Android学习札记- Notifying the User

1.Toast 式的Notification

????? Toast Notification 是一种弹出式提示，它仅仅是自动显示一个消息，并自动消失，它不能接收任何的事件，不可以对其进行中继处理。Toast 可以在Activity 或者 Service中创建。如果在一个Service中创建一个Toast,它会在当前活动中的Activity显示。只有在自定义Toast的情况下才能调用Toast的构造函数来新建一个提示窗口，不是自定义时要用Toast.makeText(context, text, duration)获取一个Toast实例。

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//默认的Toast提示		toastNotificationBtn.setOnClickListener(new OnClickListener() {			@Override			public void onClick(View v) {				Context context = getApplicationContext();				CharSequence text = "Hello toast";				int duration = Toast.LENGTH_SHORT;				Toast toast = Toast.makeText(context, text, duration);				// 设置相对位置				toast.setGravity(Gravity.TOP | Gravity.LEFT, 0, 0);				toast.show();			}		});//自定义的Toast提示		Button customToastNotificationBtn = (Button) findViewById(R.id.customToastNotificationBtn);		customToastNotificationBtn.setOnClickListener(new OnClickListener() {			@Override			public void onClick(View v) {				LayoutInflater inflater = getLayoutInflater();				View layout = inflater						.inflate(								R.layout.customer_toast_layout,								(ViewGroup) findViewById(R.layout.customer_toast_layout));				ImageView image = (ImageView) layout.findViewById(R.id.image);				image.setImageResource(R.drawable.icon);				TextView text = (TextView) layout.findViewById(R.id.text);				text.setText("Hello! This is a custom toast!");				Toast toast = new Toast(getApplicationContext());				toast.setGravity(Gravity.CENTER_VERTICAL, 0, 0);				toast.setDuration(Toast.LENGTH_LONG);				toast.setView(layout);				toast.show();			}		});

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2.Status bar 中显示的 Notification如下：

?必要的配置：
? 1)要有一个图标资源
? 2)要有一个标题和展开消息时的消息内容
? 3)PendingIntent, 在点击消息内容时，就会激活PendingIntent。
?可选的配置：
? 1)在status bar中显示的内容
? 2)可播放一段音频文件
? 3)振动设置
? 4)LED灯设置

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实现步骤：

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1)取得NotificationManager的实例

String ns = Context.NOTIFICATION_SERVICE;NotificationManager mNotificationManager = (NotificationManager) getSystemService(ns);

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?2)初始化Notification

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int icon = R.drawable.notification_icon;CharSequence tickerText = "Hello";long when = System.currentTimeMillis();Notification notification = new Notification(icon, tickerText, when);

? 3)定义展开时的内容和Intent

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Context context = getApplicationContext();CharSequence contentTitle = "My notification";CharSequence contentText = "Hello World!";Intent notificationIntent = new Intent(this, MyClass.class);PendingIntent contentIntent = PendingIntent.getActivity(this, 0, notificationIntent, 0);notification.setLatestEventInfo(context, contentTitle, contentText, contentIntent);

4)把消息显示到Status Bar上面

private static final int HELLO_ID = 1;mNotificationManager.notify(HELLO_ID, notification);

最终例子如下：

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//默认的提示barNotification.setOnClickListener(new OnClickListener(){			@Override			public void onClick(View v) {				int icon = R.drawable.icon;//icon from resources				CharSequence tickerText = "Hello";//ticker-text				long when = System.currentTimeMillis();//notification time				Context context = getApplicationContext();//application context				CharSequence contentTitle = "My notification";//expanded message title				CharSequence contentText = "Hello World!";//expanded message text								Intent notificationIntent = new Intent(getApplicationContext(),BarNotificationActivity.class);				PendingIntent contentIntent = PendingIntent.getActivity(getApplicationContext(), 0, notificationIntent, 0);				Notification notification = new Notification(icon, tickerText, when);				notification.setLatestEventInfo(context, contentTitle, contentText, contentIntent);								NotificationManager notificationManager = (NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE);				notificationManager.notify(HELLO_ID, notification);			}				});//自定义的提示barNotificationCustom.setOnClickListener(new OnClickListener(){			@Override			public void onClick(View v) {				RemoteViews contentView = new RemoteViews(getPackageName(),R.layout.customer_toast_layout);				contentView.setImageViewResource(R.id.image, R.drawable.icon);				contentView.setTextViewText(R.id.text, "Hello, this message is in a custom expanded view");				Notification notification = new Notification(R.drawable.icon,"Hello",System.currentTimeMillis());				notification.contentView = contentView;								Intent notificationIntent = new Intent(getApplicationContext(),BarNotificationActivity.class);				PendingIntent contentIntent = PendingIntent.getActivity(getApplicationContext(), 0, notificationIntent, 0);				notification.contentIntent = contentIntent;				NotificationManager manager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);				manager.notify(CUSTOM_VIEW_ID, notification);			}		});

3. 更新Status bar的提示

? ? ? ? ? 可以更新已经存在的notification用来显示最新的内容，这样就比创建一个新的notification实例更好。

????????? 由于每个Notifycation都有一个标识号，我们可以通过NotificationManager来获取到它，并调用setLatestEventInfo()来更新提示的内容，然后调用notify()来触发它。但是对于自定义的 expanded view,用这些方法来更新提示是不起作用的。


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5.给提示添加声音

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notification.defaults |= Notification.DEFAULT_SOUND;notification.sound = Uri.parse("file:///sdcard/notification/ringer.mp3");

6.给提示添加振动效果

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notification.defaults |= Notification.DEFAULT_VIBRATE;long[] vibrate = {0,100,200,300};notification.vibrate = vibrate;

?7.添加闪灯效果

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notification.defaults |= Notification.DEFAULT_LIGHTS;notification.ledARGB = 0xff00ff00;notification.ledOnMS = 300;notification.ledOffMS = 1000;notification.flags |= Notification.FLAG_SHOW_LIGHTS;

? 8.其他效果

??? 通过给Notification添加fields和flags,还可以实现更多的效果。这些属性如下：

?"FLAG_AUTO_CANCEL" flag , 这个flags field将使Notification在用户选择了该提示之后自动消失。

?"FLAG_INSISTENT" flag , 不继重复播放音频直到用户响应。

?"FLAG_ONGOING_EVENT" flag

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