handler

I implemented an Android Application that consists of four activity (A,B,C,D). A calls B; B calls C and C calls D. The activity A implements a Handler Handler handler=new Handler(){ public void handleMessage(Message msg){ Bundle bundle = new Bundle(); bundle = msg.getData(); String key = bundle.getString("Changed"); if(key.compareTo("NotificationType") == 0){ String completeStr = bundle.getString(key); if(completeStr.compareTo("Message") == 0) { // update UI of Activity A } } } }; The Activity D can send a messagge using the hadler. The question are: What happens if the Activity A is in

What made me curious is that the generic handler works just fine when I'm running the Web App in a Visual Studio ASP.NET Development Server. When I change the config to run it directly from IIS the handler just dies. It's an image handler, it writes back an array of bytes to be rendered in an Image object. As I said, it works fine in VS Development Server, but fails on IIS. It doesn't even get called... The error I get when I'm trying to call it directly is this: Parser Error Description: An error occurred during the parsing of a resource required to service this request. Please review the

在Activity可见时进行页面刷新，即处于Activity栈顶，当然，这种刷新操作 可以在onStart,onResume,onRestart，onNewIntent+singleTask中，但最好的位置是 onResume, 其他方式可能会造成窗体泄露 Service的两种启动方式，startService和bindService，根据启动方式的不同，当然也有一种称为复合方式startService+bindService，Service销毁的方式不同，startService可以做 app退出后 的后台服务，但bindService不行，startService+bindService也可以做后 app退出后 的后台服务，但app退出时必须unbind，反过来bindService+startService不能做 app退出后 的服务 建议在Activity增加一个变量activityIsActivity来判断当前Activity是否处于活动状态,Activity::onResume和Activity:onPause中改变其值，防止在无界面时发生窗体泄露问题。 在Activity的onWindowFocusChanged的方法中监听焦点的改变 使用 InputMethodManager 退出键盘最灵活的方式是 InputMethodManager imm =

更新到adt2.0的开发者们可能会在handler上发现这么一条警告：This Handler class should be static or leaks might occur 。 首先在 ADT 20 Changes 我们可以找到这样一个变化： New Lint Checks: Look for handler leaks: This check makes sure that a handler inner class does not hold an implicit reference to its outer class. 翻译过来就是，Lint会增加一个检查项目即：确保class内部的handler不含有外部类的隐式引用 。 同一个线程下的handler共享一个looper对象，消息中保留了对handler的引用，只要有消息在队列中，那么handler便无法被回收，如果handler不是static那么使用Handler的Service和Activity就也无法被回收。这就可能导致内存泄露。 当然这通常不会发生，除非你发送了一个延时很长的消息。 知道了原因我们在来看解决方法： 1.最不想动代码的同学，可以在Preference搜一下Lint,在Lint Error Checking里搜HandlerLeak,然后选择ignore，然后整个世界清净了。。。。（不推荐

##This Handler class should be static or leaks might occur 有如下代码： public class MainActivity extends AppCompatActivity { private Handler handler = new Handler(){ //其他代码省略 }; //其他代码省略 } 会提示如下信息： Since this Handler is declared as an inner class, it may prevent the outer class from being garbage collected. If the Handler is using a Looper or MessageQueue for a thread other than the main thread, then there is no issue. If the Handler is using the Looper or MessageQueue of the main thread, you need to fix your Handler declaration, as follows: Declare the Handler as a static class; In the outer class

package com.ruoyi.framework.interceptor; import java.lang.reflect.Method; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.stereotype.Component; import org.springframework.web.method.HandlerMethod; import org.springframework.web.servlet.handler.HandlerInterceptorAdapter; import com.ruoyi.common.annotation.RepeatSubmit; import com.ruoyi.common.core.domain.AjaxResult; import com.ruoyi.common.json.JSON; import com.ruoyi.common.utils.ServletUtils; /** * 防止重复提交拦截器 * * @author ruoyi */ @Component public abstract class

作者：肥宅兜 链接：https://www.cnblogs.com/doudouxiaoye/p/5693399.html 1.为什么使用Spring ? 方便解耦，简化开发; 通过Spring提供的IoC容器，可以将对象之间的依赖关系交由Spring进行控制，避免硬编码所造成的过度程序耦合。 AOP编程的支持; 通过Spring提供的AOP功能，方便进行面向切面的编程，如性能监测、事务管理、日志记录等。 声明式事务的支持; 方便集成各种优秀框架; 降低Java EE API的使用难度; 如对JDBC，JavaMail，远程调用等提供了简便封装 2. 什么是IOC，为什使用IOC ? IOC全称Iversion of Controller，控制反转。 这概念是说你不用创建对象，而只需要描述它如何被创建。 你不在代码里直接组装你的组件和服务，但是要在配置文件里描述哪些组件需要哪些服务，之后一个容器（IOC容器）负责把他们组装起来。 它能指导我们如何设计出松耦合、更优良的程序。 3. 什么是AOP，为什么使用AOP ? AOP全称：Aspect-Oriented Programming，面向切面编程。 AOP，面向切面编程，就是把可重用的功能提取出来，然后将这些通用功能在合适的时候织入到应用程序中，比如事务管理、权限控制、日志记录、性能统计等。 AOP并没有帮助我们解决任何新的问题

All: I really don't grok handlers yet. I thought that the code below -- modified so that, instead of using a handler, the UI widget (progress bar) was accessed directly -- would cause a cross-threading exception. But it doesn't. So, my question is, shouldn't this code crash? And if it doesn't, then when do I need to use a handler? public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); progress = 0; progressBar = (ProgressBar) findViewById(R.id.progressbar); progressBar.setMax(200); //---do some work in background thread--- new

Consider the following code: public class SampleActivity extends Activity { private final Handler mLeakyHandler = new Handler() { @Override public void handleMessage(Message msg) { // ... } } } While not readily obvious, this code can cause cause a massive memory leak. Android Lint will give the following warning: In Android, Handler classes should be static or leaks might occur. But where exactly is the leak and how might it happen? Let's determine the source of the problem by first documenting what we know: When an Android application first starts, the framework creates a Looper object for