我正在开发1个应用程序，因为我需要擦除Bitmap，因为我已经完成了.... （代码正在运行，但只绘制黑线..）
@Override
protected void onDraw(Canvas canvas) {
canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
for (PathPoints p : paths) {
mPaint.setColor(p.getColor());
mPaint.setXfermode(new PorterDuffXfermode(Mode.CLEAR));
Log.v("", "Color code : " + p.getColor());
if (p.isTextToDraw()) {
canvas.drawText(p.textToDraw, p.x, p.y, mPaint);
} else {
canvas.drawPath(p.getPath(), mPaint);
}
}
但上述代码仅在位图上绘制 黑线 我有Seen this link 但实际上我没有得到它LIKE THIS （在这个图像中移动鼠标在imge那种类型的工作我需要..但我不能删除部分位图只是绘制黑线）我做错了什么????? Plz帮我解决这个问题
答案 0 :(得分：1)
最后1天后我找到了解决方案......
public class FingerPaint extends Activity {
LinearLayout mainContainer;
LinearLayout buttonContainer;
LinearLayout.LayoutParams btnParams;
Button btnText, btnSketch, btnColor, btnUndo, btnRedo, btnDone;
// MyView drawView;
DrawingPanel drawView;
int lastColor = 0xFFFF0000;
public static final int SUCCESS = 200;
private final String TAG = getClass().getSimpleName();
private String textToDraw = null;
private boolean isTextModeOn = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
generateViews();
}
private void generateViews() {
btnDone = new Button(this);
btnDone.setLayoutParams(new LinearLayout.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));
btnDone.setText(getString(R.string.btn_done));
btnText = new Button(this);
btnSketch = new Button(this);
btnColor = new Button(this);
btnUndo = new Button(this);
btnRedo = new Button(this);
mainContainer = new LinearLayout(this);
mainContainer.setLayoutParams(new LinearLayout.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
mainContainer.setOrientation(LinearLayout.VERTICAL);
buttonContainer = new LinearLayout(this);
buttonContainer.setLayoutParams(new LinearLayout.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));
buttonContainer.setOrientation(LinearLayout.HORIZONTAL);
btnParams = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT, 1);
/*
* btnText.setText("Text"); btnSketch.setText("Sketch");
* btnColor.setText("Color"); btnUndo.setText("Undo");
* btnRedo.setText("Redo");
*/
btnText.setBackgroundDrawable(getResources().getDrawable(
R.drawable.text_mode_selector));
btnText.setLayoutParams(btnParams);
btnSketch.setBackgroundDrawable(getResources().getDrawable(
R.drawable.sketch_selector));
btnSketch.setLayoutParams(btnParams);
btnColor.setBackgroundDrawable(getResources().getDrawable(
R.drawable.color_selector));
btnColor.setLayoutParams(btnParams);
btnUndo.setBackgroundDrawable(getResources().getDrawable(
R.drawable.undo_selector));
btnUndo.setLayoutParams(btnParams);
btnRedo.setBackgroundDrawable(getResources().getDrawable(
R.drawable.redo_selector));
btnRedo.setLayoutParams(btnParams);
buttonContainer.addView(btnText);
buttonContainer.addView(btnSketch);
buttonContainer.addView(btnColor);
buttonContainer.addView(btnUndo);
buttonContainer.addView(btnRedo);
// drawView=new MyView(this);
drawView = new DrawingPanel(this, lastColor);
drawView.setDrawingCacheEnabled(true);
drawView.measure(
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
drawView.layout(0, 0, drawView.getMeasuredWidth(),
drawView.getMeasuredHeight());
drawView.buildDrawingCache(true);
drawView.setLayoutParams(new LinearLayout.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT, 1));
mainContainer.addView(btnDone);
mainContainer.addView(drawView);
mainContainer.addView(buttonContainer);
setContentView(mainContainer);
btnSketch.setSelected(true);
btnText.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
resetButtons();
btnText.setSelected(true);
AlertDialog.Builder alert = new AlertDialog.Builder(
FingerPaint.this);
alert.setMessage(getString(R.string.msg_enter_text_to_draw));
final EditText edText = new EditText(FingerPaint.this);
alert.setView(edText);
alert.setPositiveButton(R.string.btn_ok,
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog,
int which) {
// TODO Auto-generated method stub
if (edText.getText().toString().length() > 0) {
textToDraw = edText.getText().toString();
isTextModeOn = true;
ChooseActivity.displayAlert(
FingerPaint.this,
getString(R.string.msg_tap_image));
} else {
ChooseActivity
.displayAlert(
FingerPaint.this,
getString(R.string.msg_enter_text_to_draw));
}
}
});
alert.setNegativeButton(R.string.btn_cancel,
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog,
int which) {
// TODO Auto-generated method stub
isTextModeOn = false;
}
});
alert.show();
}
});
btnSketch.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
resetButtons();
btnSketch.setSelected(true);
isTextModeOn = false;
}
});
btnColor.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
AmbilWarnaDialog dialog = new AmbilWarnaDialog(
FingerPaint.this, lastColor,
new OnAmbilWarnaListener() {
@Override
public void onOk(AmbilWarnaDialog dialog, int color) {
// color is the color selected by the user.
colorChanged(color);
}
@Override
public void onCancel(AmbilWarnaDialog dialog) {
// cancel was selected by the user
}
});
dialog.show();
}
});
btnUndo.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
drawView.onClickUndo();
}
});
btnRedo.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
drawView.onClickRedo();
}
});
btnDone.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Log.v(TAG, "Here");
Bitmap editedImage = Bitmap.createBitmap(drawView
.getDrawingCache());
editedImage = Bitmap.createScaledBitmap(editedImage, 200, 300,
true);
if (editedImage != null) {
Intent intent = new Intent();
intent.putExtra(ChooseActivity.BITMAP, editedImage);
// AddReportItemActivity.mPhoto =
// drawView.getDrawingCache();
setResult(SUCCESS, intent);
finish();
}
}
});
}
public void resetButtons() {
btnText.setSelected(false);
btnSketch.setSelected(false);
btnColor.setSelected(false);
btnUndo.setSelected(false);
btnRedo.setSelected(false);
}
public class DrawingPanel extends ImageView implements OnTouchListener {
Paint paint = new Paint();
private Canvas mCanvas, c2;
private Path mPath;
private Paint mPaint, mBitmapPaint;
private ArrayList<PathPoints> paths = new ArrayList<PathPoints>();
private ArrayList<PathPoints> undonePaths = new ArrayList<PathPoints>();
private Bitmap mBitmap, Transparent, Bitmap2;
private int color;
private int x, y;
private boolean isTouched = false;
public DrawingPanel(Context context, int color) {
super(context);
this.color = color;
setFocusable(true);
setFocusableInTouchMode(true);
DisplayMetrics metrics = context.getResources().getDisplayMetrics();
int width = metrics.widthPixels;
int height = metrics.heightPixels;
this.setOnTouchListener(this);
Transparent = Bitmap.createBitmap(width, height,
Bitmap.Config.ARGB_8888);
mBitmapPaint = new Paint(Paint.DITHER_FLAG);
Bitmap2 = BitmapFactory.decodeResource(getResources(),
R.drawable.test);
// setBackgroundResource(R.drawable.test);
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(color);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(3);
mPaint.setTextSize(30);
c2 = new Canvas();
c2.setBitmap(Transparent);
// c2.drawBitmap(Bitmap1, 0, 0, null);
//c2.drawBitmap(Bitmap2, 0, 0, mPaint);
mPaint.setAlpha(0);
// mPaint.setStyle(Style.FILL);
mPaint.setXfermode(new PorterDuffXfermode(Mode.CLEAR));
mPaint.setAntiAlias(true);
mPath = new Path();
paths.add(new PathPoints(mPath, color, false));
mCanvas = new Canvas();
}
public void colorChanged(int color) {
this.color = color;
mPaint.setColor(color);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
// mBitmap = AddReportItemActivity.mPhoto;
Drawable myDrawable = getResources().getDrawable(
R.drawable.ic_launcher);
mBitmap = ((BitmapDrawable) myDrawable).getBitmap();
Drawable myDrawable2 = getResources().getDrawable(
R.drawable.test);
Bitmap2 = ((BitmapDrawable) myDrawable2).getBitmap();
// mBitmap =
// getIntent().getExtras().getParcelable(ChooseActivity.BITMAP);
float xscale = (float) w / (float) mBitmap.getWidth();
float yscale = (float) h / (float) mBitmap.getHeight();
if (xscale > yscale) // make sure both dimensions fit (use the
// smaller scale)
xscale = yscale;
float newx = (float) w * xscale;
float newy = (float) h * xscale; // use the same scale for both
// dimensions
float xscale1 = (float) w / (float) Bitmap2.getWidth()-10;
float yscale1 = (float) h / (float) Bitmap2.getHeight()-10;
if (xscale1 > yscale1) // make sure both dimensions fit (use the
// smaller scale)
xscale1 = yscale1;
float newx1 = (float) w * xscale;
float newy1 = (float) h * xscale;
// if you want it centered on the display (black borders)
mBitmap = Bitmap.createScaledBitmap(mBitmap, this.getWidth(),
this.getHeight(), true);
Bitmap2 = Bitmap.createScaledBitmap(Bitmap2, this.getWidth()-10,
this.getHeight()-10, true);
// mCanvas = new Canvas(mBitmap);
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
c2.drawBitmap(Bitmap2, 0, 0, mBitmapPaint);
canvas.drawBitmap(Transparent, 0, 0, null);
// c2.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
for (PathPoints p : paths) {
mPaint.setColor(p.getColor());
Log.v("", "Color code : " + p.getColor());
if (p.isTextToDraw()) {
canvas.drawText(p.textToDraw, p.x, p.y, mPaint);
} else {
// if(isTouched)
//{
// canvas.drawPath(p.getPath(), mPaint);
c2.drawPath(p.getPath(), mPaint);
//canvas.drawPath(p.getPath(),mPaint);
// canvas.drawBitmap(mBitmap, 0, 0, null);
// c2.drawPath(p.getPath(), mPaint);
// c2.drawCircle(X, Y, 50, mPaint);
// canvas.drawBitmap(mBitmap, 0, 0, null);
// canvas.drawBitmap(mBitmap, 0, 0, null);
// }
// canvas.drawBitmap(Transparent, 0, 0, null);
//canvas.drawPath(p.getPath(), mPaint);
}
}
}
private float mX, mY;
private static final float TOUCH_TOLERANCE = 0;
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(new PathPoints(mPath, color, false));
}
private void drawText(int x, int y) {
Log.v(TAG, "Here");
Log.v(TAG, "X " + x + " Y " + y);
this.x = x;
this.y = y;
paths.add(new PathPoints(color, textToDraw, true, x, y));
// mCanvas.drawText(textToDraw, x, y, mPaint);
}
@Override
public boolean onTouch(View arg0, MotionEvent event) {
isTouched=true;
float x = event.getX();
float y = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
if (!isTextModeOn) {
touch_start(x, y);
invalidate();
}
break;
case MotionEvent.ACTION_MOVE:
if (!isTextModeOn) {
touch_move(x, y);
invalidate();
}
break;
case MotionEvent.ACTION_UP:
if (isTextModeOn) {
drawText((int) x, (int) y);
invalidate();
} else {
touch_up();
invalidate();
}
break;
}
return true;
}
public void onClickUndo() {
if (paths.size() > 0) {
undonePaths.add(paths.remove(paths.size() - 1));
invalidate();
} else {
}
// toast the user
}
public void onClickRedo() {
if (undonePaths.size() > 0) {
paths.add(undonePaths.remove(undonePaths.size() - 1));
invalidate();
} else {
}
// toast the user
}
}
/*
* public class MyView extends View {
*
* private static final float MINP = 0.25f; private static final float MAXP
* = 0.75f;
*
* private Bitmap mBitmap; private Canvas mCanvas; private Path mPath;
* private Paint mBitmapPaint; private ArrayList<Path> undoablePaths;
*
* public MyView(Context c) { super(c);
*
* mPath = new Path(); mBitmapPaint = new Paint(Paint.DITHER_FLAG);
* undoablePaths=new ArrayList<Path>(); }
*
*
* @Override protected void onSizeChanged(int w, int h, int oldw, int oldh)
* { super.onSizeChanged(w, h, oldw, oldh); mBitmap =
* CaptureActivity.mPhoto; mCanvas = new Canvas(mBitmap); }
*
* @Override protected void onDraw(Canvas canvas) {
* canvas.drawColor(0xFFAAAAAA);
*
* canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
*
* canvas.drawPath(mPath, mPaint);
*
* for(Path path : undoablePaths){ canvas.drawPath(path, mPaint); } }
*
* private float mX, mY; private static final float TOUCH_TOLERANCE = 4;
*
* private void touch_start(float x, float y) { mPath=new Path();
* 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); // Path tempPath=mPath;
* undoablePaths.add(mPath); // kill this so we don't double draw
* mPath.reset(); }
*
* @Override public boolean onTouchEvent(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; }
*
* public void undoLastAction() { undoablePaths.remove(undoablePaths.size()
* - 1); invalidate();
*
* } }
*/
public void colorChanged(int color) {
// TODO Auto-generated method stub
lastColor = color;
drawView.colorChanged(lastColor);
}
class PathPoints {
private Path path;
// private Paint mPaint;
private int color;
private String textToDraw;
private boolean isTextToDraw;
private int x, y;
public PathPoints(Path path, int color, boolean isTextToDraw) {
this.path = path;
this.color = color;
this.isTextToDraw = isTextToDraw;
}
public PathPoints(int color, String textToDraw, boolean isTextToDraw,
int x, int y) {
this.color = color;
this.textToDraw = textToDraw;
this.isTextToDraw = isTextToDraw;
this.x = x;
this.y = y;
}
public Path getPath() {
return path;
}
public void setPath(Path path) {
this.path = path;
}
/*
* private Paint getPaint() { mPaint = new Paint();
* mPaint.setAntiAlias(true); mPaint.setColor(color);
* mPaint.setStyle(Paint.Style.STROKE);
* mPaint.setStrokeJoin(Paint.Join.ROUND);
* mPaint.setStrokeCap(Paint.Cap.ROUND); mPaint.setStrokeWidth(6);
* return mPaint; }
*/
public int getColor() {
return color;
}
public void setColor(int color) {
this.color = color;
}
public String getTextToDraw() {
return textToDraw;
}
public void setTextToDraw(String textToDraw) {
this.textToDraw = textToDraw;
}
public boolean isTextToDraw() {
return isTextToDraw;
}
public void setTextToDraw(boolean isTextToDraw) {
this.isTextToDraw = isTextToDraw;
}
public int getX() {
return x;
}
public void setX(int x) {
this.x = x;
}
public int getY() {
return y;
}
public void setY(int y) {
this.y = y;
}
}
}
答案 1 :(得分：0)
确保在进行任何绘图之前在画布上设置了alpha图层：
canvas.saveLayerAlpha(0, 0, canvas.getWidth(), canvas.getHeight(), 0xff, Canvas.HAS_ALPHA_LAYER_SAVE_FLAG);