iOS block circular reference

 

@interface ToolDemoViewController ()
{
    BOOL isSuccess;

    void (^testBlock2)(NSString *str);

}

@property ( strong , nonatomic ) NSString           *testName;

@property ( nonatomic , copy ) void (^testBlock)( NSString *str);

 

#pragma mark - test for circular references

- ( void )testWeakAction {
   
    // 这里不需要 __weak
    [ UIView animateWithDuration : 0.3 animations :^{
        self . view . backgroundColor = [ UIColor redColor ];
        self . testName = @"sadgf" ;
    }];
    // 这里不需要 __weak dispatch_async(dispatch_get_main_queue(), ^{self.view.backgroundColor= [UIColorblueColor];
   
       
        self . testName = @"dddd" ;
    });
   
    // Need __weak __weak typeof ( self ) wSelf = self ; testBlock2 = ^( NSString *str) { NSLog ( @"===%@" ,wSelf. testName ) ;     }; // Test call if ( self . testBlock ) { self . testBlock ( @" test " );     } if ( testBlock2 ) {
   
   
       

   
   
   
       

   
        testBlock2 ( @"ddd" );

    }

 

  void (^testTempBlock) ( NSString * str);
    // No need for __weak here
    testTempBlock = ^( NSString *str) {
        NSLog ( @"%@" , self . testName );
    };
    // The call of the block in the test method if (testTempBlock) {         testTempBlock( @"xiao" );
   

    }

    // Special handling is required when there is a delay in the block

    self.testBlock = ^(NSString *str) {

    ToolDemoViewController *strongSelf = wSelf;

      dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (2.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

          // After the page returns to the previous page, it will be executed and it will be empty. . .

          NSLog(@"name111===%@,,,%@",strongSelf.testName,str);

      });

    };

    if (self.testBlock) {

        self.testBlock(@"xiaoming");

    }

 

}