本文實例講述了Android編程開發之多點觸摸(Multitouch)實現方法。分享給大家供大家參考，具體如下：
如果您對開發多點觸摸程序感興趣的話，那么本文將是一個很好的開始，android應用程序開發中，多點觸摸不是那么遙不可及，實現起來也很簡單，本例只需要兩個類就能實現多點觸摸。
首先來看看我們的視圖類MTView.java:
package com.ideasandroid.demo;import android.content.Context;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 MTView extends SurfaceView implements SurfaceHolder.Callback { private static final int MAX_TOUCHPOINTS = 10; private static final String START_TEXT = "請隨便觸摸屏幕進行測試"; 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 MTView(Context context) { super(context); SurfaceHolder holder = getHolder(); holder.addCallback(this); setFocusable(true); // 確保我們的View能獲得輸入焦點 setFocusableInTouchMode(true); // 確保能接收到觸屏事件 init(); } private void init() { // 初始化10個不同顏色的畫筆 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]); } } /* * 處理觸屏事件 */ @Override public boolean onTouchEvent(MotionEvent event) { // 獲得屏幕觸點數量 int pointerCount = event.getPointerCount(); if (pointerCount > MAX_TOUCHPOINTS) { pointerCount = MAX_TOUCHPOINTS; } // 鎖定Canvas,開始進行相應的界面處理 Canvas c = getHolder().lockCanvas(); if (c != null) { c.drawColor(Color.BLACK); if (event.getAction() == MotionEvent.ACTION_UP) { // 當手離開屏幕時，清屏 } else { // 先在屏幕上畫一個十字，然后畫一個圓 for (int i = 0; i < pointerCount; i++) { // 獲取一個觸點的坐標，然后開始繪制 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); } } // 畫完后，unlock getHolder().unlockCanvasAndPost(c); } return true; } /** * 畫十字及坐標信息 * * @param x * @param y * @param paint * @param ptr * @param id * @param c */ 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) ((15 + 20 * ptr) * scale); c.drawText("x" + ptr + "=" + x, 10 * scale, textY, textPaint); c.drawText("y" + ptr + "=" + y, 70 * scale, textY, textPaint); c.drawText("id" + ptr + "=" + id, width - 55 * scale, textY, textPaint); } /** * 畫圓 * * @param x * @param y * @param paint * @param c */ private void drawCircle(int x, int y, Paint paint, Canvas c) { c.drawCircle(x, y, 40 * scale, paint); } /* * 進入程序時背景畫成黑色，然后把“START_TEXT”寫到屏幕 */ public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { this.width = width; this.height = height; if (width > height) { this.scale = width / 480f; } else { this.scale = height / 480f; } textPaint.setTextSize(14 * scale); 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); } } public void surfaceCreated(SurfaceHolder holder) { } public void surfaceDestroyed(SurfaceHolder holder) { }}代碼中都做了相應的注釋，這里就不多說。
接下來看看我們的Activity，MultitouchVisible.java
package com.ideasandroid.demo;import android.app.Activity;import android.os.Bundle;import android.view.Window;import android.view.WindowManager;public class MultitouchVisible extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); //隱藏標題欄 requestWindowFeature(Window.FEATURE_NO_TITLE); //設置成全屏 getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN); //設置為上面的MTView setContentView(new MTView(this)); }}更多關于Android相關內容感興趣的讀者可查看本站專題：《Android開發入門與進階教程》、《Android編程之activity操作技巧總結》、《Android視圖View技巧總結》、《Android操作SQLite數據庫技巧總結》、《Android操作json格式數據技巧總結》、《Android數據庫操作技巧總結》、《Android文件操作技巧匯總》、《Android編程開發之SD卡操作方法匯總》、《Android資源操作技巧匯總》及《Android控件用法總結》
希望本文所述對大家Android程序設計有所幫助。
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