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POANDROID - MapView
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copied!<p>Can some one please help me few things regarding mapview im trying to build. I have a renderer that takes canvas and draws a bitmap in it. I have created a view and in constructor i create:</p> <pre><code>bitmap = Bitmap.createBitmap(windowWidth, windowHeight, Bitmap.Config.ARGB_8888); canvas = new Canvas(bitmap); drawable = new BitmapDrawable(bitmap); drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight()); this.Render(); </code></pre> <p>In onDraw method i have this:</p> <pre><code>super.onDraw(canvas); canvas.save(); canvas.translate(mPosX, mPosY); canvas.scale(mScaleFactor, mScaleFactor); drawable.draw(canvas); canvas.restore(); </code></pre> <p>Now i would like to implement pan and zoom (currently im working without saved tiles) Here is my onTouch:</p> <p>mScaleDetector.onTouchEvent(ev);</p> <pre><code>final int action = ev.getAction(); switch (action & MotionEvent.ACTION_MASK) { case MotionEvent.ACTION_DOWN: { this.hasPanned = false; final float x = ev.getX(); final float y = ev.getY(); mLastTouchX = x; mLastTouchY = y; mActivePointerId = ev.getPointerId(0); break; } case MotionEvent.ACTION_MOVE: { final int pointerIndex = ev.findPointerIndex(mActivePointerId); final float x = ev.getX(pointerIndex); final float y = ev.getY(pointerIndex); if (!mScaleDetector.isInProgress()) { final float dx = x - mLastTouchX; final float dy = y - mLastTouchY; mPosX += dx; mPosY += dy; invalidate(); } mLastTouchX = x; mLastTouchY = y; break; } case MotionEvent.ACTION_UP: { mActivePointerId = INVALID_POINTER_ID; if (this.mDownTouchX != this.mLastTouchX && this.mDownTouchY != mLastTouchY) this.hasPanned = true; break; } case MotionEvent.ACTION_CANCEL: { mActivePointerId = INVALID_POINTER_ID; break; } case MotionEvent.ACTION_POINTER_UP: { final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT; final int pointerId = ev.getPointerId(pointerIndex); if (pointerId == mActivePointerId) { final int newPointerIndex = pointerIndex == 0 ? 1 : 0; mLastTouchX = ev.getX(newPointerIndex); mLastTouchY = ev.getY(newPointerIndex); mActivePointerId = ev.getPointerId(newPointerIndex); } break; } } return true; </code></pre> <p>Here is what i would like and problems i have:</p> <ol> <li>When i pan i would like to calculate distance in pixels so i can tell my renderer when it renders the image again. How is this achieved? By remembering coordinates on ACTION_DOWN and comparing with new coordinates in ACTION_UP ?</li> <li>When pan is complete (and image is re-rendered) i would like to set the canvas(image) back to its original position. Currently it stays paned (because of canvas.translate?)</li> <li>How do i handle zoom gestures? With this code when doing a zoom-out with my fingers the image is "dragged" towards top left corner ...</li> </ol> <p>Im new in android (and java) so any help is preciated.</p>

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