如何从另一个Activity更改LinerLayout扩展类中TextView的文本？

Question

I have a class that extends LinearLayout. There is a TextView in that class. I need to change the text of that TextView from another activity. I have tried by declaring the TextView object as public static. But it is not working. Please help me to do it.

This is my Code:

package com.briscommunications.bris.ui;

import android.app.Activity;
import android.content.Context;
import android.content.res.TypedArray;
import android.os.AsyncTask;
import android.os.Handler;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.briscommunications.bris.R;
import com.briscommunications.bris.GlobalVariables;
import com.briscommunications.bris.LinphonePreferences;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Timer;
import java.util.TimerTask;

/**
 * @author Guillaume Beraudo
 *
 */
public class Numpad extends LinearLayout implements AddressAware {
    private boolean mPlayDtmf;
    public void setPlayDtmf(boolean sendDtmf) {
        this.mPlayDtmf = sendDtmf;
    }

    public static Handler handler = new Handler();
    Timer timer = new Timer();
    public static TextView txtBalance;
    public static Context objNumpadContext;
    public static Activity objNumpadAct;

    public Numpad(Context context, boolean playDtmf) {
        super(context);
        mPlayDtmf = playDtmf;
        LayoutInflater.from(context).inflate(R.layout.numpad, this);
        setLongClickable(true);
        onFinishInflate();
    }

    public static void ShowBalance(){
        try {
            LinphonePreferences mPrefs = LinphonePreferences.instance();
            int defaultAccountID = mPrefs.getDefaultAccountIndex();
            GlobalVariables.UserName = mPrefs.getAccountUsername(defaultAccountID);
        }
        catch (Exception e){
            GlobalVariables.UserName ="";
        }
        new getBalance_actMain().execute();
    }

    public Numpad(Context context, AttributeSet attrs) {
        super(context, attrs);
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.Numpad);
        mPlayDtmf = 1 == a.getInt(R.styleable.Numpad_play_dtmf, 1);
        a.recycle();
        LayoutInflater.from(context).inflate(R.layout.numpad, this);
        setLongClickable(true);


        txtBalance = (TextView) findViewById(R.id.txtBalance);
        objNumpadContext = getContext();
        objNumpadAct = (Activity) objNumpadContext;

        ShowBalance();

        /*
        TimerTask doAsynchronousTask = new TimerTask() {
            @Override
            public void run() {

                //Perform background work here

                handler.post(new Runnable() {
                    public void run() {

                    }
                });
            }
        };
        timer.schedule(doAsynchronousTask, 10, 5000);*/
    }

    @Override
    protected final void onFinishInflate() {
        for (Digit v : retrieveChildren(this, Digit.class)) {
            v.setPlayDtmf(mPlayDtmf);
        }
        super.onFinishInflate();
    }
    public void setAddressWidget(AddressText address) {
        for (AddressAware v : retrieveChildren(this, AddressAware.class)) {
            v.setAddressWidget(address);
        }
    }


    private final <T> Collection<T> retrieveChildren(ViewGroup viewGroup, Class<T> clazz) {
        final Collection<T> views = new ArrayList<T>();

        for (int i = 0; i < viewGroup.getChildCount(); i++) {
            View v = viewGroup.getChildAt(i);
            if (v instanceof ViewGroup) {
                views.addAll(retrieveChildren((ViewGroup) v, clazz));
            } else {
                if (clazz.isInstance(v))
                    views.add(clazz.cast(v));
            }
        }

        return views;
    }

    public static class getBalance_actMain extends AsyncTask {
        String usrBal="Fetching Balance";
        @Override
        protected Object doInBackground(Object[] params) {
            try {
                HttpClient client=new DefaultHttpClient();
                HttpGet request=new HttpGet("some_url");
                HttpResponse response=client.execute(request);

                HttpEntity entity=response.getEntity();
                usrBal = EntityUtils.toString(entity);

                entity.consumeContent();
            } catch (ClientProtocolException e) {
                usrBal = "FALSE";
            } catch (IOException e) {
                usrBal = "FALSE";
            }
            return null;
        }

        @Override
        protected void onPostExecute(Object o) {
            if (usrBal.equals("FALSE")){
                txtBalance.setText("--.--");
                return;
            }

            //txtBalance.setText(usrBal);
            com.briscommunications.bris.ui.Numpad.txtBalance.setText(usrBal);

        }
    }

}

I am calling static ShowBalance() function from the other activity.

Thanks in advance.

Answer 1

As far as I know it's not possible to change the text in one activity from another directly, because of the main thread (UI thread) restrictions.

Try to store the value you need later in a public variabile and then in the other Activity, in onResume() or onOpen() update the value of the editText with the stored value in the public variable.