Android編程開發之多點觸摸(Multitouch)實現方法_Android

本文執行個體講述了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式感興趣的話，那麼本文將是一個很好的開始，android應用程式開發中，多點觸摸不是那麼遙不可及，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 = "請隨便觸控螢幕幕進行測試";  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) {    // 獲得螢幕觸點數量    int pointerCount = event.getPointerCount();    if (pointerCount > MAX_TOUCHPOINTS) {      pointerCount = MAX_TOUCHPOINTS;    }    // 鎖定Canvas,開始進行相應的介面處理    Canvas c = getHolder().lockCanvas();    if (c != null) {      c.drawColor(Color.BLACK);      if (event.getAction() == MotionEvent.ACTION_UP) {        // 當手離開螢幕時，清屏      } else {        // 先在螢幕上畫一個十字，然後畫一個圓        for (int i = 0; i < pointerCount; i++) {          // 擷取一個觸點的座標，然後開始繪製          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);        }      }      // 畫完後，unlock      getHolder().unlockCanvasAndPost(c);    }    return true;  }  /**   * 畫十字及座標資訊   *   * @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);  }  /*   * 進入程式時背景畫成黑色，然後把“START_TEXT”寫到螢幕   */  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，這裡就不多說。

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);    //隱藏標題列    requestWindowFeature(Window.FEATURE_NO_TITLE);    //設定成全屏    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,        WindowManager.LayoutParams.FLAG_FULLSCREEN);    //設定為上面的MTView    setContentView(new MTView(this));  }}

更多關於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資料庫技巧總結》、《Android操作json格式資料技巧總結》、《Android資料庫操作技巧總結》、《Android檔案操作技巧匯總》、《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控制項用法總結》

希望本文所述對大家Android程式設計有所協助。