Canvas change path

Canvas change path - android

I have a spinner in my layout. I would like to change the shape drawn as a path when a different item is selected. Currently my code is adding my second path to the first one, instead of just replacing it. Here is my code:
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.LinearLayout;
import android.widget.Spinner;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
public class MainActivity extends AppCompatActivity {
private MyView myView;
private boolean firstTimeThru = true;
private LinearLayout root;
private Spinner mySpinner;
private Paint myPaint;
private Path path = new Path();
float[] finalXCoord, finalYCoord;
float[] xCoord1 = {0,30, 50};
float[] yCoord1 = {0, 100, 40};
float[] xCoord2 = {52,300, 100, 60};
float[] yCoord2 = {100, 200, 40, 80};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
finalXCoord = xCoord1;
finalYCoord = yCoord1;
// Hide the Title Bar
requestWindowFeature(Window.FEATURE_NO_TITLE);
// Hide the Status Bar
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
root = new LinearLayout(this);
root.setOrientation(LinearLayout.VERTICAL);
// Create the spinner, add contents, add events, add to Layout
mySpinner = new Spinner(this);
List<String> list = new ArrayList<String>();
list.add("1st Path");
list.add("2nd Path");
ArrayAdapter<String> spinnerArrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_dropdown_item, list);
mySpinner.setAdapter(spinnerArrayAdapter);
myPaint = new Paint();
myPaint.setColor(Color.GREEN);
mySpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {
System.out.println(mySpinner.getSelectedItemId());
if (mySpinner.getSelectedItemId()==0) {
myPaint.setColor(Color.GREEN);
finalXCoord = xCoord1;
finalYCoord = yCoord1;
}
if (mySpinner.getSelectedItemId()==1) {
myPaint.setColor(Color.RED);
finalXCoord = xCoord2;
finalYCoord = yCoord2;
}
if (!firstTimeThru) {
System.out.println("Not First Time");
//demoview.changeToRed();
}
System.out.println(myPaint.getColor());
}
#Override
public void onNothingSelected(AdapterView<?> parentView) {
// your code here
}
});
root.addView(mySpinner);
// Add view with canvas
myView = new MyView(this);
root.addView(myView);
setContentView(root);
}
public class MyView extends View {
public Canvas mCanvas;
public MyView(Context context) {
super(context);
}
public void drawPath(float[] xCoord, float[] yCoord) {
path.moveTo(xCoord[0], yCoord[0]);
for(int i=1; i<xCoord.length; i++) {
path.lineTo(xCoord[i], yCoord[i]);
}
path.close();
mCanvas.drawPath(path, myPaint);
invalidate();
}
protected void onDraw(Canvas canvas) {
mCanvas = canvas;
//myPaint.setStyle(Paint.Style.FILL_AND_STROKE);
myPaint.setStrokeWidth(10);
myPaint.setPathEffect(null);
//paint.setColor(Color.BLACK);
myPaint.setStyle(Paint.Style.STROKE);
drawPath(finalXCoord, finalYCoord);
//invalidate();
}
}
}

You probably need to reset your path:
public void drawPath(float[] xCoord, float[] yCoord) {
path.reset();
path.moveTo(xCoord[0], yCoord[0]);
for(int i=1; i<xCoord.length; i++) {
path.lineTo(xCoord[i], yCoord[i]);
}
path.close();
mCanvas.drawPath(path, myPaint);
invalidate();
}

Related

Android SurfaceView never becomes valid

SurfaceView is never available for drawing after creation.
Other SO questions indicate that it can be managed with the callback functions handed to it, and it must be assigned to setContentView before the lifecycle starts.
Logcat indicates that the callbacks are assigned successfully, however they are never fired.
Full code here but I think relevant parts can be found in the main activity:
package com.example.gavin.pixelarraytest;
import android.app.Activity;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.Surface;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
GameView theGame = new GameView(this, 0,0);
SurfaceHolder testt;
testt = theGame.getHolder();
setContentView(theGame);
while(true){
if(testt.getSurface().isValid()){ // this never becomes true. isCreating is also consistently false at this point
theGame.prepareCanvas();
break;
}
}
}
}
And in the SurfaceView object:
package com.example.gavin.pixelarraytest;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.util.Log;
import android.view.Display;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
public class GameView extends SurfaceView implements Runnable {
private Paint paint;
private Canvas canvas;
private Bitmap _buffer;
private SurfaceHolder ourHolder;
private boolean running;
private boolean paused = false;
private long fps;
public GameView(Context context, int screenX, int screenY){
ourHolder = getHolder();
ourHolder.addCallback(new MyCallback());
paint = new Paint();
}
public void prepareCanvas(){
running = true;
run();
}
#Override
public void run(){
while(running){
long startFrameTime = System.currentTimeMillis();
draw();
long endFrameTime = System.currentTimeMillis() - startFrameTime;
if(endFrameTime >= 1){
fps = 1000 / endFrameTime;
}
}
private void update(){
class MyCallback implements SurfaceHolder.Callback {
#Override
public void surfaceChanged(SurfaceHolder holder, int format,
int width, int height) {
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
}
}
private void draw(){
this.setWillNotDraw(false);
if(ourHolder.getSurface().isValid()){
canvas = ourHolder.lockCanvas();
canvas.drawColor(Color.argb(255,100,40,40));
int width = 100;
int height = 100;
int colors[] = new int[width*height];
for (int i = 0; i < colors.length; i++){
int a = 255, r = 40, g = 100, b = 40;
colors[i] = (a << 24) | (r << 16) | (g << 8) | b;
_buffer = Bitmap.createBitmap(colors, width, height, Bitmap.Config.RGB_565);
canvas.drawBitmap(_buffer, 0,0,null);
}
}
}
Am I misunderstanding how SurfaceView is used or am I using it incorrectly in the above?

To inflate a canvas object you can try this:
First create a layout file in res>layout
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<GameView
android:id="+#id/mGameView"
android:layout_height="match_parent"
android:layout_width="match_parent"
/>
</LinearLayout>
Then you can inflate this by calling
setContentView(R.layout.your_file_name);
And finally access the gameview by using:
GameView gameView = findViewById(R.id.mGameView);
gameView.prepareCanvas();

How to add Color Picker in Application?

I have developed an Application , which uses screen as a Slate and finger as a Chalk, which is working properly. But I want to use different color types for chalk.
Here is my Code:
MyDemo.java
package com.example.mydemo;
import android.os.Bundle;
import android.app.Activity;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
public class MyDemo extends Activity {
private LinearLayout root;
private Button btnReset;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my_demo);
root = (LinearLayout) findViewById(R.id.root);
btnReset = (Button) findViewById(R.id.reset);
final MyImageView view = new MyImageView(this);
view.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.FILL_PARENT));
root.addView(view);
btnReset.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
view.reset();
}
});
}
}
MyImageView.java
package com.example.mydemo;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PointF;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
import java.util.ArrayList;
import java.util.List;
public class MyImageView extends ImageView implements View.OnTouchListener {
private int id = -1;
private Path path;
private List<Path> paths = new ArrayList<Path>();
private List<PointF> points = new ArrayList<PointF>();
boolean multiTouch = false;
public MyImageView(Context context) {
super(context);
this.setOnTouchListener(this);
}
public void reset() {
paths.clear();
points.clear();
path = null;
id = -1;
invalidate();
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
Paint paint = createPen(Color.BLACK);
paint.setStyle(Paint.Style.STROKE);
for (Path path : paths) {
canvas.drawPath(path, paint);
}
for (int i = 0; i < points.size(); i++) {
PointF p = points.get(i);
canvas.drawText("" + p.x, p.y, i, createPen(Color.WHITE));
}
}
private PointF copy(PointF p) {
PointF copy = new PointF();
copy.set(p);
return copy;
}
public boolean onTouch(View v, MotionEvent event) {
int action = event.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
multiTouch = false;
id = event.getPointerId(0);
PointF p = getPoint(event, id);
path = new Path();
path.moveTo(p.x, p.y);
paths.add(path);
points.add(copy(p));
break;
case MotionEvent.ACTION_POINTER_DOWN:
multiTouch = true;
for (int i = 0; i < event.getPointerCount(); i++) {
int tId = event.getPointerId(i);
if (tId != id) {
points.add(getPoint(event,i));
}
}
break;
case MotionEvent.ACTION_MOVE:
if (!multiTouch) {
p =getPoint(event, id);
path.lineTo(p.x, p.y);
}
break;
}
invalidate();
return true;
}
private PointF getPoint(MotionEvent event, int i) {
int index = 0;
return new PointF(event.getX(index), event.getY(index));
}
private Paint createPen(int color) {
Paint pen = new Paint();
pen.setColor(color);
float width = 3;
pen.setStrokeWidth(width);
return pen;
}
}
activity_my_demo.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout android:id="#+id/root" xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<Button android:id="#+id/reset" android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Reset"
/>
</LinearLayout>
Can any one tell me what should be added or changed in my code so that I can use different colors for Chalk?

You can take the sample in your android folder's..
For the color picker go to in this folder:
android/samples/android-YOURS_VERSION/ApiDemos

Use this, review this code. than your problem will be solve
package com.example.changecolor;
import android.app.Activity;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.graphics.Color;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;
public class MainActivity extends Activity
implements View.OnClickListener, UberColorPickerDialog.OnColorChangedListener {
private int mColor = 0xFFFF0000;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Write the version number
PackageManager pm = getPackageManager();
String versionName = "";
try {
PackageInfo pi = pm.getPackageInfo("com.keithwiley.android.ubercolorpickerdemo", 0);
versionName = pi.versionName;
}
catch (Exception e) {
}
TextView textView = (TextView) findViewById(R.id.version);
textView.setText(versionName);
//Initialize the sample
((LinearLayout) findViewById(R.id.LinearLayout)).setBackgroundColor(mColor);
float hsv[] = new float[3];
Color.colorToHSV(mColor, hsv);
if (UberColorPickerDialog.isGray(mColor))
hsv[1] = 0;
if (hsv[2] < .5)
((TextView) findViewById(R.id.sample)).setTextColor(Color.WHITE);
else ((TextView) findViewById(R.id.sample)).setTextColor(Color.BLACK);
//Set up the buttons
Button button = (Button) findViewById(R.id.colorPickerWithTitle);
button.setOnClickListener(this);
button = (Button) findViewById(R.id.colorPickerWithToast);
button.setOnClickListener(this);
}
protected void onPause() {
super.onPause();
}
protected void onResume() {
super.onResume();
}
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
return true;
}
public boolean onPrepareOptionsMenu(Menu menu) {
super.onPrepareOptionsMenu(menu);
return true;
}
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
}
return super.onOptionsItemSelected(item);
}
public void onClick(View v) {
if (v.getId() == R.id.colorPickerWithTitle)
new UberColorPickerDialog(this, this, mColor, true).show();
if (v.getId() == R.id.colorPickerWithToast)
new UberColorPickerDialog(this, this, mColor, false).show();
}
public void colorChanged(int color) {
((LinearLayout) findViewById(R.id.LinearLayout)).setBackgroundColor(mColor=color);
float hsv[] = new float[3];
Color.colorToHSV(mColor, hsv);
//if (UberColorPickerDialog.isGray(mColor))
// hsv[1] = 0;
if (hsv[2] < .5)
((TextView) findViewById(R.id.sample)).setTextColor(Color.WHITE);
else ((TextView) findViewById(R.id.sample)).setTextColor(Color.BLACK);
}
}
And use the color picker class

How to Draw line between two views in android?

I want to draw a line between two views how it could possible using canvas

Its simple Take one linearLayout for it between two views
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="1dp"
android:background="#285A8C" > //Give Color As u want
</LinearLayout>

Thanks every one i got the following solution for this I am using three layouts the middle layout i used for canvas and draw points in that canvas on button on click event
DrawView.java
package demo.example;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.View;
public class DrawView extends View {
Paint paint = new Paint();
float [][] points;
public DrawView(Context context, float[][] points2, int k) {
super(context);
paint.setColor(Color.BLUE);
paint.setStrokeWidth(5);
this.points=points2;
}
#Override
public void onDraw(Canvas canvas) {
for(int i=0;i<points.length;i++)
{
canvas.drawLine(points[i][0],points[i][1],points[i][2],points[i][3], paint);
}
}
}
get points using following click listener
public class listener implements OnClickListener
{
int i;
listener(int k)
{
this.i=k;
}
public void onClick(View v)
{
for(int k=0;k<match1.length;k++)
{
if(match1[k].isClickable()==false)
{
if(match1[k].getId()==match2[i].getId())
{
points[k][0]=match1[k].getLeft();
points[k]1]=match1[k].getTop()+30+linearLayout2.getTop(); points[k][2]=200;
points[k][3]=match2[i].getTop()+30+linearLayout2.getTop();
match1[k].setCompoundDrawablesWithIntrinsicBounds(null, null,null,null);
match2[i].setCompoundDrawablesWithIntrinsicBounds(getResources().getDrawable(R.drawable.bubble), null,null, null);
Toast.makeText(getBaseContext(),points[0]+"-"+points[1]+"-"+points[2]+"-"+points[3],Toast.LENGTH_SHORT).show();
ViewGroup.LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
drawView = new DrawView(getBaseContext(),points,k);
linearLayout2.addView(drawView);
}
}
}
}
}

How to clear canvas in a surface view?

I am developing an Android Digital signature app in which user can sign and i have to save this file as image.i am using SurfaceView for drawing. DigitalSignatureActivity has two Buttons Save,Clear.
1.Save Button to save file as image
2.Clear Button to clear surface.
But i am unable to clear the surface.i tried drawingSurface.setBackgroundColor(Color.BLACK); still previous sign is retained and canvas.drawColor(Color.BLACK); has no effect and
i am able to save file but its not storing signature perfectly(Some contents are missing) please help.
My code is:
DigitalSignatureActivity.java
package com.pop.digitalsign;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.os.Bundle;
import android.os.Environment;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;
public class DigitalSignatureActivity extends Activity implements
View.OnTouchListener {
private DrawingSurface drawingSurface;
private DrawingPath currentDrawingPath;
private Paint currentPaint;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
setCurrentPaint();
drawingSurface = (DrawingSurface) findViewById(R.id.drawingSurface);
drawingSurface.setOnTouchListener(this);
}
private void setCurrentPaint() {
currentPaint = new Paint();
currentPaint.setDither(true);
currentPaint.setColor(Color.WHITE);
currentPaint.setStyle(Paint.Style.STROKE);
currentPaint.setStrokeJoin(Paint.Join.ROUND);
currentPaint.setStrokeCap(Paint.Cap.ROUND);
currentPaint.setStrokeWidth(2);
}
public boolean onTouch(View view, MotionEvent motionEvent) {
if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) {
drawingSurface.setBackgroundColor(0);
currentDrawingPath = new DrawingPath();
currentDrawingPath.paint = currentPaint;
currentDrawingPath.path = new Path();
currentDrawingPath.path.moveTo(motionEvent.getX(),
motionEvent.getY());
currentDrawingPath.path.lineTo(motionEvent.getX(),
motionEvent.getY());
} else if (motionEvent.getAction() == MotionEvent.ACTION_MOVE) {
currentDrawingPath.path.lineTo(motionEvent.getX(),motionEvent.getY());
drawingSurface.addDrawingPath(currentDrawingPath);
} else if (motionEvent.getAction() == MotionEvent.ACTION_UP) {
currentDrawingPath.path.lineTo(motionEvent.getX(),motionEvent.getY());
}
return true;
}
//To save file as Image
public void saveDrawing(View v) throws IOException {
File mediaStorageDir = new File(
Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
"MySignatures");
Bitmap nBitmap = drawingSurface.getBitmap();
try {
if (!mediaStorageDir.exists()) {
mediaStorageDir.mkdirs();
}
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss")
.format(new Date());
File mediaFile = new File(mediaStorageDir.getPath()
+ File.separator + "SIGN_" + timeStamp + ".png");
FileOutputStream out = new FileOutputStream(mediaFile);
nBitmap.compress(Bitmap.CompressFormat.PNG, 90, out);
out.flush();
out.close();
Toast.makeText(this, "Signature saved to " + mediaFile,
Toast.LENGTH_LONG).show();
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(), "Not saved",
Toast.LENGTH_SHORT).show();
}
}
//To clear Surface
public void clearScreen(View v) {
//drawingSurface.setBackgroundColor(Color.BLACK);
drawingSurface.clear();
}
}
DrawingSurface.java
package com.pop.digitalsign;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.PorterDuff;
import android.util.AttributeSet;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class DrawingSurface extends SurfaceView implements SurfaceHolder.Callback {
private Boolean _run;
protected DrawThread thread;
private Bitmap mBitmap;
Canvas canvas;
private CommandManager commandManager;
public DrawingSurface(Context context, AttributeSet attrs) {
super(context, attrs);
getHolder().addCallback(this);
commandManager = new CommandManager();
thread = new DrawThread(getHolder());
}
class DrawThread extends Thread{
public SurfaceHolder mSurfaceHolder;
public DrawThread(SurfaceHolder surfaceHolder){
mSurfaceHolder = surfaceHolder;
}
public DrawThread() {
// TODO Auto-generated constructor stub
}
public void setRunning(boolean run) {
_run = run;
}
#Override
public void run() {
canvas = null;
while (_run){
try{
canvas = mSurfaceHolder.lockCanvas(null);
//canvas.drawColor(Color.WHITE);
if(mBitmap == null){
mBitmap = Bitmap.createBitmap (1, 1, Bitmap.Config.ARGB_8888);;
}
final Canvas c = new Canvas (mBitmap);
c.drawColor(0, PorterDuff.Mode.CLEAR);
commandManager.executeAll(c);
canvas.drawBitmap (mBitmap, 0, 0,null);
} finally {
if(canvas!=null){
mSurfaceHolder.unlockCanvasAndPost(canvas);
}
}
}
}
}
public void addDrawingPath (DrawingPath drawingPath){
commandManager.addCommand(drawingPath);
}
public void clear(){
//Here i want to clear surface
canvas.drawColor(Color.BLACK);//it has no effect
}
public boolean hasMoreUndo(){
return commandManager.hasMoreUndo();
}
public Bitmap getBitmap(){
return mBitmap;
}
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
mBitmap = Bitmap.createBitmap (width, height, Bitmap.Config.ARGB_8888);;
}
public void surfaceCreated(SurfaceHolder holder) {
thread.setRunning(true);
thread.start();
}
public void surfaceDestroyed(SurfaceHolder holder) {
boolean retry = true;
thread.setRunning(false);
while (retry) {
try {
thread.join();
retry = false;
} catch (InterruptedException e) {
}
}
}
}
CommandManager.java
package com.pop.digitalsign;
import android.graphics.Canvas;
import java.util.Iterator;
import java.util.List;
import java.util.Collections;
import java.util.ArrayList;
public class CommandManager {
private List<DrawingPath> currentStack;
public CommandManager(){
currentStack = Collections.synchronizedList(new ArrayList<DrawingPath>());
}
public void addCommand(DrawingPath command){
currentStack.add(command);
}
public void undo (){
final int length = currentStackLength();
if ( length > 0) {
final DrawingPath undoCommand = currentStack.get( length - 1 );
currentStack.remove( length - 1 );
undoCommand.undo();
}
}
public int currentStackLength(){
final int length = currentStack.toArray().length;
return length;
}
public void executeAll( Canvas canvas){
if( currentStack != null ){
synchronized( currentStack ) {
final Iterator<?> i = currentStack.iterator();
while ( i.hasNext() ){
final DrawingPath drawingPath = (DrawingPath) i.next();
drawingPath.draw( canvas );
}
}
}
}
public boolean hasMoreUndo(){
return currentStack.toArray().length > 0;
}
}
DrawingPath.java
package com.pop.digitalsign;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Path;
public class DrawingPath {
public Path path;
public Paint paint;
public void draw(Canvas canvas) {
canvas.drawPath( path, paint );
}
public void undo() {
}
}
main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:background="#android:color/white" >
<com.pop.digitalsign.DrawingSurface
android:id="#+id/drawingSurface"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:gravity="center" >
<Button
android:id="#+id/saveBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="saveDrawing"
android:text="#string/save" />
<Button
android:id="#+id/clearBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="clearScreen"
android:text="#string/clear" />
</LinearLayout>
</RelativeLayout>

the best suggestion i have is to use this
if (surfaceHolder.getSurface().isValid()) {
Canvas c = surfaceHolder.lockCanvas();
if (first >= 0) {
c.drawARGB(255, 255, 255, 255);
first--;
}
The value of first is 2 you can use what every name you want.
The reason is that the canvas is double buffered so you need to clear both screen by painting it white.
This stops the flickering

canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR)

In DrawingSurface add this method
public void resetCanvas(){ commandManager.clearAllPath(); }
and call this method, when you need to action for clear..
objectNameofDrawingSurefaceClass.resetCanvas();
add the code in CommandManager
public void clearAllPath(){currentStack.clear(); }
ok..

Android: attempting to draw a canvas on a relative layout and eclipse wants to initialise a variable that shouldn't need it

Hello EclipeE wants to initialise:
CustomDrawableView mCustomDrawableView;
Any ideas?
Cheers
Phil
Here's my code:
package com.android.phil.graphtoggle;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.drawable.ShapeDrawable;
import android.graphics.drawable.shapes.OvalShape;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.widget.ImageButton;
import android.widget.RelativeLayout;
public class MainActivity extends Activity
{
public int graph_toggle = 0;
public int data_toggle=0;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final ImageButton graph_toggle_button = (ImageButton) findViewById(R.id.graph_toggle);
final ImageButton graph_settings_button = (ImageButton) findViewById(R.id.graph_type);
final ImageButton data_toggle_button = (ImageButton) findViewById(R.id.data_toggle);
CustomDrawableView mCustomDrawableView;
RelativeLayout mainLayout = (RelativeLayout)findViewById(R.id.relativeLayout1);
RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(LayoutParams.FILL_PARENT,200);
lp.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);
// add here other layout params rules to make your
// custom view stay below the buttons
mCustomDrawableView.setLayoutParams(lp);
mainLayout.addView(mCustomDrawableView);
graph_toggle_button.setOnClickListener(new View.OnClickListener()
{
public void onClick(View arg0)
{
if (graph_toggle==2)
{
graph_toggle=0;
}
else
{
graph_toggle++;
}
if (graph_toggle==0)
{
graph_settings_button.setImageResource(R.drawable.close);
}
if (graph_toggle==1)
{
graph_settings_button.setImageResource(R.drawable.ohlc_bars);
}
if(graph_toggle==2)
{
graph_settings_button.setImageResource(R.drawable.candles);
}
}
});
data_toggle_button.setOnClickListener(new View.OnClickListener()
{
public void onClick(View arg0)
{
if (data_toggle==2)
{
data_toggle=0;
}
else
{
data_toggle++;
}
if (data_toggle==0)
{
data_toggle_button.setImageResource(R.drawable.ohlc_bars_daily);
}
if (data_toggle==1)
{
data_toggle_button.setImageResource(R.drawable.ohlc_bars_weekly);
}
if(data_toggle==2)
{
data_toggle_button.setImageResource(R.drawable.ohlc_bars_monthly);
}
}
});
}
public class CustomDrawableView extends View
{
private ShapeDrawable mDrawable;
public CustomDrawableView(Context context)
{
super(context);
int x = 10;
int y = 100;
int width = 300;
int height = 50;
mDrawable = new ShapeDrawable(new OvalShape());
mDrawable.getPaint().setColor(0xff74AC23);
mDrawable.setBounds(x, y, x + width, y + height);
}
protected void onDraw(Canvas canvas)
{
mDrawable.draw(canvas);
}
}
}

You aren't initializing mCustomDrawableView anywhere so mCustomDrawableView.setLayoutParams(lp); is going to cause a NullPointerException.
You are missing something like
mCustomDrawableView = (CustomDrawableView) this.findViewById(R.id.my_custom_view);

Develop Reference

The Android operating system is a mobile operating system that was developed by Google (GOOGL?) to be primarily used for touchscreen devices, cell phones, and tablets.

Canvas change path - android

You probably need to reset your path: public void drawPath(float[] xCoord, float[] yCoord) { path.reset(); path.moveTo(xCoord[0], yCoord[0]); for(int i=1; i<xCoord.length; i++) { path.lineTo(xCoord[i], yCoord[i]); } path.close(); mCanvas.drawPath(path, myPaint); invalidate(); }

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Android: attempting to draw a canvas on a relative layout and eclipse wants to initialise a variable that shouldn't need it

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