mars老师《Android开发视频教程》_01_15 handler的使用(二)视频源码

本文详细解析Android应用中如何利用Handler与线程进行高效的消息传递与处理,通过实例展示了在新线程中处理消息的方法,并深入探讨了Handler与线程之间的密切关系。

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主要内容:

1.Handler与线程

2.Bundle的用法

3.在新线程中处理消息的方法

创建项目:HandlerTest2

=>>HandlerTest.java

package mars.handler;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.SystemClock;

public class HandlerTest extends Activity {
	private Handler handler = new Handler();
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		// sendMessage();
		//handler.post(r);
		setContentView(R.layout.main);
		Thread t = new Thread(r);
		t.start();
		System.out.println("activity--->" + Thread.currentThread().getId());
		System.out.println("activityname--->" + Thread.currentThread().getName());
	}
	
	Runnable r = new Runnable(){

		@Override
		public void run() {
			// TODO Auto-generated method stub
			System.out.println("handler--->" + Thread.currentThread().getId());
			System.out.println("handlername--->" + Thread.currentThread().getName());
			try {
				Thread.sleep(10000);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		
	};

}


=>>HandlerTest2.java

package mars.handler;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.Looper;
import android.os.Message;

public class HandlerTest2 extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		//打印了当前线程的ID
		System.out.println("Activity-->" + Thread.currentThread().getId());
		//生成一个HandlerThread对象,实现了使用Looper来处理消息队列的功能,这个类由Android应用程序框架提供
		HandlerThread handlerThread = new HandlerThread("handler_thread");
		//在使用HandlerThread的getLooper()方法之前,必须先调用该类的start();
		handlerThread.start();
		MyHandler myHandler = new MyHandler(handlerThread.getLooper());
		Message msg = myHandler.obtainMessage();
		//将msg发送到目标对象,所谓的目标对象,就是生成该msg对象的handler对象
		Bundle b = new Bundle();
		b.putInt("age", 20);
		b.putString("name", "Jhon");
		msg.setData(b);
		msg.sendToTarget();
	}
	
	class MyHandler extends Handler{
		public MyHandler(){
			
		}
		public MyHandler(Looper looper){
			super(looper);
		}
		@Override
		public void handleMessage(Message msg) {
			Bundle b = msg.getData();
			int age = b.getInt("age");
			String name = b.getString("name");
			System.out.println("age is " + age + ", name is" + name);
			System.out.println("Handler--->" + Thread.currentThread().getId());
			System.out.println("handlerMessage");
		}
	}
}


以下是彩色图像的PSNRSSIMLPIPS和CIEDE2000评价算法的Matlab源码示例: 1. PSNR(峰值信噪比): ```matlab function psnr_value = PSNR(original, distorted) [M, N, ~] = size(original); mse = sum((original(:) - distorted(:)).^2) / (M * N * 3); max_value = max(original(:)); psnr_value = 10 * log10(max_value^2 / mse); end ``` 2. SSIM(结构相似性指数): ```matlab function ssim_value = SSIM(original, distorted) K1 = 0.01; K2 = 0.03; L = 255; C1 = (K1 * L)^2; C2 = (K2 * L)^2; original = double(original); distorted = double(distorted); mean_original = filter2(fspecial('gaussian', 11, 1.5), original, 'valid'); mean_distorted = filter2(fspecial('gaussian', 11, 1.5), distorted, 'valid'); var_original = filter2(fspecial('gaussian', 11, 1.5), original.^2, 'valid') - mean_original.^2; var_distorted = filter2(fspecial('gaussian', 11, 1.5), distorted.^2, 'valid') - mean_distorted.^2; cov_original_distorted = filter2(fspecial('gaussian', 11, 1.5), original .* distorted, 'valid') - mean_original .* mean_distorted; ssim_map = ((2 * mean_original .* mean_distorted + C1) .* (2 * cov_original_distorted + C2)) ./ ((mean_original.^2 + mean_distorted.^2 + C1) .* (var_original + var_distorted + C2)); ssim_value = mean2(ssim_map); end ``` 3. LPIPS(感知相似性指标):需要下载并使用LPIPS库,源码和使用说明可在https://github.com/richzhang/PerceptualSimilarity 找到。 4. CIEDE2000(CIE 2000色差公式):需要下载并使用CIEDE2000库,源码和使用说明可在https://www.mathworks.com/matlabcentral/fileexchange/46861-color-difference-cie-de2000 找到。 以上是基本的示例代码,用于评估图像质量的不同评价指标。你可以根据实际需求和图像数据进行适当的调整和修改。
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