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tag should specify a target API level Warning

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="?"


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

397LW NO topic_id

Další témata ....(Topics)


For cycle loop in Java example | for-cycle-loop-in-java-example

Cycle for in Java example

public class MainClass {
	public static void main(String[] arg) {
		String[] arrayOfString = { "Hello", "people", "hello", "world!" };

		for (int i = 0; // start position , first cycle i == 0
                      i < arrayOfString.length; // if i < 4 (length of array) do loop
                       i++ // incrementation after cycle
                       // i++ incrementation


Android studio list of useful shortcuts or like Eclipse | android-studio-list-of-useful-shortcuts

File -> Settings -> Keymap you can do select Eclipse keymap from drop down menu

Ctrl+Shift+A (Help | Find Action on the main menu) and start typing the name of the action. Choose the desired action from the suggestion list.

Ctrl+Click (on Windows) or Cmd+Click (on MacOS) a tab in the editor to navigate to any part of the file path. Select the necessary element in the drop-down, and the corresponding file path opens in an external browser (e.g., in the Explorer, if your OS is Windows).


Find - Rename

Ctrl+F find

Refactor | Rename: Shift+F6  ( +F6)

Find and replace: CTRL + R

Go to variable declaration: CTRL + B

Ctrl+Shift+I (View | Quick Definition)

Ctrl+Alt+F7  (Edit | Find | Show Usages in the main menu)

Ctrl+Shift+F find in project

Ctrl+Shift+F7 (Edit | Find | Highlight Usages in File) to quickly highlight usages of some variable in the current file.
Use F3 and Shift+F3 keys to navigate through highlighted usages.
Press Escape to remove highlighting.

Ctrl+W (extend selection) in the editor selects the word at the caret and then selects expanding areas of the source code. For example, it may select a method name, then the expression that calls this method, then the whole statement, then the containing block, etc. You can also select the word at the caret and the expanding areas of the source code by double-clicking the target areas in the editor.

To search through the classes, files, tool windows, actions, settings, and symbols of your project by double pressing the Shift key

Ctrl+P (View | Parameter Info) e.g. localURL = new URL(localUrlString); select localUrlString and press Ctrl + P

Show html documentation tooltips:  CTRL + Q



Comment uncomment single line: CTRL + /

Comment uncomment selected text: CTRL + SHIFT + /

Code completion (Ctrl+Space)

Alt key and mouse pointer dragging for column selection

If nothing is selected in the editor, and you press Ctrl+C, then the whole line at caret is copied to the clipboard.

Ctrl + Delete  delete word from caret to end.

Ctrl + Backspace delete word from caret to start.

Duplicate line: CTRL + D

To compare two directories,or  jar files, select one or both of them in the Project view and press Ctrl+D.

Editor Delete Line: CTRL + Y

Move line UP, DOWN. Select a code fragment and press Ctrl+Shift+Up or Ctrl+Shift+Down.

To open any class or file in the editor at the desired line, press Ctrl+Shift+N (Navigate | File), start typing the name, and choose the one from the suggestion list. Then type the colon (:) and a line number

Ctrl+Shift+Enter to complete a current statement such as if, do-while, try-catch, return (or a method call)

Alt+Enter to invoke a quick fix or intention action, press the right arrow key to reveal the list of additional options.

To quickly review your recent changes to the project: Alt+Shift+C

Code Completion, you can accept the currently highlighted selection in the popup list with the period character (.), comma (,), semicolon (;), space and other characters.

Quickly move between methods in the editor:  Alt+Up and Alt+Down

Ctrl+Shift+J shortcut joins two lines into one and removes unnecessary space to match your code style

Ctrl+Shift+V to choose and insert recent clipboard contents into the text

Inheritance hierarchy for a selected class: Ctrl+H

Right-clicking on a breakpoint marker  you can quickly enable/disable the breakpoint or adjust its properties.

Evaluate the value of any expression while debugging the program, select its text in the editor (you may press a Ctrl+W a few times to efficiently perform this operation) and press Alt+F8.

Quickly evaluate the value of any expression while debugging the program, hold Alt and click this expression to see its value and calculate it, call a method, etc.

You can use the Extract Variable refactoring even on incomplete statements. Just select the necessary block in the editor and press Ctrl+Alt+V.

To open any particular method or field in editor: Ctrl+Alt+Shift+N

Add unimplemented methods: CTRL + I

Override methods: CTRL + O

Format code: CTRL + ALT + L

Show project: ALT + 1

Show logcat: ALT + 6

Hide project - logcat: SHIFT + ESC

Build: CTRL + F9

Build and Run: CTRL + F10

Alt+Shift+F10  access the Run/Debug dropdown on the main toolbar

Collapse all: CTRL + SHIFT + NumPad +

Expand all: CTRL + SHIFT + NumPad -

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 = null;

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

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.

TTS text to speech Android example | tts-text-to-speech

Android development example source code

// import
import android.speech.tts.TextToSpeech;
import android.speech.tts.TextToSpeech.OnInitListener;
// you have to add implementation
public class Main extends Activity implements TextToSpeech.OnInitListener {
        private int _langTTSavailable = -1; // set up in onInit method
        // declaration
	private TextToSpeech mTts;

	public void onCreate(Bundle savedInstanceState) {
// assigned handle - initialisation
			mTts = new TextToSpeech(this,
			        (OnInitListener) this  // TextToSpeech.OnInitListener

   // Implements TextToSpeech.OnInitListener.
    public void onInit(int status) {
        if (status == TextToSpeech.SUCCESS) {
            // Set preferred language to US english.
             _langTTSavailable = mTts.setLanguage(Locale.US); // Locale.FRANCE etc.
            if (_langTTSavailable == TextToSpeech.LANG_MISSING_DATA ||
            	_langTTSavailable == TextToSpeech.LANG_NOT_SUPPORTED) {
             } else if ( _langTTSavailable >= 0) {
			 mTts.speak("Good morning",
            TextToSpeech.QUEUE_FLUSH,  // Drop all pending entries in the playback queue.
        } else {
            // Initialization failed.

    public void onDestroy() {
        // TTS shutdown!
        if (mTts != null) {



Get supported language:

private TextToSpeech mTts;
// public void onInit(int status){
int result;
String s;
result = mTts.setLanguage(	Locale.	CANADA	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	CANADA	 not supported<br>"	;}else{s+="	CANADA	 supported<br>";}
result = mTts.setLanguage(	Locale.	CANADA_FRENCH	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	CANADA_FRENCH	 not supported<br>"	;}else{s+="	CANADA_FRENCH	 supported<br>";}
result = mTts.setLanguage(	Locale.	CHINA	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	CHINA	 not supported<br>"	;}else{s+="	CHINA	 supported<br>";}
result = mTts.setLanguage(	Locale.	CHINESE	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	CHINESE	 not supported<br>"	;}else{s+="	CHINESE	 supported<br>";}
result = mTts.setLanguage(	Locale.	ENGLISH	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	ENGLISH	 not supported<br>"	;}else{s+="	ENGLISH	 supported<br>";}
result = mTts.setLanguage(	Locale.	FRANCE	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	FRANCE	 not supported<br>"	;}else{s+="	FRANCE	 supported<br>";}
result = mTts.setLanguage(	Locale.	FRENCH	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	FRENCH	 not supported<br>"	;}else{s+="	FRENCH	 supported<br>";}
result = mTts.setLanguage(	Locale.	GERMAN	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	GERMAN	 not supported<br>"	;}else{s+="	GERMAN	 supported<br>";}
result = mTts.setLanguage(	Locale.	GERMANY	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	GERMANY	 not supported<br>"	;}else{s+="	GERMANY	 supported<br>";}
result = mTts.setLanguage(	Locale.	ITALIAN	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	ITALIAN	 not supported<br>"	;}else{s+="	ITALIAN	 supported<br>";}
result = mTts.setLanguage(	Locale.	ITALY	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	ITALY	 not supported<br>"	;}else{s+="	ITALY	 supported<br>";}
result = mTts.setLanguage(	Locale.	JAPAN	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	JAPAN	 not supported<br>"	;}else{s+="	JAPAN	 supported<br>";}
result = mTts.setLanguage(	Locale.	JAPANESE	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	JAPANESE	 not supported<br>"	;}else{s+="	JAPANESE	 supported<br>";}
result = mTts.setLanguage(	Locale.	KOREA	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	KOREA	 not supported<br>"	;}else{s+="	KOREA	 supported<br>";}
result = mTts.setLanguage(	Locale.	KOREAN	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	KOREAN	 not supported<br>"	;}else{s+="	KOREAN	 supported<br>";}
result = mTts.setLanguage(	Locale.	PRC	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	PRC	 not supported<br>"	;}else{s+="	PRC	 supported<br>";}
result = mTts.setLanguage(	Locale.	ROOT	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	ROOT	 not supported<br>"	;}else{s+="	ROOT	 supported<br>";}
result = mTts.setLanguage(	Locale.	SIMPLIFIED_CHINESE	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	SIMPLIFIED_CHINESE	 not supported<br>"	;}else{s+="	SIMPLIFIED_CHINESE	 supported<br>";}
result = mTts.setLanguage(	Locale.	TAIWAN	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	TAIWAN	 not supported<br>"	;}else{s+="	TAIWAN	 supported<br>";}
result = mTts.setLanguage(	Locale.	TRADITIONAL_CHINESE	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	TRADITIONAL_CHINESE	 not supported<br>"	;}else{s+="	TRADITIONAL_CHINESE	 supported<br>";}
result = mTts.setLanguage(	Locale.	UK	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	UK	 not supported<br>"	;}else{s+="	UK	 supported<br>";}
result = mTts.setLanguage(	Locale.	US	);	if (result == TextToSpeech.LANG_MISSING_DATA ||result == TextToSpeech.LANG_NOT_SUPPORTED) {s +=	 "	US	 not supported<br>"	;}else{s+="	US	 supported<br>";}


Convert a Bitmap to Gray Scale Android example | convert-a-bitmap-to-gray-scale-android-example

Black and white bitmap image pictures, gray scale colormatrix Android example.

public class ApokusActivity extends Activity {

	protected void onCreate(Bundle savedInstanceState) {
		setContentView(new SampleView(this));

	private static class SampleView extends View {

		public SampleView(Context context) {


		protected void onDraw(Canvas canvas) {
			Paint paint = new Paint();


			// you need to insert a image flower_blue into res/drawable folder

			Bitmap bitmapOrg = BitmapFactory.decodeResource(getResources(),
			canvas.drawBitmap(bitmapOrg, 10, 10, paint);
			int width, height;

		    ColorMatrix cm = new ColorMatrix(
		    		new float[]{
		    ColorMatrixColorFilter f = new ColorMatrixColorFilter(cm);
		    int h = bitmapOrg.getHeight();
			//canvas.drawBitmap(bitmapOrg, 10, 10, paint);
			canvas.drawBitmap(bitmapOrg, 10, 10 + h + 10, paint);



gry scale bitmap android

Editace Jana Žákovská : 2014-02-15 20:27:27
Počet článků v kategorii: 397