我正在尝试在 android 中处理 multiTouch，我的计划是在应用程序中使用 2 个手指。我知道如何使用一个接触点，但我不确定如何使用多个接触点。
这是我的代码，OnTouch：
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;
}
现在在我得到每个点的 x 和 y 坐标之后，我将如何获得发生的动作？我想使用event.getAction，但它不带点索引等参数。如何获取每个接触点的动作类型？
更新：好的，所以现在我可以成功管理和处理两个手指，现在，在我完成之后，我创建了一个简单的类Finger来处理每个触摸点，现在每当我在屏幕上有两个手指时，我尝试移除其中一个，然后移动/移除另一根手指，游戏就会崩溃！
触摸：
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;
}
我为手指创建了一个列表：
列出手指 = new LinkedList();
在我输入的构造函数中：
fingers.add(0, null);
fingers.add(1, null);
最后是手指类：
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，当我这样做时，一切都很好，直到我移开一根手指并移动/移开另一根手指，我在 LogCat 中收到以下错误：
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：
而不是重新设置手指并将它们设置为null然后再次重新设置它们，我只是在手指向上时将它们移除并在手指向下时重新创建它们并在手指移动时更新它们。现在它工作得很好！
更新....
最终问题没有解决，即使应用程序没有崩溃，当一个手指被抬起时，它的行为就像两个手指都被抬起一样。
这是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:
}
}
}
因此，每当抬起一根手指时，logCat 就会像两根手指都从屏幕上抬起一样写入。有任何想法吗？