android.graphics.Color

The Color class defines methods for creating and converting color ints. Colors are represented as packed ints, made up of 4 bytes: alpha, red, green, blue. The values are unpremultiplied, meaning any transparency is stored solely in the alpha component, and not in the color components. The components are stored as follows (alpha << 24) | (red << 16) | (green << 8) | blue. Each component ranges between 0..255 with 0 meaning no contribution for that component, and 255 meaning 100% contribution. Thus opaque-black would be 0xFF000000 (100% opaque but no contributes from red, gree, blue, and opaque-white would be 0xFFFFFFFF.



main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    />
<LinearLayout
 android:id="@+id/background"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<Spinner
 android:id="@+id/colorspinner"
 android:layout_width="fill_parent"
    android:layout_height="wrap_content"
 />
</LinearLayout>
</LinearLayout>

AndroidColor.java

package com.exercise.AndroidColor;

import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.LinearLayout;
import android.widget.Spinner;
import android.widget.Toast;

public class AndroidColor extends Activity {
 
 LinearLayout background;
 Spinner spinnerColor;
 
 private static final String[] color =
  { "BLACK",  
  "BLUE",
  "CYAN",
  "DKGRAY",  
  "GRAY",
  "GREEN",  
  "LTGRAY",  
  "MAGENTA",  
  "RED",
  "TRANSPARENT",  
  "WHITE",
  "YELLOW"};
  private ArrayAdapter<String> adapter;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        background = (LinearLayout)findViewById(R.id.background);
        
        spinnerColor = (Spinner)findViewById(R.id.colorspinner);
        adapter = new ArrayAdapter<String>(this, 
          android.R.layout.simple_spinner_item, color);
        adapter.setDropDownViewResource(
          android.R.layout.simple_spinner_dropdown_item);
        spinnerColor.setAdapter(adapter);
        spinnerColor.setSelection(0);
        
        spinnerColor.setOnItemSelectedListener(
          new Spinner.OnItemSelectedListener(){

   @Override
   public void onItemSelected(AdapterView<?> arg0, View arg1,
     int arg2, long arg3) {
    // TODO Auto-generated method stub
    setBackgroundColor(spinnerColor.getSelectedItem().toString());
   }

   @Override
   public void onNothingSelected(AdapterView<?> arg0) {
    // TODO Auto-generated method stub
    
   }});
    }
    
    
    private void setBackgroundColor(String strColor){
     Toast.makeText(this, strColor, Toast.LENGTH_LONG).show();
     if (strColor == "BLACK"){
      background.setBackgroundColor(Color.BLACK);
     }else if(strColor=="BLUE"){
      background.setBackgroundColor(Color.BLUE);
     }else if(strColor=="CYAN"){
      background.setBackgroundColor(Color.CYAN);
     }else if(strColor=="DKGRAY"){
      background.setBackgroundColor(Color.DKGRAY);
     }else if(strColor=="GRAY"){
      background.setBackgroundColor(Color.GRAY);
     }else if(strColor=="GREEN"){
      background.setBackgroundColor(Color.GREEN);
     }else if(strColor=="LTGRAY"){
      background.setBackgroundColor(Color.LTGRAY);
     }else if(strColor=="MAGENTA"){
      background.setBackgroundColor(Color.MAGENTA);
     }else if(strColor=="RED"){
      background.setBackgroundColor(Color.RED);
     }else if(strColor=="TRANSPARENT"){
      background.setBackgroundColor(Color.TRANSPARENT);
     }else if(strColor=="WHITE"){
      background.setBackgroundColor(Color.WHITE);
     }else if(strColor=="YELLOW"){
      background.setBackgroundColor(Color.YELLOW);
     }
    }
}

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