多点触控Android | 获取每个触摸点的操作方式

Question

多点触控Android | 获取每个触摸点的操作方式

androidmulti-touchtouch-eventontouchlistenertouchscreen

4

我将尝试在Android中处理多点触控，我的计划是在应用程序中使用两个手指。我知道如何使用一个触摸点，但我不确定如何使用多个触摸点。

以下是我的代码，在OnTouch方法中：

    public boolean onTouch(View view, MotionEvent event) {

        for(int i = 0; i < event.getPointerCount(); i++){

            float x = event.getX(i);
            float y = event.getY(i);

           // using the data here...
          //....
       }
    return true;
}

现在，当我获取每个点的x和y坐标后，如何获取发生的动作？我想使用event.getAction，但它不接受诸如点索引之类的参数。如何获取每个触摸点的动作类型？

更新：好的，现在我可以成功地管理和处理两个手指了。现在，我创建了一个简单的名为Finger的类来处理每个触摸点。现在，每当我屏幕上有两个手指，我尝试移除其中之一，然后移动/删除另一个手指时，游戏就会崩溃！

OnTouch：

public boolean onTouch(View view, MotionEvent event) {

        int pointerCount = event.getPointerCount();

        if(pointerCount > 2){
            pointerCount = 2;
            System.out.println("too many fingers!");
        } // since i want to handle only two fingers, every other finger will be ignored.

        for (int i = 0; i < pointerCount; i++) {

            float x = event.getX(i);
            float y = event.getY(i);

            int id = event.getPointerId(i);
            int action = event.getActionMasked();
            int actionIndex = event.getActionIndex();

            if (action == MotionEvent.ACTION_DOWN
                    || action == MotionEvent.ACTION_POINTER_DOWN) {

                if (fingers.get(i) == null)
                    fingers.set(i, new Finger(x, y, id));


            }

            if (fingers.get(i).type == Finger.SCREEN_FINGER) {

                switch (action) {
                case MotionEvent.ACTION_UP:
                    fingers.set(i, null);
                    System.out.println(id + " action_up!");
                    break;
                case MotionEvent.ACTION_POINTER_UP:
                    fingers.set(i, null);
                    System.out.println(id + " pointer_up!");
                    break;
                case MotionEvent.ACTION_MOVE:
                    fingers.get(i).setPos(x, y);
                    System.out.println(id + " action_move!, x: "+fingers.get(i).x+", y: "+fingers.get(i).y);
                    break;
                default:

                }
            }else if (fingers.get(i).type == Finger.DPAD_FINGER) {
                switch (action) {
                case MotionEvent.ACTION_UP:
                    fingers.set(i, null);
                    System.out.println(id + " action_up! - dpad");
                    break;
                case MotionEvent.ACTION_POINTER_UP:
                    fingers.set(i, null);
                    System.out.println(id + " pointer_up! - dpad");
                    break;
                case MotionEvent.ACTION_MOVE:
                    fingers.get(i).setPos(x, y);
                    System.out.println(id + " action_move! - dpad, x: "+fingers.get(i).x+", y: "+fingers.get(i).y);
                    break;
                default:

                }
            }
        }


        return true;
    }

我创建了一个手指列表：

List fingers = new LinkedList();

在构造函数中，我放置了以下内容：

fingers.add(0, null);
fingers.add(1, null);

最后，Finger类：

public class Finger {
public final static int DPAD_FINGER = 0;
public final static int SCREEN_FINGER = 1;

public float x, y;
public int type;
public int id;

public Finger(float x, float y,int id) {
    this.id = id;
    checkType(x, y);
}

public void checkType(float x, float y) {
    if(x>Dpad.x && x < Dpad.x+Dpad.Width && y> Dpad.y && y<Dpad.y+Dpad.Height){
        System.out.println("inside DPAD");
        type = DPAD_FINGER;
    }else{
        System.out.println("Outside DPAD");
        type = SCREEN_FINGER;
    }

}

public void setPos(float x, float y){
    this.x = x;
    this.y = y;
}



}

现在当我做完这些操作后，一切都很正常，但是当我移开一个手指并移动/删除另一个手指时，在LogCat中会出现以下错误：

 05-18 15:22:03.812: E/InputEventReceiver(20124): Exception dispatching input event.
05-18 15:22:03.812: W/dalvikvm(20124): threadid=1: thread exiting with uncaught exception (group=0x41e00438)
05-18 15:22:03.822: E/AndroidRuntime(20124): FATAL EXCEPTION: main
05-18 15:22:03.822: E/AndroidRuntime(20124): java.lang.NullPointerException
05-18 15:22:03.822: E/AndroidRuntime(20124):    at smellychiz.projects.ogc.util.ChizView$1.onTouch(ChizView.java:70)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.View.dispatchTouchEvent(View.java:7241)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2185)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1928)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2185)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1928)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2185)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1928)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at    com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2116)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1469)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.app.Activity.dispatchTouchEvent(Activity.java:2477)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2064)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.View.dispatchPointerEvent(View.java:7430)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:3457)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:3389)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:4483)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:4461)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:4565)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:171)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.InputEventReceiver.nativeConsumeBatchedInputEvents(Native Method)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.InputEventReceiver.consumeBatchedInputEvents(InputEventReceiver.java:163)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.ViewRootImpl.doConsumeBatchedInput(ViewRootImpl.java:4533)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.ViewRootImpl$ConsumeBatchedInputRunnable.run(ViewRootImpl.java:4584)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:725)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.Choreographer.doCallbacks(Choreographer.java:555)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.Choreographer.doFrame(Choreographer.java:523)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:711)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.os.Handler.handleCallback(Handler.java:615)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.os.Handler.dispatchMessage(Handler.java:92)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.os.Looper.loop(Looper.java:137)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at android.app.ActivityThread.main(ActivityThread.java:4950)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at java.lang.reflect.Method.invokeNative(Native Method)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at java.lang.reflect.Method.invoke(Method.java:511)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1004)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:771)
05-18 15:22:03.822: E/AndroidRuntime(20124):    at dalvik.system.NativeStart.main(Native Method)

更新:

不再将手指重置并将它们设置为null，然后再重新设置它们，而是在手指抬起时将它们移除，手指按下时重新创建它们并在手指移动时进行更新。现在它完美地运作了！

更新....

最终问题并未得到解决，尽管应用程序不会崩溃，但当其中一个手指抬起时，它会像两个手指都抬起一样。

以下是onTouch方法的当前代码:

public boolean onTouch(View view, MotionEvent event) {

    int pointerCount = event.getPointerCount();

    if(pointerCount > 2){
        pointerCount = 2;
        System.out.println("too many fingers!");
    } // since i want to handle only two fingers, every other finger will be ignored.

    for (int i = 0; i < pointerCount; i++) {

        float x = event.getX(i);
        float y = event.getY(i);

        int id = event.getPointerId(i);
        int action = event.getActionMasked();
        int actionIndex = event.getActionIndex();

        if (action == MotionEvent.ACTION_DOWN
                || action == MotionEvent.ACTION_POINTER_DOWN) {

            if (fingers.get(i) == null)
                fingers.add(i, new Finger(x, y, id));


        }

        if (fingers.get(i).type == Finger.SCREEN_FINGER) {

            switch (action) {
            case MotionEvent.ACTION_UP:
                fingers.remove(i);
                System.out.println(id + " action_up!");
                break;
            case MotionEvent.ACTION_POINTER_UP:
                fingers.remove(i);
                System.out.println(id + " pointer_up!");
                break;
            case MotionEvent.ACTION_MOVE:
                fingers.get(i).setPos(x, y);
                System.out.println(id + " action_move!, x: "+fingers.get(i).x+", y: "+fingers.get(i).y);
                break;
            default:

            }
        }else if (fingers.get(i).type == Finger.DPAD_FINGER) {
            switch (action) {
            case MotionEvent.ACTION_UP:
                fingers.remove(i);
                System.out.println(id + " action_up! - dpad");
                break;
            case MotionEvent.ACTION_POINTER_UP:
                fingers.remove(i);
                System.out.println(id + " pointer_up! - dpad");
                break;
            case MotionEvent.ACTION_MOVE:
                fingers.get(i).setPos(x, y);
                System.out.println(id + " action_move! - dpad, x: "+fingers.get(i).x+", y: "+fingers.get(i).y);
                break;
            default:

            }
        }
    }

所以每当其中一根手指抬起时，logCat 会写入好像两根手指都离开了屏幕。有什么想法吗？

- Baruch

1个回答

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- pskink · Answer 1

0

例如，查看ScaleGestureDetector的源代码，可以了解如何实现它：https://android.googlesource.com/platform/frameworks/base/+/48c7c6c/core/java/android/view/ScaleGestureDetector.java

- pskink

好的，我可以成功地处理两个触点，所以我创建了一个简单的类叫做Finger来处理每个触点的ID并跟踪X和Y坐标。现在，我有一个问题，当我在屏幕上放置两个手指，并尝试移除其中一个手指，然后移动/删除另一个手指时，应用程序会崩溃！我将在问题中发布我的代码。 - Baruch

请查看最近的更新。我会非常感激任何帮助。谢谢。 - Baruch

没有错误，我认为只是我处理方法的方式有问题，当一个手指抬起时，它会报告好像两个手指都抬起了。 - Baruch