如何从其他非活动类Android中的活动中插入TextView？

Question

我需要从IncomingSms （非活动类）设置Main3Activity （活动类）的TextView对象。

public class IncomingSms extends BroadcastReceiver {

    final SmsManager sms = SmsManager.getDefault();

    @Override
    public void onReceive(Context context, Intent intent) {
         final Bundle bundle = intent.getExtras();
         try {
            if (bundle != null) {
                final Object[] pdusObj = (Object[]) bundle.get("pdus");
                for (int i = 0; i < pdusObj.length; i++) {
                    SmsMessage currentMessage = SmsMessage.createFromPdu((byte[]) pdusObj[i]);
                    String senderNum = currentMessage.getDisplayOriginatingAddress();
                    String message = currentMessage.getDisplayMessageBody();
                    if (message.equalsIgnoreCase("FIRE DETECTED")) {
                        //Problem start here: I cant able to set TextView object of Main3Activity
                        Main3Activity main3Activity = new Main3Activity();
                        TextView tv = (TextView) main3Activity.findViewById(R.id.firealert);
                        tv.setText(message);
                        //Problem end here
                        Log.i("SmsReceived", "senderNum: " + senderNum + "; message: " + message);
                        int duration = Toast.LENGTH_LONG;
                        Toast toast = Toast.makeText(context, message, duration);
                        toast.show();
                    }
                }
            }
        } catch(Exception e) {
            Log.e("SmsReceiver", "Exception smsReceiver" + e);
        }
    }
}

Answer 1

您不能像这样创建活动实例。

解决方案：1.在您的活动中创建一个广播接收器，并注册一个自定义意图。 2.从您的短信接收器发送自定义的广播意图。 因此基本上可以到达活动接收者，然后您可以在那里简单地更新文本。

如果您的活动没有开始，只需创建一个活动意图，然后将短信文本作为附加意图的一部分传递。

Answer 2

创建一个接口类，将其另存为java类，然后

public interface SmsListener {
            public void messageReceived(String messageText);
    }

和

final SmsManager sms = SmsManager.getDefault();
private static SmsListener mListener;
@Override
public void onReceive(Context context, Intent intent) {
    final Bundle bundle = intent.getExtras();
    try {
        if (bundle != null) {
            final Object[] pdusObj = (Object[]) bundle.get("pdus");
            for (int i = 0; i < pdusObj.length; i++) {
                SmsMessage currentMessage = SmsMessage.createFromPdu((byte[]) pdusObj[i]);
                String senderNum = currentMessage.getDisplayOriginatingAddress();
                String message = currentMessage.getDisplayMessageBody();
                if (message.equalsIgnoreCase("FIRE DETECTED") ){
                    mListener.messageReceived(message); //add this
                    Log.i("SmsReceived", "senderNum: "+ senderNum + "; message: " + message);
                    int duration = Toast.LENGTH_LONG;
                    Toast toast = Toast.makeText(context, message, duration);
                    toast.show();
                }
            }
        }
    } catch (Exception e) {
        Log.e("SmsReceiver", "Exception smsReceiver" +e);
    }
}
public static void bindListener(SmsListener listener) {
        mListener = listener;
    }

然后在您的Main3Activity onCreate方法中

TextView tv=(TextView) main3Activity.findViewById(R.id.firealert);


SmsReceiver.bindListener(new SmsListener() {
                @Override
                public void messageReceived(String messageText) {
                    Log.d("Text",messageText);
                     tv.setText(messageText);
                }
            });