Draw Arc Android basic example
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drawArc(), Canvas, Paint, 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(5);
// opacity
//p.setAlpha(0x80); //
RectF rectF = new RectF(50, 20, 100, 80);
canvas.drawOval(rectF, p);
p.setColor(Color.BLACK);
canvas.drawArc (rectF, 90, 45, true, p);
}
}
}
397LW NO topic_id
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Další témata ....(Topics)
If some memory leak - problem try release of memory used of a big Bitmap what already not to need;
//developer.android.com/reference/android/graphics/Bitmap.html
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.
Bitmpap bmp; // not null
bmp.recycle();
bmp = null;
final boolean bmpIsRecycled = bmp.isRecycled()
// Returns true if this bitmap has been recycled.
//developer.android.com/reference/android/graphics/Bitmap.html
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.
Convert number int to string Android Java example source code.
int n = 0;
try {
n = Integer.parseInt("21"));
} catch(NumberFormatException e) {
System.out.println("Could not parse " + e);
}
// int to string
String s = String.valueOf(24);
ImputStream is = this.getResources().openRawResource(R.drawable.colors);
Bitmap mBitmap2 = BitmapFactory.decodeStream(is);
int w = mBitmap2.getWidth();
int h = mBitmap2.getHeight();
// int x , y have to be smaller as w , h
int _color = mBitmap2.getPixel(x, y);
// single line
/*
multi line
*/
"id cannot be resolved or is not a field” error
If you copy project to workspace or some code from other project you can get this error.
Try remove or add import your R file:
Check xml files.
Clean project by menu Project-Clean
Maybe you have to create new project end copy old source files to new project folders.
If you copy project to workspace or some code from other project you can get this error.
Try remove or add import your R file:
import com.example.app.R
Check xml files.
Clean project by menu Project-Clean
Maybe you have to create new project end copy old source files to new project folders.
Editace: 2013-12-09 13:11:05
Počet článků v kategorii: 397
Url:draw-arc-android-basic-example
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