为什么广播接收器不能动态工作？

Question

I tried to do a broadcast receiver dynamically for incoming SMS will show a toast but the app doesn't show anything.

I register the broadcast dynamically in the mainActivity like this.

MainActivity.java

package com.example.smsreader;

import android.content.Intent;
import android.content.IntentFilter;
import android.net.ConnectivityManager;
import android.support.v4.content.LocalBroadcastManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {
    BroadcastReader reader = new BroadcastReader();

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

        IntentFilter filter = new IntentFilter("android.provider.Telephony.SMS_RECEIVED");
        registerReceiver(reader, filter);
    }
}

This is brodcast class, the app will show a toast when the phone will receive a SMS but it doesn't

package com.example.smsreader;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;
public class BroadcastReader extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        if("android.provider.Telephony.SMS_RECEIVED".equals(intent.getAction())){
            Toast.makeText(context, "it is working", Toast.LENGTH_LONG).show();
        }
    }
}

I don't register anything in the manifest file.

Manifest file

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

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

    <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>
    </application>
</manifest>

Answer 1

尝试以下方法：

intentFilter.addAction("android.provider.Telephony.SMS_RECEIVED");

Answer 2

您需要使用以下方法注册本地广播接收器;）

LocalBroadcastManager.getInstance(this).registerReceiver(reader, filter)