Android实现一键锁屏

（1）布局文件activity_main.xml如下：

<RelativeLayout 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"      tools:context=".MainActivity" >        <Button          android:layout_width="wrap_content"          android:layout_height="wrap_content"          android:onClick="openAdmin"          android:text="开启管理员权限" />        <Button          android:layout_width="wrap_content"          android:layout_height="wrap_content"          android:layout_centerInParent="true"          android:onClick="lockscreen"          android:text="一键锁屏" />        <Button          android:layout_width="wrap_content"          android:layout_height="wrap_content"          android:layout_alignParentBottom="true"          android:onClick="uninstall"          android:text="卸载软件" />    </RelativeLayout>

（2）MainActivity.java

package com.xuliugen.lockscreen;    import com.itheima.lockscreen.R;    import android.app.Activity;  import android.app.admin.DevicePolicyManager;  import android.content.ComponentName;  import android.content.Intent;  import android.net.Uri;  import android.os.Bundle;  import android.view.View;  import android.widget.Toast;    public class MainActivity extends Activity {        /**       * 设备策略服务       */      private DevicePolicyManager dpm;        @Override      protected void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);          setContentView(R.layout.activity_main);          dpm = (DevicePolicyManager) getSystemService(DEVICE_POLICY_SERVICE);        }        /**       * 用代码去开启管理员       */      public void openAdmin(View view) {          // 创建一个Intent          Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);          // 我要激活谁          ComponentName mDeviceAdminSample = new ComponentName(this,MyAdmin.class);            intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN,mDeviceAdminSample);          // 劝说用户开启管理员权限          intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION,"哥们开启我可以一键锁屏，你的按钮就不会经常失灵");          startActivity(intent);      }        /**       * 一键锁屏       */      public void lockscreen(View view) {          ComponentName who = new ComponentName(this, MyAdmin.class);          if (dpm.isAdminActive(who)) {              dpm.lockNow();// 锁屏              dpm.resetPassword("", 0);// 设置屏蔽密码                // 清除Sdcard上的数据              // dpm.wipeData(DevicePolicyManager.WIPE_EXTERNAL_STORAGE);              // 恢复出厂设置              // dpm.wipeData(0);          } else {              Toast.makeText(this, "还没有打开管理员权限", 1).show();              return;          }        }        /**       * 卸载当前软件       */        public void uninstall(View view) {            // 1.先清除管理员权限          ComponentName mDeviceAdminSample = new ComponentName(this,                  MyAdmin.class);          dpm.removeActiveAdmin(mDeviceAdminSample);          // 2.普通应用的卸载          Intent intent = new Intent();          intent.setAction("android.intent.action.VIEW");          intent.addCategory("android.intent.category.DEFAULT");          intent.setData(Uri.parse("package:" + getPackageName()));          startActivity(intent);      }    }

（3）根据API文档可知，需要一个类继承DeviceAdminReceiver:

package com.xuliugen.lockscreen;    import android.app.admin.DeviceAdminReceiver;    /**   * 特殊的广播接收者   *    * @author xuliugen   *    */  public class MyAdmin extends DeviceAdminReceiver {    }

（5）广播接受者的设置（清单文件）：

<?xml version="1.0" encoding="utf-8"?>  <manifest xmlns:android="http://schemas.android.com/apk/res/android"      package="com.xuliugen.lockscreen"      android:versionCode="1"      android:versionName="1.0" >        <uses-sdk          android:minSdkVersion="10"          android:targetSdkVersion="16" />        <application          android:allowBackup="true"          android:icon="@drawable/ic_launcher"          android:label="@string/app_name"          android:theme="@style/AppTheme" >          <activity              android:name="com.xuliugen.lockscreen.MainActivity"              android:label="@string/app_name" >              <intent-filter>                  <action android:name="android.intent.action.MAIN" />                    <category android:name="android.intent.category.LAUNCHER" />              </intent-filter>          </activity>            <!-- 广播接收者 -->          <receiver              android:name="com.xuliugen.lockscreen.MyAdmin"              android:description="@string/sample_device_admin_description"              android:label="@string/sample_device_admin"              android:permission="android.permission.BIND_DEVICE_ADMIN" >              <meta-data                  android:name="android.app.device_admin"                  android:resource="@xml/device_admin_sample" />                <intent-filter>                  <action android:name="android.app.action.DEVICE_ADMIN_ENABLED" />              </intent-filter>          </receiver>      </application>    </manifest>