Android实现触摸校正功能

当我第一次听到这个需求的时候，内心是迷茫的。触摸校正是个什么鬼，这个术语好像好多年之前才会有。想了想应该是电阻屏时代吧。然后又查资料知道了android不是电容屏吗，是不需要触摸校正的，而只有当年的电阻屏才需要触摸校正。这下我懵了，因为网上各种关于android触摸校正的资料都很少，还有很多是需要在源码环境改源码的，或者是通过aidl方式去做。（当时为了弄出来一个IWindowManager可是各种入坑啊！）好了，废话不多说，进入正题：

进入正题之前先给效果图吧，因为我为人比较厚道。

这一版触摸校正功能只用到了一个CalibrationActivity，onCreate里首先获取到了当前屏幕的宽高，

dpy = ((WindowManager) getSystemService(WINDOW_SERVICE)).getDefaultDisplay();X_RES = dpy.getWidth();Y_RES = dpy.getHeight();

然后会有一个初始化要触摸点的坐标的方法：

// TopLeft-->TopRight-->BottomRight-->BottomLeft-->Center// For 240 * 320 resolution, we use 50 pixel as edge gapprivate boolean initScreenPoints() {    cal.xfb[TOP_LEFT] = EDGE_GAP;                // TopLeft    cal.yfb[TOP_LEFT] = EDGE_GAP;    cal.xfb[TOP_RIGHT] = X_RES - EDGE_GAP;        // TopRight    cal.yfb[TOP_RIGHT] = EDGE_GAP;    cal.xfb[BOTTOM_RIGHT] = X_RES - EDGE_GAP;    // BottomRight    cal.yfb[BOTTOM_RIGHT] = Y_RES - EDGE_GAP;    cal.xfb[BOTTOM_LEFT] = EDGE_GAP;            // BottomLeft    cal.yfb[BOTTOM_LEFT] = Y_RES - EDGE_GAP;    cal.xfb[CENTER] = X_RES / 2;                // Center    cal.yfb[CENTER] = Y_RES / 2;    return true;}

接着就开始布局了，是new的一个自定义View：

setContentView(new MyView(this));

构造函数如下：

public MyView(Context c) {    super(c);    // set full screen and no title    requestWindowFeature(Window.FEATURE_NO_TITLE);    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,            WindowManager.LayoutParams.FLAG_FULLSCREEN);    mContext = c;    paint = new Paint();    paint.setDither(true);    paint.setAntiAlias(true); ////抗锯齿，如果没有调用这个方法，写上去的字不饱满，不美观，看地不太清楚    paint.setStrokeWidth(2); //设置空心线宽    paint.setColor(Color.WHITE);    paint.setStyle(Paint.Style.STROKE); //设置画笔风格，空心或者实心。    bmp = Bitmap.createBitmap(X_RES, Y_RES, Bitmap.Config.ARGB_8888);    cv = new Canvas(bmp);    screen_pos = 0;    drawCalibrationCross(screen_pos);}

接下来我要说的重点：是在onDraw方法里，因为原本这个触摸校正是没有界面的，只有5个触摸点，还是自己绘制的，所以我想在原有基础上不妨碍正常功能的同时，又能增加一个界面，之前试过几次，界面是弄出来了，但是会把原来的触摸点给遮住，就是空有其表，功能完全不能实现了，因此尝试过不少方法后，还是选择了canvas来绘制出我想要的效果：

前方高能预警，修改界面核心onDraw方法如下：

canvas.drawColor(Color.BLACK);canvas.drawBitmap(bmp, 0, 0, null);//“欢迎”字体大小float txt_welcome_size = 60;//“欢迎”字数float txt_welcome_count = 2;//"请按住光标……"字体大小float txt_content_size = 36;//"请按住十字光标以校准"字数float txt_content1_count = 10;//"你的屏幕"字数float txt_content2_count = 4;

//"欢迎"Paint p = new Paint();p.setTextSize(txt_welcome_size);p.setFakeBoldText(true);p.setColor(getResources().getColor(R.color.text_Welcome));canvas.drawText("欢迎",        (X_RES / 2) - (txt_welcome_size / 2) - txt_welcome_size / 2,        Y_RES / 2 - txt_welcome_size - 30,        p);//"请按住光标中央以校准"p.setFakeBoldText(false);p.setColor(getResources().getColor(R.color.text_content1));p.setTextSize(txt_content_size);//参数2（X_RES / 2 - (txt_content_size / 2 * txt_content1_count)）：当前屏幕宽度的一半减去字数canvas.drawText("请按住十字光标以校准",        X_RES / 2 - (txt_content_size / 2 * txt_content1_count),        Y_RES / 2 + 150,        p);//"你的屏幕"p.setColor(getResources().getColor(R.color.text_content1));p.setTextSize(txt_content_size);canvas.drawText("你的屏幕",        X_RES / 2 - txt_content_size / 2 * txt_content2_count,        Y_RES / 2 + 200,        p);//线,渐变效果!!!Shader shader = new LinearGradient((X_RES / 2) - (txt_welcome_size / 2) - txt_welcome_size * 2,        (Y_RES / 2) - txt_welcome_size,        X_RES / 2,        (Y_RES / 2) - txt_welcome_size,        new int[]{Color.WHITE, Color.GREEN},        null,        Shader.TileMode.MIRROR);p.setShader(shader);canvas.drawLine((X_RES / 2) - (txt_welcome_size / 2) - txt_welcome_size * 2,        (Y_RES / 2) - txt_welcome_size,        (X_RES / 2) + (txt_welcome_size / 2) + txt_welcome_size * 2,        (Y_RES / 2) - txt_welcome_size,        p);

此处主要是结合了坐标系，才能把你想要的效果摆放到正确的位置中去，因为居中显示其实在xml是很容易实现的，一个gravity=center就行，但是在代码里，特别现在还是在onDraw里，就不能这么干了，因为试了好多次都不能居中显示。

首先确定好要显示的字数，然后setTextSize，确定好字体大小，接着就调用canvas.drawText进行绘制了,

canvas.drawText("你的屏幕",        X_RES / 2 - txt_content_size / 2 * txt_content2_count,        Y_RES / 2 + 200,        p);

参数1为x轴坐标点，参数2位y轴坐标点，参数3为画笔的实例p。

如果想要居中，就是要自己算字数和字体大小，然后用屏幕宽度一减就ok了，算法不难，可以自己试试。

然后因为原本xml中是一个横线的图片作为分隔，很好看，但是这里onDraw里面不好弄图片（也许是我不知道），我就自己画了一条线，并且还弄出了渐变的效果，虽不及原图，但也六七不离八了。

CalibrationActivity.java 代码如下：

public class CalibrationActivity extends BaseActivity {    static final int SAMPLE_COUNTS = 5;    static final int POINT_DEGREE = 2;    static final int FACTOR_COUNTS = 7;    static final int TOP_LEFT = 0;    static final int TOP_RIGHT = 1;    static final int BOTTOM_RIGHT = 2;    static final int BOTTOM_LEFT = 3;    static final int CENTER = 4;    static final int X_AXIS = 0;    static final int Y_AXIS = 1;    static final int EDGE_GAP = 50;    static final String CALIBRATION_FILE = "/data/pointercal";    static final String TAG = "CalibrationActivity";    static final boolean DEBUG = true;    private int X_RES;    private int Y_RES;    private Display dpy;    private calibration cal;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        cal = new calibration();        dpy = ((WindowManager) getSystemService(WINDOW_SERVICE)).getDefaultDisplay();        X_RES = dpy.getWidth();        Y_RES = dpy.getHeight();        initScreenPoints();        setContentView(new CalibrationView(this));    }    class calibration {        int x[] = new int[5];        int y[] = new int[5];        int xfb[] = new int[5];        int yfb[] = new int[5];        int a[] = new int[7];    }    // TopLeft-->TopRight-->BottomRight-->BottomLeft-->Center    // For 240 * 320 resolution, we use 50 pixel as edge gap    private boolean initScreenPoints() {        cal.xfb[TOP_LEFT] = EDGE_GAP;                // TopLeft        cal.yfb[TOP_LEFT] = EDGE_GAP;        cal.xfb[TOP_RIGHT] = X_RES - EDGE_GAP;        // TopRight        cal.yfb[TOP_RIGHT] = EDGE_GAP;        cal.xfb[BOTTOM_RIGHT] = X_RES - EDGE_GAP;    // BottomRight        cal.yfb[BOTTOM_RIGHT] = Y_RES - EDGE_GAP;        cal.xfb[BOTTOM_LEFT] = EDGE_GAP;            // BottomLeft        cal.yfb[BOTTOM_LEFT] = Y_RES - EDGE_GAP;        cal.xfb[CENTER] = X_RES / 2;                // Center        cal.yfb[CENTER] = Y_RES / 2;        return true;    }    private boolean perform_calibration() {        float n, x, y, x2, y2, xy, z, zx, zy;        float det, a, b, c, e, f, g;        float scaling = (float) 65536.0;        n = x = y = x2 = y2 = xy = 0;        for (int i = 0; i < SAMPLE_COUNTS; i++) {            n += 1.0;            x += (float) cal.x[i];            y += (float) cal.y[i];            x2 += (float) (cal.x[i] * cal.x[i]);            y2 += (float) (cal.y[i] * cal.y[i]);            xy += (float) (cal.x[i] * cal.y[i]);        }        det = n * (x2 * y2 - xy * xy) + x * (xy * y - x * y2) + y * (x * xy - y * x2);        if (det < 0.1 && det > -0.1) {            Log.w(TAG, "determinant is too small, det =" + det);            return false;        }        if (DEBUG) {            Log.i(TAG, "(n,x,y,x2,y2,xy,det)=("                    + n + ","                    + x + ","                    + y + ","                    + x2 + ","                    + y2 + ","                    + xy + ","                    + det + ")");        }        a = (x2 * y2 - xy * xy) / det;        b = (xy * y - x * y2) / det;        c = (x * xy - y * x2) / det;        e = (n * y2 - y * y) / det;        f = (x * y - n * xy) / det;        g = (n * x2 - x * x) / det;        Log.i(TAG, "(a,b,c,e,f,g)=("                + a + ","                + b + ","                + c + ","                + e + ","                + f + ","                + g + ")");        // Get sums for x calibration        z = zx = zy = 0;        for (int i = 0; i < SAMPLE_COUNTS; i++) {            z += (float) cal.xfb[i];            zx += (float) (cal.xfb[i] * cal.x[i]);            zy += (float) (cal.xfb[i] * cal.y[i]);        }        // Now multiply out to get the calibration for X coordination        cal.a[0] = (int) ((a * z + b * zx + c * zy) * (scaling));        cal.a[1] = (int) ((b * z + e * zx + f * zy) * (scaling));        cal.a[2] = (int) ((c * z + f * zx + g * zy) * (scaling));        // Get sums for y calibration        z = zx = zy = 0;        for (int i = 0; i < SAMPLE_COUNTS; i++) {            z += (float) cal.yfb[i];            zx += (float) (cal.yfb[i] * cal.x[i]);            zy += (float) (cal.yfb[i] * cal.y[i]);        }        // Now multiply out to get the calibration for Y coordination        cal.a[3] = (int) ((a * z + b * zx + c * zy) * (scaling));        cal.a[4] = (int) ((b * z + e * zx + f * zy) * (scaling));        cal.a[5] = (int) ((c * z + f * zx + g * zy) * (scaling));        cal.a[6] = (int) scaling;        return true;    }    private boolean saveCalibrationResult() {        FileOutputStream fos;        String res = "";        // save the calibration factor in file system for InputDevice        try {            fos = openFileOutput("pointercal.txt", Context.MODE_PRIVATE);            res = String.format("%d %d %d %d %d %d %d", cal.a[1], cal.a[2], cal.a[0], cal.a[4], cal.a[5], cal.a[3], cal.a[6]);            if (DEBUG) {                Log.i(TAG, "calibration result=" + res);            }            fos.write(res.getBytes());            fos.close();        } catch (FileNotFoundException e1) {            // TODO Auto-generated catch block            e1.printStackTrace();            Log.w(TAG, "open calibration file write error: " + CALIBRATION_FILE);        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        return true;    }    public class CalibrationView extends View {        private Canvas cv;        private Paint paint;        private Bitmap bmp;        private int screen_pos;        private Context mContext;        public CalibrationView(Context c) {            super(c);            // set full screen and no title            requestWindowFeature(Window.FEATURE_NO_TITLE);            getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,                    WindowManager.LayoutParams.FLAG_FULLSCREEN);            mContext = c;            paint = new Paint();            paint.setDither(true);            paint.setAntiAlias(true); ////抗锯齿，如果没有调用这个方法，写上去的字不饱满，不美观，看地不太清楚            paint.setStrokeWidth(2); //设置空心线宽            paint.setColor(Color.WHITE);            paint.setStyle(Paint.Style.STROKE); //设置画笔风格，空心或者实心。            bmp = Bitmap.createBitmap(X_RES, Y_RES, Bitmap.Config.ARGB_8888);            cv = new Canvas(bmp);            screen_pos = 0;            drawCalibrationCross(screen_pos);        }        protected void onDraw(Canvas canvas) {            canvas.drawColor(Color.BLACK);            canvas.drawBitmap(bmp, 0, 0, null);            //“欢迎”字体大小            float txt_welcome_size = 60;            //“欢迎”字数            float txt_welcome_count = 2;            //"请按住十字光标以校准"字体大小            float txt_content_size = 36;            //"请按住十字光标以校准"字数            float txt_content1_count = 10;            //"你的屏幕"字数            float txt_content2_count = 4;            //"欢迎"            Paint p = new Paint();            p.setTextSize(txt_welcome_size);            p.setFakeBoldText(true);            p.setColor(getResources().getColor(R.color.text_Welcome));            canvas.drawText("欢迎",                    (X_RES / 2) - (txt_welcome_size / 2) - txt_welcome_size / 2,                    Y_RES / 2 - txt_welcome_size - 30,                    p);            //"请按住光标中央以校准"            p.setFakeBoldText(false);            p.setColor(getResources().getColor(R.color.text_content1));            p.setTextSize(txt_content_size);            //参数2（X_RES / 2 - (txt_content_size / 2 * txt_content1_count)）：当前屏幕宽度的一半减去字数            canvas.drawText("请按住十字光标以校准",                    X_RES / 2 - (txt_content_size / 2 * txt_content1_count),                    Y_RES / 2 + 150,                    p);            //"你的屏幕"            p.setColor(getResources().getColor(R.color.text_content1));            p.setTextSize(txt_content_size);            canvas.drawText("你的屏幕",                    X_RES / 2 - txt_content_size / 2 * txt_content2_count,                    Y_RES / 2 + 200,                    p);            //线,渐变效果!!!            Shader shader = new LinearGradient((X_RES / 2) - (txt_welcome_size / 2) - txt_welcome_size * 2,                    (Y_RES / 2) - txt_welcome_size,                    X_RES / 2,                    (Y_RES / 2) - txt_welcome_size,                    new int[]{Color.WHITE, Color.GREEN},                    null,                    Shader.TileMode.MIRROR);            p.setShader(shader);            canvas.drawLine((X_RES / 2) - (txt_welcome_size / 2) - txt_welcome_size * 2,                    (Y_RES / 2) - txt_welcome_size,                    (X_RES / 2) + (txt_welcome_size / 2) + txt_welcome_size * 2,                    (Y_RES / 2) - txt_welcome_size,                    p);        }        private boolean drawCalibrationCross(int pos) {            if (DEBUG) {                Log.i(TAG, "draw cross at pos " + pos);            }            cv.drawColor(Color.BLACK);            // draw X line            cv.drawLine(cal.xfb[pos] - 10, cal.yfb[pos],                    cal.xfb[pos] - 2, cal.yfb[pos], paint);            cv.drawLine(cal.xfb[pos] + 2, cal.yfb[pos],                    cal.xfb[pos] + 10, cal.yfb[pos], paint);            // draw Y line            cv.drawLine(cal.xfb[pos], cal.yfb[pos] - 10,                    cal.xfb[pos], cal.yfb[pos] - 2, paint);            cv.drawLine(cal.xfb[pos], cal.yfb[pos] + 2,                    cal.xfb[pos], cal.yfb[pos] + 10, paint);            invalidate();            return true;        }        public boolean onTouchEvent(MotionEvent event) {            float tmpx, tmpy;            boolean ret;            if (screen_pos > SAMPLE_COUNTS - 1) {                Log.i(TAG, "get sample ok");                return true;            }            if (event.getAction() == MotionEvent.ACTION_UP) {                tmpx = event.getX();                tmpy = event.getY();                if (Math.abs(cal.xfb[screen_pos] - tmpx) > 15 &&                        Math.abs(cal.yfb[screen_pos] - tmpy) > 15) {                    UIUtils.showToast(mContext, "无效的校准点");                    return false;                }                cal.x[screen_pos] = (int) (event.getX() * 4096.0 / (float) X_RES + 0.5);                cal.y[screen_pos] = (int) (event.getY() * 4096.0 / (float) Y_RES + 0.5);                if (screen_pos == 4) {                    ret = perform_calibration();                    if (ret) {                        saveCalibrationResult();                        UIUtils.showToast(mContext, "校正完毕!");                        Intent intent = new Intent(CalibrationActivity.this, CalibrationCompleteActivity.class);                        startActivity(intent);                        return true;                    } else {                        screen_pos = 0;                        Log.w(TAG, "Calibration failed");                    }                } else {                    screen_pos++;                    drawCalibrationCross(screen_pos);                }            }            return true;        }    }}

要点解释：BaseActivity里面主要就写了两个方法，一个是将所有Activity添加进一个Activity的list，命名为ActivityCollector，这样是为了当校正完成跳转到第二个Activity后，点击确定能关闭所有Activity直接退出程序；第二个是remove掉Activity，使其finish。ActivityCollector里面分别有：

public static void addActivity(Activity activity) {    activities.add(activity);}public static void removeActivity(Activity activity) {    activities.remove(activity);}public static void finishAll() {    for (Activity activity : activities) {        if (!activity.isFinishing()) {            activity.finish();        }    }}

这三个方法。

目测我写的代码还是很好懂的，触摸校正的具体算法代码是参照网上的，针对当前触摸校正功能的界面以及其他的一些细节是我修改的。有写的不对或有更好方法实现的话，还请大神们不吝赐教，本人将虚心接受，在撸码的道路上越走越远！

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