STOP MAINTENANCE！(2017-05-25）

　　刚在做复习时发现了一个问题，加入了Handler的线程，即使调用了removeCallbacks线程还是存在，而且退出了Activity之后线程还在运行。难道是removeCallBacks无效？还是我哪里写错了？

package cfuture09.handlerProgress;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ProgressBar;

public class HandlerProgressActivity extends Activity {
	
	Button start;
	ProgressBar progressBar;
	Handler handler = new Handler() {

		@Override
		public void handleMessage(Message msg) {
			// TODO Auto-generated method stub
			progressBar.setProgress(msg.arg1);
			handler.post(r);
		}

	};
	
	Runnable r = new Runnable() {
		
		int i = 0;
		@Override
		public void run() {
			// TODO Auto-generated method stub
			System.out.println("Begin thread");
			i += 10;
			Message msg = handler.obtainMessage();
			msg.arg1 = i;
			try {
				Thread.sleep(1000);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
//			if ( i < 100) { 
				handler.sendMessage(msg);
//			}
			if ( i >= 100) {
				handler.removeCallbacks(r);
				System.out.println("end");
			}
		}
	};
	
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        start = (Button) findViewById(R.id.start);
        progressBar = (ProgressBar) findViewById(R.id.progress);
        start.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				progressBar.setVisibility(ProgressBar.VISIBLE);
				handler.post(r);
			}
		});
    }
}

　　刚和一个同学聊天说到这一段，跟他一说，忽然之间自己想明白了。原来还是代码的逻辑错误。这段代码我是看视频写的，可能视频的作者在写这段代码时也没注意到这个问题。在看了之后的视频我才想明白。聊天记录用图片贴上来吧。