 
}