px,dp,sp单位转换工具类

1.官方文档

1.1 通知相关全部、详细文档

　　https://developer.android.com/guide/topics/ui/notifiers/notifications

1.2 通知官方示例

　　https://github.com/googlesamples/android-Notifications

　　https://github.com/googlesamples/android-NotificationChannels

1.3 自定义通知文档

　　https://developer.android.com/training/notify-user/custom-notification

• https://developer.android.com/training/notify-user/expanded.html  已有通知的样式,可以扩展它们.

1. 1. NotificationCompat.BigPictureStyle,
   2. NotificationCompat.BigTextStyle
   3. NotificationCompat.InboxStyle ,
   4. NotificationCompat.MessagingStyle,
   5. NotificationCompat.MediaStyle  音乐播放.

• setStyle(new NotificationCompat.DecoratedCustomViewStyle()) 使用自定义样式.
• 何时用@style/TextAppearance.Compat.Notification.Title
• avoid setting a background image on your RemoteViews object, because your text color may become unreadable.
• 完全自定义时: use setCustomBigContentView(), but do not call setStyle().
• setContent() 兼容4.1及以下.

1.4 通过通知栏启动activity的方式

　　https://developer.android.com/training/notify-user/navigation　　

• 启动常规Activity(含任务栈,保留原来顺序),使用TaskStackBuilder
• 启动特殊Activity ,intent设置 FLAG_ACTIVITY_NEW_TASK

1.5 通知组

　　https://developer.android.com/training/notify-user/group

• Note: Notification groups are not the same as notification channel groups.
• Note: If your app sends four or more notifications and does not specify a group, the system automatically groups them together on Android 7.0 and higher.
• 关键api : setGroup()  setGroupSummary(true)

1.6 渠道管理

　　https://developer.android.com/training/notify-user/channels

• 8.0通过渠道设置通知优先级
• 如何打开通知设置页面. Intent intent = new Intent(Settings.ACTION_CHANNEL_NOTIFICATION_SETTINGS); 等等...
• 删除渠道.
• 创建渠道组及何时有必要使用渠道组.

1.7 应用图标的通知角标

　　https://developer.android.com/training/notify-user/badges

• 8.0开始的新特性.
• 通过渠道参数设置开启这个功能
• setNumber() 设置通知角标数.

2.自定义通知示例

样式大致这样

2.1 自定义通知布局

 <?xml version="1.0" encoding="utf-8"?>
 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     android:orientation="vertical"
     android:layout_gravity="center"
     android:layout_width="match_parent"
     android:layout_height="64dp">

     <ImageView
         android:id="@+id/notify_icon"
         android:layout_width="22dp"
         android:layout_height="22dp"
         android:layout_alignParentLeft="true"
         android:layout_alignParentTop="true"
         android:layout_gravity="center_vertical"
         android:layout_marginLeft="8dp"
         android:layout_marginTop="8dp"
         app:srcCompat="@mipmap/notify_icon" />

     <TextView
         android:id="@+id/notify_title"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_gravity="center_vertical"
         android:layout_marginLeft="8dp"
         android:ellipsize="end"
         android:gravity="center_vertical"
         android:maxEms="9"
         android:maxLines="1"
         android:text="@string/app_name"
         android:textColor="#333333"
         android:layout_toRightOf="@+id/notify_icon"
         android:layout_alignTop="@+id/notify_icon"
         android:layout_alignBottom="@+id/notify_icon"
         android:textSize="10sp" />

     <TextView
         android:id="@+id/notify_progress_title"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_below="@+id/notify_icon"
         android:layout_alignLeft="@+id/notify_icon"
         android:layout_marginTop="4dp"
         android:ellipsize="end"
         android:gravity="left|center_vertical"
         android:maxEms="9"
         android:maxLines="1"
         android:text="title"
         android:layout_toLeftOf="@+id/notify_progress_status"
         android:textAllCaps="false"
         android:textColor="#333333"
         android:textSize="12sp"
         android:textStyle="bold" />

     <ProgressBar
         android:id="@+id/notify_progress"
         style="?android:attr/progressBarStyleHorizontal"
         android:layout_width="wrap_content"
         android:layout_height="4dp"
         android:layout_below="@+id/notify_progress_title"
         android:layout_alignLeft="@+id/notify_progress_title"
         android:layout_alignRight="@+id/notify_progress_status"
         android:layout_marginTop="4dp"
         android:progressDrawable="@drawable/notify_progress_bar" />

     <TextView
         android:id="@+id/notify_progress_status"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginRight="25dp"
         android:layout_alignBottom="@+id/notify_progress_title"
         android:layout_alignTop="@+id/notify_progress_title"
         android:layout_toLeftOf="@+id/notify_down_btn"
         android:maxLines="1"
         android:maxEms="9"
         android:ellipsize="end"
         android:textAllCaps="false"
         android:textColor="#999999"
         android:textSize="10sp"
         android:gravity="center"
         android:text="status" />

     <ImageView
         android:layout_width="15dp"
         android:layout_height="15dp"
         android:id="@+id/notify_down_btn"
         android:background="@null"
         android:layout_alignTop="@+id/notify_close_btn"
         android:layout_marginRight="20dp"
         android:layout_toLeftOf="@+id/notify_close_btn"
         android:src="@mipmap/notify_start"
          />

     <ImageView
         android:layout_width="15dp"
         android:layout_height="15dp"
         android:id="@+id/notify_close_btn"
         android:layout_marginRight="15dp"
         android:layout_alignTop="@+id/notify_progress_title"
         android:src="@mipmap/notify_close"
         android:background="@null"
         android:layout_alignParentRight="true"
         android:layout_alignParentEnd="true"
         />
     <LinearLayout
         android:orientation="vertical"
         android:layout_width="40dp"
         android:layout_height="match_parent"
         android:id="@+id/notify_close"
         android:background="@color/hot_color"
         android:layout_alignBottom="@+id/notify_progress"
         android:layout_alignParentRight="true"
         android:visibility="visible"
         />
     <LinearLayout
         android:id="@+id/notify_down"
         android:layout_width="50dp"
         android:layout_height="match_parent"
         android:layout_alignBottom="@+id/notify_close"
         android:layout_toLeftOf="@+id/notify_close"
         android:background="@color/hot_color"
         android:src="@mipmap/notify_start"
         android:orientation="vertical"
         android:visibility="visible" />

 </RelativeLayout>

注意事项：

• 参考官方文档，考虑不同屏幕大小，通知栏的高度限制为：收起时为64dp,展开时为256dp
• notify根布局目前（sdk api 28）还不能用约束布局。
• 布局内不能出现　<View ....>
• ImageView不要使用 app:srcCompat,用 android:src

2.2 初始化

     NotificationManagerCompat   mNotificationManager;
     RemoteViews                 notifyView;
     NotificationCompat.Builder  builder;

     private void initNotify() {
         //1.得到 NotificationManagerCompat

         mNotificationManager = NotificationManagerCompat.from(getApplicationContext());
         //2.构造Notify上的View
         notifyView = new RemoteViews(getPackageName(), R.layout.notify);

         //自定义notify上按钮的事件
         Intent downIntent = new Intent(getApplicationContext(), NotifyReceiver.class);
         downIntent.setAction(NotifyReceiver.DOWN_ACTION);
         //用广播接收按钮事件，也可以用服务组件或者activity　PendingIntent有一系列函数可选。
         PendingIntent down = PendingIntent.getBroadcast(getApplicationContext(), , downIntent, PendingIntent.FLAG_UPDATE_CURRENT);
         notifyView.setOnClickPendingIntent(R.id.notify_down, down);

         Intent closeIntent = new Intent(getApplicationContext(), NotifyReceiver.class);
         closeIntent.setAction(NotifyReceiver.CLOSE_ACTION);

         PendingIntent close = PendingIntent.getBroadcast(getApplicationContext(), , closeIntent, PendingIntent.FLAG_UPDATE_CURRENT);
         notifyView.setOnClickPendingIntent(R.id.notify_close, close);

         //3.构造Notify,设置通知的参数
         String channelId = getString(R.string.notify_id);//在 strings.xml中定义
         builder = new NotificationCompat.Builder(getApplicationContext(),channelId);

         //点击整个通知栏时，响应通知的应用组件。
         Intent intent = new Intent(getApplicationContext(), MainActivity.class);
         PendingIntent notifyIntent = PendingIntent.getActivity(getApplicationContext(), , intent, PendingIntent.FLAG_UPDATE_CURRENT);

         //设置通知栏参数
         builder.setWhen(System.currentTimeMillis())
                 .setPriority(NotificationCompat.PRIORITY_MAX)           //优先级.
                 .setAutoCancel(true)
                 .setOngoing(false)
                 .setContentIntent(notifyIntent)
                 .setCustomContentView(notifyView)                       //完全自定义,不调用.setStyle()
                 .setContent(notifyView)                                 //兼容4.1及以下
                 .setVisibility(NotificationCompat.VISIBILITY_PRIVATE)
                 .setOnlyAlertOnce(true)
                 .setSmallIcon(R.mipmap.notify_logo);
     }

• 初始notify上自定义的view,重点在按钮事件
• 如果在一定时间内通知的频繁,系统会忽略其中的一部分.
• OnlyAlterOnce保证频频调用时,声音等警示事件只1次.
• RemoteViews和NotificationCompat.Builder 保存成成员变量是因为notify的频次高,不用每次都构造.

2.3 发出通知

     public synchronized void showDownloadingNotify() {
         //4.根据业务逻辑控制notify上控件的状态
         //...这里略
         int icon = downloading ? R.mipmap.notify_pause : R.mipmap.notify_start;

         int pro = (int) (downloaded * 100.00F / total);
         Log.e(TAG, "showDownloadingNotify: downloading progress =  " + pro);

         notifyView.setTextViewText(R.id.notify_progress_title, title);
         notifyView.setTextViewText(R.id.notify_progress_status,getString(R.string.downloading_downloaded) + " " + pro + "%" );
         notifyView.setImageViewResource(R.id.notify_down_btn, icon);
         notifyView.setProgressBar(R.id.notify_progress,, pro,false);

         Notification notify = builder.build();

         //5.发出通知
         String channelId = getString(R.string.notify_id);//在 strings.xml中定义
         mNotificationManager.notify(Integer.valueOf(channelId), notify);
     }

　　注意控制发出通知的频率,不要太快,如:

         if(last < ){
             last = SystemClock.elapsedRealtime() / ;
         }
         long now = SystemClock.elapsedRealtime() / ;
         if (now - last > ){
             last = now;
             showDownloadingNotify();
         }

2.4 接收通知按钮事件的组件

本示例中使用的是广播，也可以用服务和activity

 public class NotifyReceiver extends BroadcastReceiver {
     public final static String DOWN_ACTION = "com.cnblogs.sjjg.notifications.intent.action.DownClick";
     public final static String CLOSE_ACTION = "com.cnblogs.sjjg.notifications.intent.action.CloseClick";

     @Override
     public void onReceive(Context context, Intent intent) {
         String action = intent.getAction();
         Log.e("NotifyReceiver", "onReceive: action = " + action);
         switch (action) {
             case DOWN_ACTION:
                 //处理第1个按钮事件，开始下载
                 break;
             case CLOSE_ACTION:
                 //处理第2个按钮事件，关闭通知
                 break;
             default:
                 break;
         }
     }
 }

在AndroidManifest.xml中注册

      ...
      <receiver
             android:name=".main.NotifyReceiver"
             android:enabled="true"
             android:exported="true">
             <intent-filter>
                 <action android:name="com.cnblogs.sjjg.notifications.intent.action.DownClick" />
                 <action android:name="com.cnblogs.sjjg.notifications.intent.action.CloseClick" />
             </intent-filter>
         </receiver>
     ...

2.5 取消通知

　　取消的id要与发出的id相同。

     public void cancelNotify(){
         String channelId = getString(R.string.notify_id);
         mNotificationManager.cancel(Integer.valueOf(channelId));
     }

3.android 8.0适配

3.1 变化

• 必须将各个通知放入特定渠道中,否则不显示.一个应用可以有多个渠道.
• 用户可以按渠道关闭通知，而非关闭来自某个应用的所有通知。
• 包含有效通知的应用将在主屏幕/启动器屏幕上相应应用图标的上方显示通知“标志”。
• 用户可以从抽屉式通知栏中暂停某个通知。可以为通知设置自动超时时间。
• 可以设置通知的背景颜色。
• 部分与通知行为相关的 API 从 Notification 移至了 NotificationChannel。例如，在搭载 Android 8.0 及更高版本的设备中，使用 NotificationChannel.setImportance()，而非 NotificationCompat.Builder.setPriority()。

3.2 创建通知渠道

选择适当时机,创建渠道.

  　　@RequiresApi(api = Build.VERSION_CODES.O)
     private void createNotifyChannel(){
         NotificationManager nm = (NotificationManager) getContext().getSystemService(Context.NOTIFICATION_SERVICE);
         String channelId = getString(R.string.notify_id);
         NotificationChannel channel = nm.getNotificationChannel(channelId);
         if (channel == null){
             channel = new NotificationChannel(channelId, "Downloader", NotificationManager.IMPORTANCE_DEFAULT);
             channel.enableLights(true);
             channel.setLightColor(Color.RED);
             channel.setImportance(NotificationManager.IMPORTANCE_DEFAULT);
             channel.setShowBadge(true);
             nm.createNotificationChannel(channel);
         }
     }

3.3 检测通知权限是否打开

     　　 NotificationManagerCompat mNotificationManager;
         mNotificationManager = NotificationManagerCompat.from(getContext());
         boolean enable = mNotificationManager.areNotificationsEnabled();
         if (!enable){
             //打开通知权限
             ...
         }

3.4 打开通知权限

         final int NOTIFY_PER = ;
         Intent intent = new Intent();
         Context context = getContext();
         if (Build.VERSION.SDK_INT > Build.VERSION_CODES.N_MR1) {
             intent.setAction(Settings.ACTION_APP_NOTIFICATION_SETTINGS);
             intent.putExtra("android.provider.extra.APP_PACKAGE", context.getPackageName());
         }else if(Build.VERSION.SDK_INT > Build.VERSION_CODES.KITKAT_WATCH){
             intent.setAction(Settings.ACTION_APP_NOTIFICATION_SETTINGS);
             intent.putExtra("app_package", context.getPackageName());
             intent.putExtra("app_uid", context.getApplicationInfo().uid);
         }else if (Build.VERSION.SDK_INT == Build.VERSION_CODES.KITKAT){
             intent.setAction(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
             intent.addCategory(Intent.CATEGORY_DEFAULT);
             intent.setData(Uri.parse("package:" + context.getPackageName()));
         }else{
             intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
             intent.setAction(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
             intent.setData(Uri.fromParts("package", context.getPackageName(), null));
         }
         startActivityForResult(intent, NOTIFY_PER);

3.5 接收打开结果

     @Override
     public void onActivityResult(int requestCode, int resultCode, Intent data) {
         final int NOTIFY_PER = ;
         if (requestCode == NOTIFY_PER){
             NotificationManagerCompat notifyMgr = NotificationManagerCompat.from(getContext());
             boolean enable = notifyMgr.areNotificationsEnabled();
             Log.e("MainPresenter", "onActivityResult: request notify = " + enable );
             if (!enable){
                 Snackbar.make(more,"通知功能没有打开,无法在通知栏上显示进度!",Snackbar.LENGTH_SHORT).show();
             }
         }
     }

4.系统自带通知栏

      fun showNotify(warning: Warning){
         var mgr = NotificationManagerCompat.from(applicationContext)
         var notifyId = getString(R.string.notify_id)

         var content = warning.oldie.name + " " + warning.getTypeString()
         var builder =  NotificationCompat.Builder(applicationContext,notifyId)
         var intent = Intent(applicationContext, MainActivity::class.java)
         var pendingIntent = PendingIntent.getActivity(this, , intent, );
         builder.setContentIntent(pendingIntent);
         builder.setWhen(System.currentTimeMillis())
             .setPriority(NotificationCompat.PRIORITY_MAX)           //优先级.
             .setAutoCancel(true)
             .setOngoing(false)                                      //常驻通知栏
             .setContentText(content)
             .setLargeIcon(BitmapFactory.decodeResource(getResources(),R.mipmap.warning))
             .setContentTitle("监护警报")
             .setVisibility(NotificationCompat.VISIBILITY_PRIVATE)
             .setOnlyAlertOnce(true)
             .setSmallIcon(R.mipmap.icon)
         var notify = builder.build()
         mgr.notify(notifyId.toInt(),notify)
     }
     fun cancelNotify(){
         var mgr = NotificationManagerCompat.from(applicationContext)

         val channelId = getString(R.string.notify_id)

         mgr.cancel(channelId.toInt())
     }