Question

我正在使用广播类来使用此代码来收听短信消息

package com.escortme.basic;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.telephony.SmsMessage;
import android.widget.Toast;

public class SMSReceiverActivity extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        // Parse the SMS.
        Bundle bundle = intent.getExtras();
        SmsMessage[] msgs = null;
        String str = "";
        if (bundle != null)
        {
            // Retrieve the SMS.
            Object[] pdus = (Object[]) bundle.get("pdus");
            msgs = new SmsMessage[pdus.length];
            for (int i=0; i<msgs.length; i++)
            {
                msgs[i] = SmsMessage.createFromPdu((byte[])pdus[i]);
                // In case of a particular App / Service.
                //if(msgs[i].getOriginatingAddress().equals("+91XXX"))
                //{
                str += "SMS from " + msgs[i].getOriginatingAddress();
                str += " :";
                str += msgs[i].getMessageBody().toString();
                str += "\n";
                //}
            }
            // Display the SMS as Toast.
            Toast.makeText(context, str, Toast.LENGTH_SHORT).show();


            Pol_ViewActivity appState = ((Pol_ViewActivity)getApplicationContext()); // ERROR
            appState.move_map_to("33.786047","-59.187287");
        }
    }
}

并且它在清单中定义如此

    <receiver 
      android:name="com.escortme.basic.SMSReceiverActivity"
      android:enabled="true">
      <intent-filter>
        <action android:name="android.provider.Telephony.SMS_RECEIVED" />
      </intent-filter>
    </receiver>

但问题是它说“方法getApplicationContext（）未定义类型SMSReceiverActivity”。

有谁知道为什么会发生这种情况以及如何解决这个问题？感谢

Answer 1

查看onReceive（）

的方法签名

public void onReceive(Context context, Intent intent) {

您正在将上下文作为参数传递。您应该在需要时使用该上下文。

Pol_ViewActivity appState = ((Pol_ViewActivity)context);

编辑：我也不确切地知道你要做什么。但是你可能不应该尝试获取一个Activity对象并像上面那样调用一个方法。

Answer 2

我希望这对你的朋友有所帮助。

尝试导入此包（ import android.telephony.gsm.SmsManager; ）

// ---向另一台设备发送短信--- private void sendSMS（String phoneNumber，String message） {
String SENT =“SMS_SENT”; String DELIVERED =“SMS_DELIVERED”;

    PendingIntent sentPI = PendingIntent.getBroadcast(this, 0,
        new Intent(SENT), 0);

    PendingIntent deliveredPI = PendingIntent.getBroadcast(this, 0,
        new Intent(DELIVERED), 0);

    //---when the SMS has been sent---
    registerReceiver(new BroadcastReceiver(){
        @Override
        public void onReceive(Context arg0, Intent arg1) {
            switch (getResultCode())
            {
                case Activity.RESULT_OK:
                    Toast.makeText(getBaseContext(), "SMS sent", 
                            Toast.LENGTH_SHORT).show();
                    break;
                case SmsManager.RESULT_ERROR_GENERIC_FAILURE:
                    Toast.makeText(getBaseContext(), "Generic failure", 
                            Toast.LENGTH_SHORT).show();
                    break;
                case SmsManager.RESULT_ERROR_NO_SERVICE:
                    Toast.makeText(getBaseContext(), "No service", 
                            Toast.LENGTH_SHORT).show();
                    break;
                case SmsManager.RESULT_ERROR_NULL_PDU:
                    Toast.makeText(getBaseContext(), "Null PDU", 
                            Toast.LENGTH_SHORT).show();
                    break;
                case SmsManager.RESULT_ERROR_RADIO_OFF:
                    Toast.makeText(getBaseContext(), "Radio off", 
                            Toast.LENGTH_SHORT).show();
                    break;
            }
        }
    }, new IntentFilter(SENT));

    //---when the SMS has been delivered---
    registerReceiver(new BroadcastReceiver(){
        @Override
        public void onReceive(Context arg0, Intent arg1) {
            switch (getResultCode())
            {
                case Activity.RESULT_OK:
                    Toast.makeText(getBaseContext(), "SMS delivered", 
                            Toast.LENGTH_SHORT).show();
                    break;
                case Activity.RESULT_CANCELED:
                    Toast.makeText(getBaseContext(), "SMS not delivered", 
                            Toast.LENGTH_SHORT).show();
                    break;                      
            }
        }
    }, new IntentFilter(DELIVERED));        

    SmsManager sms = SmsManager.getDefault();
    sms.sendTextMessage(phoneNumber, null, message, sentPI, deliveredPI);               
}

Answer 3

获取应用程序上下文的一个原因是获取def compare_and_divide(df): for i in range(len(df)-1): # df[0] for all values in col 0 .iloc[i] for value in row if df[0].iloc[i+1] >= df[0].iloc[i]: continue else: df[0].iloc[i+1] = df[0].iloc[i] return df[0].div(df[1]) # .div() function to divide values in col 0 by col 1 compare_and_divide(dataframe) 0 0.422500 1 0.614545 2 0.505970 3 0.566667 4 0.680000 # 340/500 value mentioned in the question 5 0.790698 6 0.971429 7 1.002950 8 1.005917 9 1.014925 10 1.030303 11 1.096774 12 1.096774 13 1.133333 14 1.133333 15 1.172414 dtype: float64，因为它必须在应用程序上下文中查找，否则内存将在设备上泄漏＆lt; Android N。

正如Someone Somewhere所述，在WIFI_SERVICE内，只需使用onReceive()。

如何在BroadcastReceiver类中使用getApplicationContext？

3 个答案: