锁屏DevicePolicyManager申请系统管理权限

效果图：

Caused by: java.lang.SecurityException: No active admin owned by uid 10038 for policy #3
该错误需要把应用程序升级为拥有系统管理员权限，写一个广播接收者，给该广播接收者去申请系统管理员的权限，让操作系统给广播接收者授权。（其实就去激活系统的一个授权的组件）让用户自己激活。

锁屏步骤:

1.创建 MyAdmin 的广播接受者继承 DeviceAdminReceiver

1 package com.example.lockscreen;
2 
3 import android.app.admin.DeviceAdminReceiver;
4 
5 public class MyAdmin extends DeviceAdminReceiver {
6 
7 }

2.清单文件中的配置：

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
 3     package="com.example.lockscreen"
 4     android:versionCode="1"
 5     android:versionName="1.0" >
 6 
 7     <uses-sdk
 8         android:minSdkVersion="8"
 9         android:targetSdkVersion="8" />
10 
11     <application
12         android:allowBackup="true"
13         android:icon="@drawable/ic_launcher"
14         android:label="@string/app_name"
15         android:theme="@style/AppTheme" >
16         <activity
17             android:name="com.example.lockscreen.MainActivity"
18             android:label="@string/app_name" >
19             <intent-filter>
20                 <action android:name="android.intent.action.MAIN" />
21 
22                 <category android:name="android.intent.category.LAUNCHER" />
23             </intent-filter>
24         </activity>
25 
26         <receiver android:name=".MyAdmin" >
27             <meta-data android:name="android.app.device_admin"
28                 android:resource="@xml/my_admin"/>
29             <intent-filter >
30                 <action android:name="android.app.action.DEVICE_ADMIN_ENABLED"/>
31             </intent-filter>
32         </receiver>
33     </application>
34 
35 </manifest>

3.在res文件建立xml/my_admin.xml文件：

 1 <?xml version="1.0" encoding="utf-8" ?>
 2 <device-admin xmlns:android="http://schemas.android.com/apk/res/android">
 3     <!-- 
 4     limit-password  设置密码的规则
 5     watch-login 监控屏幕解锁尝试次数
 6     reset-password 更改屏幕解锁密码
 7     force-lock 设备自动锁屏
 8     wipe-data 删除全部的数据
 9     
10      -->
11     <uses-policies>
12         <limit-password/>
13         <watch-login />
14         <reset-password />
15         <force-lock />
16         <wipe-data />
17     </uses-policies>
18 </device-admin>

4.MainActivity代码：

 1 package com.example.lockscreen;
 2 
 3 import android.app.Activity;
 4 import android.app.admin.DevicePolicyManager;
 5 import android.content.ComponentName;
 6 import android.content.Context;
 7 import android.content.Intent;
 8 import android.os.Bundle;
 9 import android.view.View;
10 
11 public class MainActivity extends Activity {
12 
13     @Override
14     protected void onCreate(Bundle savedInstanceState) {
15         super.onCreate(savedInstanceState);
16         setContentView(R.layout.activity_main);
17     }
18 
19     public void onClick(View v){
20         // 设备安全管理服务    2.2之前的版本是没有对外暴露的 只能通过反射技术获取  
21         DevicePolicyManager devicePolicyManager = (DevicePolicyManager) getSystemService(Context.DEVICE_POLICY_SERVICE);
22         
23         // 申请权限
24         ComponentName componentName = new ComponentName(this, MyAdmin.class);
25         // 判断该组件是否有系统管理员的权限
26         boolean isAdminActive = devicePolicyManager.isAdminActive(componentName);
27         if(isAdminActive){
28             
29             devicePolicyManager.lockNow(); // 锁屏
30             
31             devicePolicyManager.resetPassword("123", 0); // 设置锁屏密码
32 //            devicePolicyManager.wipeData(0);  恢复出厂设置  (建议大家不要在真机上测试) 模拟器不支持该操作
33             
34         } else {
35             Intent intent = new Intent();
36             // 指定动作名称
37             intent.setAction(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
38             // 指定给哪个组件授权
39             intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, componentName);
40             startActivity(intent);
41         }
42         
43         
44     }
45 }

注：如果是在2.2版本之前的话，那么必须用反射来解决，

 1 DevicePolicyManager mService = (DevicePolicyManager) getSystemService(Context.DEVICE_POLICY_SERVICE);
 2 Method method = Class.forName("android.os.ServiceManager").getMethod("getService", String.class);
 3 IBinder binder = (IBinder) method.invoke(null,new Object[] { Context.DEVICE_POLICY_SERVICE });
 4 mService = IDevicePolicyManager.Stub.asInterface(binder);
 5 
 6 
 7 
 8 3.注册广播接受者为admin设备
 9 ComponentName mAdminName = new ComponentName(this, MyAdmin.class);
10 if (mService != null) {
11         if (!mService.isAdminActive(mAdminName)) {
12                     Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
13                     intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN,mAdminName);
14                     startActivity(intent);
15                 }
16 }