Android 系统级APP锁屏

权限：

代码：
DevicePolicyManager devicePolicyManager = (DevicePolicyManager) getSystemService(Context.DEVICE_POLICY_SERVICE);
ComponentName adminComponent = new ComponentName(this, WDeviceAdminReceiver.class);
if (devicePolicyManager.isAdminActive(adminComponent)) {
    devicePolicyManager.lockNow();
} else {
    // 如果设备管理器未激活，请提示用户激活设备管理器
    Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
    intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, adminComponent);
    intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION, "请激活设备管理器以使用锁屏功能");
    startActivity(intent);
}

广播：

public class WDeviceAdminReceiver extends DeviceAdminReceiver {
//空的就行
}

res下创建XML文件夹创建device_admin：：