Android getContentResolver() 设置手机屏幕休眠时间

XML文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.screenofftime.MainActivity"
    android:gravity="center_horizontal" >

    <Button 
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="选择屏幕休眠时间"
        android:onClick="chooseTime"/>

</LinearLayout>

MainActivity:

package com.example.screenofftime;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.provider.Settings;
import android.view.View;
import android.content.DialogInterface.OnClickListener;

public class MainActivity extends Activity {
    private SharedPreferences sp;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        sp = getSharedPreferences("lastChoice",Activity.MODE_PRIVATE);
    }

    public void chooseTime(View v){
        AlertDialog.Builder alertDialog = new AlertDialog.Builder(this);
        alertDialog.setTitle("选择背光时间");
        final String[] onScreenTime =new String[] {"15秒","30秒","1分钟","2分钟","5分钟","10分钟"};
            int lastChoice = sp.getInt("time", -1);//获取SharedPreferences中保存的上次选择,没有则默认为-1
            /**
             * 第二个参数表示默认选中的item的下标 -1代表没有默认的选项,设置为上次默认选中项
             * 
             */
            alertDialog.setSingleChoiceItems(onScreenTime, lastChoice, new OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {

                    switch (which) {
                    case 0:
                        setScreenOffTime(15000);
                        saveLastChoice(which);
                        break;
                    case 1:
                        setScreenOffTime(30000);
                        saveLastChoice(which);
                        break;
                    case 2:
                        setScreenOffTime(60000);
                        saveLastChoice(which);
                        break;
                    case 3:
                        setScreenOffTime(120000);
                        saveLastChoice(which);
                        break;
                    case 4:
                        setScreenOffTime(300000);
                        saveLastChoice(which);
                        break;
                    case 5:
                        setScreenOffTime(600000);
                        saveLastChoice(which);
                        break;

                    default:
                        break;
                    }
                }
            });

            alertDialog.setNegativeButton("取消", new OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {
                }
            });
            alertDialog.setPositiveButton("确定", new OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {

                }
        });
            alertDialog.create().show();

    }
    /***
     * 设置背光时间
     * @param paramInt
     */
    private void setScreenOffTime(int paramInt) {
        try {
            Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_OFF_TIMEOUT,paramInt);
        } catch (Exception localException) {
            localException.printStackTrace();

        }
    }
    /***
     * 将上次选择保存到SharedPreferences中，下次打开时默认选中上次所选项
     * @param which
     */
    private void saveLastChoice(int which){
        Editor edit = sp.edit();
        edit.putInt("time", which);
        edit.commit();
    }


}