Random number Java
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.
396LW NO topic_id
AD
Další témata ....(Topics)
putString(), putBoolean(), putInt() etc.¨
How we can start an activity programmatically.
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));
Try this code:
final String ERROR = "my error message....";
private class DownloadWebPageTask extends AsyncTask<String, Void, String> {
// some code and method ..... see AsyncTask
@Override
protected String doInBackground(String... urls) {
URL urlL = null;
try {
urlL = new URL(url);//"//chmi.cz..../"
HttpURLConnection urlConnection = null;
try {
urlConnection = (HttpURLConnection) urlL.openConnection();
InputStream in = new BufferedInputStream(urlConnection.getInputStream());
response = readStream(in);
return response;
} catch (IOException e) {
//throw new RuntimeException(e);
} finally {
if(urlConnection != null)
urlConnection.disconnect();
return ERROR;
}
} catch (MalformedURLException e) {
e.printStackTrace();
return ERROR;
}
}
return response;
}
private String readStream(InputStream is) {
try {
ByteArrayOutputStream bo = new ByteArrayOutputStream();
int i = is.read();
while(i != -1) {
bo.write(i);
i = is.read();
}
return bo.toString();
} catch (IOException e) {
return "";
}
}
/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");
Change the title associated with this activity. If this is a top-level activity, the title for its window will change. If it is an embedded activity, the parent can do whatever it wants with it.
String sTitle = "My new title";
setTitle(sTitle);
Rotate a bitmap Android source code.
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.YELLOW);
// Bitmap b = Bitmap.createBitmap(200, 200, Bitmap.Config.ARGB_8888);
// you need to insert a image flower_blue into res/drawable folder
Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.flower_blue);
Matrix mat = new Matrix();
mat.postRotate(90);
Bitmap bmpRotate = Bitmap.createBitmap(bmp, 0, 0,
bmp.getWidth(), bmp.getHeight(),
mat, true);
int h = bmp.getHeight();
canvas.drawBitmap(bmp, 10,10, paint);
canvas.drawBitmap(bmpRotate, 10,10 + h + 10, paint);
}
}
}
Editace: 2013-12-09 10:54:07
Počet článků v kategorii: 396
Url:random-number-java