Android多點觸控遊戲

Question

我目前正在製作遊戲，其中用戶使用屏幕左側的屏幕操縱桿控制船隻，並通過點擊屏幕右側進行觸發。但是，我嘗試多點觸控並不成功。當用戶先觸摸操縱桿然後觸發時，它完美地工作，但是當用戶在觸發時觸摸該操縱桿時，用戶不能拖動操縱桿。我還是新來的機器人，所以任何幫助將不勝感激。我將粘貼下面的代碼。

@Override 
public boolean onTouch(View v, MotionEvent event) { 
    int action = event.getAction() & MotionEvent.ACTION_MASK; 
    int pointerIndex=(event.getAction()&MotionEvent.ACTION_POINTER_ID_MASK) 
    >>MotionEvent.ACTION_POINTER_ID_SHIFT; 
    int pI = event.getPointerId(pointerIndex); 
    //On screen joystick 
    if(event.getX(pI)<pad.getWidth()+(screenWidth*.18)&&event.getX(pI)>0&&event.getY(pI)<(screenHeight)&&event.getY(pI)>(screenHeight-(0.42*screenHeight))){ 
     sx2=event.getX(pI)-(stick.getWidth()/2); 
     sy2=event.getY(pI); 
     angle=(Math.atan2((sy2-sy),(sx2-sx))); 
    } 
    //firing system 
    if(event.getX(pI)>screenWidth/3){ 
     switch(action){ 
     case MotionEvent.ACTION_DOWN: 
      incrementRunnable.run(); 
      break; 
     case MotionEvent.ACTION_POINTER_DOWN: 
      incrementRunnable.run(); 
      break; 
     case MotionEvent.ACTION_UP: 
      handler.removeCallbacks(incrementRunnable); 
      break; 
     case MotionEvent.ACTION_POINTER_UP: 
      handler.removeCallbacks(incrementRunnable); 
      break; 
     } 

    } 
    //reset joystick 
    if(event.getAction()==MotionEvent.ACTION_UP||event.getAction()==MotionEvent.ACTION_POINTER_UP){ 
     sx2=sx; 
     sy2=sy; 
     handler.removeCallbacks(incrementRunnable); 
    } 
    return true; 
} 

Answer 1

既然你可以操縱孤立的操縱桿和開火按鈕，按理說，你得到正確的屏幕尺寸和其他一切有關檢測指針的附近，以你的遊戲目標是正確的。我已閱讀了某些Android版本和多點觸控的問題，但讓我們假設這不是問題。

MotionEvent這個棘手的問題是，它會被多個指針觸發，如果你對觸摸和移動感興趣，你需要考慮所有可能的指針。我認爲這個問題可能在於你的方法。

與其確定用戶正在觸摸什麼，然後確定在給定不同類型的事件時該怎麼做，您應該弄清楚發生了什麼類型的事件，然後確定用戶正在與哪些對象進行交互。這將使您的代碼更清晰一些，並且可以更輕鬆地在將來發現問題。

我把上面的例子重寫了下面的代碼。這個例子只是寫文本到屏幕上來顯示用戶正在觸摸什麼/在哪裏。它能夠在火災按鈕之後確定操縱桿觸摸，反之亦然。

MultiTouchGame.java

package com.droidhut.stackoverflow; 

import android.app.Activity; 
import android.content.Context; 
import android.os.Bundle; 
import android.util.DisplayMetrics; 
import android.view.MotionEvent; 
import android.view.View; 
import android.view.View.OnTouchListener; 
import android.view.WindowManager; 
import android.widget.TextView; 

public class MultiTouchGame extends Activity implements OnTouchListener { 
    StringBuilder builder = new StringBuilder(); 
    TextView textView; 

    boolean[] joystickTouched = new boolean[10]; 
    boolean[] fireButtonTouched = new boolean[10]; 
    int joyX = 0; 
    int joyY = 0; 

    int screenHeight; 
    int screenWidth; 
    Pad pad = new Pad(); 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     textView = new TextView(this); 
     textView.setText("Touch and drag (multiple fingers supported)!"); 
     textView.setOnTouchListener(this); 
     setContentView(textView); 

     WindowManager mWinMgr = (WindowManager)getSystemService(Context.WINDOW_SERVICE); 
     DisplayMetrics dm = new DisplayMetrics(); 
     mWinMgr.getDefaultDisplay().getMetrics(dm); 
     screenHeight = dm.heightPixels; 
     screenWidth = dm.widthPixels; 

    } 

    @Override 
    public boolean onTouch(View v, MotionEvent event) { 
     int action = event.getAction() & MotionEvent.ACTION_MASK; 
     int pointerIndex = (event.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT; 
     int pI = event.getPointerId(pointerIndex); 
     switch (action) { 
      case MotionEvent.ACTION_DOWN: 
      case MotionEvent.ACTION_POINTER_DOWN: 
       joystickTouched[pI] = isPointerOnJoystick(event, pointerIndex); 
       fireButtonTouched[pI] = isPointerOnFireButton(event, pointerIndex); 
       break; 
      case MotionEvent.ACTION_UP:   
      case MotionEvent.ACTION_POINTER_UP: 
      case MotionEvent.ACTION_CANCEL: 
       joystickTouched[pI] = false; 
       fireButtonTouched[pI] = false; 
       break; 
      case MotionEvent.ACTION_MOVE: 
       joystickTouched[pI] = isPointerOnJoystick(event, pointerIndex); 
       fireButtonTouched[pI] = isPointerOnFireButton(event, pointerIndex); 
       if (isTouchingJoystick()){ 
        int index = getJoystickPointer(); 
        if (index != -1 && index < event.getPointerCount()){ 
         joyX = (int)event.getX(index); 
         joyY = (int)event.getY(index); 
        } 
       } 
       break; 
     } 

     updateTextView();  
     return true; 
    } 

    private boolean isPointerOnJoystick(MotionEvent event, int pointerIndex){ 
     return (event.getX(pointerIndex)<pad.getWidth()+(screenWidth*.18)&&event.getX(pointerIndex)>0&& 
       event.getY(pointerIndex)<(screenHeight)&&event.getY(pointerIndex)>(screenHeight-(0.42*screenHeight))); 
    } 

    private boolean isPointerOnFireButton(MotionEvent event, int pointerIndex){ 
     return (event.getX(pointerIndex)>screenWidth/3); 
    } 

    private boolean isTouchingJoystick(){ 
     for (int i = 0; i < joystickTouched.length; i++){ 
      if (joystickTouched[i]){ 
       return true; 
      } 
     } 
     return false; 
    } 

    private boolean isTouchingFireButton(){ 
     for (int i = 0; i < fireButtonTouched.length; i++){ 
      if (fireButtonTouched[i]){ 
       return true; 
      } 
     } 
     return false; 
    } 

    private int getJoystickPointer(){ 
     for (int i = 0; i < joystickTouched.length; i++){ 
      if (joystickTouched[i]){ 
       return i; 
      } 
     } 

     return -1; 
    } 

    private void updateTextView() { 
     builder.setLength(0); 
     builder.append(String.format("screenWidth[%d], screenHeight[%d]\n",screenWidth, screenHeight)); 
     builder.append(String.format("joystickTouched[%s]\n", isTouchingJoystick())); 
     builder.append(String.format("fireButtonTouched[%s]\n", isTouchingFireButton())); 
     builder.append(String.format("joystickMovement[%d,%d]",joyX,joyY)); 

     textView.setText(builder.toString()); 
    } 

    private static class Pad { 
     public int getWidth(){ 
     return 200; 
     } 
    } 

}