StackOverflow2013

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copied!<p>I adapted some code to create a TouchImageView that supports multitouch (>2.1). It is inspired by the book <a href="http://pragprog.com/titles/eband3/hello-android" rel="noreferrer">Hello, Android! (3rd edition)</a></p> <p>It is contained within the following 3 files TouchImageView.java WrapMotionEvent.java EclairMotionEvent.java</p> <p><strong>TouchImageView.java</strong></p> <pre><code>import se.robertfoss.ChanImageBrowser.Viewer; import android.content.Context; import android.graphics.Bitmap; import android.graphics.Matrix; import android.graphics.PointF; import android.util.FloatMath; import android.util.Log; import android.view.MotionEvent; import android.view.View; import android.widget.ImageView; public class TouchImageView extends ImageView { private static final String TAG = "Touch"; // These matrices will be used to move and zoom image Matrix matrix = new Matrix(); Matrix savedMatrix = new Matrix(); // We can be in one of these 3 states static final int NONE = 0; static final int DRAG = 1; static final int ZOOM = 2; int mode = NONE; // Remember some things for zooming PointF start = new PointF(); PointF mid = new PointF(); float oldDist = 1f; Context context; public TouchImageView(Context context) { super(context); super.setClickable(true); this.context = context; matrix.setTranslate(1f, 1f); setImageMatrix(matrix); setScaleType(ScaleType.MATRIX); setOnTouchListener(new OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent rawEvent) { WrapMotionEvent event = WrapMotionEvent.wrap(rawEvent); // Dump touch event to log if (Viewer.isDebug == true){ dumpEvent(event); } // Handle touch events here... switch (event.getAction() & MotionEvent.ACTION_MASK) { case MotionEvent.ACTION_DOWN: savedMatrix.set(matrix); start.set(event.getX(), event.getY()); Log.d(TAG, "mode=DRAG"); mode = DRAG; break; case MotionEvent.ACTION_POINTER_DOWN: oldDist = spacing(event); Log.d(TAG, "oldDist=" + oldDist); if (oldDist > 10f) { savedMatrix.set(matrix); midPoint(mid, event); mode = ZOOM; Log.d(TAG, "mode=ZOOM"); } break; case MotionEvent.ACTION_UP: int xDiff = (int) Math.abs(event.getX() - start.x); int yDiff = (int) Math.abs(event.getY() - start.y); if (xDiff < 8 && yDiff < 8){ performClick(); } case MotionEvent.ACTION_POINTER_UP: mode = NONE; Log.d(TAG, "mode=NONE"); break; case MotionEvent.ACTION_MOVE: if (mode == DRAG) { // ... matrix.set(savedMatrix); matrix.postTranslate(event.getX() - start.x, event.getY() - start.y); } else if (mode == ZOOM) { float newDist = spacing(event); Log.d(TAG, "newDist=" + newDist); if (newDist > 10f) { matrix.set(savedMatrix); float scale = newDist / oldDist; matrix.postScale(scale, scale, mid.x, mid.y); } } break; } setImageMatrix(matrix); return true; // indicate event was handled } }); } public void setImage(Bitmap bm, int displayWidth, int displayHeight) { super.setImageBitmap(bm); //Fit to screen. float scale; if ((displayHeight / bm.getHeight()) >= (displayWidth / bm.getWidth())){ scale = (float)displayWidth / (float)bm.getWidth(); } else { scale = (float)displayHeight / (float)bm.getHeight(); } savedMatrix.set(matrix); matrix.set(savedMatrix); matrix.postScale(scale, scale, mid.x, mid.y); setImageMatrix(matrix); // Center the image float redundantYSpace = (float)displayHeight - (scale * (float)bm.getHeight()) ; float redundantXSpace = (float)displayWidth - (scale * (float)bm.getWidth()); redundantYSpace /= (float)2; redundantXSpace /= (float)2; savedMatrix.set(matrix); matrix.set(savedMatrix); matrix.postTranslate(redundantXSpace, redundantYSpace); setImageMatrix(matrix); } /** Show an event in the LogCat view, for debugging */ private void dumpEvent(WrapMotionEvent event) { // ... String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE", "POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" }; StringBuilder sb = new StringBuilder(); int action = event.getAction(); int actionCode = action & MotionEvent.ACTION_MASK; sb.append("event ACTION_").append(names[actionCode]); if (actionCode == MotionEvent.ACTION_POINTER_DOWN || actionCode == MotionEvent.ACTION_POINTER_UP) { sb.append("(pid ").append( action >> MotionEvent.ACTION_POINTER_ID_SHIFT); sb.append(")"); } sb.append("["); for (int i = 0; i < event.getPointerCount(); i++) { sb.append("#").append(i); sb.append("(pid ").append(event.getPointerId(i)); sb.append(")=").append((int) event.getX(i)); sb.append(",").append((int) event.getY(i)); if (i + 1 < event.getPointerCount()) sb.append(";"); } sb.append("]"); Log.d(TAG, sb.toString()); } /** Determine the space between the first two fingers */ private float spacing(WrapMotionEvent event) { // ... float x = event.getX(0) - event.getX(1); float y = event.getY(0) - event.getY(1); return FloatMath.sqrt(x * x + y * y); } /** Calculate the mid point of the first two fingers */ private void midPoint(PointF point, WrapMotionEvent event) { // ... float x = event.getX(0) + event.getX(1); float y = event.getY(0) + event.getY(1); point.set(x / 2, y / 2); } } </code></pre> <p><strong>WrapMotionEvent.java</strong></p> <pre><code>import android.view.MotionEvent; public class WrapMotionEvent { protected MotionEvent event; protected WrapMotionEvent(MotionEvent event) { this.event = event; } static public WrapMotionEvent wrap(MotionEvent event) { try { return new EclairMotionEvent(event); } catch (VerifyError e) { return new WrapMotionEvent(event); } } public int getAction() { return event.getAction(); } public float getX() { return event.getX(); } public float getX(int pointerIndex) { verifyPointerIndex(pointerIndex); return getX(); } public float getY() { return event.getY(); } public float getY(int pointerIndex) { verifyPointerIndex(pointerIndex); return getY(); } public int getPointerCount() { return 1; } public int getPointerId(int pointerIndex) { verifyPointerIndex(pointerIndex); return 0; } private void verifyPointerIndex(int pointerIndex) { if (pointerIndex > 0) { throw new IllegalArgumentException( "Invalid pointer index for Donut/Cupcake"); } } } </code></pre> <p><strong>EclairMotionEvent.java</strong></p> <pre><code>import android.view.MotionEvent; public class EclairMotionEvent extends WrapMotionEvent { protected EclairMotionEvent(MotionEvent event) { super(event); } public float getX(int pointerIndex) { return event.getX(pointerIndex); } public float getY(int pointerIndex) { return event.getY(pointerIndex); } public int getPointerCount() { return event.getPointerCount(); } public int getPointerId(int pointerIndex) { return event.getPointerId(pointerIndex); } } </code></pre>

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