尋尋覓覓，終於讓我找到了一種在安卓6.0以上可以用的關機方法，當然了，前提是手機必須root。因為我要實現的是斷電關機，所以首先得檢測電源事件。

一、監測電源事件：

1.建立Broad類

package com.slq.shutdownafterdisconnect;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.drm.DrmStore;
 
/**
 * Created by 15265 on 2017/11/17.
 */
public class Broad {

    private BatteryStateListener mBatteryStateListener;
    private Context mContext;
    private BroadCast receiver;
    public Broad(Context context)
    {
        mContext = context;
receiver = new BroadCast();
}

    public void register
 
(BatteryStateListener listener) {
        mBatteryStateListener = listener;
        if (receiver != null) {
            IntentFilter filter = new IntentFilter();
filter.addAction(Intent.ACTION_BATTERY_CHANGED);
filter.addAction(Intent.ACTION_BATTERY_LOW);
filter.addAction(Intent.ACTION_BATTERY_OKAY);
 
filter.addAction(Intent.ACTION_POWER_CONNECTED);
filter.addAction(Intent.ACTION_POWER_DISCONNECTED);
mContext.registerReceiver(receiver, filter);
}
    }

    public void unregister() {
        if (receiver != null) {
            mContext.unregisterReceiver(receiver);
}
    }

    private class BroadCast extends BroadcastReceiver
    {
        String action=null;
@Override
public void onReceive(Context context, Intent intent) {

            if (intent!=null)
            {
                action=intent.getAction();
                switch (action)
                {
                    //接通電源
case Intent.ACTION_POWER_CONNECTED:
                        if (mBatteryStateListener!=null)
                        {
                            mBatteryStateListener.onStatePowerConnected();
}
                        break;
//拔出電源
case Intent.ACTION_POWER_DISCONNECTED:
                        if (mBatteryStateListener!=null)
                        {
                            mBatteryStateListener.onStatePowerDisconnected();
}
                        //MyShutDown();
break;
//電量低
case Intent.ACTION_BATTERY_LOW:
                        break;
//電量發生變化
case Intent.ACTION_BATTERY_CHANGED:
                        break;
//電量充滿
case Intent.ACTION_BATTERY_OKAY:
                        break;
}
            }
        }
    }

    //監聽介面
public interface BatteryStateListener {


        public void onStatePowerConnected();
        public void onStatePowerDisconnected();
}
}

二、在MainActivity編寫關機方法：

private void MyShutDown()
{
    try
{
        Process process=Runtime.getRuntime().exec("reboot -p");
String data=null;
BufferedReader errorLine=new BufferedReader(new InputStreamReader(process.getErrorStream()));
BufferedReader inputLine=new BufferedReader(new InputStreamReader(process.getInputStream()));
String error=null;
        while ((error=errorLine.readLine())!=null&&!error.equals("null"))
        {
            data+=error+"\n";
}

        String input=null;
        while((input= inputLine.readLine())!=null&&!input.equals("null"))
        {
            data+=input+"\n";
}

    }
    catch (Exception e)
    {

    }
}

三、在onCreate中呼叫

Broad listener;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listener=new Broad(this);
listener.register(new Broad.BatteryStateListener(){
        @Override
public void onStatePowerConnected() {
            Toast.makeText(MainActivity.this,"接通電源",Toast.LENGTH_LONG).show();
}

        @Override
public void onStatePowerDisconnected() {
            Toast.makeText(MainActivity.this,"斷開電源",Toast.LENGTH_LONG).show();
MyShutDown();
}
    });
}

四、在onDestroy中登出

@Override
protected void onDestroy() {
    if (listener!=null)
    {
        listener.unregister();
}
    super.onDestroy();
}