在做一个TabHost的练习时，发现在清单文件中是否设置

<uses-sdk android:minSdkVersion="8" />

会导致相同的程序呈现不同的界面：

设置<uses-sdk android:minSdkVersion="4" /> 对应Android SDK1.6

则与不设置相同的效果

如果设置为5,6,7,8 ; 则效果发生改变

//主要代码

package com.ck;

import android.app.Activity;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class NotificationActivity extends Activity {
	
	private Button button1,button2;
	private Notification n;
	private NotificationManager nm;
	private static final int ID = 1;
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        button1 = (Button)findViewById(R.id.button1);
        button2 = (Button)findViewById(R.id.button2);
        
        nm = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
        n = new Notification();
        
        int icon = n.icon = R.drawable.ic_launcher;
        String test = "this is notification speaking,,";
        long when = System.currentTimeMillis();
        n.icon = icon;
        n.tickerText = test;
        n.when = when;
        
        button1.setOnClickListener(sendListener);
        button2.setOnClickListener(cancelListener);
    }
    
    private OnClickListener sendListener = new OnClickListener() {
		
		@Override
		public void onClick(View v) {
			// TODO Auto-generated method stub
			Intent intent = new Intent(NotificationActivity.this,SecondActivity.class);
			PendingIntent pi = PendingIntent.getActivity(getApplicationContext(), 0, intent, 0);
			n.setLatestEventInfo(getApplicationContext(), "ck", "chenkai", pi);
			nm.notify(ID,n);
		}
	};
	
	private OnClickListener cancelListener = new OnClickListener() {
		
		@Override
		public void onClick(View v) {
			// TODO Auto-generated method stub
			nm.cancel(ID);
		}
	};
    
}