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Draw color line set stroke width Android basic example


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Canvas, drawLine(), setStrokeWidth(), Paint, setAntiAlias(boolean), onDraw()

public class MainActivity 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) {

			canvas.drawColor(Color.YELLOW);
			Paint p = new Paint();
			// smooths
			p.setAntiAlias(true);
			p.setColor(Color.RED);
			p.setStrokeWidth(4.5f);
			// opacity
			p.setAlpha(0x80); //
			// drawLine (float startX, float startY, float stopX, float stopY,
			// Paint paint)
			canvas.drawLine(0, 0, 40, 40, p);
			canvas.drawLine(40, 0, 0, 40, p);

		}

	}
}

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69

Timer task TimerTask run cancel Android example | timer-task-timertask-run-cancel-android-example


Update TextView from TimerTask, Handler, schedule, run, cancel TimerTask, Android example

public class TimerActivity extends Activity {
	TimerTask mTimerTask;
	final Handler handler = new Handler();
	Timer t = new Timer();	
TextView hTextView;
TableRow hTableRow;
Button hButton, hButtonStop;


private int nCounter = 0;
@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        hTextView = (TextView)findViewById(R.id.idTextView);
        hButton = (Button)findViewById(R.id.idButton);
        hButton.setOnClickListener(mButtonStartListener);
        hButtonStop = (Button)findViewById(R.id.idButtonStop);
        hButtonStop.setOnClickListener(mButtonStopListener);

         
        
    } // end onCreate

View.OnClickListener mButtonStartListener = new OnClickListener() {
	public void onClick(View v) {
		doTimerTask();
    }
};



	
	View.OnClickListener mButtonStopListener = new OnClickListener() {
    	public void onClick(View v) {
    		stopTask();
    		
    	}
    };
    
    
    public void doTimerTask(){

    	mTimerTask = new TimerTask() {
    	        public void run() {
    	                handler.post(new Runnable() {
    	                        public void run() {
    	                        	nCounter++;
                                        // update TextView
    	                        	hTextView.setText("Timer: " + nCounter);

    	                        	Log.d("TIMER", "TimerTask run");
    	                        }
    	               });
    	        }};

            // public void schedule (TimerTask task, long delay, long period) 
    	    t.schedule(mTimerTask, 500, 3000);  // 

    	 }

    	  public void stopTask(){

    	   if(mTimerTask!=null){
    	      hTextView.setText("Timer canceled: " + nCounter);

    	      Log.d("TIMER", "timer canceled");
    	      mTimerTask.cancel();
    	 }
    
    }    
}


161

Append text and ad text to TextView Android example | append-text-and-ad-text-to-textview-android-example



String s = "Some text for appending

"; TextView mTitle = (TextView) findViewById(R.id.title_text); mTitle.setText(R.string.app_name); // insert text from strings.xml mTitle.append(s); // append string like a variable value mTitle.append("My string will appended
"); // append string

You can insert this source code into onCreate in your activity file
17

double in Java example for Android development | double-in-java-example-for-android-development


Java double is 64 bit double precision type used when fractional
precision calculation is required.

Java double je datový typ (reálné číslo) o velikosti 64 bitů. Používá se například pro přesný výsledek po dělení za desetinnou tečkou. Pokud nepotřebuje tak veliké číslo použijte raději typ float, šetříte tím paměť mobilního telefonu.


		// declaration and assignment of value  type double
		double x = 18.41785;
		//print formated  value
		System.out.printf("The value of x is %.3f%n", x); // 18.418
                
                // declaring more variables in single statement
                double d1 = 12.4, d2 = 564.5, d3 = 14.589;

		// double range of value
		System.out.println(Double.MIN_VALUE); // 4.9E-324
		System.out.println(Double.MAX_VALUE); // 1.7976931348623157E308

		// is NaN  Not-a-Number
		double f = (double) Math.sqrt(-15);
		boolean bNaN = Double.isNaN(f);
		System.out.print(bNaN); // true
		
                // check if a string is a valid number in Java example
                // convert string to double Java example
		String sD = "12.8";
		double dParse = Double.parseDouble(sD);

	       // convert strings to numbers
	      String sDl = "15.48";
	      double dFromString = (Double.valueOf(sDl)).doubleValue();

// format double, float or long value to string
	DecimalFormat formatter = new DecimalFormat(".##");
	String s = formatter.format(-.5678);             // -0.57
// .###  -0.568
// .#### -0.5678
// .000000  -.567800

// -123.456
// .##  -123.46
// #.##  -123.46

// #E0  -.1E3
// ##E0  -1.2E2
//###E0  -123E0

// double to string in Java example code
Double dObj = new Double(68.5);
String str = dObj.toString();
// else 
Double dS = 11.6;
String sdouble = dS.toString();

// compare two double variables
	      Double dComp1 = 4.3;
	      if(dComp1.equals(4.3))
	  		System.out.print("true");

	// compares the two specified double values in Java example
	// int i =	compare(double d1, double d2);
	    int i =	Double.compare(11.5, 11.7); // -1 first < second
	    // 0 first == second
	    // 1 first > second
	    System.out.print(i);


3

Download file from URL | download-file-from-url


Download image file from URL to ImageView Java Android source example code.



Context context = thisClass.this;
Drawable image = ImageOperations(context,
"//www.okhelp.cz/images/android/ad_4.png"
,"image.jpg");
ImageView imgView;
imgView = (ImageView)findViewById(R.id.idImageView);
imgView.setImageDrawable(image);

	private Drawable ImageOperations(Context ctx, String url, String saveFilename) {
		try {
			InputStream is = (InputStream) this.fetch(url);
			Drawable d = Drawable.createFromStream(is, "src");
			return d;
		} catch (MalformedURLException e) {
			e.printStackTrace();
			return null;
		} catch (IOException e) {
			e.printStackTrace();
			return null;
		}
	}

	public Object fetch(String address) throws MalformedURLException,IOException {
		URL url = new URL(address);
		Object content = url.getContent();
		return content;
	}
341

Android widget SearchView in onCreateOptionsMenu is null | android-widget-searchview-in-oncreateoptionsmenu-is-null


If your class extends AppCompatActivity
public class SearchableActivity extends AppCompatActivity


Check if linked appropriate library for:
import android.support.v4.view.MenuItemCompat;

import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;

Check if you have to properly sett SearchView in menu xml for onCreateOptionsMenu menu_main.xml

<menu xmlns:android="//schemas.android.com/apk/res/android" xmlns:app="//schemas.android.com/apk/res-auto"
xmlns:tools="//schemas.android.com/tools"
tools:context=".SearchableActivity">
<item

  android:id="@+id/menu_search_my"

android:title="@string/menu_search"
android:icon="@drawable/ic_menu_search"
app:showAsAction="collapseActionView|ifRoom"
app:actionViewClass="android.support.v7.widget.SearchView"

/></menu>

Check your SearchableActivity onCreateOptionsMenu
   @TargetApi(Build.VERSION_CODES.HONEYCOMB) @SuppressLint("NewApi") @Override

public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {

android.support.v7.widget.SearchView searchView = (android.support.v7.widget.SearchView)
MenuItemCompat.getActionView(menu.findItem(R.id.menu_search_my));
SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);
if(null!=searchManager ) {
searchView.setSearchableInfo(searchManager.getSearchableInfo(getComponentName()));
}
searchView.setIconifiedByDefault(false);
}
return true;
}


Editace: 2013-12-09 13:11:39
Počet článků v kategorii: 397
Url:draw-line-android-basic-example

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