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android多点触控的运用

热度:55   发布时间:2016-05-01 15:14:11.0
android多点触控的使用

最近没什么事看了一下多点触控的例子,跟我开始想的实现方法一样,只是一些函数不知道:下面是常用的函数解释(copy过来滴....)

event.getAction() //获取触控动作比如ACTION_DOWN
event.getPointerCount(); //获取触控点的数量,比如2则可能是两个手指同时按压屏幕
event.getPointerId(nID); //对于每个触控的点的细节,我们可以通过一个循环执行getPointerId方法获取索引
event.getX(nID); //获取第nID个触控点的x位置
event.getY(nID); //获取第nID个点触控的y位置
event.getPressure(nID); //LCD可以感应出用户的手指压力,当然具体的级别由驱动和物理硬件决定的
event.getDownTime() //按下开始时间
event.getEventTime() // 事件结束时间
event.getEventTime()-event.getDownTime()); //总共按下时花费时间


下面是一个例子,其实很简单,不过是拷贝过来的,放在这里可以备忘,以后的学习.......:

代码如下:

package com.xy.multitouchvisible;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.view.MotionEvent;import android.view.SurfaceHolder;import android.view.SurfaceView;public class MyView extends SurfaceView implements SurfaceHolder.Callback {	MainActivity father;	private static final int MAX_TOUCHPOINTS = 10;	private static final String START_TEXT = "请随便触摸屏幕进行测试";	private Paint textPaint = new Paint();	private Paint touchPaints[] = new Paint[MAX_TOUCHPOINTS];	private int colors[] = new int[MAX_TOUCHPOINTS];	private int width, height;	// private float scale = 1.0f;	public MyView(MainActivity father) {		super(father);		// TODO Auto-generated constructor stub		this.father = father;		SurfaceHolder holder = getHolder();		holder.addCallback(this);		setFocusable(true); // 确保我们的View能获得输入焦点		setFocusableInTouchMode(true); // 确保能接收到触屏事件		init();	}	private void init() {		// 初始化10个不同颜色的画笔		textPaint.setColor(Color.WHITE);		colors[0] = Color.BLUE;		colors[1] = Color.RED;		colors[2] = Color.GREEN;		colors[3] = Color.YELLOW;		colors[4] = Color.CYAN;		colors[5] = Color.MAGENTA;		colors[6] = Color.DKGRAY;		colors[7] = Color.WHITE;		colors[8] = Color.LTGRAY;		colors[9] = Color.GRAY;		for (int i = 0; i < MAX_TOUCHPOINTS; i++) {			touchPaints[i] = new Paint();			touchPaints[i].setColor(colors[i]);		}	}	/*	 * 处理触屏事件	 */	@Override	public boolean onTouchEvent(MotionEvent event) {		// 获得屏幕触点数量		int pointerCount = event.getPointerCount();		if (pointerCount > MAX_TOUCHPOINTS) {			pointerCount = MAX_TOUCHPOINTS;		}		// 锁定Canvas,开始进行相应的界面处理		Canvas c = getHolder().lockCanvas();		if (c != null) {			c.drawColor(Color.BLACK);			if (event.getAction() == MotionEvent.ACTION_UP) {				// 当手离开屏幕时,清屏			} else {				// 先在屏幕上画一个十字,然后画一个圆				for (int i = 0; i < pointerCount; i++) {					// 获取一个触点的坐标,然后开始绘制					int id = event.getPointerId(i);					int x = (int) event.getX(i);					int y = (int) event.getY(i);					drawCrosshairsAndText(x, y, touchPaints[id], i, id, c);				}				for (int i = 0; i < pointerCount; i++) {					int id = event.getPointerId(i);					int x = (int) event.getX(i);					int y = (int) event.getY(i);					drawCircle(x, y, touchPaints[id], c);				}			}			// 画完后,unlock			getHolder().unlockCanvasAndPost(c);		}		return true;	}	/**	 * 画十字及坐标信息	 */	private void drawCrosshairsAndText(int x, int y, Paint paint, int ptr,			int id, Canvas c) {		c.drawLine(0, y, width, y, paint);		c.drawLine(x, 0, x, height, paint);		int textY = (int) (5 + 20 * ptr);		c.drawText("x" + ptr + "=" + x, 10, textY, textPaint);		c.drawText("y" + ptr + "=" + y, 70, textY, textPaint);		c.drawText("id" + ptr + "=" + id, width - 55, textY, textPaint);	}	/**	 * 画圆	 */	private void drawCircle(int x, int y, Paint paint, Canvas c) {		c.drawCircle(x, y, 40, paint);	}	@Override	public void surfaceChanged(SurfaceHolder holder, int format, int width,			int height) {		// TODO Auto-generated method stub		this.width = width;		this.height = height;		textPaint.setTextSize(14);		Canvas c = getHolder().lockCanvas();		if (c != null) {			// 背景黑色			c.drawColor(Color.BLACK);			float tWidth = textPaint.measureText(START_TEXT);			c.drawText(START_TEXT, width / 2 - tWidth / 2, height / 2,					textPaint);			getHolder().unlockCanvasAndPost(c);		}	}	@Override	public void surfaceCreated(SurfaceHolder holder) {		// TODO Auto-generated method stub	}	@Override	public void surfaceDestroyed(SurfaceHolder holder) {		// TODO Auto-generated method stub	}}用真机测试采用感觉哦.........


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