Android 5.X 新特性详解（五）——Notification

Google在Android 5.0 上又进一步改进了通知栏，优化了Notification。当长按Notification的时候，会显示消息来源。Notification会有一个从白色到灰色的动画切换效果，最终显示发出这个Notification的调用者。同时，在Android 5.X 设备上，锁屏状态下我们也可以看见Notification通知了。

基本Notification

        /**         * 给点击Notification后要执行的操作增进一个Intent，由于这个Intent不是马上执行的，而是由用户触发的，         * 所以Android给这样的Intent提供了一个PendingIntent来帮助完成这样的延迟操作。         */        Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.baidu.com"));        // 构造PendingIntent        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, 0);        // 创建Notification对象        Notification.Builder builder = new Notification.Builder(this);        // 设置Notification的各种属性        builder.setSmallIcon(R.mipmap.ic_launcher);        builder.setContentIntent(pendingIntent);        builder.setAutoCancel(true);        builder.setLargeIcon(BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher));        builder.setContentTitle("Basic Notifications");        builder.setContentText("I am a basic notification");        builder.setSubText("it is really basic");        // 通过NotificationManager来发出Notification        NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);        //调用notify方法时，需要传进去一个ID。每个Notification都会有一个ID，这个ID就是用来区分不同的APP的Notification的。        notificationManager.notify(NOTIFICATION_ID_BASIC, builder.build());

折叠式Notification

折叠式Notification也是一种自定义视图的Notification，常常用于显示长文本。它拥有两个视图状态，一个是普通状态下的视图状态，另一个是展开状态下的视图状态。

        Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.sina.com"));        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, 0);        Notification.Builder builder = new Notification.Builder(this);        builder.setSmallIcon(R.mipmap.ic_launcher);        builder.setContentIntent(pendingIntent);        builder.setAutoCancel(true);        builder.setLargeIcon(BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher));        //通过RemoteViews来创建自定义的Notification视图        RemoteViews contentView = new RemoteViews(getPackageName(), R.layout.notification);        contentView.setTextViewText(R.id.textView, "show me when collapsed");        RemoteViews expandedView = new RemoteViews(getPackageName(), R.layout.notification_expanded);        Notification notification = builder.build();        //将一个视图指定为Notification正常状态下的视图        notification.contentView = contentView;        //将一个视图指定为Notification展开时的视图        notification.bigContentView = expandedView;        NotificationManager nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);        nm.notify(NOTIFICATION_ID_COLLAPSE, notification);

悬挂式Notification

这种被称为Headsup的Notification方式，可以在屏幕上方产生Notification且不会打断用户的操作，能给用户以Notification形式的通知。

        Notification.Builder builder = new Notification.Builder(this)                .setSmallIcon(R.mipmap.ic_launcher)                .setPriority(Notification.PRIORITY_DEFAULT)                .setCategory(Notification.CATEGORY_MESSAGE)                .setContentTitle("Headsup Notification")                .setContentText("I am a Headsup notification.")                .setSubText("Heads-Up Notification on Android 5.0");        Intent intent = new Intent();        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);        intent.setClass(this, MainActivity.class);        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_CANCEL_CURRENT);        //通过setFullScreenIntent将一个Notification变成悬挂式Notification        builder.setFullScreenIntent(pendingIntent, true);        NotificationManager nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);        nm.notify(NOTIFICATION_ID_HEADSUP, builder.build());

显示等级的Notification

Android 5.X 将Notification分成了三个等级。

• VISIBILITY_PRIVATE——表明只有当没有锁屏的时候会显示
• VISIBILITY_PUBLIC——标明在任何情况下都会显示
• VISIBILITY_SECRET——表明在pin、password等安全锁和没有锁的情况下才能够显示

        RadioGroup radioGroup = (RadioGroup) findViewById(R.id.visibility_radio_group);        Notification.Builder builder = new Notification.Builder(this)                .setContentTitle("Notification for Visibility Test")                //设置Notification显示的位置                .setCategory(Notification.CATEGORY_EMAIL)                //设置Notification背景颜色                .setColor(Color.RED);        switch (radioGroup.getCheckedRadioButtonId()) {            case R.id.radio_button_public:                //设置Notification的显示等级                builder.setVisibility(Notification.VISIBILITY_PUBLIC);                builder.setContentText("Public");                builder.setSmallIcon(R.mipmap.ic_public);                break;            case R.id.radio_button_private:                builder.setVisibility(Notification.VISIBILITY_PRIVATE);                builder.setContentText("Private");                builder.setSmallIcon(R.mipmap.ic_private);                break;            case R.id.radio_button_secret:                builder.setVisibility(Notification.VISIBILITY_SECRET);                builder.setContentText("Secret");                builder.setSmallIcon(R.mipmap.ic_secret);                break;        }        NotificationManager nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);        nm.notify(NOTIFICATION_ID_VISIBILITY, builder.build());

程序运行效果图如下：

代码地址