13：自定义view、自定义签字板

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

import com.landicorp.android.unionpay.util.TerminalInfo;

public class PaintView extends View {
    private Resources myResources;

    // 画笔，定义绘制属性
    private Paint myPaint;
    private Paint mBitmapPaint;

    // 绘制路径
    private Path myPath;

    // 画布及其底层位图
    private Bitmap myBitmap;
    private Canvas myCanvas;

    private float mX, mY;
    private static final float TOUCH_TOLERANCE = 4;

    // 记录宽度和高度
    private int mWidth;
    private int mHeight;

    public PaintView(Context context) {
        super(context);
    }

    public PaintView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public PaintView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
    
    public Bitmap getBitmap() {
        return myBitmap;
    }
    
    public void recycleBitmap() {
        if (myBitmap != null && !myBitmap.isRecycled()) {
            myBitmap.recycle();
            myBitmap = null;
        }
    }

    /**
     * 初始化工作
     */
    private void initialize() {
        // Get a reference to our resource table.
        myResources = getResources();
        
        float strokeWidth = 10;
        switch (TerminalInfo.getInstance().getDensityDPI()) {
        case 120:
        case 160:
            strokeWidth = 4f;
            break;
        case 240:
            strokeWidth = 6f;
            break;
        case 320:
            strokeWidth = 8f;
            break;
        case 480:
        default:
            strokeWidth = 12f;
            break;
        }

        // 绘制自由曲线用的画笔
        myPaint = new Paint();
        myPaint.setAntiAlias(true);
        myPaint.setDither(true);
        myPaint.setColor(myResources.getColor(android.R.color.background_dark));
        myPaint.setStyle(Paint.Style.STROKE);
        myPaint.setStrokeJoin(Paint.Join.ROUND);
        myPaint.setStrokeCap(Paint.Cap.ROUND);
        myPaint.setStrokeWidth(strokeWidth);

        myPath = new Path();
        
        myBitmap = Bitmap.createBitmap(mWidth, mHeight, Bitmap.Config.RGB_565);
        myCanvas = new Canvas(myBitmap);
        myCanvas.drawColor(0xffffffff);

        mBitmapPaint = new Paint(Paint.DITHER_FLAG);

    }
    
    @Override
    protected void onLayout(boolean changed, int left, int top, int right,
            int bottom) {        
        if(myCanvas == null) {
            this.mWidth = right - left;
            this.mHeight = bottom - top;
            
            initialize();
        }
        super.onLayout(changed, left, top, right, bottom);
    }

//    @Override
//    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
//        super.onSizeChanged(w, h, oldw, oldh);
//        mWidth = w;
//        mHeight = h;
//    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        float x = event.getX();
        float y = event.getY();

        switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            touch_start(x, y);
            invalidate();
            break;
        case MotionEvent.ACTION_MOVE:
            touch_move(x, y);
            invalidate();
            break;
        case MotionEvent.ACTION_UP:
            touch_up();
            invalidate();
            break;
        }
        return true;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        if (myBitmap != null && !myBitmap.isRecycled()) {
            // 背景颜色
            // canvas.drawColor(getResources().getColor(R.color.blue_dark));

            // 如果不调用这个方法，绘制结束后画布将清空
            canvas.drawBitmap(myBitmap, 0, 0, mBitmapPaint);

            // 绘制路径
            canvas.drawPath(myPath, myPaint);
        }

    }

    private void touch_start(float x, float y) {
        myPath.reset();
        myPath.moveTo(x, y);
        mX = x;
        mY = y;
    }

    private void touch_move(float x, float y) {
        float dx = Math.abs(x - mX);
        float dy = Math.abs(y - mY);
        if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {
            myPath.quadTo(mX, mY, (x + mX) / 2, (y + mY) / 2);
            mX = x;
            mY = y;
        }
    }

    private void touch_up() {
        myPath.lineTo(mX, mY);
        // commit the path to our offscreen
        // 如果少了这一句，笔触抬起时myPath重置，那么绘制的线将消失
        myCanvas.drawPath(myPath, myPaint);
        // kill this so we don‘t double draw
        myPath.reset();
    }

    /**
     * 清除整个图像
     */
    public void clear() {
        // 清除方法1：重新生成位图
//         myBitmap = Bitmap.createBitmap(mWidth, mHeight, Bitmap.Config.ARGB_8888);
//         myCanvas = new Canvas(myBitmap);

        // 清除方法2：将位图清除为白色
        myBitmap.eraseColor(myResources.getColor(android.R.color.white));

        // 两种清除方法都必须加上后面这两步：
        // 路径重置
        myPath.reset();
        myCanvas.drawColor(0xffffffff);
        // 刷新绘制
        invalidate();

    }

    public Bitmap getWaterMarkBitmap(String transCode, int width, int height) {

        // Typeface fontFace =
        // Typeface.createFromAsset(getContext().getAssets(),
        // "fonts/TIMES.TTF");

        Bitmap bitmap = Bitmap.createBitmap(width, height, Config.ARGB_8888);

        Canvas canvas = new Canvas(bitmap);

        int fontSize = 20;
        Path path = new Path();
        path.moveTo(0, height / 2);
        path.lineTo(width, height / 2);
        path.close();

        Paint paint = new Paint();
        paint.setColor(0xfff4f4f4);
        paint.setTextSize(fontSize);
        paint.setTypeface(TerminalInfo.getInstance().getSigndataTypeface(
                getContext()));
        paint.setStyle(Paint.Style.FILL_AND_STROKE);
        paint.setStrokeWidth(0);
        paint.setAntiAlias(false);
        paint.setDither(true);
        Rect bounds = new Rect();
        paint.getTextBounds(transCode, 0, transCode.length(), bounds);

        // float[] pos = new float[16];
        // for(int i=0; i<16; i++) {
        // pos[i] = 30 + i*12;
        // pos[i++] = 30;
        // }
        // canvas.drawPosText(transCode, pos, paint);

        // 璁剧疆闂磋窛
        int extend = 7;// 1px*7
        int hOffset = (width - (bounds.right - bounds.left) - extend) / 2;

        for (int i = 0; i < transCode.length(); i++) {
            canvas.drawTextOnPath(transCode.substring(i, i + 1), path, hOffset,
                    fontSize / 2, paint);
            hOffset += (bounds.right - bounds.left + extend) / 7;
        }

        return bitmap;
    }

    public Bitmap getOverLayBitmap(Bitmap src, Bitmap watermark) {

        if (src == null) {
            return null;
        }

        int srcWidth = src.getWidth();
        int srcHeight = src.getHeight();
        int markWidth = watermark.getWidth();
        int markHeight = watermark.getHeight();

        int width = srcWidth > markWidth ? srcWidth : markWidth;
        int height = srcHeight > markHeight ? srcHeight : markHeight;

        // 鍒涘缓涓?釜鍜屾簮浣嶅浘涓?牱澶у皬鐨勬柊浣嶅浘
        Bitmap bitmap = Bitmap.createBitmap(width, height, Config.ARGB_8888);

        Canvas canvas = new Canvas(bitmap);

        canvas.drawBitmap(src, Math.abs(width - srcWidth) / 2,
                Math.abs(height - srcHeight), null);// 浠?0,0)浣嶇疆寮?鐢绘簮浣嶅浘
        canvas.drawBitmap(watermark, Math.abs(width - markWidth) / 2,
                Math.abs(height - markHeight), null);// 浠?0,0)浣嶇疆寮?鐢绘按鍗?

        canvas.save(Canvas.ALL_SAVE_FLAG);

        canvas.restore();

        return bitmap;

    }
}