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Convert a Bitmap to Gray Scale Android example


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

397LW NO topic_id



Další témata ....(Topics)


332

Android Studio reduce memory usage of PC | android-studio-reduce-memory-usage


File->Settings->Plugins and disable some plugins:

  • Google Cloud Testing

  • Google Cloud Tools Core

  • Google Cloud Tools for Android Studio

  • CVS Integration

  • Git Integration

  • GitHub

  • hg4idea

  • Subversion Integration


Use Emulator AVD with small memmory usage. For example: Virtual tablet with hight resolution have big memmory usage. Virtual phone with 240x320 resolution have small memmory usage.

Use instaed of Emulator, real device connected by USB (smarphone Samsung Galaxy or other recommended by Google whit debugable mode).

If you notice that Android Studio works slowly, consider the possibility to reduce the number of folders under antivirus protection.
Each antivirus check in your project consumes resources. You can significantly improve the performance, if you exclude certain folders from the antivirus protection.
236

tag should specify a target API level Warning | uses-sdk-tag-should-specify-target-api


Warning in AndroidManifest.xml:
tag should specify a target API level (the highest verified version; when running on
later versions, compatibility behaviors may be enabled) with android:targetSdkVersion="?"

Solution:

    <uses-sdk android:minSdkVersion="4"
         android:targetSdkVersion="16" />
101

Start an new Activity Intent with a parameter Android example | start-an-activity-with-a-parameter-android-example


putString(), putBoolean(), putInt() etc.¨
How we can start an activity programmatically.

// MainActivity.java
//  myButton.setOnClickListener
Intent binary = new Intent(getApplicationContext(),Calculate.class);
	Bundle b = new Bundle();
	b.putString("prvni_label", "Decimal");
	b.putString("druhy_label", "Binary");
	b.putString("mode", "binary_to_decimal");
        binary.putExtras(b);
	startActivityForResult(binary, 0);
						
// in Calculate.java onCreate

   TextView mTextView1 = (TextView)findViewById(R.id.textView1);
   TextView mTextView2 = (TextView)findViewById(R.id.textView2);    
     Bundle _bundle = getIntent().getExtras();
		mTextView1.setText(_bundle.getString("prvni_label"));
		mTextView2.setText(_bundle.getString("druhy_label"));




//.................. HOW OPEN START NEW ACTIVITY WITHOUT A PARAMETER .........................

startActivity(new Intent(ThisActivity.this, NewActivity.class));
353

Fragment FragmentBasic.zip null pointer TextView article | fragment-fragmentbasic-zip-null-pointer-textview-article


Example have error code:
//developer.android.com/training/basics/fragments/creating.html

Try to change ArticleFragment.java

/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      //www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.example.android.fragments;

import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class ArticleFragment extends Fragment {
    final static String ARG_POSITION = "position";
    int mCurrentPosition = -1;
    TextView articleText;
    @Override
//    public View onCreateView(LayoutInflater inflater, ViewGroup container,
//        Bundle savedInstanceState) {
//
//        // If activity recreated (such as from screen rotate), restore
//        // the previous article selection set by onSaveInstanceState().
//        // This is primarily necessary when in the two-pane layout.
//        if (savedInstanceState != null) {
//            mCurrentPosition = savedInstanceState.getInt(ARG_POSITION);
//        }
//
//        // Inflate the layout for this fragment
//        return inflater.inflate(R.layout.article_view, container, false);
//    }
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        // If activity recreated (such as from screen rotate), restore
        // the previous article selection set by onSaveInstanceState().
        // This is primarily necessary when in the two-pane layout.
        if (savedInstanceState != null) {
            mCurrentPosition = savedInstanceState.getInt(ARG_POSITION);
        }

        // Inflate the layout for this fragment
        View rootView = inflater.inflate(R.layout.article_view, container, false);
        articleText = (TextView) rootView.findViewById(R.id.article);
        return rootView;
    }
    @Override
    public void onStart() {
        super.onStart();

        // During startup, check if there are arguments passed to the fragment.
        // onStart is a good place to do this because the layout has already been
        // applied to the fragment at this point so we can safely call the method
        // below that sets the article text.
        Bundle args = getArguments();
        if (args != null) {
            // Set article based on argument passed in
            updateArticleView(args.getInt(ARG_POSITION));
        } else if (mCurrentPosition != -1) {
            // Set article based on saved instance state defined during onCreateView
            updateArticleView(mCurrentPosition);
        }
    }

    public void updateArticleView(int position) {
        //TextView article = (TextView) getActivity().findViewById(R.id.article); //Error: article=null.
        if (articleText != null)
            articleText.setText(Ipsum.Articles[position]);
        mCurrentPosition = position;
    }
/* ERROR   public void updateArticleView(int position) {
        TextView article = (TextView) getActivity().findViewById(R.id.article);
        article.setText(Ipsum.Articles[position]);
        mCurrentPosition = position;
    }*/

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);

        // Save the current article selection in case we need to recreate the fragment
        outState.putInt(ARG_POSITION, mCurrentPosition);
    }
}
77

break statement in Java Android example | break-statement-in-java-android-example


break statement in Java Android basic example

MainClass.java

public class MainClass {
	public static void main(String[] arg) {
		String[] arrayOfString = {"nothing", "Hello", "people"
				, "bye-bye", "hello", "world!", "end" };
		
		for (int i = 0; i < arrayOfString.length; i++) {
				System.out.println(arrayOfString[i]);
				if(i > 2) 
					break; // end of loop
		}
	}
}
/*
nothing
Hello
people
bye-bye
*/


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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