安卓开发_浅谈Notification（通知栏）

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发布于 2018-05-18 13:17:18

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发布于 2018-05-18 13:17:18

文章被收录于专栏：Android干货

Notification通知栏是显示在手机状态的消息，代表一种全局效果的通知

快速创建一个Notification的步骤简单可以分为以下四步：

第一步：通过getSystemService（）方法得到NotificationManager对象；

第二步：对Notification的一些属性进行设置比如：内容，图标，标题，相应notification的动作进行处理等等；

第三步：通过NotificationManager对象的notify（）方法来执行一个notification的快讯；

第四步：通过NotificationManager对象的cancel（）方法来取消一个notificatioin的快讯；

示例：

布局:

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:orientation="vertical" >
 6 
 7     <Button
 8         android:id="@+id/notification_open"
 9         android:layout_width="fill_parent"
10         android:layout_height="wrap_content"
11         android:text="打开通知栏" />
12 
13     <Button
14         android:id="@+id/notification_close"
15         android:layout_width="fill_parent"
16         android:layout_height="wrap_content"
17         android:text="取消通知栏" />
18 
19 </LinearLayout>

JAVA文件：

 1 package information;
 2 
 3 
 4 
 5 import android.annotation.SuppressLint;
 6 import android.app.Activity;
 7 import android.app.Notification;
 8 import android.app.Notification.Builder;
 9 import android.app.NotificationManager;
10 import android.app.PendingIntent;
11 import android.content.Context;
12 import android.content.Intent;
13 import android.os.Bundle;
14 import android.view.View;
15 import android.view.View.OnClickListener;
16 import android.widget.Button;
17 
18 import com.example.allcode.R;
19 
20 public class Notification_text_one extends Activity implements OnClickListener{
21     NotificationManager manger; //通知控制类
22     int notification_id;
23     private Button open;
24     private Button close;
25     @Override
26     protected void onCreate(Bundle savedInstanceState) {
27         // TODO Auto-generated method stub
28         super.onCreate(savedInstanceState);
29         setContentView(R.layout.notification);
30         
31         open = (Button) findViewById(R.id.notification_open);
32         close = (Button) findViewById(R.id.notification_close);
33         //系统服务
34         manger = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
35         
36         open.setOnClickListener(this);
37         close.setOnClickListener(this);
38     }
39     @Override
40     public void onClick(View v) {
41         // TODO Auto-generated method stub
42         switch (v.getId()) {
43         case R.id.notification_open:  //打开通知栏
44             sendNotification();
45             
46             break;
47         case R.id.notification_close:
48             manger.cancel(notification_id);  //取消通知栏
49             
50             break;
51 
52         default:
53             break;
54         }
55     }
56     
57     private void sendNotification(){
58         Intent intent = new Intent(this,AlertDialog_text.class);
59         
60         PendingIntent pi = PendingIntent.getActivity(this, 0, intent, 0);
61         Builder builder = new Notification.Builder(this);
62         builder.setSmallIcon(R.drawable.icon_72);  //设置通知栏图标
63         builder.setTicker("Hello");  //设置通知栏提示
64         builder.setWhen(System.currentTimeMillis());//设置时间
65         builder.setContentTitle("这是通知栏标题");//通知栏标题
66         builder.setContentText("这里是通知栏内容");//通知栏内容
67         builder.setContentIntent(pi);//设置点击后的意图
68         //效果，需要添加相应的权限
69         builder.setDefaults(Notification.DEFAULT_SOUND);//设置提示声音
70         builder.setDefaults(Notification.DEFAULT_LIGHTS);//设置指示灯
71         builder.setDefaults(Notification.DEFAULT_VIBRATE);//设置震动
72         //builder.setDefaults(Notification.DEFAULT_ALL);//设置全部效果
　　　　　　//权限 <uses-permission android:name="android.permission.VIBRATE" />
73         //Notification notification = builder.build();//安卓版本4.1及以上
74         Notification notification = builder.getNotification();//安卓版本4.1以下
75         manger.notify(notification_id,notification);
76     }
77 }

效果图：

下面看一个具体应用，异步任务下载网络上的一个图片，将下载进度放到通知栏里，要求下载时，通知栏不能被删除，下载完成时，通知栏可以被删除

 1 package com.example.work;
 2 
 3 import java.io.ByteArrayOutputStream;
 4 import java.io.IOException;
 5 import java.io.InputStream;
 6 import java.net.HttpURLConnection;
 7 import java.net.MalformedURLException;
 8 import java.net.ProtocolException;
 9 import java.net.URL;
10 
11 import android.app.Activity;
12 import android.app.ProgressDialog;
13 import android.graphics.Bitmap;
14 import android.graphics.BitmapFactory;
15 import android.os.AsyncTask;
16 import android.os.Bundle;
17 import android.util.Log;
18 import android.view.View;
19 import android.view.View.OnClickListener;
20 import android.widget.Button;
21 import android.widget.ImageView;
22 public class MainActivity extends Activity {
23     private Button btn_load;
24     private ImageView image_load;
25     private ProgressDialog dialog;
26     @Override
27     protected void onCreate(Bundle savedInstanceState) {
28         super.onCreate(savedInstanceState);
29         setContentView(R.layout.activity_main);
30     
31         btn_load = (Button) findViewById(R.id.btn_submit);
32         image_load = (ImageView) findViewById(R.id.image);
33         
34         
35         btn_load.setOnClickListener(new OnClickListener() {        
36             @Override
37             public void onClick(View v) {
38                 // TODO Auto-generated method stub            
39                 new DownImageAsyncTask(MainActivity.this,image_load).execute("http://images2015.cnblogs.com/blog/493196/201509/493196-20150901203057606-579869820.jpg");
40             }
41         });
42     }
43     
44     
45 
46 }

异步任务类：

  1 package com.example.work;
  2 
  3 import java.io.ByteArrayOutputStream;
  4 import java.io.IOException;
  5 import java.io.InputStream;
  6 import java.net.HttpURLConnection;
  7 import java.net.MalformedURLException;
  8 import java.net.ProtocolException;
  9 import java.net.URL;
 10 
 11 import android.app.Notification;
 12 import android.app.NotificationManager;
 13 import android.content.Context;
 14 import android.graphics.Bitmap;
 15 import android.graphics.BitmapFactory;
 16 import android.os.AsyncTask;
 17 import android.support.v4.app.NotificationCompat;
 18 import android.util.Log;
 19 import android.widget.ImageView;
 20 
 21 class DownImageAsyncTask extends AsyncTask<String, Integer, byte[]>
 22 {
 23     
 24     private Context context;
 25     private ImageView image;
 26     public DownImageAsyncTask(Context context ,ImageView image)
 27     {
 28         this.context = context;
 29         this.image = image;
 30     }
 31     @Override
 32     protected byte[] doInBackground(String... params) {
 33         // TODO Auto-generated method stub
 34         byte b[] = new byte[1024*1024];
 35 
 36         if(params[0]!=null)
 37         {
 38             URL url;
 39             try {
 40                 url = new URL(params[0]);
 41                 HttpURLConnection conn = (HttpURLConnection) url.openConnection();
 42                 conn.setRequestMethod("GET");
 43                 conn.setConnectTimeout(5000);
 44                 conn.setDoInput(true);
 45                 
 46                 //记录当前下载量
 47                 int current_len = 0;
 48                 if(conn.getResponseCode()==200)
 49                 {
 50                     //获取下载文件的总大小
 51                     InputStream in = conn.getInputStream();
 52                     int len=0;
 53                     //获取总长度
 54                     long total = conn.getContentLength();
 55                     ByteArrayOutputStream out = new ByteArrayOutputStream();
 56                     while((len = in.read(b))!=-1)
 57                     {
 58                         out.write(b,0,len);
 59                         current_len+=len;
 60                         int progress = (int)(current_len/(float)total*100);
 61                         //发布进度
 62                         publishProgress(progress);
 63                         Log.i("-------------------", progress+"");
 64                     }
 65                     b = out.toByteArray();
 66                 }
 67             
 68             } catch (MalformedURLException e) {
 69                 // TODO Auto-generated catch block
 70                 e.printStackTrace();
 71             } catch (ProtocolException e) {
 72                 // TODO Auto-generated catch block
 73                 e.printStackTrace();
 74             } catch (IOException e) {
 75                 // TODO Auto-generated catch block
 76                 e.printStackTrace();
 77             }
 78         
 79         
 80         }
 81         
 82         return b;
 83     }
 84     
 85     @Override
 86     protected void onPostExecute(byte[] result) {
 87         // TODO Auto-generated method stub
 88         super.onPostExecute(result);
 89         //将网络解析数据转换成bitmap图片格式
 90         Bitmap bitmap = BitmapFactory.decodeByteArray(result, 0, result.length);
 91         //下载完成后 关闭对话框
 92         image.setImageBitmap(bitmap);
 93         NotificationCompat.Builder builder = new NotificationCompat.Builder(context);
 94 
 95         builder.setContentTitle("下载");
 96         builder.setContentText("下载完成");
 97         builder.setSmallIcon(R.drawable.ic_launcher);
 98 //        builder.setOngoing(true);//设置不可以被删除
 99         
100         
101         Notification n = builder.build();
102         
103         NotificationManager manager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
104         
105         manager.notify(188, n);
106     }
107     //在执行doInputBackground方法前主线程自动执行
108     @Override
109     protected void onPreExecute() {
110         // TODO Auto-generated method stub
111         super.onPreExecute();
112         
113     }
114     
115     //当使用publishProgress()方法时 自动调用此方法来更新进度
116     @Override
117     protected void onProgressUpdate(Integer... values) {
118         // TODO Auto-generated method stub
119 NotificationCompat.Builder builder = new NotificationCompat.Builder(context);
120         
121         builder.setContentTitle("下载");
122         builder.setContentText("已经下载"+values[0]+"%");
123         builder.setSmallIcon(R.drawable.ic_launcher);
124         builder.setOngoing(true);//设置不可以被删除
125         //设置通知栏进度条，第一个参数为最大进度，第二个参数为进度，第三个参数为显示进度，为true时不显示进度条填充效果，
126         builder.setProgress(100, values[0], false);
127 
128         
129         Notification n = builder.build();
130         
131         NotificationManager manager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
132         
133         manager.notify(188, n);
134         super.onProgressUpdate(values);
135     }
136 }

布局文件

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     xmlns:tools="http://schemas.android.com/tools"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5        android:orientation="vertical"
 6        android:gravity="center_horizontal"
 7     >
 8 
 9     <ImageView
10         android:layout_width="wrap_content"
11         android:layout_height="wrap_content"
12         android:id="@+id/image"
13         android:src="@drawable/ic_launcher" 
14         />
15     
16     <Button 
17         android:layout_width="wrap_content"
18         android:layout_height="wrap_content"
19         android:id="@+id/btn_submit"
20         android:text="下载"
21         />
22 
23 </LinearLayout>

效果图：