Android通知

通知能提醒我们。Android提供了强大的通知功能，现在创建一个简单的通知测试项目：
NotificationTest

添加依赖

通知需要依赖support-compat，以后可能更多的使用AndroidX。

dependencies {
    implementation "com.android.support:support-compat:28.0.0"
}

创建活动

要创建两个活动，一个是主活动，一个是结果活动，用来显示点击通知后的结果页。

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.notificationtest">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".ResultActivity"
            android:launchMode="singleTask"
            android:taskAffinity=""
            android:excludeFromRecents="true"
            android:parentActivityName=".MainActivity">
        </activity>
    </application>
</manifest>

布局activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <Button
        android:id="@+id/send_notice"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="发送通知"/>
</LinearLayout>

布局activity_result.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_height="match_parent"
    android:layout_width="match_parent">
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:textSize="24sp"
        android:text="结果页"/>
</RelativeLayout>

MainActivity

package com.example.notificationtest;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.NotificationCompat;

import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.graphics.BitmapFactory;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button sendNotice = findViewById(R.id.send_notice);
        sendNotice.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        final String CHANNEL_ID = "1";
        switch (view.getId()) {
            case R.id.send_notice:
                Log.d("test", "测试");

                // 创建通知“意图”
                Intent notifyIntent = new Intent(this, ResultActivity.class);
                notifyIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK |
                        Intent.FLAG_ACTIVITY_CLEAR_TASK);
                PendingIntent notifyPendingIntent = PendingIntent.getActivity(this,
                        0, notifyIntent, PendingIntent.FLAG_UPDATE_CURRENT);

                NotificationManager manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                    NotificationChannel notificationChannel = new NotificationChannel(CHANNEL_ID,
                            "默认通知", NotificationManager.IMPORTANCE_HIGH);
                    manager.createNotificationChannel(notificationChannel);
                }
                Notification notification = new NotificationCompat.Builder(this, CHANNEL_ID)
                        .setDefaults(Notification.DEFAULT_ALL)
                        .setContentTitle("这是内容标题")
                        .setContentText("这是正文内容")
                        .setWhen(System.currentTimeMillis()) // 指定被通知的时间
                        .setSmallIcon(R.mipmap.ic_launcher) // 设置小图标
                        .setLargeIcon(BitmapFactory.decodeResource(getResources(), R.mipmap.xiong))
                        .setAutoCancel(true) // 设置自动隐藏
                        .setPriority(NotificationCompat.PRIORITY_DEFAULT)
                        .setContentIntent(notifyPendingIntent) // 设置意图
                        .build();
                manager.notify(1, notification);
                break;
            default:
               break;
        }
    }
}

ResultActivity

package com.example.notificationtest;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

public class ResultActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_result);
    }
}

参考：
​​​https://developer.android.google.cn/guide/topics/ui/notifiers/notifications​​