Develop Reference

Android app has stopped and attempt to invoke virtual method on a null object reference [duplicate]

This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 2 years ago.
When I run my android app, it crashes and says that Android app has stopped. It also gives this error message:
java.lang.NullPointerException: Attempt to invoke virtual method 'com.esimerkki.doodl2.DoodleView com.esimerkki.doodl2.FirstFragment.getDoodleView()' on a null object reference
What is wrong with this? Is the reference really null? How could I make this work? I thought these original settings in doodleView have start values?
Here is the code of doodleView class:
package com.esimerkki.doodl2;
import android.content.Context;
import android.view.View;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Point;
import android.provider.MediaStore;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.MotionEvent;
import android.widget.Toast;
import androidx.print.PrintHelper;
import java.util.HashMap;
import java.util.Map;
public class DoodleView extends View {
public DoodleView(Context context, Paint paintScreen, Paint paintLine) {
super( context );
this.paintScreen = paintScreen;
this.paintLine = paintLine;
}
private static final float TOUCH_TOLERANCE = 10;
private Bitmap bitmap; // drawing area
private Canvas bitmapCanvas; //
private final Paint paintScreen; //
private final Paint paintLine; //
private final Map<Integer, Path> pathMap = new HashMap<>();
private final Map<Integer, Point> previousPointMap = new HashMap<>();
public DoodleView(Context context, AttributeSet attrs) {
super(context, attrs); // kutsutaan yliluokanalustajaa
paintScreen = new Paint(); // bittikartan näyttämiseen ruudulla
paintLine = new Paint();
paintLine.setAntiAlias(true);
paintLine.setColor(Color.BLACK);
paintLine.setStyle(Paint.Style.STROKE);
paintLine.setStrokeWidth(5);
paintLine.setStrokeCap(Paint.Cap.ROUND);
#Override
public void onSizeChanged(int w, int h, int OldW, int oldH) {
bitmap = Bitmap.createBitmap(getWidth(), getHeight(),
Bitmap.Config.ARGB_8888);
bitmapCanvas = new Canvas(bitmap);
bitmap.eraseColor(Color.WHITE);
}
public void clear() {
pathMap.clear();
previousPointMap.clear();
bitmap.eraseColor(Color.WHITE);
invalidate();
}
public void setDrawingColor(int color) {
paintLine.setColor(color);
}
public int getDrawingColor() {
return paintLine.getColor();
}
public void setLineWidth(int width) {
paintLine.setStrokeWidth(width);
}
public int getLineWidth() {
return (int) paintLine.getStrokeWidth();
}
#Override
protected void onDraw(Canvas canvas) {
canvas.drawBitmap(bitmap, 0, 0, paintScreen);
for (Integer key : pathMap.keySet())
canvas.drawPath(pathMap.get(key), paintLine); // piirretään viiva
}
#Override
public boolean onTouchEvent(MotionEvent event) {
int action = event.getActionMasked(); // tapahtumatyyppi
int actionIndex = event.getActionIndex(); // osoitin
if (action == MotionEvent.ACTION_DOWN ||
action == MotionEvent.ACTION_POINTER_DOWN) {
touchStarted(event.getX(actionIndex), event.getY(actionIndex),
event.getPointerId(actionIndex));
}
else if (action == MotionEvent.ACTION_UP ||
action == MotionEvent.ACTION_POINTER_UP) {
touchEnded(event.getPointerId(actionIndex));
}
else {
touchMoved(event);
}
invalidate();
return true;
}
private void touchStarted(float x, float y, int lineID) {
Path path; // tallennetaan tietyn id:n polku
Point point; // tallennetaan polun viimeinen piste
if (pathMap.containsKey(lineID)) {
path = pathMap.get(lineID);
path.reset();
point = previousPointMap.get(lineID);
}
else {
path = new Path();
pathMap.put(lineID, path);
point = new Point();
previousPointMap.put(lineID, point);
}
path.moveTo(x, y);
point.x = (int) x;
point.y = (int) y;
}
private void touchMoved(MotionEvent event) {
for (int i = 0; i < event.getPointerCount(); i++) {
// luetaan pointtein id ja indeksi
int pointerID = event.getPointerId(i);
int pointerIndex = event.findPointerIndex(pointerID);
if (pathMap.containsKey(pointerID)) {
float newX = event.getX(pointerIndex);
float newY = event.getY(pointerIndex);
Path path = pathMap.get(pointerID);
Point point = previousPointMap.get(pointerID);
// lasketaan kuinka kauas liikuttu
float deltaX = Math.abs(newX - point.x);
float deltaY = Math.abs(newY - point.y);
if (deltaX >= TOUCH_TOLERANCE || deltaY >= TOUCH_TOLERANCE) {
path.quadTo(point.x, point.y, (newX + point.x) / 2,
(newY + point.y) / 2);
point.x = (int) newX;
point.y = (int) newY;
}
}
}
}
private void touchEnded(int lineID) {
Path path = pathMap.get(lineID);
bitmapCanvas.drawPath(path, paintLine);
path.reset(); // tyhjennetään polku
}
public void saveImage() {
final String name = "Doodlz" + System.currentTimeMillis() + ".jpg";
String location = MediaStore.Images.Media.insertImage(
getContext().getContentResolver(), bitmap, name,
"Doodlz Drawing"
);
if (location != null) {
Toast message = Toast.makeText(getContext(),
R.string.message_saved,
Toast.LENGTH_SHORT);
message.setGravity(Gravity.CENTER, message.getXOffset() / 2,
message.getYOffset() / 2);
message.show();
}
else {
Toast message = Toast.makeText(getContext(),
R.string.message_error_saving, Toast.LENGTH_SHORT);
message.setGravity(Gravity.CENTER, message.getXOffset() / 2,
message.getYOffset() / 2);
message.show();
}
}
public void printImage() {
if (PrintHelper.systemSupportsPrint()) {
PrintHelper printHelper = new PrintHelper(getContext());
printHelper.setScaleMode(printHelper.SCALE_MODE_FIT);
printHelper.printBitmap("Doodlz Imate", bitmap);
}
else {
Toast message = Toast.makeText(getContext(),
R.string.message_error_printing, Toast.LENGTH_SHORT);
message.setGravity(Gravity.CENTER, message.getXOffset() / 2,
message.getYOffset() / 2);
message.show();
}
}
}
And here is the code of a LineWidthFragment class:
package com.esimerkki.doodl2;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.Context;
import android.content.DialogInterface;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.os.Bundle;
//import android.support.v4.app.DialogFragment;
import android.view.View;
import android.widget.ImageView;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;
import androidx.fragment.app.DialogFragment;
public class LineWidthFragment extends DialogFragment {
private ImageView widthImageView;
#Override
public Dialog onCreateDialog(Bundle bundle) {
AlertDialog.Builder builder =
new AlertDialog.Builder(getActivity());
View lineWidthDialogView =
getActivity().getLayoutInflater().inflate(
R.layout.fragment_line_width, null);
builder.setView(lineWidthDialogView); // lisätään GUI dialogiin
builder.setTitle(R.string.title_line_width_dialog);
widthImageView = (ImageView) lineWidthDialogView.findViewById(
R.id.widthImageView);
final DoodleView doodleView = getDoodleFragment().getDoodleView();
final SeekBar widthSeekBar = (SeekBar)
lineWidthDialogView.findViewById(R.id.widthSeekBar);
widthSeekBar.setOnSeekBarChangeListener(lineWidthChanged);
widthSeekBar.setProgress(doodleView.getLineWidth());
builder.setPositiveButton(R.string.button_set_line_width,
new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int id) {
doodleView.setLineWidth(widthSeekBar.getProgress());
}
}
);
return builder.create();
}
private FirstFragment getDoodleFragment() {
return (FirstFragment) getChildFragmentManager().findFragmentById(
R.id.doodleFragment);
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
FirstFragment fragment = getDoodleFragment();
if (fragment != null)
fragment.setDialogOnScreen(true);
}
#Override
public void onDetach() {
super.onDetach();
FirstFragment fragment = getDoodleFragment();
if (fragment != null)
fragment.setDialogOnScreen(false);
}
private final OnSeekBarChangeListener lineWidthChanged =
new OnSeekBarChangeListener() {
final Bitmap bitmap = Bitmap.createBitmap(
400, 100, Bitmap.Config.ARGB_8888);
final Canvas canvas = new Canvas(bitmap); // piirtää bittikarttaan
#Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
Paint p = new Paint();
p.setColor(
getDoodleFragment().getDoodleView().getDrawingColor());
p.setStrokeCap(Paint.Cap.ROUND);
p.setStrokeWidth(progress);
bitmap.eraseColor(
getResources().getColor(android.R.color.transparent,
getContext().getTheme()));
canvas.drawLine(30, 50, 370, 50, p);
widthImageView.setImageBitmap(bitmap);
}
#Override
public void onStartTrackingTouch(SeekBar seekBar) { // tarvitaan
}
#Override
public void onStopTrackingTouch(SeekBar seekBar) { // tarvitaan
}
};
}

Your error says the following:
null object reference
This means that 1 object gives the value 0.
Your code looks fine but if you rewrite the code once again you may solve the mistake.
It is caused by a pitty error in your code.
When rewriting it. You can find that error.
Even if this was a bug with some plugin or anything else.
Also after you rewrote it, if you get the same error then you need to look onto a reference.

How to disable rounded images in android studio

I bought a template for android app which has listview and another file with rounded images in and i want to disable it
here is the roundimage.java file
package com.TEST.TEST;
import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.ColorFilter;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.drawable.Drawable;
public class RoundImage extends Drawable {
private final Bitmap mBitmap;
private final Paint mPaint;
private final RectF mRectF;
private final int mBitmapWidth;
private final int mBitmapHeight;
public RoundImage(Bitmap bitmap) {
mBitmap = bitmap;
mRectF = new RectF();
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
final BitmapShader shader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
mPaint.setShader(shader);
mBitmapWidth = mBitmap.getWidth();
mBitmapHeight = mBitmap.getHeight();
}
#Override
public void draw(Canvas canvas) {
canvas.drawOval(mRectF, mPaint);
}
#Override
protected void onBoundsChange(Rect bounds) {
super.onBoundsChange(bounds);
mRectF.set(bounds);
}
#Override
public void setAlpha(int alpha) {
if (mPaint.getAlpha() != alpha) {
mPaint.setAlpha(alpha);
invalidateSelf();
}
}
#Override
public void setColorFilter(ColorFilter cf) {
mPaint.setColorFilter(cf);
}
#Override
public int getOpacity() {
return PixelFormat.TRANSLUCENT;
}
#Override
public int getIntrinsicWidth() {
return mBitmapWidth;
}
#Override
public int getIntrinsicHeight() {
return mBitmapHeight;
}
public void setAntiAlias(boolean aa) {
mPaint.setAntiAlias(aa);
invalidateSelf();
}
#Override
public void setFilterBitmap(boolean filter) {
mPaint.setFilterBitmap(filter);
invalidateSelf();
}
#Override
public void setDither(boolean dither) {
mPaint.setDither(dither);
invalidateSelf();
}
public Bitmap getBitmap() {
return mBitmap;
}
}
and this is a part from the file which i want to disable rounding from
if (isExist != false){
Bitmap theImage = BitmapFactory.decodeStream(imageStream);
roundedImage = new RoundImage(theImage);
imgIcon.setImageDrawable(roundedImage);
}
else {
Bitmap bm = BitmapFactory.decodeResource(getResources(),R.mipmap.author);
roundedImage = new RoundImage(bm);
imgIcon.setImageDrawable(roundedImage);
}
how can i disable rounding for images or control its corners to change it into zero

If you want a rectangular image you can edit
canvas.drawOval(mRectF, mPaint);
to
canvas.drawRect(mRectF, mPaint);

Please test this code instead of yours:
if (isExist != false){
roundedImage = BitmapFactory.decodeStream(imageStream);
imgIcon.setImageDrawable(roundedImage);
}
else {
roundedImage = BitmapFactory.decodeResource(getResources(),R.mipmap.author);
imgIcon.setImageDrawable(roundedImage);
}
In this code we omit the line which uses RoundImage class.

my image not set in the center of relative layout and its not showing complete image using flood-fill and canvas

I want to set my bitmap converted image in relative layout with the help of custom view but my image not set in the center of relative layout and its not showing complete image
My relative layout where I set my bitmap image`package org.boostram.justcolor;
import android.app.ActionBar;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
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.Point;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.support.annotation.RequiresApi;
import android.transition.TransitionManager;
import android.util.Log;
import android.view.Display;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.Toast;
import com.flask.colorpicker.ColorPickerView;
import com.flask.colorpicker.OnColorChangedListener;
import com.flask.colorpicker.OnColorSelectedListener;
import org.boostram.justcolor.Utils.util;
import static android.R.attr.src;
public class FillPaintActivity extends Activity implements View.OnTouchListener {
private RelativeLayout dashBoard;
Paint paint;
private MyView myView;
int a = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
myView = new MyView(this);
setContentView(R.layout.activity_fill_paint);
ColorPickerView colorPickerView = (ColorPickerView) findViewById(R.id.color_picker_view);
// colorPickerView.setColor(Color.WHITE,true);
paint.setColor(Color.WHITE);
colorPickerView.setInitialColor(Color.WHITE, true);
colorPickerView.addOnColorChangedListener(new OnColorChangedListener() {
#Override
public void onColorChanged(int selectedColor) {
a = 1;
paint.setColor(selectedColor);
// Handle on color change
// Log.d("ColorPicker", "onColorChanged: 0x" + Integer.toHexString(selectedColor));
}
});
colorPickerView.addOnColorSelectedListener(new OnColorSelectedListener() {
#Override
public void onColorSelected(int selectedColor) {
paint.setColor(selectedColor);
// myView.changePaintColor(selectedColor);
Toast.makeText(FillPaintActivity.this, "selectedColor: " +
Integer.toHexString(selectedColor).toUpperCase(),
// Toast.LENGTH_SHORT).show();
}
});
dashBoard = (RelativeLayout) findViewById(R.id.dashBoard);
dashBoard.addView(myView);
}
#Override
public boolean onTouch(View view, MotionEvent motionEvent) {
return false;
}
public class MyView extends View {
// private Paint paint;
private Path path;
public Bitmap mBitmap;
public ProgressDialog pd;
final Point p1 = new Point();
public Canvas canvas;
public MyView(Context context) {
super(context);
paint = new Paint();
paint.setAntiAlias(true);
pd = new ProgressDialog(context);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeJoin(Paint.Join.ROUND);
// paint.setStrokeWidth(5f);
// BitmapDrawable drawable = (BitmapDrawable)
context.getDrawable(R.drawable.unnamed);
// Bitmap bmp = drawable.getBitmap();
// Bitmap mBitmap = Bitmap.createScaledBitmap(bmp, 120, 120,
false);
mBitmap = BitmapFactory.decodeResource(getResources(),
util.Id).copy(Bitmap.Config.ARGB_8888, true);
//mBitmap =
Bitmap.createScaledBitmap((BitmapFactory.decodeResource(getResources(),
util.Id).copy(Bitmap.Config.ARGB_8888, true)),1500,1380,false);
this.path = new Path();
}
#Override
protected void onDraw(Canvas canvas) {
this.canvas = canvas;
// Display display = getWindowManager().getDefaultDisplay();
// int displayWidth = display.getWidth();
// BitmapFactory.Options options = new BitmapFactory.Options();
// options.inJustDecodeBounds = true;
// BitmapFactory.decodeResource(getResources(), util.Id, options);
// int width = options.outWidth;
// if (width > displayWidth)
// {
// int widthRatio = Math.round((float) width / (float)
displayWidth);
// options.inSampleSize = widthRatio;
// }
// options.inJustDecodeBounds = false;
// Bitmap scaledBitmap =
BitmapFactory.decodeResource(getResources(),util.Id , options);
canvas.drawBitmap(mBitmap,0,0 ,paint);
// mBitmap = BitmapFactory.decodeResource
}
#Override
public boolean onTouchEvent(MotionEvent event) {
if (a == 0) {
Toast.makeText(FillPaintActivity.this, "Select Any Color First",
Toast.LENGTH_SHORT).show();
}
// Toast.makeText(FillPaintActivity.this, myView.getWidth()+""+myView.getHeight(), Toast.LENGTH_LONG).show();
float x = event.getX();
float y = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
p1.x = (int) x;
p1.y = (int) y;
if (p1.x < mBitmap.getWidth() && p1.y < mBitmap.getHeight()) {
final int sourceColor = mBitmap.getPixel((int) x, (int) y);
final int targetColor = paint.getColor();
new TheTask(mBitmap, p1, sourceColor, targetColor).execute();
invalidate();
}
// else {
// Toast.makeText(FillPaintActivity.this, "You touched outside the Image", Toast.LENGTH_SHORT).show();
// }
}
return true;
}
public void clear() {
path.reset();
invalidate();
}
public void changePaintColor(int color) {
paint.setColor(color);
}
class TheTask extends AsyncTask<Void, Integer, Void> {
Bitmap bmp;
Point pt;
int replacementColor, targetColor;
public TheTask(Bitmap bm, Point p, int sc, int tc) {
this.bmp = bm;
this.pt = p;
this.replacementColor = tc;
this.targetColor = sc;
}
#Override
protected void onPreExecute() {
// pd.show();
}
#Override
protected void onProgressUpdate(Integer... values) {
}
#Override
protected Void doInBackground(Void... params) {
FloodFill floodFill = new FloodFill(bmp, targetColor, replacementColor);
floodFill.floodFill(pt.x, pt.y);
return null;
}
#Override
protected void onPostExecute(Void result) {
invalidate();
}
}
}
}
https://i.stack.imgur.com/AHpcb.png
My bitmap converted image not set in center of relative layout through view. Kindly help me i'm stuck here for almost two week. Help

layerlist drawable is not changed with imageview on click

I am setting a layer list to an imageview with drawable programatically in android
My custom Drawable is as follows,
package cl.tk.ui.iBAPView;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.ColorFilter;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.drawable.Drawable;
import cl.tk.R;
public class CircleDrawable extends Drawable {
private int color;
private boolean checked = false;
private int size;
private Paint paint= new Paint(Paint.DITHER_FLAG);
private Context context;
public CircleDrawable(Context context,boolean checked,int color,int size) {
this.checked=checked;
this.color=color;
this.size=size;
this.context=context;
}
#Override
public void draw(Canvas canvas) {
paint.setAntiAlias(true);
paint.setFilterBitmap(true);
paint.setDither(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawCircle(size/ 2, size / 2,size / 2, paint);
if (checked)
drawChecked(canvas);
}
private void drawChecked(Canvas canvas) {
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.ic_check);
float posX = (canvas.getWidth() - bitmap.getWidth()) / 2;
float posY = (canvas.getHeight() - bitmap.getHeight()) / 2;
canvas.drawBitmap(bitmap, posX, posY, paint);
}
#Override
public void setAlpha(int alpha) {
// do nothing
}
#Override
public void setColorFilter(ColorFilter cf) {
// do nothing
}
#Override
public int getOpacity() {
return PixelFormat.UNKNOWN;
}
}
This is my code to create layer list drawable and set it to imageview,
public static void setChecked_Selector(Context context,ImageView view) {
try {
int size= (int) context.getResources().getDimension(R.dimen._17sdp);
/* Drawable pressed=squareView(ContextCompat.getColor(context,R.color.colorBlue),ContextCompat.getColor(context,R.color.colorRed),size);//new BadgeDrawable(context,colorPressed);
Drawable normal=squareView(ContextCompat.getColor(context,R.color.colorwhite),ContextCompat.getColor(context,R.color.colorRed),size);*/
Drawable pressed=new CircleDrawable(context,true,ContextCompat.getColor(context,R.color.colorGreen),size);
Drawable normal=new CircleDrawable(context,false,ContextCompat.getColor(context,R.color.colorGray),size);
Drawable[] drawarray = {pressed, normal};
LayerDrawable layerdrawable = new LayerDrawable(drawarray);
view.setBackgroundDrawable(layerdrawable);
view.setImageLevel(0);
view.setTag(0);
} catch (Exception e) {
}
}
and on click of imageview, i am trying to change the drawable but failed as the condition is working perfectly but layerlist drawable is not changing,
My code on click listener of imageView,
case R.id.ah_img_agree:
{
int imageLevel=-1;
if(0==(int)v.getTag())
imageLevel=1;
else
imageLevel=0;
((ImageView)v).setImageLevel(imageLevel);
rbAgreed.setTag(imageLevel);
}
break;

How to clear canvas in android on button click

import android.content.Context;
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.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
public class SingleTouchEventView extends View {
private Paint paint = new Paint();
private Path path = new Path();
public boolean cc = false;
public SingleTouchEventView(Context context, AttributeSet attrs) {
super(context, attrs);
paint.setAntiAlias(true);
paint.setStrokeWidth(18f);
paint.setColor(Color.LTGRAY);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeJoin(Paint.Join.ROUND);
paint.setStrokeCap(Paint.Cap.ROUND);
}
#Override
protected void onDraw(Canvas canvas) {
if(cc)
{
Bitmap back = BitmapFactory.decodeResource(getResources(), R.drawable.black_square);
Bitmap cb = Bitmap.createScaledBitmap(back, 0, 0, false);
canvas.drawBitmap(cb,0,0,null);
cc = false;
}
canvas.drawPath(path, paint);
}
public void clearCanvas()
{
cc =true;
invalidate();
}
#Override
public boolean onTouchEvent(MotionEvent event) {
float eventX = event.getX();
float eventY = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
path.moveTo(eventX, eventY);
return true;
case MotionEvent.ACTION_MOVE:
path.lineTo(eventX, eventY);
break;
case MotionEvent.ACTION_UP:
// nothing to do
break;
default:
return false;
}
// Schedules a repaint.
invalidate();
return true;
}
}
The above file is my SingleTouchEventView.Java
Here is my MainActivity.java
public class MainActivity extends Activity {
Button reset;;
LinearLayout canvasAlphabets;
SingleTouchEventView myView;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
reset = (Button)findViewById(R.id.reset_canvas);
myView = new SingleTouchEventView(this, null);
canvasAlphabets = (LinearLayout)findViewById(R.id.canvas_Alphabets);
canvasAlphabets.addView(myView);
reset.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
}
});
}
}
My question is what code should I use in reset button to delete all contents of canvas.
Please help me
I have tried implementing myView.clearCanvas() but that doesn't help. If I add this code to reset buutons on Click it causes FC
Thanks

path = new Path();
Paint clearPaint = new Paint();
clearPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
canvas.drawRect(0, 0, 0, 0, clearPaint);
cc = false;
I got it fixed with above code

Maybe I do not understand what you want to draw, but have you tried this:
protected void onDraw(Canvas canvas)
{
if (cc)
{
Bitmap back = BitmapFactory.decodeResource(getResources(), R.drawable.black_square);
Bitmap cb = Bitmap.createScaledBitmap(back, 0, 0, false);
canvas.drawBitmap(cb,0,0,null);
cc = false;
}
else
canvas.drawPath(path, paint);
}
}
Otherwise, if you want to erase all, you can use this new paint:
Paint transparent = new Paint();
transparent.setAlpha(0);

You can panit everything with a transparent color, to clear everything.