BroadcastReceiver和AlarmManager Android

Posted 2021-04-09

我正在尝试使用BroadcastReceiver的警报管理器。我尝试使用Tutorial: System Services and BroadcastReceiver中给出的示例。但是当我在结束后运行示例时，吐司不会出现。代码如下：

我的主要活动：

public class AlarmActivity extends Activity {


    /** Called when the activity is first created. */

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

    public void startAlert(View view) {
        EditText text = (EditText) findViewById(R.id.time);
        int i = Integer.parseInt(text.getText().toString());
        Intent intent = new Intent(this, MyBroadcastReceiver.class);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(this.getApplicationContext(), 234324243, intent, 0);
        AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
        alarmManager.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis()
                + (i * 1000), pendingIntent);
        Toast.makeText(this, "Alarm set in " + i + " seconds",
                Toast.LENGTH_LONG).show();
    }


}

我的broadCastReceiver：

public class MyBroadcastReceiver {
    public void onReceive(Context context, Intent intent) {
        Toast.makeText(context, "Don't panic but your time is up!!!!.",
                Toast.LENGTH_LONG).show();
        // Vibrate the mobile phone
        Vibrator vibrator = (Vibrator) context.getSystemService(Context.VIBRATOR_SERVICE);
        vibrator.vibrate(2000);
    }

}

我的主要布局：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:orientation="vertical" >

    <EditText
            android:id="@+id/time"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:hint="Number of seconds"
            android:inputType="numberDecimal" >
    </EditText>

    <Button
            android:id="@+id/ok"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="startAlert"
            android:text="Start Counter" >
    </Button>

</LinearLayout>

和manifestfile：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.broadcastreceiver"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />
    <uses-permission android:name="android.permission.VIBRATE" >
    </uses-permission>

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.broadcastreceiver.AlarmActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
         <receiver android:name="com.example.android_alarm.MyBroadcastReceiver" >
        </receiver>
    </application>

</manifest>

答案

接收器必须从BroadcastReceiver扩展

public class MyBroadcastReceiver extends BroadcastReceiver {
    // ...
}

还要确保清单文件中的接收者名称是正确的。

另一答案

你的MyBroadcastReceiver类放错了这段代码

public class MyBroadcastReceiver extends BroadcastReceiver
{
@Override
public void onReceive(Context context, Intent intent) {
     Toast.makeText(context, "Don't panik but your time is up!!!!.",
                Toast.LENGTH_LONG).show();
        // Vibrate the mobile phone
        /*Vibrator vibrator = (Vibrator) context.getSystemService(Context.VIBRATOR_SERVICE);
        vibrator.vibrate(2000);*/       
}
}

只需要添加“extends BroadcastReceiver”并获取onReceive（）覆盖方法。

另一答案

你只是忘了重写OnReceive()方法。 public void onReceive(Context context, Intent intent)是BroadcastReceiver的预定义方法，当你使用它时，你必须@Override如下，

public class MyBroadcastReceiver extends BroadcastReceiver
{
    @Override   // You forgot this line 
    public void onReceive(Context context, Intent intent) 
    {
          Toast.makeText(context, "Don't panik but your time is up!!!!.",Toast.LENGTH_LONG).show();
    }
}

另一答案

你已经创建了一个你没有在任何地方调用的startAlert函数。所以首先在onCreate中调用该方法，然后你会收到一个toast。