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Android Build a Simple Android App (2014) Improving Our Code Adding More Colors

Dylan Cairns
Dylan Cairns
11,191 Points
Posted by Dylan Cairns
Dylan Cairns
11,191 Points

How to access strings.xml from the new classes?

I'm following along with the new first lesson: building a simple android app and I wanted to use the string.xml resource instead of hardcoding the facts and hexadecimals. But I cannot access it from the new classes I make FactBook and ColorWheel.java

Trying this inside of FactBook.java

public String[] mFacts = Context.getResources().getStringArray(R.array.array_of_facts);

I get an error "non-static method 'getResources() cannot be referenced from a static context".

These are my arrays in the .xml 

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">Fun Facts</string>
    <string name="hello_world">Hello world!</string>
    <string name="action_settings">Settings</string>
    <string name="did_you_know">Did you konw?</string>
    <string name="fact_ants">Ants stretch when they wake up in the morning.</string>
    <string name="button_show_another_fact">Show Another Fun Fact</string>
    <string-array name="array_of_facts">
        <item> meow 1 </item>
        <item> meow 2</item>
        <item> meow 3</item>
        <item> meow 4</item>
        <item> meow 5</item>
    </string-array>
    <string-array name="array_of_colors">
        <item> #39add1 </item>
        <item> #3079ab</item>
        <item> #838cc7</item>
        <item> #53bbb4</item>
        <item> #e15258</item>
    </string-array>
</resources>

I've been searching everywhere but don't understand how to get the context or whatever I need for these new classes in order to access the resources

For reference this is my FactBook code: 

package com.endofdaze.funfacts;


import android.content.Context;

import java.util.Random;

public class FactBook {
    public String[] mFacts =  Context.getResources().getStringArray(R.array.array_of_facts);
    public String mFact = null;

    public String getFact() {




        // Randomly select a fact
        Random randomGenerator = new Random(); // construct new RNG
        int randomNumber = randomGenerator.nextInt(mFacts.length);

        mFact = mFacts[randomNumber];
        return mFact;
    }
}

2 Answers

Dylan Cairns
Dylan Cairns
11,191 Points
Dylan Cairns
Dylan Cairns
11,191 Points

Through a lot of trial and error I think I got this to work. I had to extend ContextWrapper to the ColorWheel and FactBook classes and give them the context of the main activity 

package com.endofdaze.funfacts;


import android.content.Context;
import android.content.ContextWrapper;
import android.graphics.Color;

import java.util.Random;

public class ColorWheel extends ContextWrapper {
    private String[] mColors;
    private String mColor = "";
    public ColorWheel(Context base) {
        super(base);
            mColors = getResources().getStringArray(R.array.array_of_colors);
            mColor = "";

    }

then I had to create the instances of these classes inside of the OnCreate method as "final" rather than at the top of the class itself 

package com.endofdaze.funfacts;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.RelativeLayout;
import android.widget.TextView;


public class FunFactsActivity extends Activity {

    public static final String TAG = FunFactsActivity.class.getSimpleName();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fun_facts);

        // declare view variables & assign the views from layout file.
        final TextView factLabel = (TextView)findViewById(R.id.factTextView);
        final Button showFactButton = (Button)findViewById(R.id.showFactButton);
        final RelativeLayout layout = (RelativeLayout)findViewById(R.id.relativeLayout);
        final FactBook mFactBook = (new FactBook(this));
        final ColorWheel mColorWheel = (new ColorWheel(this));

if anyone else is interested in getting rid of their hardcoded Strings then I hope this helps you out too. It took a few hours to figure it out, as simple as it seems!

Trainer Workout
Trainer Workout
22,341 Points
Trainer Workout
Trainer Workout
22,341 Points

How did you access the color value from the xml in your Java code ? I ask this because I can access the color reference (@color/android) but I don't know how to use it.

// ColorBook.java
    private String[] colors;

    public ColorBook(Context mContext) {
        super(mContext);
        colors = getResources().getStringArray(R.array.fun_facts_colors);
    } // FactBook()

    public int getColor() {
        Random mRandom = new Random();
        int randomNumber = mRandom.nextInt(colors.length);
        String color = colors[randomNumber];
        // the code crashes here because color is a string reference ((@color/android)
       // what I need is the value (#51B46D)
        return Color.parseColor(color);
    } // getColor()

// FunFactsActivity.java
// Generate a random background color
int color = mColorBook.getColor();
mRelativeLayout.setBackgroundColor(color);
Barry May
Barry May
3,963 Points
Barry May
Barry May
3,963 Points

Thanks for this. Much simpler approach than any others I found online!