随机数

package com.example.test;

import java.util.Date;
import java.util.Random;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.TextView;

public class MainActivity extends Activity {

private TextView mText;@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    mText=(TextView)findViewById(R.id.text);    Date IDate = new Date();    String fileName = "Android_"            + String.format("%1$04d%2$02d%3$02d%4$02d%5$02d%6$02d",                    IDate.getYear() + 1900, IDate.getMonth() + 1,                    IDate.getDate(), IDate.getHours(),                    IDate.getMinutes(), IDate.getSeconds())                    + getRandomNum(4);    mText.setText(fileName);}public static String  getRandomNum(int ANumLong){    Random random = new Random(new Date().getTime());//随机数种子    double IMax = Math.pow(10, ANumLong);    int IMaxValue = random.nextInt((int)Math.round(IMax));    String IFormat = "%1$0"+Integer.toString(ANumLong)+"d";    return String.format(IFormat,IMaxValue);}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {    // Inflate the menu; this adds items to the action bar if it is present.    getMenuInflater().inflate(R.menu.main, menu);    return true;}

}