[android-developers] Re: How to draw directly on screen without calling invalidate?
Thank you... On May 6, 11:21 am, Dianne Hackborn wrote: > You can look at the Touch Paint API demo as an example of one approach. > > On Tue, May 5, 2009 at 9:04 PM, Sukitha Udugamasooriya > wrote: > > > > > Thanks. Is there a way to save the Canvas object on re-draw that in > > the onDraw()?? > > -- > Dianne Hackborn > Android framework engineer > hack...@android.com > > Note: please don't send private questions to me, as I don't have time to > provide private support, and so won't reply to such e-mails. All such > questions should be posted on public forums, where I and others can see and > answer them. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: How to draw directly on screen without calling invalidate?
You can look at the Touch Paint API demo as an example of one approach. On Tue, May 5, 2009 at 9:04 PM, Sukitha Udugamasooriya wrote: > > Thanks. Is there a way to save the Canvas object on re-draw that in > the onDraw()?? > > > -- Dianne Hackborn Android framework engineer hack...@android.com Note: please don't send private questions to me, as I don't have time to provide private support, and so won't reply to such e-mails. All such questions should be posted on public forums, where I and others can see and answer them. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: How to draw directly on screen without calling invalidate?
Thats how I do it in my apps.
On May 5, 4:30 am, Mariano Kamp wrote:
> The onDraw() method starts from the scratch every time and so doesn't keep
> your drawings from the last invocation. Instead you would need to save all
> the previous points yourself and use them in onDraw().
>
> On Tue, May 5, 2009 at 9:25 AM, Sukitha Udugamasooriya
> wrote:
>
>
>
> > I want to draw strokes on my screen when the user touches. Next stroke
> > should be drawn from the end point
> > of the previous stroke.
> > This is my code. What happens here is just only the current stroke is
> > drawn. Previous strokes are vanished? What is wrong here? Please
> > help..
>
> > package src.test;
>
> > import android.app.Activity;
> > import android.content.Context;
> > import android.graphics.Bitmap;
> > import android.graphics.Canvas;
> > import android.graphics.Color;
> > import android.graphics.Paint;
> > import android.os.Bundle;
> > import android.view.MotionEvent;
> > import android.view.View;
> > import android.view.View.OnTouchListener;
>
> > public class ActDraw extends Activity implements OnTouchListener {
>
> > float x = 200;
> > float y = 200;
> > float x1 = 10;
> > float y1 = 45;
> > float prvx = 150;
> > float prvy = 150;
> > MyView m;
>
> > �...@override
> > public void onCreate(Bundle savedInstanceState) {
> > super.onCreate(savedInstanceState);
>
> > m = new MyView(this);
> > m.setOnTouchListener(this);
> > setContentView(m);
>
> > }
> > public boolean onTouch(View v, MotionEvent event) {
> > switch (event.getAction()) {
> > case MotionEvent.ACTION_DOWN: {
> > prvx = x;
> > prvy = y;
> > x = event.getX();
> > y = event.getY();
> > m.invalidate();
> > }
> > }
> > return false;
> > }
>
> > class MyView extends View {
> > Paint p = new Paint();
> > Bitmap bm;
> > int i;
>
> > public MyView(Context context) {
> > super(context);
>
> > }
>
> > �...@override
> > protected void onDraw(Canvas canvas) {
> > super.onDraw(canvas);
> > p.setColor(Color.GREEN);
> > p.setStrokeWidth(4);
> > canvas.drawLine(prvx, prvy, x, y, p);
> > }
> > }
>
>
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[android-developers] Re: How to draw directly on screen without calling invalidate?
Thanks. Is there a way to save the Canvas object on re-draw that in the onDraw()?? --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: How to draw directly on screen without calling invalidate?
The onDraw() method starts from the scratch every time and so doesn't keep
your drawings from the last invocation. Instead you would need to save all
the previous points yourself and use them in onDraw().
On Tue, May 5, 2009 at 9:25 AM, Sukitha Udugamasooriya wrote:
>
> I want to draw strokes on my screen when the user touches. Next stroke
> should be drawn from the end point
> of the previous stroke.
> This is my code. What happens here is just only the current stroke is
> drawn. Previous strokes are vanished? What is wrong here? Please
> help..
>
> package src.test;
>
> import android.app.Activity;
> import android.content.Context;
> import android.graphics.Bitmap;
> import android.graphics.Canvas;
> import android.graphics.Color;
> import android.graphics.Paint;
> import android.os.Bundle;
> import android.view.MotionEvent;
> import android.view.View;
> import android.view.View.OnTouchListener;
>
> public class ActDraw extends Activity implements OnTouchListener {
>
>float x = 200;
>float y = 200;
>float x1 = 10;
>float y1 = 45;
>float prvx = 150;
>float prvy = 150;
>MyView m;
>
>@Override
>public void onCreate(Bundle savedInstanceState) {
>super.onCreate(savedInstanceState);
>
>m = new MyView(this);
>m.setOnTouchListener(this);
>setContentView(m);
>
>}
>public boolean onTouch(View v, MotionEvent event) {
>switch (event.getAction()) {
>case MotionEvent.ACTION_DOWN: {
>prvx = x;
>prvy = y;
>x = event.getX();
>y = event.getY();
> m.invalidate();
>}
>}
>return false;
>}
>
>class MyView extends View {
>Paint p = new Paint();
>Bitmap bm;
>int i;
>
>public MyView(Context context) {
>super(context);
>
>}
>
>@Override
>protected void onDraw(Canvas canvas) {
>super.onDraw(canvas);
>p.setColor(Color.GREEN);
>p.setStrokeWidth(4);
>canvas.drawLine(prvx, prvy, x, y, p);
> }
>}
> >
>
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[android-developers] Re: How to draw directly on screen without calling invalidate?
I want to draw strokes on my screen when the user touches. Next stroke
should be drawn from the end point
of the previous stroke.
This is my code. What happens here is just only the current stroke is
drawn. Previous strokes are vanished? What is wrong here? Please
help..
package src.test;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
public class ActDraw extends Activity implements OnTouchListener {
float x = 200;
float y = 200;
float x1 = 10;
float y1 = 45;
float prvx = 150;
float prvy = 150;
MyView m;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
m = new MyView(this);
m.setOnTouchListener(this);
setContentView(m);
}
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN: {
prvx = x;
prvy = y;
x = event.getX();
y = event.getY();
m.invalidate();
}
}
return false;
}
class MyView extends View {
Paint p = new Paint();
Bitmap bm;
int i;
public MyView(Context context) {
super(context);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
p.setColor(Color.GREEN);
p.setStrokeWidth(4);
canvas.drawLine(prvx, prvy, x, y, p);
}
}
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[android-developers] Re: How to draw directly on screen without calling invalidate?
You can't :) On Sun, May 3, 2009 at 11:57 PM, Sukitha Udugamasooriya wrote: > > Hello, > > I'm also facing this problem. I'm relatively new to Android. > > Have you found the solution?? > > > > -- Romain Guy Android framework engineer romain...@android.com Note: please don't send private questions to me, as I don't have time to provide private support. All such questions should be posted on public forums, where I and others can see and answer them --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: How to draw directly on screen without calling invalidate?
Hello, I'm also facing this problem. I'm relatively new to Android. Have you found the solution?? --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: How to draw directly on screen without calling invalidate?
This is one of the things SurfaceView is for. For a regular view hierarchy you can't draw outside of updates, period. I don't know what you mean by clearing the screen with black. We don't do that. Within your window, if the window is translucent, we will clear the update region back to translucent before drawing the view hierarchy just so that the drawing will be correct. Unfortunately there isn't a way right now to say that a particular view is opaque so the hierarchy can skip drawing of its parents if the update region is only within that view. On Wed, Apr 1, 2009 at 12:01 PM, Tomei Ningen wrote: > I need to animate at a very fast rate (without using OpenGL). Now I am > calling View.invalidate() to paint to the screen, but this has the effect of > > A: clearing the screen with black > B: drawing the content view > C: drawing the child view (which occupies only part of the screen, and is > the only thing that's animating) > > How can I avoid doing A and B at every frame? I am looking for > > Canvas c = getWindow().getCanvas(); > c.drawSomething(); > c.doneDrawing(); > > If this is not possible, can I at least get rid of A? > > Thanks > > > > > > -- Dianne Hackborn Android framework engineer hack...@android.com Note: please don't send private questions to me, as I don't have time to provide private support. All such questions should be posted on public forums, where I and others can see and answer them. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
