显示刀锋的View
package com.wbhuang.myninjia;import java.util.ArrayList;
import java.util.List;import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.DisplayMetrics;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;/**
* @author wbhuang
* 20130821
*/
public class ShadeView extends View {
static final int MAX_POINTS_NUM = 10;
static final float CENTER_RATIO = 0.5f;
static final float SHAPE_RATIO = 0.02f;//点类
static class Vertex {
public float x;
public float y;
public Vertex() {}
public Vertex(float x, float y) {
this.x = x;
this.y = y;
}
}List<Vertex> leftVertexs = new ArrayList<Vertex>(MAX_POINTS_NUM);//刀锋上边线点集
List<Vertex> rightVertexs = new ArrayList<Vertex>(MAX_POINTS_NUM);//刀锋下边线点集
List<Vertex> sampleVertexs = new ArrayList<Vertex>(MAX_POINTS_NUM);//刀锋路径的点集float shape_width = 10;
private Paint paint;
private static final int gestureColor = Color.rgb(153, 153, 153);
private static final int alpha = 220;
private static final int alpha_full = 255;
private static long last_time;
private static final int MIN_TIME_INTERVAL = 10;public ShadeView(Context context) {
super(context);
paint = new Paint();
paint.setStyle(Paint.Style.FILL);DisplayMetrics metric = new DisplayMetrics();
((WindowManager)context.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay().getMetrics(metric);
int width = metric.widthPixels;
shape_width = width * SHAPE_RATIO;//刀锋长度
}//计算路径上面和下面的点集
private void calcVertexs() {
int len = sampleVertexs.size();
leftVertexs.clear();
rightVertexs.clear();
for (int i = 1; i < len; i++) {
Vertex cur = sampleVertexs.get(i);
Vertex pre = sampleVertexs.get(i-1);Vertex center = new Vertex();
center.x = cur.x - (cur.x - pre.x) * CENTER_RATIO;
center.y = cur.y - (cur.y - pre.y) * CENTER_RATIO;float w = cur.x - pre.x;
float h = cur.y - pre.y;
double angle = Math.atan(h/w);Vertex leftVertex = new Vertex();
Vertex rightVertex = new Vertex();float centerShapeWidth = shape_width * i / len; if (i == (len - 2))
centerShapeWidth = shape_width;
if (cur.x > pre.x) {
leftVertex.x = (float) (center.x + Math.sin(angle) * centerShapeWidth);
leftVertex.y = (float) (center.y - Math.cos(angle) * centerShapeWidth);
rightVertex.x = (float) (center.x - Math.sin(angle) * centerShapeWidth);
rightVertex.y = (float) (center.y + Math.cos(angle) * centerShapeWidth);
} else {
rightVertex.x = (float) (center.x + Math.sin(angle) * centerShapeWidth);
rightVertex.y = (float) (center.y - Math.cos(angle) * centerShapeWidth);
leftVertex.x = (float) (center.x - Math.sin(angle) * centerShapeWidth);
leftVertex.y = (float) (center.y + Math.cos(angle) * centerShapeWidth);
}
leftVertexs.add(leftVertex);
rightVertexs.add(rightVertex);
}
}@Override
public void onDraw(Canvas canvas) {
Path path = new Path();
if (sampleVertexs.size() > 1) {
calcVertexs();
Vertex begin = sampleVertexs.get(0);
Vertex end = sampleVertexs.get(sampleVertexs.size()-1);path.moveTo(begin.x, begin.y);
for (int i= 0; i < leftVertexs.size(); i++) {
Vertex vertex = leftVertexs.get(i);
path.lineTo(vertex.x, vertex.y);
}
path.lineTo(end.x, end.y);
for (int i = rightVertexs.size() - 1; i > 0; i--) {
Vertex vertex = rightVertexs.get(i);
path.lineTo(vertex.x, vertex.y);
}paint.setColor(Color.WHITE);
paint.setAlpha(alpha_full);
canvas.drawPath(path, paint);
}
super.onDraw(canvas);
}
@Override
public boolean onTouchEvent(android.view.MotionEvent event) {
if(event.getPointerCount() == 1){
int action = event.getAction();
if (MotionEvent.ACTION_DOWN == action) {
leftVertexs.clear();
rightVertexs.clear();
sampleVertexs.clear();
} else if (MotionEvent.ACTION_MOVE == action) {
//if (event.getEventTime() - last_time > MIN_TIME_INTERVAL) {
last_time = event.getEventTime();
if (sampleVertexs.size() > MAX_POINTS_NUM) {
sampleVertexs.remove(0);
}
Vertex vertex = new Vertex(event.getX(), event.getY());
sampleVertexs.add(vertex);
//}
} else if (MotionEvent.ACTION_UP == action) {
leftVertexs.clear();
rightVertexs.clear();
sampleVertexs.clear();
}
this.invalidate();
}
return true;
}
}
package com.wbhuang.myninjia;import android.app.Activity;
import android.os.Bundle;public class NinjiaActivity extends Activity {
/** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(new ShadeView(this));
}}
