Runnable 试验一

最近老是困惑与Runnable与handler,thread,UI线程如何更新的问题,所以今天写第一个测试demo来帮组理解.

package com.yijun;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.text.StaticLayout;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

public class TestHandlerActivity extends Activity {
	private Button bt1, bt2;
	private TextView tView;
	private ImageView iView;
	static int i = 0;
	// 用图片的id,要用包裹类Integer
	private Integer[] images = { R.drawable.n0, R.drawable.n1, R.drawable.n2,
			R.drawable.n3, R.drawable.n4, R.drawable.n5, R.drawable.n6,
			R.drawable.n7, R.drawable.n8, R.drawable.n9 };

	Handler mHandler = new Handler();

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		bt1 = (Button) findViewById(R.id.btn1);
		bt2 = (Button) findViewById(R.id.btn2);
		tView = (TextView) findViewById(R.id.tv);
		iView = (ImageView) findViewById(R.id.img);

		bt1.setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View v) {
				String string = Thread.currentThread().getName();
				System.out.println("The thread is +" + string);
				// 把runnable对象投入UI线程队列,这样runnanble里的run方法就在ui线程里了,这样就可以更新画面了
				mHandler.post(mrunnable);
			}
		});

		bt2.setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View v) {
				// 移除
				mHandler.removeCallbacks(mrunnable);
			}
		});

	}

	Runnable mrunnable = new Runnable() {
		@Override
		public void run() {
			String string = Thread.currentThread().getName();
			System.out.println("Now thread is " + string + "更新线程");
			// 在run方法内部，执行postXX的方法，每隔3秒会执行一次run方法
			// 如果不写,那每次按启动按钮,才会执行一次run方法,数字才会变化
			mHandler.postDelayed(mrunnable, 300);

			iView.setBackgroundResource(images[i]);
			tView.setText(string + (i++));
			if (i == 8) {
				i = 0;
			}
		}
	};
}

这个是第一个小demo,明天继续