I am new to Android.My application requires to redraw a canvas circle over and over again. However, the speed of redraw is less than what I want. How may I increase the same.
My code is as follows:
--> ImagePracActivity.java
package com.pkg.ImagPrac;
import android.app.Activity;
import android.os.Bundle;
import android.view.Window;
import android.view.WindowManager;
public class ImagePracActivity extends Activity {
//DrawView drawView;
movement mv;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Set full screen view
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
requestWindowFeature(Window.FEATURE_NO_TITLE);
mv=new movement(getApplicationContext());
setContentView(mv);
mv.requestFocus();
}
}
--> movement.java
package com.pkg.ImagPrac;
import android.content.Context;
import android.content.Intent;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.Log;
import android.view.Display;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.WindowManager;
public class movement extends View implements OnTouchListener{
Display display;
float x=0,y=0;
Paint paint=new Paint();
private boolean flag;
public movement(Context context) {
super(context);
setFocusable(true);
setFocusableInTouchMode(true);
this.setOnTouchListener(this);
paint.setColor(Color.BLUE);
paint.setAntiAlias(true);
display = ((WindowManager)
context.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
x = 0;
y = display.getHeight();
}
#Override
protected void onDraw(Canvas canvas) {
if(x<(display.getWidth()/2))
{
canvas.drawCircle(x++, y--, 5, paint);
}
else if(x<(display.getWidth()))
{
canvas.drawCircle(x++, y++, 5, paint);
}
this.invalidate();
}
public boolean onTouch(View arg0, MotionEvent arg1) {
// TODO Auto-generated method stub
return false;
}
}
A would advice you to use SurfaceView class instead of View, because SurfaceView faster and allows you to have all drawing logic in separate thread. Read more about SurfaceView : http://developer.android.com/guide/topics/graphics/2d-graphics.html
try this
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(Color.BLUE);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(5);
Related
Desired Outcome
I want to draw a red circle at the position the screen is touched then remove it when the touch is released.
Current Outcome
Whenever I touch the screen the red circle appears in the touched location, however when I release the touch the circle stays on the screen.
Extra Help
I am pretty new to coding for android and if a quick gloss over my code shows that I'm using anything unnecessary I would love to be told so I can improve.
My Code
package com.mr.mwood.thumbinput;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class MainActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(new SampleView(this));
}
class SampleView extends SurfaceView {
private final SurfaceHolder surfaceHolder;
private final Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
// CONSTRUCTOR
public SampleView(Context context) {
super(context);
surfaceHolder = getHolder();
paint.setColor(Color.RED);
paint.setStyle(Style.FILL);
}
#Override
public boolean onTouchEvent(MotionEvent event) {
Canvas canvas = surfaceHolder.lockCanvas();
switch (event.getActionMasked()) {
case (MotionEvent.ACTION_DOWN):
canvas.drawColor(Color.BLACK);
canvas.drawCircle(event.getX(), event.getY(), 50, paint);
break;
case (MotionEvent.ACTION_UP):
canvas.drawColor(Color.BLACK);
break;
}
surfaceHolder.unlockCanvasAndPost(canvas);
return false;
}
}
}
I have an imageView and I draw the diagram in imageView according to the coordinate array. Every diagram has an onclick event.
Activity.java
package com.example.floorexhibitiontest;
import com.floor.DrawView;
import android.app.Activity;
import android.os.Bundle;
import android.widget.LinearLayout;
public class HallActivity extends Activity {#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.hall);
}
float[][][] points = new float[][][] {
{
{213,264},
{247,232},
{345,338},
{310,371}
},
{
{171,305},
{205,272},
{302,373},
{267,406}
},
{
{571,320},
{606,320},
{606,428},
{571,428}
}
};
LinearLayout layout = (LinearLayout)findViewById(R.id.root);
final DrawView draw = new DrawView(this,points);
layout.addView(draw);
}
DrawView.java
package com.floor;
import com.example.floorexhibitiontest.R;
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Path;
import android.graphics.Paint.Style;
import android.graphics.Shader.TileMode;
import android.graphics.Shader;
import android.util.DisplayMetrics;
import android.view.View;
public class DrawView extends View{
private float[][][] points = null;
DisplayMetrics metric = new DisplayMetrics();
public DrawView(Context context,float[][][] p) {
super(context);
metric = context.getApplicationContext().getResources().getDisplayMetrics();
points = p;
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
float density=metric.density;
for(int i = 0; i < points.length; i++){
Paint p = new Paint();
p.setAntiAlias(true);
p.setColor(Color.BLUE);
Path path=new Path();
path.moveTo(points[i][0][0] / density, points[i][0][1] / density);
path.lineTo(points[i][1][0] / density, points[i][1][1] / density);
path.lineTo(points[i][2][0] / density, points[i][2][1] / density);
path.lineTo(points[i][3][0] / density, points[i][3][1] / density);
path.close();
p.setStyle(Style.STROKE);
canvas.drawPath(path, p);
}
}
}
At present effect：
How to let each rectangular drawed produce their own onclick event?
There is an ImageView in Layout file. My purpose is to put the graphics paint on the ImageView. But the result is ImageView can display. The painted graphics can not display. If I hide
ImageView, the image can display.
Ask everyone’s help. Thanks in advice.
Try smth like this:
public boolean onTouch(View v, MotionEvent event) {
if((event.getX(0)>=x_coord) &&
(event.getY(0)>=y_coord) &&
( event.getX(0)<=x_coord + your_rectangle_width) &&
(event.getY(0)<=y_coord + your_rectangle_heigth))
{
//rectangle selected
}
return true;
}
Or use in onTouch() your actual coordinates from points[] array
I am trying to draw an oval to the screen but all I am getting is a blank white canvas. Not only am I unsure whether I am drawing the oval correctly, but also am getting nothing to the screen. Does anyone know why this is happening, I think the problem is that it isnt getting to the drawing section of the thread...
package hidden;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.PorterDuff;
import android.graphics.RectF;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.shapes.OvalShape;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.view.View.OnTouchListener;
public class Surface extends Activity implements OnTouchListener
{
SurfaceView v;
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_main);
setRequestedOrientation(1);
v = new SView(this);
v.setOnTouchListener(this);
v.setZOrderOnTop(true);
setContentView(v);
}
public class SView extends SurfaceView implements Runnable
{
Thread t1 = null;
SurfaceHolder holder;
boolean isItOk = false;
public SView(Context context)
{
super(context);
holder = getHolder();
holder.setFormat(PixelFormat.TRANSPARENT);
}
public void run()
{
while(isItOk)
{
if(!holder.getSurface().isValid())
{
continue;
}
Canvas c = holder.lockCanvas();
Paint p = new Paint();
p.setColor(Color.BLUE);
//OvalShape oval = new OvalShape();
//oval.draw(c, p);
Paint paint = new Paint();
paint.setColor(Color.GREEN);
paint.setStyle(Paint.Style.STROKE);
float leftx = 20;
float topy = 20;
float rightx = 50;
float bottomy = 100;
RectF ovalBounds = new RectF(leftx, topy, rightx, bottomy);
c.drawOval(ovalBounds, paint);
holder.unlockCanvasAndPost(c);
}
}
public void pause()
{
isItOk = false;
while(true)
{
try
{
t1.join();
}
catch(InterruptedException e)
{
e.printStackTrace();
}
break;
}
t1 = null;
}
public void resume()
{
isItOk = true;
t1 = new Thread(this);
t1.start();
}
}
public boolean onTouch(View arg0, MotionEvent arg1)
{
return false;
}
}
I want to rotate circle continuously in canvas on android. i am drawing circle using canvas and i am rotate circle continuously.it is possible,if possible how do it
with code or example can help me with greatly appreciated!
Here's my code for draw circle on canvas:
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.view.View;
public class AnimationActivity extends Activity {
/** Called when the activity is first created. */
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(new SampleView(this));
}
public class SampleView extends View
{
public SampleView(Context context)
{
super(context);
// TODO Auto-generated constructor stub
}
#Override
protected void onDraw(Canvas canvas)
{
Paint mPaint = new Paint();
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeWidth(10);
mPaint.setColor(Color.RED);
canvas.drawCircle(75, 75, 75, mPaint);
}
}
}
Thanks in Advance!
You can use Animation to rotate the circle you've drawn (using Canvas). The code below works. I've modified your code and added necessary changes.
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.view.View;
public class AnimationActivity extends Activity {
public class SampleView extends View {
Paint mPaint = new Paint();
private Animation anim;
public SampleView(Context context) {
super(context);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeWidth(10);
mPaint.setColor(Color.RED);
}
private void createAnimation(Canvas canvas) {
anim = new RotateAnimation(0, 360, getWidth()/2, getHeight()/2);
anim.setRepeatMode(Animation.RESTART);
anim.setRepeatCount(Animation.INFINITE);
anim.setDuration(10000L);
startAnimation(anim);
}
protected void onDraw(Canvas canvas) {
int cx = getWidth()/2; // x-coordinate of center of the screen
int cy = getHeight()/2; // y-coordinate of the center of the screen
// Starts the animation to rotate the circle.
if (anim == null)
createAnimation(canvas)
canvas.drawCircle(cx, cy, 150, mPaint); // drawing the circle.
}
}
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(new SampleView(this));
}
}
Enjoy!
canvas.rotate(-rotate_angle, rotate_center_x, rotate_center_y);
paint.setStyle(Paint.Style.FILL);
paint.setColor(Color.RED);
RectF oval3 = new RectF(rotate_center_x-150, rotate_center_y-50, rotate_center_x+150, rotate_center_y+50);
canvas.drawOval(oval3, paint);
//resume original angle
canvas.rotate(rotate_angle, rotate_center_x, rotate_center_y);
For More Information, click here.. :)
Hi All
I tried to use SurfaceView, but the view appeared black and nothing painted
Here My code
package com.samples;
import android.app.Activity;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.BlurMaskFilter;
import android.graphics.BlurMaskFilter.Blur;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PorterDuff;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.RectF;
import android.graphics.Region;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceHolder.Callback;
import android.view.SurfaceView;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.ImageView;
public class Galary extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(new GalaryView(this));
}
private static class GalaryView extends SurfaceView implements Callback {
private SurfaceHolder surfaceHolder;
public GalaryView(Context context) {
super(context);
surfaceHolder = getHolder();
surfaceHolder.addCallback(this);
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
Effects effects= new Effects(surfaceHolder, this);
effects.start();
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
}
}
and the second file
package com.samples;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.graphics.Region;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class Effects extends Thread {
private SurfaceView surfaceView;
private SurfaceHolder surfaceHolder;
private Bitmap bitmap1;
private Path mPath;
private Bitmap bitmap2;
private Paint paint;
public Effects(SurfaceHolder surfaceHolder, SurfaceView surfaceView) {
this.surfaceView = surfaceView;
this.surfaceHolder = surfaceHolder;
this.mPath = new Path();
bitmap1 = BitmapFactory.decodeResource(surfaceView.getContext()
.getResources(), R.drawable.qina1);
bitmap2 = BitmapFactory.decodeResource(surfaceView.getContext()
.getResources(), R.drawable.qina2);
paint= new Paint();
}
#Override
public void run() {
Canvas canvas = surfaceHolder.lockCanvas();
canvas.drawColor(Color.WHITE);
for (int i = 1; i < 100; i++) {
canvas.drawBitmap(bitmap1, 0, 0, null);
canvas.save();
canvas.translate(0, 0);
mPath.reset();
canvas.clipPath(mPath);
int ovalWidth = (int) (surfaceView.getWidth() * (i / 100.0));
int ovalHeight = (int) (surfaceView.getHeight() * (i / 100.0));
int ovalX = (surfaceView.getWidth() - ovalWidth) / 2;
int ovalY = (surfaceView.getHeight() - ovalHeight) / 2;
mPath.addOval(new RectF(ovalX, ovalY, ovalWidth + ovalX, ovalHeight
+ ovalY), Path.Direction.CCW);
canvas.clipPath(mPath, Region.Op.REPLACE);
canvas.drawBitmap(bitmap2, 0, 0, paint);
canvas.restore();
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
Please could you tell me what is the problem?
Thanks a lot
Have a onDraw() inside the class "GalaryView" and draw your graphics there. From the run() of the thread call the onDraw(). This post has some sample code Android:Crash: Binary XML file line : Error inflating class (using SurfaceView) . Hope this helps !