Android LockScreen (锁屏弹窗)

在要弹窗的Activity需要进行以下设置，才可以在锁屏状态下弹窗

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        final Window win = getWindow();
        win.addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED //锁屏状态下显示
//              | WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD     //解锁
                | WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON      //保持屏幕长亮
                | WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);    //打开屏幕
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

AndroidManifest.xml文件当中，对该activity的声明需要加上以下属性：

<activity android:name=".Activity"
          android:launchMode="singleInstance"
          android:excludeFromRecents="true"
          android:taskAffinity=""
          android:theme="@android:style/Theme.Wallpaper.NoTitleBar"/> 

在MainActivity:

public class MainActivity extends Activity {
     IntentFilter intentFilter;
     LocalBroadcastManager localBroadcastManager;
     LocalBroadcastReceiver localBroadcastReceiver;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Thread thread =new Thread(
                new Runnable() {
                    @Override
                    public void run() {
                        while (true) {
                            try {
                                Thread.sleep(5000);
                                Log.i("send", "send ok");
                                Intent intent = new Intent("com.example.stuart.LOCAL_BROADCAST");
                                localBroadcastManager.sendBroadcast(intent);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }

                        }
                    }
                }

        );
        thread.start();//模拟5秒自动发送广播

        localBroadcastManager =LocalBroadcastManager.getInstance(this);
        intentFilter =new IntentFilter();
        intentFilter.addAction("com.example.stuart.LOCAL_BROADCAST");
        localBroadcastReceiver =new LocalBroadcastReceiver();
        localBroadcastManager.registerReceiver(localBroadcastReceiver,intentFilter);

    }

    public void check_lock(){

//        KeyguardManager km = (KeyguardManager) this.getSystemService(Context.KEYGUARD_SERVICE);
//            if (km.isKeyguardLocked()) {
//                Intent intent =new Intent("com.example.stuart.LOCAL_BROADCAST");
//                intent .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
//                localBroadcastManager.sendBroadcast(intent);
//
//            }
//          Thread thread =new Thread(
//            new Runnable() {
//                @Override
//                public void run() {
//                    try {
//                        Thread.sleep(5000);
//                        Intent intent =new Intent("com.example.stuart.LOCAL_BROADCAST");
//                        localBroadcastManager.sendBroadcast(intent);
//                    } catch (InterruptedException e) {
//                        e.printStackTrace();
//                    }
//
//                }
//            }
//
//
//
//        );
//        thread.start();

    }
    class  LocalBroadcastReceiver extends BroadcastReceiver{

        @Override
        public void onReceive(Context context, Intent intent) {
            Log.d("LOG_TAG", intent.getAction());
            KeyguardManager km = (KeyguardManager) context.getSystemService(Context.KEYGUARD_SERVICE);
            if (km.isKeyguardLocked()) {
                Intent alarmIntent = new Intent(context, AlarmActivity.class);
                alarmIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                context.startActivity(alarmIntent);
            }
        }
    }

我们设置的是锁屏下才弹窗的，非锁屏下就不适合弹出这个窗口了（你可以试一下，效果会很怪）。一般是注册一个广播接收器，在接收到指定广播之后判断是否需要弹窗，所以在BroadcastReceiver的接收代码中需要先判断是否为锁屏状态下：

这里用到的是KeyguardManager类，用来管理锁屏的，4.1之后该类的API新增了一个isKeyguardLocked()的方法判断是否锁屏，但在4.1之前，我们只能用inKeyguardRestrictedInputMode()方法，如果为true，即为锁屏状态。需要注意的是，在广播中启动Activity的context可能不是Activity对象，所以需要添加NEW_TASK的标志，否则启动时可能会报错。

再次亮起屏幕

如果该Activity并未退出，但是被手动按了锁屏键，当前面的广播接收器再次去启动它的时候，屏幕并不会被唤起，所以我们需要在activity当中添加唤醒屏幕的代码，这里用的是电源锁。可以添加在onNewIntent(Intent intent)，因为它会被调用。也可以添加在其他合适的生命周期方法

PowerManager pm = (PowerManager) this.getSystemService(Context.POWER_SERVICE);
if (!pm.isScreenOn()) {
    PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.ACQUIRE_CAUSES_WAKEUP |
            PowerManager.SCREEN_BRIGHT_WAKE_LOCK, "bright");
    wl.acquire();
    wl.release();
}  

权限

<uses-permission android:name="android.permission.DISABLE_KEYGUARD"/>
<uses-permission android:name="android.permission.WAKE_LOCK"/>  

参考：http://blog.csdn.net/maosidiaoxian/article/details/40587935

http://bbs.csdn.net/topics/390425777