Android手机一般不用时,都会通过电源键来锁定屏幕同时关闭屏幕灯。
锁定效果:
要让自己的应用实现该屏幕锁定,主要需要用到以下几个类:DevicePolicyManager
这是设备管理的主类。通过它可以实现屏幕锁定、屏幕亮度调节、出厂设置等功能。
DeviceAdminReceiver
该类继承自 BroadcastReceiver 。 从源码可以看到,其实就是实现了一个OnReceive方法,该方法中根据不同的Action,执行相应的操作。 比如,如果激活成功,那么Action就是ACTION_DEVICE_ADMIN_ENABLED, 据此调用 onEnabled 方法。
系统源码:
/** * Intercept standard device administrator broadcasts. Implementations * should not override this method; it is better to implement the * convenience callbacks for each action. */ @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction(); if (ACTION_PASSWORD_CHANGED.equals(action)) { onPasswordChanged(context, intent); } else if (ACTION_PASSWORD_FAILED.equals(action)) { onPasswordFailed(context, intent); } else if (ACTION_PASSWORD_SUCCEEDED.equals(action)) { onPasswordSucceeded(context, intent); } else if (ACTION_DEVICE_ADMIN_ENABLED.equals(action)) { onEnabled(context, intent); } else if (ACTION_DEVICE_ADMIN_DISABLE_REQUESTED.equals(action)) { CharSequence res = onDisableRequested(context, intent); if (res != null) { Bundle extras = getResultExtras(true); extras.putCharSequence(EXTRA_DISABLE_WARNING, res); } } else if (ACTION_DEVICE_ADMIN_DISABLED.equals(action)) { onDisabled(context, intent); } }
具体中的简单引用:
屏幕锁定和恢复出厂设置
1.创建 MyAdmin 的广播接受者 继承 DeviceAdminReceiver
<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>
my_admin.xml
<?xml version="1.0" encoding="utf-8"?> <device-admin xmlns:android="http://schemas.android.com/apk/res/android"> <uses-policies> <limit-password /> <watch-login /> <reset-password /> <force-lock /> <wipe-data /> </uses-policies> </device-admin>
2.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); } }
3.获取IDevicePolicyManager
public void lockScreen() { DevicePolicyManager dm = (DevicePolicyManager) getSystemService(DEVICE_POLICY_SERVICE); ComponentName componentName = new ComponentName(this, MyDeviceAdmin.class); boolean isAdminActive = devicePolicyManager.isAdminActive(componentName); if(isAdminActive) //是否获得权限 { dm.resetPassword("123", 0); //滑动解锁屏幕条后需要输入密码(方法中新设置的密码)才能真正解锁 dm.lockNow(); //dm.setMaximumTimeToLock(mDeviceComponentName, timeout); 相应时间后锁屏 //恢复出厂设置. //dm.wipeData(0); }else{ //获取管理员权限 Intent intent = new Intent( DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN); intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN,mDeviceComponentName); intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION,"这里可以输入一些额外的说明,比如提示用户什么的"); startActivityForResult(intent, RESULT_ENABLE_LOCKVIEW); } } protected void onActivityResult(int paramInt1, int paramInt2, Intent paramIntent) { super.onActivityResult(paramInt1, paramInt2, paramIntent); DevicePolicyManager dm = (DevicePolicyManager) getSystemService(DEVICE_POLICY_SERVICE); ComponentName componentName = new ComponentName(this, MyDeviceAdmin.class); boolean isAdminActive = devicePolicyManager.isAdminActive(componentName); if (paramInt1 == RESULT_ENABLE_LOCKVIEW && isAdminActive) { lockScreen(); } else{ Toast.makeText(this, "激活失败,无法获得管理员权限", 1).show(); } }
4.MyDeviceAdmin
import android.app.admin.DeviceAdminReceiver; import android.content.Context; import android.content.Intent; import android.content.SharedPreferences; import android.widget.Toast; public class MyDeviceAdmin extends DeviceAdminReceiver { public static String PREF_MAX_FAILED_PW; public static String PREF_PASSWORD_LENGTH; public static String PREF_PASSWORD_QUALITY = "password_quality"; static { PREF_PASSWORD_LENGTH = "password_length"; PREF_MAX_FAILED_PW = "max_failed_pw"; } public static SharedPreferences getDevicePreference(Context paramContext) { return paramContext.getSharedPreferences(DeviceAdminReceiver.class.getName(), 0); } public CharSequence onDisableRequested(Context paramContext, Intent paramIntent) { return "这是一个可选的消息,警告有关禁止用户的请求"; } public void onDisabled(Context paramContext, Intent paramIntent) { showToast(paramContext, "设备管理:不可用"); } public void onEnabled(Context paramContext, Intent paramIntent) { showToast(paramContext, "设备管理:可用"); } public void onPasswordChanged(Context paramContext, Intent paramIntent) { showToast(paramContext, "设备管理:密码己经改变"); } public void onPasswordExpiring(Context paramContext, Intent paramIntent) { showToast(paramContext, "设备管理:密码过期"); super.onPasswordExpiring(paramContext, paramIntent); } public void onPasswordFailed(Context paramContext, Intent paramIntent) { showToast(paramContext, "设备管理:输入密码错误"); } public void onPasswordSucceeded(Context paramContext, Intent paramIntent) { } void showToast(Context paramContext, CharSequence paramCharSequence) { Toast.makeText(paramContext, paramCharSequence, 0).show(); } }
<uses-permission android:name="android.permission.RECEIVE_USER_PRESENT"/>
<uses-permission android:name="android.permission.WAKE_LOCK"/