Question

在firebase的structure data页面中，有一个用户＆lt; - ＆gt;组关系的示例。这是一种存储包含双向关系的数据的好方法。

以下是该页面上解释的关系：

#import "RCTBridgeModule.h"
#import <AssetsLibrary/AssetsLibrary.h>
#import <UIKit/UIKit.h>
@interface ReadImageData : NSObject <RCTBridgeModule>
@end

@implementation ReadImageData

RCT_EXPORT_MODULE();

RCT_EXPORT_METHOD(readImage:(NSString *)input callback:(RCTResponseSenderBlock)callback)
{

  // Create NSURL from uri
  NSURL *url = [[NSURL alloc] initWithString:input];

  // Create an ALAssetsLibrary instance. This provides access to the
  // videos and photos that are under the control of the Photos application.
  //ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];

  // Using the ALAssetsLibrary instance and our NSURL object open the image.
  //[library assetForURL:url resultBlock:^(ALAsset *asset) {

    // Create an ALAssetRepresentation object using our asset
    // and turn it into a bitmap using the CGImageRef opaque type.
    //CGImageRef imageRef = [asset thumbnail];

    // Create UIImageJPEGRepresentation from CGImageRef
   // NSData *imageData = UIImageJPEGRepresentation([UIImage imageWithCGImage:imageRef], 0.1);

    // Convert to base64 encoded string
    // NSString *base64Encoded = [imageData base64EncodedStringWithOptions:0];

    callback(@[url]);

  //} failureBlock:^(NSError *error) {
    //NSLog(@"that didn't work %@", error);
  //}];



}
@end

通过这种方式存储数据，如何查询该数据以显示特定用户的组列表？

如何查询该数据？ // An index to track Ada's memberships { "users": { "alovelace": { "name": "Ada Lovelace", // Index Ada's groups in her profile "groups": { // the value here doesn't matter, just that the key exists "techpioneers": true, "womentechmakers": true } }, ... }, "groups": { "techpioneers": { "name": "Historical Tech Pioneers", "members": { "alovelace": true, "ghopper": true, "eclarke": true } }, ... } }不能这样做，因为它只需要一个密钥。

使用密钥存储为Firebase中的列表来查询数据

0 个答案: