How to change background colour of an Android activity

Question

I want to change the background colour of an activity using AlertDialog. Here is what I have done:

private SharedPreferences prefs;    
private static final String SELECTED_ITEM = "SelectedItem"; 
private Editor sharedPrefEditor;

btnchangeColor = (ImageButton) findViewById(R.id.btnchangeColor);
btnchangeColor.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View v) {

        final CharSequence[] items={"Red","Green","Blue", "Yellow", "#EE82EE"};

        AlertDialog.Builder builder = new AlertDialog.Builder(
                ContentView_2.this);

        builder.setTitle("Pick a Color");
        builder.setPositiveButton("ok", new DialogInterface.OnClickListener() { 

            @Override
            public void onClick(DialogInterface dialog, int which) {}
        });

        builder.setSingleChoiceItems(items, getSelectedItem(), new DialogInterface.OnClickListener() {

            @Override
            public void onClick(DialogInterface dialog, int which) {
                // TODO Auto-generated method stub
                wvContent = (WebView) findViewById(R.id.wvContent);
                //LinearLayout ll=(LinearLayout)findViewById(R.id.wvContent); 

                if("Red".equals(items[which]))
                {
                    wvContent.setBackgroundColor(Color.RED);
                }
                else if("Green".equals(items[which]))
                {
                    wvContent.setBackgroundColor(Color.GREEN);
                    }
                else if("Blue".equals(items[which]))
                {
                    wvContent.setBackgroundColor(Color.BLUE);
                    }
                else if("Yellow".equals(items[which]))
                {
                    wvContent.setBackgroundColor(Color.YELLOW);
                    }
                else if("#EE82EE".equals(items[which]))
                {
                    wvContent.setBackgroundColor(Color.rgb(184,184,184));
                    }
                saveSelectedItem(which);
            }
        });
        builder.show();

    }});
    }

private int getSelectedItem() {
    if (prefs == null) {
        prefs = PreferenceManager
                .getDefaultSharedPreferences(this);
    }
    return prefs.getInt(SELECTED_ITEM, -1);
}

private void saveSelectedItem(int which) {
    if (prefs == null) {
        prefs = PreferenceManager
                .getDefaultSharedPreferences(this);
    }
    sharedPrefEditor = prefs.edit();
    sharedPrefEditor.putInt(SELECTED_ITEM, which);
    sharedPrefEditor.commit();
}

I also add this code to OnCreate:

wvContent = (WebView) findViewById(R.id.wvContent); 
    wvContent.setBackgroundColor(getSelectedItem());

The colour is selected and the web view (wvContent) changes to chosen colour, BUT this is not saved to and/or loaded from Shared Preferences. It returns to its default colour when the activity is relaunched.

So the question is: How can properly I save the selected colour to SharedPreferences and load it when activity relaunches?

Many thanks for help.

You might as well change your activity background in the activity them right. Why do you need an alert dialog to change the color of your activity? — amalBit, Mar 22 '14 at 07:21
For this you need to use sharedPrefernce and store the value in it.. — kalyan pvs, Mar 22 '14 at 07:22

score 3 · Accepted Answer · answered Mar 22 '14 at 07:58

3

Currently you are saving position of selected item instead of color code in SharedPreferences. do it as:

wvContent = (WebView) findViewById(R.id.wvContent);
int bg_color=Color.TRANSPARENT;
 if("Red".equals(items[which]))
   {
       wvContent.setBackgroundColor(Color.RED);
       bg_color=Color.RED;
   }
 else if("Green".equals(items[which]))
  {
      wvContent.setBackgroundColor(Color.GREEN);
       bg_color=Color.GREEN;
  }
........
// save color in SharedPreferences
 saveSelectedItem(bg_color);

Now getSelectedItem() method return color code for previously selected value from spinner.

answered Mar 22 '14 at 07:58

ρяσѕρєя K

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Superb! This is exactly what I have been looking for. Thank you so much. – Niamh Doyle Mar 22 '14 at 08:14
I have no idea why in Jelly Bean it changes the colour right when a radio (colour) is selected, but it doesn't in Ice Cream until the activity is relaunched. Is this the problem of the Android versions or of my code? – Niamh Doyle Mar 23 '14 at 10:56

How to change background colour of an Android activity

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