Apache Pivot教程 -- Background Task(Thread Safe) -- 线程安全

女爷i 2022-12-02 04:11 87阅读 0赞

# Apache Pivot教程 #

在做Apache Pivot的时候有一个很重要的部分，就是线程安全，在比较基础的Java Swing中可以用SwingWorker实现线程安全，在Python tkinter中可以使用mttkinter实现线程安全，而Apache Pivot中就用Background Task实现线程安全  
首先要创建一个Background Task类

class ThreadSafe extends Task<String>
    {
        
    	public ThreadSafe()
    	{
        
    	}
    	@Override
    	public String execute() throws TaskExecutionException
    	{
        
    		return "";
    	}
    }

然后调用

new ThreadSafe().execute();

package background_thread;
    
    import org.apache.pivot.wtk.*;
    import org.apache.pivot.wtk.ScrollPane.ScrollBarPolicy;
    import org.apache.pivot.collections.*;
    import org.apache.pivot.util.concurrent.*;
    
    class ThreadSafe extends Task<String>
    {
        
    	public BoxPane panel=null;
    	public ThreadSafe(BoxPane p)
    	{
        
    		panel=p;
    	}
    	@Override
    	public String execute() throws TaskExecutionException
    	{
        
    		int doing=0;
    		panel.setOrientation(Orientation.VERTICAL);
    		while(doing<100)
    		{
        
    			panel.add(new Label("hello"));
    			doing+=1;
    		}
    		return "";
    	}
    }
    
    public class thread_safe implements Application
    {
        
    	private Window window=null;
    	public static void main(String [] args)
    	{
        
    		try
    		{
        
    			DesktopApplicationContext.main(thread_safe.class, args);
    		}
    		catch(Throwable err)
    		{
        
    		}
    	}
    	@Override
    	public void startup(Display display, Map<String, String>properties)
    	{
        
    		window=new Window();
    		ScrollPane s=new ScrollPane();
    		s.setVerticalScrollBarPolicy(ScrollBarPolicy.AUTO);
    		BoxPane panel=new BoxPane();
    		s.setView(panel);
    		window.setContent(s);
    		window.setTitle("Thread safe");
    		window.setMaximized(true);
    		window.open(display);
    		ThreadSafe t=new ThreadSafe(panel);
    		try
    		{
        
    			t.execute();
    		}
    		catch (TaskExecutionException err)
    		{
        
    		}
    	}
    	@Override
    	public boolean shutdown(boolean optional)
    	{
        
    		if(window!=null)
    		{
        
    			window.close();
    		}
    		return false;
    	}
    	@Override
    	public void suspend()
    	{
        
    	}
    	@Override
    	public void resume()
    	{
        
    	}
    }

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