是否有从其他活动 class 访问 MainActivity 的解决方案？

Question

I want to call function below.

mobileView.loadUrl("javascript:setUserId () ");

And mobileView is in MainActivity.

public class MainActivity extends AppCompatActivity {
    private WebView mobileView;
}

I want to call function above after SecondActivity is finished.

public class SecondActivity extends AppCompatActivity {
    ...
    private void getUserId () {
        ...
        finish();
    }
}

And SecondActivity starts from AReceiver.

public class AReceiver extends BroadcastReceiver {
    public void onReceive(Context context, Intent intent) {
        ...
        Intent i = new Intent(context, SecondActivity.class);
        i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        ...
        context.startActivity(i);
    }
}

And AReceiver is called by below code...

class MainActivity {
    ...
    private void userId () {
        ...
        intent = new Intent(MainActivity.this, AReceiver.class);
        pendingIntent = PendingIntent.getBroadcast(
                MainActivity.this, 
                alarmID, 
                intent, 
                PendingIntent.FLAG_UPDATE_CURRENT
        );
        alarmManager.set(
                AlarmManager.RTC_WAKEUP, 
                mCalendar.getTimeInMillis(), 
                pendingIntent
        );
        ...
    }
    ...
}

But I don't know how to access mobileView from SecondActivity. Is there any solution?

---

What I've tried...

1. change variable from

private webView mobileView 

to

public webView mobileView

2. call from SecondActivity Using

MainActivity.mobileView

It doesn't work for me.

Answer 1

You can try This option

Intent

..............

You opened the new activity from another activity with startActivityForResult . In that case you can just call the f inishActivity() function from your code and it'll take you back to the previous activity.

it work only if you start the second activity from main activity

Answer 2

I solved this problem using local broad cast manager: .D Thank you @Shripad Jadhav who help this answer.

Below description is solution. Hope it helpes somebody: :D

---

MainActivity.java

public class MainActivity extends AppCompatActivity {
    private WebView wv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        ...
        LocalBroadcastManager.getInstance(this)
            .registerReceiver(mBroadcastReceiver, new IntentFilter("webview-filter"));
        ...
    }
    ...
    private BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            mv.loadUrl("javascript: loadMainData ()");
        }
    };
    @Override
    protected void onDestroy() {
        LocalBroadcastManager.getInstance(this).unregisterReceiver(mBroadcastReceiver);
        super.onDestroy();
    }
}

SecondActivity.java

public class SecondActivity extends AppCompatActivity {
    private void someFunction () {
        sendMessage ();
    }
    ...
    private void sendMessage() {
        Log.d("sender", "Broadcasting message");
        Intent intent = new Intent("webview-filter");

        LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
    }
    ...
}