block | 易学教程

WebViewClient shouldInterceptRequest Freezes the WebView

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问题 I want to cache images displayed in the WebView for a specific time, for e.g. 7 days, so I needed to both save image caches to disk and load them from disk and provide them to the WebView. Also I needed to resize the images to avoid the WebView; Crash on High Memory Usage, so I implemented the caching and resizing logic in a Blocking Function named " fetchBitmap ". As the Android documentation states, the " shouldInterceptRequest " runs on a Thread Other than the UI Thread, so I can do

replace the clear:both with pseudo class

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问题 Previously, when I had floatings blocks, and i will stop the float, i used ; <div style="clear:both"></div> But now, i'm solve this problem with pseudo class : .last_floating_div:after { content: ""; display: table; clear: both; } I has always works perfectly. But today... It doesn't work... ! Look at this clear example : http://jsfiddle.net/YsueS/2/ I know my problem is a total beginner problem. I have sold this problem so many times... I really don't understand why it doesn't work here !

Best practice when displaying inline HTML elements next to a h1 element?

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问题 I have a webpage that displays the name of a "product", with edit/delete links next to it on the same line. Example: Product 1 (Edit | Delete) I want the product name to have a large font size, and the edit/delete buttons to have regular font size (i.e. same as paragraphs and whatnot). And I want them to appear inline, like the example above. I'm just wondering what HTML/CSS I should utilise in order to achieve this. If I use a h1 element for the product name, it pushes the edit/delete links

On understanding how printf(“%d\n”, ( { int n; scanf(“%d”, &n); n*n; } )); works in C

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问题 I came across this program via a quora answer #include<stdio.h> int main() { printf("%d\n", ( { int n; scanf("%d", &n); n*n; } )); return 0; } I was wondering how does this work and if this conforms the standard? 回答1: This code is using a "GNU C" feature called statement-expressions, whereby a parentheses-enclosed compound statement can be used as an expression, whose type and value match the result of the last statement in the compound statement. This is not syntactically valid C, but a GCC

Return NSString which is set from inside a block

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问题 I have a method which looks like this: -(NSString *)getCityFromLocation:(CLLocation *)location { __block NSString *city; CLGeocoder *geocoder = [[CLGeocoder alloc] init]; [geocoder reverseGeocodeLocation: location completionHandler: ^(NSArray *placemarks, NSError *error) { //Get address CLPlacemark *placemark = [placemarks objectAtIndex:0]; city = [placemark.addressDictionary objectForKey:@"City"]; NSLog(@"city 1: %@", city); }]; return city; } And I call it like this: NSString *city = [self

Wait until animation block finishes before segue

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问题 I'm implementing some simple animations to my cards app. Everything is working great so far but I have just one more detail to fix before I can say it is done. The scenario is pretty simple: Three cards must exit the screen with an animation before segue modally brings up the new screen. Up until now he animation gets executed and the new view is loaded, but the detail I haven't been able to work out is the "wait until the animation finishes before bringing the new view". This is how I'm

spark源码系列（9）BlockManager的原理

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上一篇说到CacheManager和checkpoint来管理缓存和数据相关的东西。但实际上，他们底层都是通过BlockManger来管理数据的。找到RDD#getOrCompute中的 SparkEnv.get.blockManager.getOrElseUpdate(blockId, storageLevel, elementClassTag,我们就可以看到最终是通过BlockManager来管理数据。在分析源码前老规矩，先画一张整体的图首先Driver上有一个BlockManagerMaster，它的功能就是负责各个节点上的BlockManager元数据管理，进行维护。比如block的增删改查等操作，都会在这里维护变更。每个节点上都会有blockManager，BlockManager有几个关键组件： DiskStore：负责磁盘上的数据进行读写 MemoryStore：负责对内存上的数据进行读写 BlockTransferService：负责和远程节点建立数据传输的组件每个BlockManager创建之后，向Driver中的BlockManagerMaster进行注册，此时BlockManager会为创建对应的BlockManagerInfo。使用BlockManager进行读写操作时，比如RDD运行过程中间数据，或者手动指定了persisit，优先将数据写入内存

iOS进阶（一）block与property

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iOS进阶（一）block与property 这篇读书笔记主要介绍了C语言内存分配、block疑难点、property的深入理解，自己对这三块做了系统性的总结，希望对你有所帮助。 C语言内存分配 Objective-C从名字来看就可以知道是一门超C语言，所以了解C语言的内存模型对于理解Objective-C的内存管理有很大的帮助。C语言内存模型图如下： 1-1 C内存分配.png 从图中可以看出内存被分成了5个区，每个区存储的内容如下：栈区(stack)：存放函数的参数值、局部变量的值等，由编译器自动分配释放，通常在函数执行结束后就释放了，其操作方式类似数据结构中的栈。栈内存分配运算内置于处理器的指令集，效率很高，但是分配的内存容量有限，比如iOS中栈区的大小是2M。堆区(heap)：就是通过new、malloc、realloc分配的内存块，它们的释放编译器不去管，由我们的应用程序去释放。如果应用程序没有释放掉，操作系统会自动回收。分配方式类似于链表。静态区：全局变量和静态变量的存储是放在一块的，初始化的全局变量和静态变量在一块区域，未初始化的全局变量和未初始化的静态变量在相邻的另一块区域。程序结束后，由系统释放。常量区：常量存储在这里，不允许修改的。代码区：存放函数体的二进制代码。栈区在什么时候释放内存呢？我们通过下面的一个例子来说明下： 1 2 3 4

Block 在不同情况下的变量存储区域

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一.如果只使用全局或静态变量或不使用外部变量, 那么Block块的代码会存储在全局区; 二.如果使用了外部变量, 在ARC中, Block块的代码会存储在堆区; 在MRC中, Block快的代码会存储在栈区; 三.block默认情况下不能修改外部变量, 只能读取外部变量: 在ARC中, 外部变量存在堆中, 这个变量在Block块内与在Block块外地址相同; 外部变量存在栈中, 这个变量会被copy到为Block代码块所分配的堆中; 在MRC中, 外部变量存在堆中, 这个变量在Block块内与Block块外相同; 外部变量存在栈中, 这个变量会被copy到为Block代码块所分配的栈中; 四.如果需要修改外部变量, 需要在外部变量前面声明 __block 在ARC中, 外部变量存在堆中, 这个变量在Block块内与Block块外地址相同; 外部变量存在栈中, 这个变量会被转移到堆区, 不是复制, 是转移. 在MRC中, 外部变量存在堆中, 这个变量在Block块内与Block块外地址相同; 外部变量存在栈中, 这个变量在Block块内与Block块外地址相同; 来源： oschina 链接： https://my.oschina.net/u/1389202/blog/501419

iOS之Block详解

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iOS Block实例： https://my.oschina.net/Jacedy/blog/842167 一、Block定义闭包是一个函数（或指向函数的指针），再加上该函数执行的外部的上下文变量（有时候也称作自由变量）。 block 实际上就是 Objective-C 语言对于闭包的实现。二、Block原理 // main.m int main(int argc, const char * argv[]) { @autoreleasepool { // static int age = 20; __block int age = 20; void (^blcok)(void) = ^ { age = 21; NSLog(@"%d", age); }; age = 22; NSLog(@"%d", age); blcok(); NSLog(@"%@", blcok); } } 将上述代码使用命令：$ clang -rewrite-objc main.m 编译后，截取C++代码如下： ....... __attribute__((visibility("default"))) __attribute__((availability(macosx,introduced=10_8))) #ifndef _REWRITER_typedef_NSXPCListenerEndpoint

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