水果忍者源代码（有说明）

package com.game.android.ninjia; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Path; import android.view.MotionEvent; import android.view.View; public class GestureView extends View { private Paint paint; private float startX = Float.NaN; private float startY = Float.NaN; private float endX = Float.NaN; private float endY = Float.NaN; //下层view //private View viewer; private static final int gestureColor = Color.rgb(153, 153, 153); private static final int alpha = 220; private static final int alpha_full = 255; //刀锋长度 private static final int shape_length = 40; //刀锋截短时间 private static final int shape_cut_time = 150; public static final float getGap(float x0, float y0, float x1, float y1) { return (float) Math.pow(Math.pow((x0 - x1), 2) + Math.pow((y0 - y1), 2), 0.5); } public GestureView(Context context) { super(context); paint = new Paint(); paint.setStyle(Paint.Style.FILL); } @Override public void onDraw(Canvas canvas) { super.onDraw(canvas); if (!Float.isNaN(startX) && !Float.isNaN(endY)) { float gap = getGap(startX, startY, endX, endY); float w = gap / 10; //背景shape外侧点高度 float h = w > 7 ? 7 : w; //填充shape外侧点高度 float h2 = h * 2 / 3; double length = Math.pow(Math.pow(w, 2) + Math.pow((h), 2), 0.5); double length2 = Math.pow(Math.pow(w, 2) + Math.pow((h2), 2), 0.5); double ang1_1 = Math.atan((endY - startY) / (endX - startX)); double ang1_2 = Math.atan(h / w); double angle1_1 = ang1_1 + ang1_2; double angle1_2 = ang1_1 - ang1_2; double ang2_2 = Math.atan(h2 / w); double angle2_1 = ang1_1 + ang2_2; double angle2_2 = ang1_1 - ang2_2; if (endX > startX) { float xx1 = endX - (float) (length * Math.cos(angle1_1)); float yy1 = endY - (float) (length * Math.sin(angle1_1)); float xx2 = endX - (float) (length * Math.cos(angle1_2)); float yy2 = endY - (float) (length * Math.sin(angle1_2)); float xx12 = endX - (float) (length2 * Math.cos(angle2_1)); float yy12 = endY - (float) (length2 * Math.sin(angle2_1)); float xx22 = endX - (float) (length2 * Math.cos(angle2_2)); float yy22 = endY - (float) (length2 * Math.sin(angle2_2)); Path backPath = new Path(); backPath.moveTo(startX, startY); backPath.lineTo(xx1, yy1); backPath.lineTo(endX, endY); backPath.lineTo(xx2, yy2); backPath.close(); Path fillPath = new Path(); fillPath.moveTo(startX, startY); fillPath.lineTo(xx12, yy12); fillPath.lineTo(endX, endY); fillPath.lineTo(xx22, yy22); fillPath.close(); paint.setColor(gestureColor); paint.setAlpha(alpha); canvas.drawPath(backPath, paint); paint.setColor(Color.WHITE); paint.setAlpha(alpha_full); canvas.drawPath(fillPath, paint); } else { float xx1 = endX + (float) (length * Math.cos(angle1_1)); float yy1 = endY + (float) (length * Math.sin(angle1_1)); float xx2 = endX + (float) (length * Math.cos(angle1_2)); float yy2 = endY + (float) (length * Math.sin(angle1_2)); float xx12 = endX + (float) (length2 * Math.cos(angle2_1)); float yy12 = endY + (float) (length2 * Math.sin(angle2_1)); float xx22 = endX + (float) (length2 * Math.cos(angle2_2)); float yy22 = endY + (float) (length2 * Math.sin(angle2_2)); Path backPath = new Path(); backPath.moveTo(startX, startY); backPath.lineTo(xx1, yy1); backPath.lineTo(endX, endY); backPath.lineTo(xx2, yy2); backPath.close(); Path fillPath = new Path(); fillPath.moveTo(startX, startY); fillPath.lineTo(xx12, yy12); fillPath.lineTo(endX, endY); fillPath.lineTo(xx22, yy22); fillPath.close(); paint.setColor(gestureColor); paint.setAlpha(alpha); canvas.drawPath(backPath, paint); paint.setColor(Color.WHITE); paint.setAlpha(alpha_full); canvas.drawPath(fillPath, paint); } } } @Override public boolean onTouchEvent(android.view.MotionEvent event) { if(event.getPointerCount() == 1){ int action = event.getAction(); if (MotionEvent.ACTION_DOWN == action) { startX = event.getX(); startY = event.getY(); } else if (MotionEvent.ACTION_MOVE == action) { endX = event.getX(); endY = event.getY(); //刀锋截短时间，则截短至一半 if ((event.getEventTime() - event.getDownTime()) > shape_cut_time) { if(Math.abs(endX - startX) > shape_length && Math.abs(endY - startY) > shape_length){ startX = (float) (startX + (endX - startX) * 0.5); startY = (float) (startY + (endY - startY) * 0.5); } } invalidate(); } else if (MotionEvent.ACTION_UP == action) { startX = Float.NaN; startY = Float.NaN; endX = Float.NaN; endY = Float.NaN; invalidate(); } } //该view消费了event，所以下层的view必须dispatchTouchEvent才能获得事件 //MotionEvent newEvent = MotionEvent.obtain(event); //viewer.dispatchTouchEvent(newEvent); return true; } }