activity

既然对外号称全栈，算法，后端，大数据，AI，网页，数据库都要懂。自然，移动端也绝不例外。IOS太贵，作为穷鬼，只好学习安卓。 安卓和Linux的恩怨与区别 Android系统层面的底层是Linux，并且在中间加上了一个叫做Dalvik的Java虚拟机，从表面层看是Android运行库。每个Android应用都运行在自己的进程上，享有Dalvik虚拟机为它分配的专有实例。为了支持多个虚拟机在同一设备上高效运行，dalvik被改写过。Dalvik虚拟机执行的是Dalvik格式的可执行文件（.dex）-该格式经过优化，以将内存好用降到最低。 这是一个很最大程度利用现有软件的做法，但是毫无疑问和linux基金会还有甲骨文产生了过节。 关于开源协议的一些问题记载在了这里。 https://blog.csdn.net/define_us/article/details/84775031 安卓和linux的正式分手是在2010年，Linux2.6.33发布并且删除了Android内核代码。 安卓内核虽然是在linux内核基础上改的，但是也有很大差别 Android Binder Android Binder是基于Openbinder框架的一个驱动，用于提供Android平台的进程间的通信(IPC)。原来的Linux系统上层应用的进程间通信主要是D-bus，采用消息总线的方式来进行IPC

前言 学 Android 有一段时间了，想必不少人也和我一样，平时经常东学西凑，感觉知识点有些凌乱难成体系。所以趁着这几天忙里偷闲，把学的东西归纳下，捋捋思路。 这篇文章主要针对 Service 相关的知识点，进行详细的梳理，祝大家食用愉快！ 文章目录 方便大家学习，我在 GitHub 建立了 仓库 仓库内容与博客同步更新。由于我在 稀土掘金 简书 CSDN 博客园 等站点，都有新内容发布。所以大家可以直接关注该仓库，以免错过精彩内容！ 仓库地址： 超级干货！精心归纳 Android 、 JVM 、算法等，各位帅气的老铁支持一下！给个 Star ！ # 第一篇：Service 是什么 1.1 什么是 Service Service (服务) 是一个一种可以在后台执行长时间运行操作而没有用户界面的应用组件。 服务可由其他应用组件启动（如 Activity ），服务一旦被启动将在后台一直运行，即使启动服务的组件（ Activity ）已销毁也不受影响。 此外，组件可以绑定到服务，以与之进行交互，甚至是执行进程间通信 ( IPC )。 1.2 Service 通常总是称之为 “后台服务” 其中 “后台” 一词是相对于前台而言的，具体是指：其本身的运行并不依赖于用户可视的 UI 界面 因此，从实际业务需求上来理解， Service 的适用场景应该具备以下条件： 并不依赖于用户可视的 UI

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: How can I access the current Android activity class? I am using the necessitas framework (QT in Android). Basically, using the Android NDK an activity calls a QT application (.so). All runs fine. Now I am working on some bindings to access the GPS from the QT application. From some java examples that access the GPS I saw that the most vital part is to allow access to the GPS service: LocationManager lm; lm = (LocationManager) getSystemService(LOCATION_SERVICE); Here getSystemService is a method of class activity. Because I am using the JNI

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I'm pretty new to android and I've got a question. I'm playing around with a simple Twitter client tutorial which is on github. however I can't manage to get a onClickListener working properly. How can I retrieve the position of any item on the list that is being clicked on? I've tried playing around by combining tutorials with no luck yet. Here is the code: https://github.com/cacois/TweetView/blob/progress_bar/src/com/example/TweetItemAdapter.java package com.example; import java.util.ArrayList; import com.example.Example.Tweet; import

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I've been trying to create a simple form in symfony but each time I try to submit I get the following error: ERROR: The CSRF token is invalid. Please try to resubmit the form. After surfing on the Internet and reducing the code to almost empty. I still get that error. Most of the people who I've seen asking for that solved the error using the following twig code {{ form_rest(form) }} The problem is that I'm using it, it's like when I bind the request it doesn't do it correctly. I don't know what else can I do. This is my small twig template:

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: In my app I have three activity as Activity 1 Activity 2 Activity 3 How to switch between activities. So how can this be done? public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case R.id.settingOpt: Intent intent = new Intent(this, SettingsForm.class); this.startActivity(intent); this.finish(); break; case R.id.reminderOpt: Intent intentR = new Intent(this, ReminderForm.class); this.startActivity(intentR); break; case R.id.helpOpt: Intent intentH = new Intent(this, HelpForm.class); this.startActivity(intentH);

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I am creating a project where I have a login screen, which is used for user to login into the Application. This login screen should only be visible the first time, so the user can fill it and log in, but when user opens the application at the second time the application must show main.activity. How to use Shared preference . I don't understand how to do this. 回答1: To achieve this with SharedPreferences you might do something like this: Insert the following in any Class you see more fit. Let's suppose you insert this in class Example . //Give

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I wanted to use ViewPager to display some encrypted images. For that I created an extension of PagerAdapter and put my decryption code inside instantiateItem method. But the problem is that the process of decryption takes too long. So, I used AsyncTask inside instantiateItem method to show a progress dialog. Now, ViewPager displays a blank screen at first and I should swipe to view the first image. Moreover setCurrentItem() does not work. My Code: public class FullScreenImageAdapter extends PagerAdapter { private Activity _activity; private

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I need to extract disk statistics for a given process, I can get the processes listed and get overall information such as CPU and Memory listed using WMI and PerformanceCounters. But the information is all bundled up, is there any way to extract those data per process. Kind of like in Windows Resource Monitor? Thanks in Advance 回答1: If you need live data, you should implement ETW listener. ETW are the way of tracing performance information in Windows. It is supported back to Windows 2000. Every component in Windows report ETW events (if

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I upgraded IntelliJ Idea 12.0.4 to 12.10. Now all the modules in my Android project give the error: Error: Default Activity Not Found I reverted to 12.0.4 and it works. Any ideas ?? I think it might be related to some plugins not being installed cause the only other thing could have been a local config but I deleted the configuration folder to confirm and that didn't change anything. 回答1: If you see that error occur after upgrading versions of IntelliJ IDEA or Android Studio, or after Generating a new APK, you may need to refresh the IDE's