Question

I just started with Android programming and here’s the thing.

How can i check if the item in GridView was already clicked? Something like assigning a boolean ‘clicked’ for EACH item in Grid and changing it’s value every time i click the item.

Currently i’m just using an array of bools so if i click item[x] it switches the bool[x] and then i do the check if it’s true/false and modify the item accordingly, but there has to be a neater way of doing the same!

My code:

package com.example.mojrecnik;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;

import android.os.Bundle;
import android.os.Environment;
import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.GridView;
import android.widget.AdapterView;
import android.widget.TextView;
import android.widget.Toast;
import android.support.v4.app.NavUtils;

public class Glavna extends Activity implements AdapterView.OnItemClickListener {

    private static final int LENGTH_SHORT = 0;
    GridView grid;
    TextView tekst;
    String[] izfajla = new String[200];
    String[] izfajla2 = new String[200];
    boolean[] kliknutmrs = new boolean[200];

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_glavna);

        grid=(GridView)findViewById(R.id.grid);
        grid.setAdapter(new MojAdapter());
        grid.setOnItemClickListener(this);

        //tekst=(TextView)findViewById(R.id.tekst);

        citaFajl();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_glavna, menu);
        return true;
    }

    public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
        TextView klik = (TextView)arg1.findViewById(R.id.gridtekst2);
        if(kliknutmrs[arg2]) {
            kliknutmrs[arg2]=!kliknutmrs[arg2];
            klik.setText(izfajla[arg2]); }
        else {
            kliknutmrs[arg2]=!kliknutmrs[arg2];
            klik.setText(izfajla2[arg2]); }
    }

    public void onNothingSelected(AdapterView<?> arg0) {

    }

    public void citaFajl() {
        File kartica = Environment.getExternalStorageDirectory();
        File fajl = new File(kartica, "reci.txt");
        StringBuilder tekst = new StringBuilder();
        int i=0;
        try {
            BufferedReader br = new BufferedReader(new FileReader(fajl));
            String linija;
            String[] prva;

            while ((linija = br.readLine())!=null) {
                prva = linija.split("-");
                izfajla[i]=prva[0];
                if(prva[1].length()>0)
                    izfajla2[i]=prva[1];
                i++;
            }
        }
        catch (IOException e) {
            Toast greska = Toast.makeText(this, e.getMessage().toString(), LENGTH_SHORT);
            greska.show();
        }
    }

    private class MojAdapter extends ArrayAdapter {

        public MojAdapter() {
            super(Glavna.this, R.layout.gridvju, izfajla);
        }

        public View getView(int position, View convertView, ViewGroup parent) {
            //vazno!! pravim vju od inflatera i vracam vju a ne convertvju!
            View gridvju;

            if(convertView==null) {
                LayoutInflater inflater = getLayoutInflater();
                gridvju = inflater.inflate(R.layout.gridvju, parent, false);
            }
            else
                gridvju=convertView;

            TextView tekst2 = (TextView)gridvju.findViewById(R.id.gridtekst2);
            tekst2.setLines(2);
            tekst2.setText(izfajla[position]);

            return(gridvju);
        }
    }
} 

And XML(main):

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
<!--  
    <TextView
        android:id="@+id/tekst"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:textSize="20dp"
        android:layout_below="@id/tekst" >
    </TextView> -->

    <GridView
        android:id="@+id/grid"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:horizontalSpacing="@dimen/padding_medium"
        android:numColumns="3"
        android:stretchMode="columnWidth" >

    </GridView>

</RelativeLayout>

And layout:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical" >

    <TextView
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/gridtekst2" />

</LinearLayout>

Answer 1

Here is how i worked it in the end. I created a custom class to contain text which is displayed and also added a bool in there so now every element in my gridview has its own ‘click-checker’.
note: this program simply alternates between 2 words onClick, if you wanna try it use text file with data formated ‘word1 – word2’

Code:

package com.example.mojrecnik;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import android.os.Bundle;
import android.os.Environment;
import android.app.Activity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.GridView;
import android.widget.AdapterView;
import android.widget.TextView;
import android.widget.Toast;

public class Glavna extends Activity implements AdapterView.OnItemClickListener {

    private static final int LENGTH_LONG = 1;
    GridView grid;
    List<Rec> lReci = new ArrayList<Rec>(); //this is our list of data which contains text and bool check

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_glavna);

        citaFajl();

        grid=(GridView)findViewById(R.id.grid);
        grid.setAdapter(new MojAdapter());
        grid.setOnItemClickListener(this);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_glavna, menu);
        return true;
    }

    public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
        VjuHolder holder=(VjuHolder)arg1.getTag();

        if(!lReci.get(arg2).clicked)
            holder.text.setText(lReci.get(arg2).rec2);
        else
            holder.text.setText(lReci.get(arg2).rec1);

        lReci.get(arg2).clicked = !lReci.get(arg2).clicked;
    }

    public void onNothingSelected(AdapterView<?> arg0) {
        //////////////////////////////////////////
    }

    public void citaFajl() {

        try {
            BufferedReader br = new BufferedReader(new FileReader(new File(Environment.getExternalStorageDirectory(), "reci.txt")));
            String[] reci = new String[2];
            String linija;
            Rec rec;

            while ((linija = br.readLine()) != null) {
                reci = linija.split("-"); //because data in my file is formatted 'word1 - word2', we separate them now so we can alternate between them
                reci[1]=reci[1].trim();
                rec = new Rec(reci[0], reci[1], false);
                lReci.add(rec);
            }
        }
        catch (IOException e) {
            Toast.makeText(this, e.getMessage().toString(), LENGTH_LONG).show();
        }
    }

    private class MojAdapter extends ArrayAdapter<String> {

        public MojAdapter() {
            super(Glavna.this, R.layout.gridvju);
        }

        public int getCount() {
            return lReci.size(); //here we explicitly set the total number of grid elements so it doesn't go out of index range
        }

        public View getView(int position, View convertView, ViewGroup parent) {
            VjuHolder holder;

            if(convertView==null) {
                LayoutInflater inflater = getLayoutInflater();
                convertView = inflater.inflate(R.layout.gridvju, parent, false);
                holder = new VjuHolder();
                holder.text = (TextView)convertView.findViewById(R.id.gridtekst2);
                convertView.setTag(holder); }
            else
                holder=(VjuHolder)convertView.getTag();

                if(lReci.get(position).clicked) //check to make grid update according to the clicked state of our elements [when scrolling]
                    holder.text.setText(lReci.get(position).rec2);
                else
                    holder.text.setText(lReci.get(position).rec1);

                holder.text.setLines(2);

            return(convertView);
        }
    }
}

//holder class
class VjuHolder {
    TextView text;
}

//here we put the text to be displayed along with bool to check in which state is the clicked element
class Rec {
    String rec1, rec2;
    boolean clicked;

    Rec(String rec, String druga, boolean klik) {
        rec1 = rec;
        rec2 = druga;
        clicked = klik;
    }
}