Draw circle Android basic example
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Canvas, drawCircle(), Paint, onDraw(), setStrokeWidth(), setStyle()
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.CYAN);
Paint p = new Paint();
// smooths
p.setAntiAlias(true);
p.setColor(Color.RED);
p.setStyle(Paint.Style.STROKE);
p.setStrokeWidth(4.5f);
// opacity
//p.setAlpha(0x80); //
canvas.drawCircle(50, 50, 30, p);
}
}
}
396LW NO topic_id
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Další témata ....(Topics)
R.string.app_name to String example.
MyActivity.java
res/values/string.xml
MyActivity.java
Resources res = getResources();
String sText = res.getString(R.string.app_name);
res/values/string.xml
<resources>
<string name="app_name">My app name</string>
</resources>
TypeFace, setTypeface, font, font family, array of String, Button create dynamically
@Override
protected void onStart() {
LinearLayout.LayoutParams p = new LinearLayout.LayoutParams(
48,
55
);
Typeface typeFace = Typeface.MONOSPACE;
String [] ar = {"A","B","C","D","E","F","G","H","J","K"};
for (int i = 0; i < ar.length; i++) {
Button buttonView = new Button(this);
buttonView.setText(Html.fromHtml("<b>"+ar[i]+"</b>"));
buttonView.setTextColor(Color.BLUE);
buttonView.setTextSize(27.f);
buttonView.setTypeface(typeFace,Typeface.BOLD);
buttonView.setOnClickListener(mThisButtonListener);
if(i%2==0)
mLayoutButtons.addView(buttonView, p);
else
mLayoutButtonsNextRow.addView(buttonView, p);
_listOfButtons.add(buttonView);
}
super.onStart();
}
//////// xml file
<TextView
android:id="@+id/text01"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20dp"
android:fontFamily="Arial"
/>
int nf = Math.round(5.789f);
System.out.print(nf); // 6
float f = 28.611f;
int n3 = Math.round(f);
System.out.println(n3); // 29
double d = 1234.56;
long lon = Math.round(d);
System.out.println(lon); // 1235
int diff = 90 - 40;
// float fDeleni = diff / 10; // error code
float fDeleni = (float)diff / 10.f; // ok
int nRound = Math.round(fDeleni);
// Caution:
int n2 = (int) 8.999f;
System.out.println(n2); // 8
package cz.okhelp.surfview;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.View.OnTouchListener;
public class MainActivity extends Activity implements OnTouchListener {
OurView v;
Bitmap ball, blob;
float x, y;
Sprite sprite;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// setContentView(R.layout.activity_our_view);
v = new OurView(this);
v.setOnTouchListener(this);
ball = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
x = y = 0;
setContentView(v);
}
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
v.pause();
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
v.resume();
}
public class OurView extends SurfaceView implements Runnable {
Thread t = null;
SurfaceHolder holder;
boolean isItOK = false;
public OurView(Context context) {
super(context);
// TODO Auto-generated constructor stub
holder = getHolder();
}
public void run() {
// TODO Auto-generated method stub
while (isItOK == true) {
// perform canvas drawing
if (!holder.getSurface().isValid()) {
continue;
}
// sprite = new Sprite(OurView.this,blob);
Canvas c = holder.lockCanvas();
c.drawARGB(255, 100, 100, 10);
c.drawBitmap(ball, x, y, null);
// onDraw(c);
holder.unlockCanvasAndPost(c);
}
}
protected void onDraw(Canvas canvas) {
// sprite.onDraw(canvas);
}
public void pause() {
isItOK = false;
while (true) {
try {
t.join();
} catch (InterruptedException e) {
// TODO: handle exception
e.printStackTrace();
}
break;
}// end while
}
public void resume() {
isItOK = true;
t = new Thread(this);
t.start();
}
}
@Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
try {
Thread.sleep(50);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
x = event.getX();
y = event.getY();
break;
case MotionEvent.ACTION_UP:
x = event.getX();
y = event.getY();
break;
case MotionEvent.ACTION_MOVE:
x = event.getX();
y = event.getY();
break;
}// end switch
return true;
}
}
Physical pixel (px)
Density independent pixel (dp)
Dots per inch (dpi) .. physical pixels per inch
px = dp * (dpi / 160)
Density independent pixel (dp)
Dots per inch (dpi) .. physical pixels per inch
px = dp * (dpi / 160)
public static int dpToPx(int dp)
{
return (int) (dp * Resources.getSystem().getDisplayMetrics().density);
}
public static int pxToDp(int px)
{
return (int) (px / Resources.getSystem().getDisplayMetrics().density);
}
Editace: 2013-12-09 13:11:26
Počet článků v kategorii: 396
Url:draw-circle-android-basic-example
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