DrawActivity
public class DrawActivity extends Activity {
private Canvas mCanvas;
private Path mPath;
private Paint mPaint;
private ArrayList<Path> paths = new ArrayList<Path>();
private ArrayList<Path> undonePaths = new ArrayList<Path>();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
final DrawView drawView = new DrawView(this);
setContentView(R.layout.activity_main);
FrameLayout frm_layout=(FrameLayout) findViewById(R.id.main_frame);
frm_layout.addView(drawView);
Button btn_undo=(Button) findViewById(R.id.undo);
btn_undo.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
drawView.onClickUndo();
}
});
Button btn_redo=(Button) findViewById(R.id.redo);
btn_redo.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
drawView.onClickRedo();
}
});
/*Button color = (Button) findViewById (R.id.color);
color.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
int _color = R.color.red;
new PickerDialog(v.getContext(),new OnColorChangedListener() {
public void colorChanged(int color) {
mPaint.setColor(color);
}
}, mPaint.getColor(), _color).show();
}
}); */
}
/// color changed function, getting value from ColorPickerDialog ///
public void colorChanged(int color) {
mPaint.setColor(color);
}
public class DrawView extends View implements OnTouchListener {
public DrawView(Context context) {
super(context);
setFocusable(true);
setFocusableInTouchMode(true);
this.setOnTouchListener(this);
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(Color.GREEN);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(5);
mCanvas = new Canvas();
mPath = new Path();
paths.add(mPath);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
}
@Override
protected void onDraw(Canvas canvas) {
for (Path p : paths){
canvas.drawPath(p, mPaint);
}
}
private float mX, mY;
private static final float TOUCH_TOLERANCE = 4;
private void touch_start(float x, float y) {
mPath.reset();
mPath.moveTo(x, y);
mX = x;
mY = y;
}
private void touch_move(float x, float y) {
float dx = Math.abs(x - mX);
float dy = Math.abs(y - mY);
if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {
mPath.quadTo(mX, mY, (x + mX)/2, (y + mY)/2);
mX = x;
mY = y;
}
}
private void touch_up() {
mPath.lineTo(mX, mY);
// commit the path to our offscreen
mCanvas.drawPath(mPath, mPaint);
// kill this so we don't double draw
mPath = new Path();
paths.add(mPath);
}
public void onClickUndo () {
if (paths.size()>0) {
undonePaths.add(paths.remove(paths.size()-1));
invalidate();
} else {
Log.i("undo", "Undo elsecondition");
}
}
public void onClickRedo (){
if (undonePaths.size()>0) {
paths.add(undonePaths.remove(undonePaths.size()-1));
invalidate();
}
else {
Log.i("undo", "Redo elsecondition");
}
}
public boolean onTouch(View arg0, MotionEvent event) {
float x = event.getX();
float y = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
touch_start(x, y);
invalidate();
break;
case MotionEvent.ACTION_MOVE:
touch_move(x, y);
invalidate();
break;
case MotionEvent.ACTION_UP:
touch_up();
invalidate();
break;
}
return true;
}
}
}
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" >
<LinearLayout
android:id="@+id/linearlayout"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#FF4500"
android:orientation="horizontal" >
<Button
android:id="@+id/undo"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Undo" />
<Button
android:id="@+id/redo"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Redo" />
<!-- <Button
android:id="@+id/color"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Color" /> -->
</LinearLayout>
<FrameLayout
android:id="@+id/main_frame"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_below="@+id/linearlayout" >
<ImageView
android:id="@+id/imageView1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:src="@drawable/cat" />
</FrameLayout>
</RelativeLayout>
