创建一个名为“创建服务”的程序,该程序一启动服务就会在状态栏显示一条通知。
下面的代码能运行,但是通知栏没有显示通知,并且运行显示了这个,不知道是哪里的问题,求解答
这是给的案例图
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<Button
android:id="@+id/btn_start"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="开启服务"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
MyService.java
package com.example.myservice;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.os.IBinder;
public class MyService extends Service {
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public void onCreate() {
super.onCreate();
final NotificationManager notification = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
// 创建Notification对象
Notification.Builder builder = new Notification.Builder(this);
builder.setSmallIcon(R.drawable.advise2);
builder.setTicker("显示第一个通知");
builder.setContentTitle("标题");
builder.setContentText("我是在服务中创建的Notification");
builder.setWhen(System.currentTimeMillis()); //发送时间
builder.setDefaults(Notification.DEFAULT_ALL);
notification.notify(123, builder.build());
}
}
MainActivity.java
package com.example.myservice;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import androidx.appcompat.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final Intent intent = new Intent(MainActivity.this,MyService.class);
Button start = (Button) findViewById(R.id.btn_start);
}
//开启服务的方法
public void start(View view){
Intent intent = new Intent(this,MyService.class);
startService(intent);
}
@Override
protected void onStart() {
startService(new Intent(MainActivity.this,MyService.class)); //开机启动
super.onStart();
}
}
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com.example.myservice">
<application
android:allowBackup="true"
android:dataExtractionRules="@xml/data_extraction_rules"
android:fullBackupContent="@xml/backup_rules"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/Theme.MyService"
tools:targetApi="31">
<service android:name=".MyService"
android:enabled="true"
android:exported="true">
</service>
<activity
android:name=".MainActivity"
android:exported="true">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
ps:这是teacher给的代码,但是我自己运行不出来
“创建服务”程序对应的布局文件activity_main.xml代码如下所示:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<Button
android:id="@+id/btn_start"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="开启服务"
android:textColor="@android:color/white"
android:background="@drawable/soil_backgroud_content3" />
</RelativeLayout>
2、创建服务(MyService)
接下来创建一个类继承自Service,并在该类中的onCreate()方法中向状态栏发送通知,具体代码如下所示:
public class MyService extends Service {
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public void onCreate() {
super.onCreate();
// 创建Notification对象
Notification notification = new Notification(R.drawable.ic_launcher,
"我是状态栏通知", System.currentTimeMillis());
// 设置点击Notification就进入主界面
Intent intent = new Intent(this, MainActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(this, 0,
intent, 0);
notification.setLatestEventInfo(this, "标题",
"我是在服务中创建的Notification",pendingIntent);
// 让Myservice变成前台服务,并在系统状态栏显示出来
startForeground(1, notification);
}
}
应该是通知权限的问题