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

package com.example.lockscreen;

import android.app.admin.DeviceAdminReceiver;

public class MyAdmin extends DeviceAdminReceiver {

}

2.清单文件中的配置：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.lockscreen"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="8" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.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>

        <receiver android:name=".MyAdmin" >
            <meta-data android:name="android.app.device_admin"
                android:resource="@xml/my_admin"/>
            <intent-filter >
                <action android:name="android.app.action.DEVICE_ADMIN_ENABLED"/>
            </intent-filter>
        </receiver>
    </application>

</manifest>

3.在res文件建立xml/my_admin.xml文件：

<?xml version="1.0" encoding="utf-8" ?>
<device-admin xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- 
    limit-password  设置密码的规则
    watch-login 监控屏幕解锁尝试次数
    reset-password 更改屏幕解锁密码
    force-lock 设备自动锁屏
    wipe-data 删除全部的数据
    
     -->
    <uses-policies>
        <limit-password/>
        <watch-login />
        <reset-password />
        <force-lock />
        <wipe-data />
    </uses-policies>
</device-admin>

4.MainActivity代码：

package com.example.lockscreen;

import android.app.Activity;
import android.app.admin.DevicePolicyManager;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void onClick(View v){
        // 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  
        DevicePolicyManager devicePolicyManager = (DevicePolicyManager) getSystemService(Context.DEVICE_POLICY_SERVICE);
        
        // 申请权限
        ComponentName componentName = new ComponentName(this, MyAdmin.class);
        // 判断该组件是否有系统管理员的权限
        boolean isAdminActive = devicePolicyManager.isAdminActive(componentName);
        if(isAdminActive){
            
            devicePolicyManager.lockNow(); // 锁屏
            
            devicePolicyManager.resetPassword("123", 0); // 设置锁屏密码
//            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
            
        } else {
            Intent intent = new Intent();
            // 指定动作名称
            intent.setAction(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
            // 指定给哪个组件授权
            intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, componentName);
            startActivity(intent);
        }
        
        
    }
}

 注：如果是在2.2版本之前的话，那么必须用反射来解决，

DevicePolicyManager mService = (DevicePolicyManager) getSystemService(Context.DEVICE_POLICY_SERVICE);
Method method = Class.forName("android.os.ServiceManager").getMethod("getService", String.class);
IBinder binder = (IBinder) method.invoke(null,new Object[] { Context.DEVICE_POLICY_SERVICE });
mService = IDevicePolicyManager.Stub.asInterface(binder);



3.注册广播接受者为admin设备
ComponentName mAdminName = new ComponentName(this, MyAdmin.class);
if (mService != null) {
        if (!mService.isAdminActive(mAdminName)) {
                    Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
                    intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN,mAdminName);
                    startActivity(intent);
                }
}