Question

我已经构建了一个应用程序来读取传入的短信。但每当有任何新的短信出现时，它都会异常。 logcat提供以下消息：

goto

这是错误吗？我怎么解决这个问题？

SmsBroadcastReceiver的代码如下：

10-04 12:18:47.392: E/AndroidRuntime(8225): java.lang.RuntimeException: Unable to start receiver com.commlink.smscheck.SmsBroadcastReceiver: java.lang.NullPointerException
10-04 12:18:47.392: E/AndroidRuntime(8225):     at android.app.ActivityThread.handleReceiver(ActivityThread.java:2616)
10-04 12:18:47.392: E/AndroidRuntime(8225):     at android.app.ActivityThread.access$1700(ActivityThread.java:151)
10-04 12:18:47.392: E/AndroidRuntime(8225):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1418)
10-04 12:18:47.392: E/AndroidRuntime(8225):     at android.os.Handler.dispatchMessage(Handler.java:110)
10-04 12:18:47.392: E/AndroidRuntime(8225):     at android.os.Looper.loop(Looper.java:193)
10-04 12:18:47.392: E/AndroidRuntime(8225):     at android.app.ActivityThread.main(ActivityThread.java:5330)
10-04 12:18:47.392: E/AndroidRuntime(8225):     at java.lang.reflect.Method.invokeNative(Native Method)
10-04 12:18:47.392: E/AndroidRuntime(8225):     at java.lang.reflect.Method.invoke(Method.java:515)
10-04 12:18:47.392: E/AndroidRuntime(8225):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:828)
10-04 12:18:47.392: E/AndroidRuntime(8225):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:644)
10-04 12:18:47.392: E/AndroidRuntime(8225):     at dalvik.system.NativeStart.main(Native Method)
10-04 12:18:47.392: E/AndroidRuntime(8225): Caused by: java.lang.NullPointerException
10-04 12:18:47.392: E/AndroidRuntime(8225):     at com.commlink.smscheck.SmsBroadcastReceiver.onReceive(SmsBroadcastReceiver.java:44)
10-04 12:18:47.392: E/AndroidRuntime(8225):     at android.app.ActivityThread.handleReceiver(ActivityThread.java:2609)
10-04 12:18:47.392: E/AndroidRuntime(8225):     ... 10 more

实例方法如下：

public class SmsBroadcastReceiver extends BroadcastReceiver {

    public static final String SMS_BUNDLE = "pdus";
    public String pre_address = "03590000004";
    String smsBody;
    String address;

    public void onReceive(Context context, Intent intent) {  
        Bundle intentExtras = intent.getExtras();
        if (intentExtras != null) {
            Object[] sms = (Object[]) intentExtras.get(SMS_BUNDLE);
            String smsMessageStr = "";
            for (int i = 0; i < sms.length; ++i) {
                SmsMessage smsMessage = SmsMessage
                        .createFromPdu((byte[]) sms[i]);

                smsBody = smsMessage.getMessageBody().toString();
                address = smsMessage.getOriginatingAddress();
                if (pre_address.equals(address)) {

                    smsMessageStr += "SMS From: " + address + "\n";
                    smsMessageStr += smsBody + "\n";
                }
            }

            Toast.makeText(context, smsMessageStr, Toast.LENGTH_SHORT).show();

            // this will update the UI with message
            SmsActivity inst = SmsActivity.instance();
            inst.updateList(smsBody);
            if (pre_address.equals(address))
                inst.Notify(inst.getMessageCountUnread()
                        + " unread message", address);
        }
    }

}

Answer 1

NPE之所以发生，是因为您尝试从BroadcastReceiver访问actvity方法。这不是正确的方法。要在收到短信时通知您的活动，您可以从广播接收器发送广播。

public class SmsReceiver extends BroadcastReceiver {

    public static final String ACTION_UNREAD_SMS = "YOUR.PACKAGENAME.ACTION_UNREAD_SMS";
    public static final String EXTRA_SMS_BODY = "YOUR.PACKAGENAME.EXTRA_SMS_BODY";
    public static final String EXTRA_SMS_ADDRESS = "YOUR.PACKAGENAME.EXTRA_SMS_ADDRESS";
    public static final String SMS_BUNDLE = "pdus";
    public static final String PRE_ADDRESS = "03590000004";
    String smsBody;
    String address;

    public void onReceive(Context context, Intent intent) {
        Bundle intentExtras = intent.getExtras();
        if (intentExtras != null) {
            Object[] sms = (Object[]) intentExtras.get(SMS_BUNDLE);
            String smsMessageStr = "";
            for (int i = 0; i < sms.length; ++i) {
                SmsMessage smsMessage = SmsMessage
                        .createFromPdu((byte[]) sms[i]);

                smsBody = smsMessage.getMessageBody().toString();
                address = smsMessage.getOriginatingAddress();
                if (PRE_ADDRESS.equals(address)) {

                    smsMessageStr += "SMS From: " + address + "\n";
                    smsMessageStr += smsBody + "\n";
                }
            }

            Toast.makeText(context, smsMessageStr, Toast.LENGTH_SHORT).show();

            Intent smsIntent = new Intent(ACTION_UNREAD_SMS);
            smsIntent.putExtra(EXTRA_SMS_BODY, smsBody);
            smsIntent.putExtra(EXTRA_SMS_ADDRESS, address);
            context.sendBroadcast(smsIntent);
        }
    }
}

要捕捉广播，您可以在活动中这样做。

public class MainActivity extends AppCompatActivity {

    private BroadcastReceiver mUnreadSmsBroadCastReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String smsBody = intent.getStringExtra(SmsReceiver.EXTRA_SMS_BODY);
            String smsAddress = intent.getStringExtra(SmsReceiver.EXTRA_SMS_ADDRESS);
            updateList(smsBody);
            if (SmsReceiver.PRE_ADDRESS.equals(smsAddress)) {
                // notify your unread message
            }
        }
    };

    @Override
    protected void onResume() {
        super.onResume();
        registerReceiver(mUnreadSmsBroadCastReceiver, new IntentFilter(SmsReceiver.ACTION_UNREAD_SMS));
    }

    @Override
    protected void onPause() {
        super.onPause();
        unregisterReceiver(mUnreadSmsBroadCastReceiver);
    }

}

希望它对你有用。

无法启动接收器com.commlink.smscheck.SmsBroadcastReceiver：java.lang.NullPointerException

1 个答案: