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Random number Java


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Generate random number Android Java example source code.

		Random rand = new Random();
		int i = rand.nextInt() % 256; // range -255  +255
		System.out.print(i + "

"); // -184 i = Math.abs(rand.nextInt() % 12); // range 0 +11 System.out.print(i); // 7



// Math.random() start with 0.  e.g. 0.35981234 
int nRan = (int) (Math.random()*10); // 0 - 10

// nextDouble(), nextFloat(), nextInt(), nextLong() returns 0 - 10
import java.util.Random;´

Random r = new Random();
int nRan = r.nextInt(); // 0 - 10
double dRan = r.nextDouble() * 10; // e.g. 7.496285271597397

nextDouble – return 0 - 1
nextFloat – same as double
nextInt –  -2147483648  +2147483647
nextLong –  -922337203685775808  +9223372036854775807
nextGaussian –  0.0 aberation 1.0.

397LW NO topic_id




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Další témata ....(Topics)


297

Shared Preferences file path Android | shared-preferences-file-path-android



/data/data/<package>/shared_prefs/<package>_preferences.xml

String TAG = "MyActivityName";
File f = new File("/data/data/"+this.getPackageName()
+"/shared_prefs/"+this.getPackageName()+"_preferences.xml");
if(f.exists())
	Log.d(TAG, "exist");
else
	Log.d(TAG, "not exist");

143

Rounded rect RectF Android example | rounded-rect-rectf-android-example


RectF, drawRoundRect(),

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) {
			Paint paint = new Paint();
			
			canvas.drawColor(Color.GREEN);
            
           Bitmap b = Bitmap.createBitmap(200, 200, Bitmap.Config.ALPHA_8);
           Canvas c = new Canvas(b);
           RectF rectF = new RectF();
           rectF.set(5,5,150,150);
           c.drawRoundRect(rectF, 10, 10, paint);
           
            paint.setColor(Color.RED);
           
           canvas.drawBitmap(b, 10,10, paint);
		}

	}
}


draw-rounded-rect-android
154

Create own custom Title Bar TitleBar with a Icon Android example | create-own-custom-title-titlebar-android-example


onCreate in MainActivity.java

    @Override
	protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
        setContentView(R.layout.main.xml);
        getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.custom_title);
}


You can add to titlebar different Views by xml file.
custom_title.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="//schemas.android.com/apk/res/android" android:id="@+id/screen"
    android:layout_width="fill_parent" android:layout_height="fill_parent"
    android:orientation="vertical">
    <TextView android:id="@+id/left_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:text="Some text" />

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_alignParentRight="true"
       
        android:src="@drawable/ic_launcher" />
    
</RelativeLayout>





custom-title-titlebar-android
335

IllegalArgumentException Unknown Uri content SearchableDict | illegalargumentexception-unknown-uri-content-searchabledict


If you change the package name, you have to add new package name in:

DictionaryProvider.java


public class DictionaryProvider extends ContentProvider {
    String TAG = "DictionaryProvider";

//    public static String AUTHORITY = "com.example.android.searchabledict.DictionaryProvider";
// change to your new package name
public static String AUTHORITY = "com.myweb.mysubdomen.searchabledict.DictionaryProvider";
    public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/dictionary");


// in AndroidManifest.xml
//change com.example.android to your package e.g. com.myweb.mysubdomen
<!-- Provides search suggestions for words and their definitions. -->
        <provider android:name="com.example.android.searchabledict.DictionaryProvider"
            android:configChanges="keyboard|keyboardHidden|orientation"
                  android:authorities="com.example.android.searchabledict.DictionaryProvider" />

        <!-- Points to searchable activity so the whole app can invoke search. -->
        <meta-data android:name="android.app.default_searchable"
            android:configChanges="keyboard|keyboardHidden|orientation"
                   android:value=".SearchableDictionary" />

// I change like this:
        <!-- Provides search suggestions for words and their definitions. -->
        <provider android:name=".DictionaryProvider"
            android:configChanges="keyboard|keyboardHidden|orientation"
                  android:authorities="cz.okhelp.android.searchabledict.DictionaryProvider" />

        <!-- Points to searchable activity so the whole app can invoke search. -->
        <meta-data android:name="android.app.default_searchable"
            android:configChanges="keyboard|keyboardHidden|orientation"
                   android:value=".SearchableDictionary" />


Do not forget change package name in all java class and xml/searchable.xml
In my project I changed like this:

<searchable xmlns:android="//schemas.android.com/apk/res/android"
        android:label="@string/search_label"
        android:hint="@string/search_hint"
        android:searchSettingsDescription="@string/settings_description"
        android:searchSuggestAuthority="cz.okhelp.android.searchabledict.DictionaryProvider"
        android:searchSuggestIntentAction="android.intent.action.VIEW"
        android:searchSuggestIntentData="content://cz.okhelp.android.searchabledict.DictionaryProvider/dictionary"
        android:searchSuggestSelection=" ?"
        android:searchSuggestThreshold="1"
        android:includeInGlobalSearch="true"
        >
 </searchable>


51

Get assets folder files to array of strings Android example | get-assets-folder-files-to-array-of-strings-android-example


Get assets folder files to array of strings.
Its show files in assets folder and sub folders:


    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        final AssetManager assetManager = getAssets();
        try {
			// for assets folder add empty string
                        String[] filelist = assetManager.list("");
                        // for assets/subFolderInAssets add only subfolder name
                        String[] filelistInSubfolder = assetManager.list("subFolderInAssets");
			if (filelist == null) {
			    // dir does not exist or is not a directory
			} else {
			    for (int i=0; i<filelist.length; i++) {
			        // Get filename of file or directory
			        String filename = filelist[i];
			    }
			}
                     
                        // if(filelistInSubfolder == null) ............  

		} catch (IOException e) {
			e.printStackTrace();
		}
     }




Editace: 2013-12-09 10:54:07
Počet článků v kategorii: 397
Url:random-number-java

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