我目前正在制作一款游戏，其中用户使用屏幕左侧的屏幕操纵杆控制一艘船，并通过点击屏幕右侧开火。但是，我对多点触控的尝试没有成功。当用户先触摸操纵杆然后开火时，它工作得很好，但是当用户在开火时触摸操纵杆时，用户无法拖动操纵杆。我还是 android 的新手，所以任何帮助将不胜感激。我将粘贴下面的代码。

@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;
}

最佳答案

鉴于您可以单独操作操纵杆和开火按钮，因此您正确获得屏幕尺寸以及检测指针与游戏对象附近的所有其他内容都是正确的，这是理所当然的。我读过有关某些 Android 版本和多点触控的问题，但我们假设这不是问题所在。

MotionEvent 的棘手之处在于它会针对多个指针触发，如果您对触摸和移动感兴趣，则需要考虑所有可能的指针。我认为问题可能出在您的方法上。

与其确定用户正在触摸什么，然后根据不同类型的事件确定要执行的操作，不如先确定正在发生的事件类型，然后确定用户正在与什么对象交互。这将使您的代码更清晰一些，并使将来更容易发现问题。

我将上面的示例重写为如下所示。此示例将只向屏幕写入文本以显示用户正在触摸的内容/位置。它能够确定点火按钮之后的操纵杆触摸，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;
      }
    }

}

关于java - 安卓多点触控游戏，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/9425326/