Sorry, perhaps I was not clear in the description what the bug is. I will attempt to explain it in better detail here.
When you perform the following touch pattern: 1) place finger 1 down 2) place finger 2 down 3) remove finger 1 4) place finger 1 back down again The ACTION_POINTER_DOWN event that is generated during step 4 returns the incorrect X and Y location for where the event occurred. In fact, the X, and Y that is returned is the X and Y location for the other finger. Searching the entire history of the motionevent shows that there is no record of the X, Y for finger 1. Running the above code illustrates the problem and makes it obvious. As when you replace finger 1 and start to move it, it suddenly draws a line from finger 2 to finger 1, connecting the two, thus illustrating the bug. If you run the code and observe the output when performing the above actions, you will see clearly the problem. I have debugged this and looked at every point in every motionevent that is captured, and during step 4, the X, Y locations for finger 1 are not anywhere to be found. Ot is only during an ACTION_MOVE that new X, Y values for finger 1 appear. As an aside, if you then remove finger 1 again, the ACTION_POINTER_UP event tells you that finger 2 is coming up according to the ID. This is also a bug. I hope this helps. I can try to post screens of this if that will also help. -Colin On Jan 15, 2:35 pm, rollbak <[email protected]> wrote: > Can you please explain which the issue is? > > On Jan 15, 1:09 pm, Mirmathrax <[email protected]> wrote: > > > Multi-touch API is bugged (at least on Motorola Droid). Here is a > > method to reproduce the error for analysis: > > > 1) Create a new android project in Eclipse with the following fields: > > > Project name: PointerLocation > > Build target: Android 2.0.1 > > Application Name: PointerLocation > > Package Name: com.example.pointerlocation > > Create Activity: PointerLocation > > > 2) Copy the following code and paste this into the > > PointerLocation.java file that is automatically created > > > /* > > * Copyright (C) 2007 The Android Open Source Project > > * > > * Licensed under the Apache License, Version 2.0 (the "License"); > > * you may not use this file except in compliance with the License. > > * You may obtain a copy of the License at > > * > > * http://www.apache.org/licenses/LICENSE-2.0 > > * > > * Unless required by applicable law or agreed to in writing, software > > * distributed under the License is distributed on an "AS IS" BASIS, > > * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or > > implied. > > * See the License for the specific language governing permissions and > > * limitations under the License. > > */ > > > package com.example.pointerlocation; > > > import android.app.Activity; > > import android.content.Context; > > import android.graphics.Canvas; > > import android.graphics.Paint; > > import android.graphics.Paint.FontMetricsInt; > > import android.os.Bundle; > > import android.util.Log; > > import android.view.MotionEvent; > > import android.view.ViewConfiguration; > > import android.view.WindowManager; > > import android.view.VelocityTracker; > > import android.view.View; > > > import java.util.ArrayList; > > > /** > > * Demonstrates wrapping a layout in a ScrollView. > > * > > */ > > public class PointerLocation extends Activity { > > @Override > > protected void onCreate(Bundle icicle) { > > super.onCreate(icicle); > > setContentView(new MyView(this)); > > > // Make the screen full bright for this activity. > > WindowManager.LayoutParams lp = getWindow().getAttributes(); > > lp.screenBrightness = 1.0f; > > getWindow().setAttributes(lp); > > } > > > public static class PointerState { > > private final ArrayList<Float> mXs = new ArrayList<Float>(); > > private final ArrayList<Float> mYs = new ArrayList<Float>(); > > private boolean mCurDown; > > private int mCurX; > > private int mCurY; > > private float mCurPressure; > > private float mCurSize; > > private int mCurWidth; > > private VelocityTracker mVelocity; > > } > > > public class MyView extends View { > > private final ViewConfiguration mVC; > > private final Paint mTextPaint; > > private final Paint mTextBackgroundPaint; > > private final Paint mTextLevelPaint; > > private final Paint mPaint; > > private final Paint mTargetPaint; > > private final Paint mPathPaint; > > private final FontMetricsInt mTextMetrics = new FontMetricsInt > > (); > > private int mHeaderBottom; > > private boolean mCurDown; > > private int mCurNumPointers; > > private int mMaxNumPointers; > > private final ArrayList<PointerState> mPointers > > = new ArrayList<PointerState>(); > > > public MyView(Context c) { > > super(c); > > mVC = ViewConfiguration.get(c); > > mTextPaint = new Paint(); > > mTextPaint.setAntiAlias(true); > > mTextPaint.setTextSize(10 > > * getResources().getDisplayMetrics().density); > > mTextPaint.setARGB(255, 0, 0, 0); > > mTextBackgroundPaint = new Paint(); > > mTextBackgroundPaint.setAntiAlias(false); > > mTextBackgroundPaint.setARGB(128, 255, 255, 255); > > mTextLevelPaint = new Paint(); > > mTextLevelPaint.setAntiAlias(false); > > mTextLevelPaint.setARGB(192, 255, 0, 0); > > mPaint = new Paint(); > > mPaint.setAntiAlias(true); > > mPaint.setARGB(255, 255, 255, 255); > > mPaint.setStyle(Paint.Style.STROKE); > > mPaint.setStrokeWidth(2); > > mTargetPaint = new Paint(); > > mTargetPaint.setAntiAlias(false); > > mTargetPaint.setARGB(255, 0, 0, 192); > > mPathPaint = new Paint(); > > mPathPaint.setAntiAlias(false); > > mPathPaint.setARGB(255, 0, 96, 255); > > mPaint.setStyle(Paint.Style.STROKE); > > mPaint.setStrokeWidth(1); > > > PointerState ps = new PointerState(); > > ps.mVelocity = VelocityTracker.obtain(); > > mPointers.add(ps); > > } > > > @Override > > protected void onMeasure(int widthMeasureSpec, int > > heightMeasureSpec) { > > super.onMeasure(widthMeasureSpec, heightMeasureSpec); > > mTextPaint.getFontMetricsInt(mTextMetrics); > > mHeaderBottom = -mTextMetrics.ascent+mTextMetrics.descent > > +2; > > Log.i("foo", "Metrics: ascent=" + mTextMetrics.ascent > > + " descent=" + mTextMetrics.descent > > + " leading=" + mTextMetrics.leading > > + " top=" + mTextMetrics.top > > + " bottom=" + mTextMetrics.bottom); > > } > > > @Override > > protected void onDraw(Canvas canvas) { > > final int w = getWidth(); > > final int itemW = w/7; > > final int base = -mTextMetrics.ascent+1; > > final int bottom = mHeaderBottom; > > > final int NP = mPointers.size(); > > > if (NP > 0) { > > final PointerState ps = mPointers.get(0); > > canvas.drawRect(0, 0, itemW-1, > > bottom,mTextBackgroundPaint); > > canvas.drawText("P: " + mCurNumPointers + " / " + > > mMaxNumPointers, > > 1, base, mTextPaint); > > > final int N = ps.mXs.size(); > > if ((mCurDown && ps.mCurDown) || N == 0) { > > canvas.drawRect(itemW, 0, (itemW * 2) - 1, bottom, > > mTextBackgroundPaint); > > canvas.drawText("X: " + ps.mCurX, 1 + itemW, base, > > mTextPaint); > > canvas.drawRect(itemW * 2, 0, (itemW * 3) - 1, > > bottom, mTextBackgroundPaint); > > canvas.drawText("Y: " + ps.mCurY, 1 + itemW * 2, > > base, mTextPaint); > > } else { > > float dx = ps.mXs.get(N-1) - ps.mXs.get(0); > > float dy = ps.mYs.get(N-1) - ps.mYs.get(0); > > canvas.drawRect(itemW, 0, (itemW * 2) - 1, bottom, > > Math.abs(dx) < mVC.getScaledTouchSlop() > > ? mTextBackgroundPaint : mTextLevelPaint); > > canvas.drawText("dX: " + String.format("%.1f", > > dx), 1 + itemW, base, mTextPaint); > > canvas.drawRect(itemW * 2, 0, (itemW * 3) - 1, > > bottom, > > Math.abs(dy) < mVC.getScaledTouchSlop() > > ? mTextBackgroundPaint : mTextLevelPaint); > > canvas.drawText("dY: " + String.format("%.1f", > > dy), 1 + itemW * 2, base, mTextPaint); > > } > > > canvas.drawRect(itemW * 3, 0, (itemW * 4) - 1, bottom, > > mTextBackgroundPaint); > > int velocity = ps.mVelocity == null ? 0 : (int) > > (ps.mVelocity.getXVelocity() * 1000); > > canvas.drawText("Xv: " + velocity, 1 + itemW * 3, > > base, mTextPaint); > > > canvas.drawRect(itemW * 4, 0, (itemW * 5) - 1, bottom, > > mTextBackgroundPaint); > > velocity = ps.mVelocity == null ? 0 : (int) > > (ps.mVelocity.getYVelocity() * 1000); > > canvas.drawText("Yv: " + velocity, 1 + itemW * 4, > > base, mTextPaint); > > > canvas.drawRect(itemW * 5, 0, (itemW * 6) - 1, bottom, > > mTextBackgroundPaint); > > canvas.drawRect(itemW * 5, 0, (itemW * 5) + > > (ps.mCurPressure * itemW) - 1, > > bottom, mTextLevelPaint); > > canvas.drawText("Prs: " + String.format("%.2f", > > ps.mCurPressure), 1 + itemW * 5, > > base, mTextPaint); > > > canvas.drawRect(itemW * 6, 0, w, bottom, > > mTextBackgroundPaint); > > canvas.drawRect(itemW * 6, 0, (itemW * 6) + > > (ps.mCurSize * itemW) - 1, > > bottom, mTextLevelPaint); > > canvas.drawText("Size: " + String.format("%.2f", > > ps.mCurSize), 1 + itemW * 6, > > base, mTextPaint); > > } > > > for (int p=0; p<NP; p++) { > > final PointerState ps = mPointers.get(p); > > > if (mCurDown && ps.mCurDown) { > > canvas.drawLine(0, (int)ps.mCurY, getWidth(), (int) > > ps.mCurY, mTargetPaint); > > canvas.drawLine((int)ps.mCurX, 0, (int)ps.mCurX, > > getHeight(), mTargetPaint); > > > > ... > > read more »
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