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Convert a Bitmap to Gray Scale Android example


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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);

		}

	}
}




gry scale bitmap android

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Další témata ....(Topics)


302

Layout not found on Android 2.1 | layout-not-found-on-android-2-1


If I create own folder layout-w320dp with Eclipse Android 4.4
layout was correctly loaded.
If I trying this application on tablet with Android 2.1 application crashed.


layout-not-loaded-android-2-1
315

Importing google-play-service library project to workspace issue | importing-google-play-service-library-project-to-workspace-issue


Try two way in Eclipse IDE:

1.) Import the library project into your Eclipse workspace.
Click File > Import,
select Android > Existing Android Code into Workspace, and browse to the copy of the library project to import it.
If project not visible with checkbox try next step as see below.

2.) Click
File > New > Other
select Android > Existing Android Code into Workspace, and browse to the copy of the library project to import it.
267

Eclipse revert old version Android Development Tools | eclipse-revert-old-version-android-development-tools


If you have trouble with compilation of new project after you make a update of android development tools you can go back to old version of the tools.




    • Open Help > About Eclipse... use the menu > About...

    • Click the "Installation Details" button.

    • Select the "Installation History" tab.

    • Select one of the previous configurations.

    • Click the "Revert" button at the bottom.





eclipse-revert-android-development-tools-1

eclipse-revert-android-development-tools-2


189

Invalid proguard configuration file path Android Eclipse Error | invalid-proguard-configuration-file-path-android-eclipse-error


Invalid proguard configuration file path
C:\documents\my_android_projects\my_project\proguard.cfg does not exist or is not a regular file

Solution:
Check if exist file proguard.cfg in your project on the path C:\docum.........
If not exist, copy a file proguard.cfg from other project or create file proguard.cfg and insert
this source code to file and save this file.



-optimizationpasses 5
-dontusemixedcaseclassnames
-dontskipnonpubliclibraryclasses
-dontpreverify
-verbose
-optimizations !code/simplification/arithmetic,!field/*,!class/merging/*

-keep public class * extends android.app.Activity
-keep public class * extends android.app.Application
-keep public class * extends android.app.Service
-keep public class * extends android.content.BroadcastReceiver
-keep public class * extends android.content.ContentProvider
-keep public class * extends android.app.backup.BackupAgentHelper
-keep public class * extends android.preference.Preference
-keep public class com.android.vending.licensing.ILicensingService

-keepclasseswithmembernames class * {
    native <methods>;
}

-keepclasseswithmembers class * {
    public <init>(android.content.Context, android.util.AttributeSet);
}

-keepclasseswithmembers class * {
    public <init>(android.content.Context, android.util.AttributeSet, int);
}

-keepclassmembers class * extends android.app.Activity {
   public void *(android.view.View);
}

-keepclassmembers enum * {
    public static **[] values();
    public static ** valueOf(java.lang.String);
}

-keep class * implements android.os.Parcelable {
  public static final android.os.Parcelable$Creator *;
}



From more details see:
//developer.android.com/guide/developing/tools/proguard.html
258

Delete Bitmap Android Example | delete-bitmap-android-example


If some memory leak - problem try release of memory used of a big Bitmap what already not to need;
Bitmpap bmp; // not null
bmp.recycle();
bmp = null;

final boolean bmpIsRecycled = bmp.isRecycled()
// Returns true if this bitmap has been recycled.


//developer.android.com/reference/android/graphics/Bitmap.html
Free the native object associated with this bitmap, and clear the reference to the pixel data. This will not free the pixel data synchronously; it simply allows it to be garbage collected if there are no other references. The bitmap is marked as "dead”, meaning it will throw an exception if getPixels() or setPixels() is called, and will draw nothing. This operation cannot be reversed, so it should only be called if you are sure there are no further uses for the bitmap. This is an advanced call, and normally need not be called, since the normal GC process will free up this memory when there are no more references to this bitmap.


Editace: 2013-12-09 13:09:13
Počet článků v kategorii: 397
Url:convert-a-bitmap-to-gray-scale-android-example

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