【发布时间】：2013-05-13 07:18:08
【问题描述】：
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，在我获得每个点的 x 和 y 坐标后，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，我创建了一个名为 Finger 的简单类来处理每个触摸点，现在每当我有两个手指在屏幕上时，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！
触摸屏：
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;
}
我为手指创建一个列表：
列出手指 = new LinkedList();
在我放入的构造函数中：
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，当我执行所有这些操作时，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：
我没有重新设置手指并将它们设置为空然后再次重新设置它们，而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，只要一根手指抬起，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？
【问题讨论】：
标签： android multi-touch touch-event ontouchlistener touchscreen