objective-c - 在 iOS 中从 SQLite 保存和检索图像

Question

我正在尝试将图像保存到 Sqlite，然后将图像加载到 UIImageView。但它没有得到工作。我不知道出了什么问题。这是我正在使用的代码。谁能帮我解决这个问题。

- (void)saveImage {
    sqlite3_stmt *compiledStmt;
    if(sqlite3_open([dbPath UTF8String], &db)==SQLITE_OK){
        const char *insertSQL="insert into Image(Image)values(?)";
        if(sqlite3_prepare_v2(db,insertSQL, -1, &compiledStmt, NULL) == SQLITE_OK){
            UIImage *image = [UIImage imageNamed:@"farmhouse.png"];
            NSData *imageData=UIImagePNGRepresentation(image);
            sqlite3_bind_blob(compiledStmt, 1, [imageData bytes], [imageData length], NULL);

            sqlite3_step(compiledStmt);

            char *errMsg;
            sqlite3_exec(db, insertSQL, NULL,compiledStmt,&errMsg);

        }
    }
}

- (void)showImage {
    sqlite3_stmt *compiledStmt;
    if(sqlite3_open([dbPath UTF8String], &db)==SQLITE_OK){
        const char *insertSQL = "Select Image from Image Where Sl.No = ?";
        sqlite3_prepare_v2(db,insertSQL, -1, &compiledStmt, NULL);
        if(sqlite3_prepare_v2(db,insertSQL, -1, &compiledStmt, NULL) == SQLITE_OK){
            sqlite3_bind_int(compiledStmt, 1, 1);
            if(SQLITE_DONE != sqlite3_step(compiledStmt)) {                
                NSData *data = [[NSData alloc] initWithBytes:sqlite3_column_blob(compiledStmt, 1) length:sqlite3_column_bytes(compiledStmt, 1)];

                if(data == nil)
                    NSLog(@"No image found.");
                else
                    imgView.image = [UIImage imageWithData:data];


            }
        }
    }
}

谁能指出上面代码的问题。

提前致谢

Answer 1

- (void)saveImage 
{
  sqlite3_stmt *compiledStmt;
  sqlite3 *db;
  if(sqlite3_open([dbPath UTF8String], &db)==SQLITE_OK){
  NSString *insertSQL=@"insert into Image(image) VALUES(?)";
  if(sqlite3_prepare_v2(db,[insertSQL cStringUsingEncoding:NSUTF8StringEncoding], -1, &compiledStmt, NULL) == SQLITE_OK){
  UIImage *image = [UIImage imageNamed:@"vegextra.png"];
  NSData *imageData=UIImagePNGRepresentation(image);

  sqlite3_bind_blob(compiledStmt, 1, [imageData bytes], [imageData length], SQLITE_TRANSIENT);

  if(sqlite3_step(compiledStmt) != SQLITE_DONE ) {
      NSLog( @"Error: %s", sqlite3_errmsg(db) );
  } else {
      NSLog( @"Insert into row id = %lld", (sqlite3_last_insert_rowid(db)));
  }

sqlite3_finalize(compiledStmt);
  }
 }
sqlite3_close(db);
}

- (void)showImage
 {
   sqlite3_stmt *compiledStmt;
   sqlite3 *db;
   int i = 1;
   if(sqlite3_open([dbPath UTF8String], &db)==SQLITE_OK){
   NSString *insertSQL = [NSString stringWithFormat:@"Select image from Image Where Id = %d",i];
   if(sqlite3_prepare_v2(db,[insertSQL cStringUsingEncoding:NSUTF8StringEncoding], -1, &compiledStmt, NULL) == SQLITE_OK) {
   while(sqlite3_step(compiledStmt) == SQLITE_ROW) {

   int length = sqlite3_column_bytes(compiledStmt, 0);
   NSData *imageData = [NSData dataWithBytes:sqlite3_column_blob(compiledStmt, 0) length:length];

   NSLog(@"Length : %d", [imageData length]);

  if(imageData == nil)
     NSLog(@"No image found.");
  else
     imgView.image = [UIImage imageWithData:imageData];
   }
 }
 sqlite3_finalize(compiledStmt);
}
sqlite3_close(db);
}