Wordpress comments

Black and white bitmap image pictures, gray scale colormatrix Android example.

public class ApokusActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(new SampleView(this));
	}

	private static class SampleView extends View {

		// CONSTRUCTOR
		public SampleView(Context context) {
			super(context);
			setFocusable(true);

		}

		@Override
		protected void onDraw(Canvas canvas) {
			Paint paint = new Paint();

			canvas.drawColor(Color.YELLOW);


			// you need to insert a image flower_blue into res/drawable folder

			paint.setFilterBitmap(true);
			Bitmap bitmapOrg = BitmapFactory.decodeResource(getResources(),
					R.drawable.flower_blue);
			canvas.drawBitmap(bitmapOrg, 10, 10, paint);
			int width, height;

		    ColorMatrix cm = new ColorMatrix(
		    		new float[]{
		    		0.5f,0.5f,0.5f,0,0,
		            0.5f,0.5f,0.5f,0,0,
		            0.5f,0.5f,0.5f,0,0,
		            0,0,0,1,0,0,
		            0,0,0,0,1,0
		            });
		    cm.setSaturation(0);
		    ColorMatrixColorFilter f = new ColorMatrixColorFilter(cm);
		    paint.setColorFilter(f);
		    int h = bitmapOrg.getHeight();
			//canvas.drawBitmap(bitmapOrg, 10, 10, paint);
			canvas.drawBitmap(bitmapOrg, 10, 10 + h + 10, paint);

		}

	}
}

If you change android:versionCode="224" and android:versionName="2.2.4" in AndroidManifest.xml you have to change this in build.gradle file too.
Click on build.gradle in package explorer tree change your new version name and code:

  defaultConfig {
        applicationId "cz.okhelp.pocasiwidget"
        minSdkVersion 11
        targetSdkVersion 23
        versionCode 224
        versionName "2.2.4"
    }

How to change the image dynamically in ImageView and button setOnClickListener Android sample.


Main.java

ipackage cz.okhelp.my_game;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;


public class Main extends Activity {
private ImageView hImageViewSemafor;
private Button hButton;
	
	@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        hImageViewSemafor = (ImageView)findViewById(R.id.idImageViewSemafor);
        hButton = (Button) findViewById(R.id.idBtnChangeImage);
        hButton.setOnClickListener(mButtonChangeImageListener);
 
 
       
       
    }
	
    View.OnClickListener mButtonChangeImageListener = new OnClickListener() {
        public void onClick(View v) {
                // setImageResource will change image in ImageView
        	hImageViewSemafor.setImageResource(R.drawable.semafor_green);
            
        }
    };

}

main.xml
Put into res/drawable this pictures:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="//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"
    />
    
       <ImageView
            android:src="@drawable/semafor_red"
            android:id="@+id/idImageViewSemafor"
            android:background="#66FFFFFF"
            android:adjustViewBounds="true"
            android:maxWidth="47dip"
            android:maxHeight="91dip"
            android:padding="10dip"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />    
    
</LinearLayout>

Android development
Java float is 32 bit single precision type and used when fractional precision calculation is required.

Java float je 32 bitů veliké číslo sloužící především pro přesný výsledek za desetinnou tečkou například při dělení čísel. Pro větší přesnost použíijte 64 bitový typ Double.

		// declaration and assignment of value  type float
		float x = 18.41785f;
		//print formated  value
		System.out.printf("The value of x is %.3f%n", x); // 18.418
                
                // declaring more variables in single statement
                float f1 = 12.4F, f2 = 564.5F, f3 = 14.589F;

		// float range of value
		System.out.println(Float.MIN_VALUE); // 4E-45
		System.out.println(Float.MAX_VALUE); // 4028235E38

		// is NaN  Not-a-Number
		float f = (float) Math.sqrt(-15);
		boolean bNaN = Float.isNaN(f);
		System.out.print(bNaN); // true
		
                // check if a string is a valid number in Java example
                // convert string to float Java example
		String sF = "12.8";
		float fParse = Float.parseFloat(sF);

	       // convert strings to numbers
	      String sFl = "15.48";
	      float fFromString = (Float.valueOf(sFl)).floatValue();

// float to string in Java example code
Float fObj = new Float(68.5);
String str = fObj.toString();
// else 
Float fS = 11.6f;
String sFloat = fS.toString();

              // compare two float variables
	      Float fComp1 = 4.3f;
	      if(fComp1.equals(4.3f))
	  		System.out.print("true");

	    // compares the two specified float values in Java example
	    int i =	Float.compare(11.5f, 11.7f); // -1 first < second
	    // 0 first == second
	    // 1 first > second
	    System.out.print(i);

HorizontalScrollView ScrollView LinearLayout horizontal vertical Android xml basic example and image.

[caption id="attachment_889" align="alignleft" width="200" caption="horizontal scrollview horizontalscrollview android"][/caption]

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout android:id="@+id/LinearLayout01"
	android:layout_width="fill_parent" android:layout_height="fill_parent"
	xmlns:android="//schemas.android.com/apk/res/android">

	// horizontal and vertical Scrollview
	<ScrollView android:id="@+id/ScrollView01"
		android:layout_height="135px" android:layout_width="wrap_content"
		android:scrollbars="horizontal|vertical">

		// HorizontalScrollview
		<HorizontalScrollView android:id="@+id/HorizontalScrollView01"
			android:layout_height="fill_parent" android:layout_width="wrap_content">

			<LinearLayout android:id="@+id/LinearLayout02"
				android:layout_width="wrap_content" android:orientation="vertical"
				android:layout_height="fill_parent">
				<LinearLayout android:orientation="horizontal"
					android:layout_width="fill_parent" android:layout_height="fill_parent"
					android:layout_weight="1">
					<TextView android:text="red" android:gravity="center_horizontal"
						android:background="#aa0000" android:layout_width="200px"
						android:layout_height="fill_parent" android:layout_weight="1" />
					<TextView android:text="green" android:gravity="center_horizontal"
						android:background="#00aa00" android:layout_width="200px"
						android:layout_height="fill_parent" android:layout_weight="1" />
					<TextView android:text="blue" android:gravity="center_horizontal"
						android:background="#0000aa" android:layout_width="200px"
						android:layout_height="fill_parent" android:layout_weight="1" />
					<TextView android:text="yellow" android:gravity="center_horizontal"
						android:background="#aaaa00" android:layout_width="200px"
						android:layout_height="fill_parent" android:layout_weight="1" />
				</LinearLayout>

				<LinearLayout android:orientation="vertical"
					android:layout_width="fill_parent" android:layout_height="fill_parent"
					android:layout_weight="1">
					<TextView android:text="row one" android:textSize="15pt"
						android:layout_width="fill_parent" android:layout_height="wrap_content"
						android:layout_weight="1" />
					<TextView android:text="row two" android:textSize="15pt"
						android:layout_width="fill_parent" android:layout_height="wrap_content"
						android:layout_weight="1" />
					<TextView android:text="row three" android:textSize="15pt"
						android:layout_width="fill_parent" android:layout_height="wrap_content"
						android:layout_weight="1" />
					<TextView android:text="row four" android:textSize="15pt"
						android:layout_width="fill_parent" android:layout_height="wrap_content"
						android:layout_weight="1" />
				</LinearLayout>


			</LinearLayout>
		</HorizontalScrollView>
	</ScrollView>
</LinearLayout>

Other sample

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="//schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:id="@+id/layout"
    android:orientation="vertical" >

    <HorizontalScrollView
        android:id="@+id/horizontalScrollView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" >

        <LinearLayout
            android:id="@+id/linearLayout1"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:orientation="horizontal" >
        <TextView
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Hello world! First TextView" />

        <TextView
            android:id="@+id/textView1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Large Text"
            android:textAppearance="?android:attr/textAppearanceLarge" />

        <TextView
            android:id="@+id/textView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Medium Text"
            android:textAppearance="?android:attr/textAppearanceMedium" />

        </LinearLayout>



    </HorizontalScrollView>

</LinearLayout>