Force Screen On - dont use WakeLock - use getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON) - Android sample

Integer, Float, String, List passed as reference in JAVA example source code:

// List passed as reference JAVA
List<Integer>list = new ArrayList<Integer>();

public void fc (List<Integer>listRef){
listRef.add(7);
listRef.add(5);
}
fc(list); // 7, 5 


// String passed as reference JAVA
	public void mutate(AtomicReference<Object> ref) { ref.set("Goodbye"); }

		AtomicReference<Object> ref = new AtomicReference<Object>("Hello");
		mutate(ref);
		System.out.println(ref.get()); //Goodbye!
             String s = (String) ref.get();


// Integer passed as reference JAVA
	private static void mutate(AtomicReference<Object> ref) { ref.set(7); }

	//public static void main(String[] arg) {
		AtomicReference<Object> ref = new AtomicReference<Object>(5);
		mutate(ref);
		System.out.println(ref.get()); // 7
int n = (Integer) ref.get();


// Float passed as reference JAVA
	private static void mutate(AtomicReference<Object> ref) { ref.set(14.8f); }

	//public static void main(String[] arg) {
		AtomicReference<Object> ref = new AtomicReference<Object>(12.1f);
		mutate(ref);
		float f = (Float) ref.get();
		System.out.println(f); //14.8

Cross Button in EditText Android for deleting clearing text in EditText Example source code:
Example allow delete text in EditText by cross button, or do Button click performance.

main.xml type your package name and class
Put into drawable folder cross and ok image.

       <cz.okhelp.wiktionary.CustomEditText
            android:id="@+id/editTextZadejSlovo"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="2"
            android:ems="10"
            android:hint="TypeAndPressGreen"
            android:singleLine="true"
            android:lines="1"
            android:maxLines="1" 
            android:drawableLeft="@drawable/cross"
            android:drawableRight="@drawable/ok" />
<!--button is invisible 0 height 0 width for performance click on button in EditText-->
        <Button
            android:id="@+id/btnGO"
            android:layout_width="0sp"
            android:layout_height="0sp"
            android:layout_weight="0"
            android:text="GO" />

CustomEditText.java

package cz.okhelp.wiktionary; // your package name

import android.content.Context;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.widget.Button;
import android.widget.EditText;

public class CustomEditText extends EditText
{
  private Drawable dLeft,dRight;
  private Rect lBounds,rBounds;
  private static Button btnOk;

  public CustomEditText(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
  }
  public CustomEditText(Context context, AttributeSet attrs) {
    super(context, attrs);
  }
  public CustomEditText(Context context) {
    super(context);
  }

  @Override
  public void setCompoundDrawables(Drawable left, Drawable top,
      Drawable right, Drawable bottom)
  {
   if(left !=null) {
    	dLeft = left;
    }
   if(right !=null){
      dRight = right;
    } 
    
    super.setCompoundDrawables(left, top, right, bottom);
  }

	@Override
	public boolean onKeyUp(int keyCode, KeyEvent event) {
		if (keyCode == KeyEvent.KEYCODE_ENTER) {
    	btnOk.requestFocus();
    	btnOk.performClick();

		}
		return super.onKeyUp(keyCode, event);
	}
  
  @Override
  public boolean onTouchEvent(MotionEvent event)
  {
  	final int x = (int)event.getX();
  	final int y = (int)event.getY();

  	if(event.getAction() == MotionEvent.ACTION_UP && dLeft!=null) {
  		lBounds = dLeft.getBounds();
  		
  		int n1 = this.getLeft();
  		int n2 = this.getLeft()+lBounds.width();
  		int n3 = this.getPaddingTop();
  		int n4 = this.getHeight()-this.getPaddingBottom();
  		// leva strana
  		if(    x>=(this.getLeft()) 
  				&& x<=(this.getLeft()+lBounds.width())
  				&& y>=this.getPaddingTop() 
  				&& y<=(this.getHeight()-this.getPaddingBottom()))
  		{
  			this.setText("");
  			event.setAction(MotionEvent.ACTION_CANCEL);//use this to prevent the keyboard from coming up
  		}
  	}
  	if(event.getAction() == MotionEvent.ACTION_UP && dRight!=null)
    {
      rBounds = dRight.getBounds();
      int n1 = this.getRight()-rBounds.width();
      int n2 = this.getRight()-this.getPaddingRight();
      int n3 = this.getPaddingTop();
      int n4 = this.getHeight()-this.getPaddingBottom();
      // prava strana
      if(x>=(this.getRight()-rBounds.width()) && x<=(this.getRight()-this.getPaddingRight())
      		&& y>=this.getPaddingTop() && y<=(this.getHeight()-this.getPaddingBottom()))
      {
      	btnOk.requestFocus();
      	btnOk.performClick();
      	event.setAction(MotionEvent.ACTION_CANCEL);//use this to prevent the keyboard from coming up
      }
    }
    
    return super.onTouchEvent(event);
  }

  @Override
  protected void finalize() throws Throwable
  {
    dRight = null;
    rBounds = null;
    super.finalize();
  }
	public void setBtnOk(Button btnOk) {
		this.btnOk = btnOk;
	}
	public Button getBtnOk() {
		return btnOk;
	}
}  

YourActivity.java

//onCreate
        Button  mBtnGO = (Button)findViewById(R.id.btnGO);
        CustomEditText mEditZadani = (CustomEditText)this.findViewById(R.id.editTextZadejSlovo);
        mEditZadani.setBtnOk(mBtnGO);
        mBtnGO.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View v) {
             // do stuff for signInButtonClick
          }
        });

//android.okhelp.cz/wiktionary-aplikace-pro-android/

Bitmap size calculation:
bmpHeight * bmpWidth
For example:
Resolution of image 1024x860 = 880 640 pixels
If every pixel get 4 byte of memory:
880 640x4= 3 522 560 (3.5MB)

Get bitmap size without allocation of memory:

   	BitmapFactory.Options options = new BitmapFactory.Options();
        // If set to true, the decoder will return null (no bitmap), but the out... fields will still
        // be set, allowing the caller to query the bitmap without having to allocate the memory for its pixels. 
    	options.inJustDecodeBounds = true; 
    	BitmapFactory.decodeResource(getResources(), R.drawable.my_image, options);
    	int imageHeight = options.outHeight; // 1024
    	int imageWidth = options.outWidth; // 860
    	String imageType = options.outMimeType; // .jpg .png .gif
 

Get Memory size:
Make your bitmap not bigger as maxMemory size
final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);

    float density = getResources().getDisplayMetrics().density;

    Debug.MemoryInfo memoryInfo = new Debug.MemoryInfo();
    Debug.getMemoryInfo(memoryInfo);
    final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);
    final int freeMemory = (int) (Runtime.getRuntime().freeMemory() / 1024);
    String memMessage = String.format(
        "Free=%d kB,

MaxMem=%d kB,

 Memory: Pss=%.2f MB, Private=%.2f MB, Shared=%.2f MB",
        freeMemory,
        maxMemory,
        memoryInfo.getTotalPss() / 1024.0,
        memoryInfo.getTotalPrivateDirty() / 1024.0,
        memoryInfo.getTotalSharedDirty() / 1024.0);
    ((TextView)findViewById(R.id.textViewInfo)).setText(memMessage );

5. Fragments Tutorial Ipsum.java – Czech language


Dil 5. Ipsum.java
V 1. dílu jsme se něco dozvěděli od XML souborech a typu procesoru pro správný běh Android Studia a emulátoru různých typů zařizení s Androidem.
V 2. dílu jsme rozebrali MainActivity.java
V 3. dílu jsme se zabývali HeadlinesFragment.java
V 4. dílu jsme se podívali na ArticleFragment.java


V tomto dílu je na řadě Ipsum.java soubor.
Používáme příklad i zip porojekt z https://developer.android.com/training/basics/fragments/creating.html
Pozorně si jej nastudujte.

package com.example.android.fragments;
/** Ipsum je veřejná třída, která obsahuje
dvě pole řetězců - stringů.
Pole Headlines slouží jako uložiště pro názvy, které
budou načteny do ListView - seznamu v HeadlinesFragment.java
Pole Articles je v našem případě zásobárnou článků, které
budou načteny dle pozice položky ListView předané z HeadlinesFragment
zoětbě do MainActivity a
odtud do ArticleFragment.java, jako parametr metody
articleFrag.updateArticleView(position);
nebo jako argument Bundle
Bundle args = new Bundle();
    args.putInt(ArticleFragment.ARG_POSITION, position);
	
Stringy - ukládat do souboru java je ošemetné (problémy s kódováním, vyhledávání výrazů atd.) 
U většího množství článků pak nepřehledné.
Navíc, uživatel nemůže tento text editovat.
K ukládaní většího množství dat, k jejich vyhledávání 
a editaci je lépe používat databáze.	
*/
public class Ipsum {

    static String[] Headlines = {
        "Article One",
        "Article Two"
    };

    static String[] Articles = {
        "Article One



Excepteur pour-over occaecat squid biodiesel umami ... farm-to-table.",
        "Article Two



Vinyl williamsburg non ... synth, vegan carles odd future."
    };
}

Change table row background color if user click on row Android example code.
MainActivity.java

public class MainActivity extends Activity {
Boolean bColorYellow = true;
TextView hTextView;
TableRow hTableRow;
@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        hTextView = (TextView)findViewById(R.id.idTextView);
        hTableRow = (TableRow)findViewById(R.id.idTableRow1);


        
        
    } // end onCreate
  
    
    public void myTableRowClickHandler(View view) {
		switch (view.getId()) {
		case R.id.idTableRow1:{
			
			if(bColorYellow){
			hTableRow.setBackgroundColor(Color.GREEN);
			bColorYellow = false;
			}
			else{
			hTableRow.setBackgroundColor(Color.YELLOW);
			bColorYellow = true;
			}
		}
		break;
		}
  }
}

main.xml

<?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"
    >


<TableLayout android:layout_height="wrap_content" android:layout_width="fill_parent" android:id="@+id/tableLayout1">
    <TableRow android:id="@+id/idTableRow1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:background="#5655AA"
    android:onClick="@string/myTableRowClick"
    android:focusable="true">
<TextView  
	android:id="@+id/idTextView"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    />
    
    </TableRow>
</TableLayout>
    
    
</LinearLayout>

strings.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="hello">Hello World!</string>
    <string name="app_name">TableRow</string>
    <string name="myTableRowClick">myTableRowClickHandler</string>
</resources>