1.在AndroidManifest.xml文件的manifest标签中加入一条android:sharedUserId="android.uid.system"

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.ipanel.update"
    android:versionCode="1"
    android:versionName="1.0" 
    android:sharedUserId="android.uid.system" >

    <uses-sdk
        android:minSdkVersion="9"
        android:targetSdkVersion="15" />   
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
	<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/title_activity_main" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

2.在MainActivity中,有以下2种方式实现：

/*Intent reboot = new Intent(Intent.ACTION_REBOOT);  
    reboot.putExtra("nowait", 1);  
    reboot.putExtra("interval", 1);  
    reboot.putExtra("window", 0);  
    sendBroadcast(reboot); */ 
PowerManager pManager=(PowerManager) getSystemService(Context.POWER_SERVICE);
pManager.reboot("");

整个代码：

package com.demo.reboot;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.os.PowerManager;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		Button rebootBtn = (Button) findViewById(R.id.button2);
		rebootBtn.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				new AlertDialog.Builder(MainActivity.this)
				.setTitle("提示")
				.setMessage("确认重启么？")
				.setPositiveButton("重启", new DialogInterface.OnClickListener() {
					@Override
					public void onClick(DialogInterface dialog, int which) {
						// 重启
						/*String str = "重启";
						try {
							str = runCmd("reboot", "/system/bin");
						} catch (IOException e) {
							e.printStackTrace();
						}*/
						/*Intent reboot = new Intent(Intent.ACTION_REBOOT);  
						reboot.putExtra("nowait", 1);  
						reboot.putExtra("interval", 1);  
						reboot.putExtra("window", 0);  
						sendBroadcast(reboot); */ 
						PowerManager pManager=(PowerManager) getSystemService(Context.POWER_SERVICE);
						pManager.reboot("重启");
						System.out.println("execute cmd--> reboot\n" + "重启");
					}
				})
				.setNegativeButton("取消", new DialogInterface.OnClickListener() {
					@Override
					public void onClick(DialogInterface dialog, int which) {
						// 取消当前对话框
						dialog.cancel();
					}
				}).show();
			}
			
		});
	}

}