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 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;
}

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);
getWindo
23ff7
w().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：

[java] view
plain copy

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！