android - 无法实例化接收者没有零参数构造函数

Question

我在使用 BroadCastReceiver 时遇到一些问题。这里是 AndroidManifest.xml

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

    <uses-permission android:name="android.permission.RECEIVE_SMS"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        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=".NotificationActivity"></activity>
        <receiver android:name=".NotificationActivity$SMSReceiver">
            <intent-filter>
                <action android:name="android.provider.Telephony.SMS_RECEIVED" />
            </intent-filter>
        </receiver>
    </application>

</manifest>

以及我的部分代码

公共(public)类NotificationActivity扩展了AppCompatActivity{

public TextView textViewFrom, textViewContent;
public IntentFilter intentFilter;
public SMSReceiver smsReceiver;

@Override
protected void onDestroy() {
    super.onDestroy();
    unregisterReceiver(smsReceiver);
}

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

    textViewContent = (TextView)findViewById(R.id.textViewContent);
    textViewFrom = (TextView)findViewById(R.id.textViewFrom);

    intentFilter = new IntentFilter("android.provider.Telephony.SMS_RECEIVED");
    smsReceiver = new SMSReceiver();

    registerReceiver(smsReceiver,intentFilter);
}

public class SMSReceiver extends BroadcastReceiver{

    public SMSReceiver(){
    }

    @Override
    public void onReceive(Context context, Intent intent) {
        Bundle bundle = intent.getExtras();
        Object[] pdus = (Object[]) bundle.get("pdus");
        SmsMessage[] smsMessages = new SmsMessage[pdus.length];
        for (int i = 0; i < smsMessages.length; i++)
            smsMessages[i] = SmsMessage.createFromPdu((byte[])pdus[i]);
        String from = smsMessages[0].getOriginatingAddress();
        StringBuilder content = new StringBuilder("");
        for (SmsMessage element: smsMessages)
            content.append(element.getMessageBody());
        textViewFrom.setText(from);
        textViewContent.setText(content.toString());
    }
}

}谁能给我一些帮助并告诉我为什么会发生这种情况？非常感谢!

Answer 1

您的SMSReceiver是一个非静态实例类。这意味着它只能在持有类 NotificationActivity 的上下文中构造。这很好，但您无法在 list 中注册它，因为系统需要构造一个 NotificationActivity 才能实例化您的接收器来处理广播。

顺便说一句，要么在 list 中注册接收器，要么在您的 Activity 中注册它，但不能同时注册。