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Android example source code file (PointerLocationView.java)

This example Android source code file (PointerLocationView.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" TM.

Java - Android tags/keywords

android, arraylist, down, drawing, fontmetricsint, graphics, ni, np, override, paint, pointer, pointerlocationview, pointerstate, prs, size, ui, up, util, velocitytracker, view

The PointerLocationView.java Android example source code

/*
 * Copyright (C) 2010 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.android.internal.widget;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Paint.FontMetricsInt;
import android.util.Log;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewConfiguration;

import java.util.ArrayList;

public class PointerLocationView extends View {
    public static class PointerState {
        private final ArrayList<Float> mXs = new ArrayList();
        private final ArrayList<Float> mYs = new ArrayList();
        private boolean mCurDown;
        private int mCurX;
        private int mCurY;
        private float mCurPressure;
        private float mCurSize;
        private int mCurWidth;
        private VelocityTracker mVelocity;
    }

    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>();
    
    private boolean mPrintCoords = true;
    
    public PointerLocationView(Context c) {
        super(c);
        setFocusable(true);
        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);
    }

    public void setPrintCoords(boolean state) {
        mPrintCoords = state;
    }
    
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        mTextPaint.getFontMetricsInt(mTextMetrics);
        mHeaderBottom = -mTextMetrics.ascent+mTextMetrics.descent+2;
        if (false) {
            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) {
        synchronized (mPointers) {
            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);
                    int pressureLevel = (int)(ps.mCurPressure*255);
                    mPaint.setARGB(255, pressureLevel, 128, 255-pressureLevel);
                    canvas.drawPoint(ps.mCurX, ps.mCurY, mPaint);
                    canvas.drawCircle(ps.mCurX, ps.mCurY, ps.mCurWidth, mPaint);
                }
            }
            
            for (int p=0; p<NP; p++) {
                final PointerState ps = mPointers.get(p);
                
                final int N = ps.mXs.size();
                float lastX=0, lastY=0;
                boolean haveLast = false;
                boolean drawn = false;
                mPaint.setARGB(255, 128, 255, 255);
                for (int i=0; i<N; i++) {
                    float x = ps.mXs.get(i);
                    float y = ps.mYs.get(i);
                    if (Float.isNaN(x)) {
                        haveLast = false;
                        continue;
                    }
                    if (haveLast) {
                        canvas.drawLine(lastX, lastY, x, y, mPathPaint);
                        canvas.drawPoint(lastX, lastY, mPaint);
                        drawn = true;
                    }
                    lastX = x;
                    lastY = y;
                    haveLast = true;
                }
                
                if (drawn) {
                    if (ps.mVelocity != null) {
                        mPaint.setARGB(255, 255, 64, 128);
                        float xVel = ps.mVelocity.getXVelocity() * (1000/60);
                        float yVel = ps.mVelocity.getYVelocity() * (1000/60);
                        canvas.drawLine(lastX, lastY, lastX+xVel, lastY+yVel, mPaint);
                    } else {
                        canvas.drawPoint(lastX, lastY, mPaint);
                    }
                }
            }
        }
    }

    public void addTouchEvent(MotionEvent event) {
        synchronized (mPointers) {
            int action = event.getAction();
            
            //Log.i("Pointer", "Motion: action=0x" + Integer.toHexString(action)
            //        + " pointers=" + event.getPointerCount());
            
            int NP = mPointers.size();
            
            //mRect.set(0, 0, getWidth(), mHeaderBottom+1);
            //invalidate(mRect);
            //if (mCurDown) {
            //    mRect.set(mCurX-mCurWidth-3, mCurY-mCurWidth-3,
            //            mCurX+mCurWidth+3, mCurY+mCurWidth+3);
            //} else {
            //    mRect.setEmpty();
            //}
            if (action == MotionEvent.ACTION_DOWN) {
                for (int p=0; p<NP; p++) {
                    final PointerState ps = mPointers.get(p);
                    ps.mXs.clear();
                    ps.mYs.clear();
                    ps.mVelocity = VelocityTracker.obtain();
                    ps.mCurDown = false;
                }
                mPointers.get(0).mCurDown = true;
                mMaxNumPointers = 0;
                if (mPrintCoords) {
                    Log.i("Pointer", "Pointer 1: DOWN");
                }
            }
            
            if ((action&MotionEvent.ACTION_MASK) == MotionEvent.ACTION_POINTER_DOWN) {
                final int index = (action&MotionEvent.ACTION_POINTER_INDEX_MASK)
                        >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
                final int id = event.getPointerId(index);
                while (NP <= id) {
                    PointerState ps = new PointerState();
                    ps.mVelocity = VelocityTracker.obtain();
                    mPointers.add(ps);
                    NP++;
                }
                final PointerState ps = mPointers.get(id);
                ps.mVelocity = VelocityTracker.obtain();
                ps.mCurDown = true;
                if (mPrintCoords) {
                    Log.i("Pointer", "Pointer " + (id+1) + ": DOWN");
                }
            }
            
            final int NI = event.getPointerCount();
            
            mCurDown = action != MotionEvent.ACTION_UP
                    && action != MotionEvent.ACTION_CANCEL;
            mCurNumPointers = mCurDown ? NI : 0;
            if (mMaxNumPointers < mCurNumPointers) {
                mMaxNumPointers = mCurNumPointers;
            }
            
            for (int i=0; i<NI; i++) {
                final int id = event.getPointerId(i);
                final PointerState ps = mPointers.get(id);
                ps.mVelocity.addMovement(event);
                ps.mVelocity.computeCurrentVelocity(1);
                final int N = event.getHistorySize();
                for (int j=0; j<N; j++) {
                    if (mPrintCoords) {
                        Log.i("Pointer", "Pointer " + (id+1) + ": ("
                                + event.getHistoricalX(i, j)
                                + ", " + event.getHistoricalY(i, j) + ")"
                                + " Prs=" + event.getHistoricalPressure(i, j)
                                + " Size=" + event.getHistoricalSize(i, j));
                    }
                    ps.mXs.add(event.getHistoricalX(i, j));
                    ps.mYs.add(event.getHistoricalY(i, j));
                }
                if (mPrintCoords) {
                    Log.i("Pointer", "Pointer " + (id+1) + ": ("
                            + event.getX(i) + ", " + event.getY(i) + ")"
                            + " Prs=" + event.getPressure(i)
                            + " Size=" + event.getSize(i));
                }
                ps.mXs.add(event.getX(i));
                ps.mYs.add(event.getY(i));
                ps.mCurX = (int)event.getX(i);
                ps.mCurY = (int)event.getY(i);
                //Log.i("Pointer", "Pointer #" + p + ": (" + ps.mCurX
                //        + "," + ps.mCurY + ")");
                ps.mCurPressure = event.getPressure(i);
                ps.mCurSize = event.getSize(i);
                ps.mCurWidth = (int)(ps.mCurSize*(getWidth()/3));
            }
            
            if ((action&MotionEvent.ACTION_MASK) == MotionEvent.ACTION_POINTER_UP) {
                final int index = (action&MotionEvent.ACTION_POINTER_INDEX_MASK)
                        >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
                final int id = event.getPointerId(index);
                final PointerState ps = mPointers.get(id);
                ps.mXs.add(Float.NaN);
                ps.mYs.add(Float.NaN);
                ps.mCurDown = false;
                if (mPrintCoords) {
                    Log.i("Pointer", "Pointer " + (id+1) + ": UP");
                }
            }
            
            if (action == MotionEvent.ACTION_UP) {
                for (int i=0; i<NI; i++) {
                    final int id = event.getPointerId(i);
                    final PointerState ps = mPointers.get(id);
                    if (ps.mCurDown) {
                        ps.mCurDown = false;
                        if (mPrintCoords) {
                            Log.i("Pointer", "Pointer " + (id+1) + ": UP");
                        }
                    }
                }
            }
            
            //if (mCurDown) {
            //    mRect.union(mCurX-mCurWidth-3, mCurY-mCurWidth-3,
            //            mCurX+mCurWidth+3, mCurY+mCurWidth+3);
            //}
            //invalidate(mRect);
            postInvalidate();
        }
    }
    
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        addTouchEvent(event);
        return true;
    }

    @Override
    public boolean onTrackballEvent(MotionEvent event) {
        Log.i("Pointer", "Trackball: " + event);
        return super.onTrackballEvent(event);
    }
    
}

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