删除在另一个函数中启动的函数中的事件侦听器
Removing Event Listeners in a Function that were started in another function
所以我一直在努力改造我早年在学校制作的一个简单的猜谜游戏。基本上我已经弄清楚了，但是我似乎总是遗漏了一些东西，那就是在游戏结束时删除事件监听器和计时器，这样用户就可以开始一个新的会话，如果他们想这样做的话。
在研究这个问题时，我找不到任何关于相同信息的内容。除了这个链接，但它仍然没有多大帮助。
Can I create EventListener in AS3 from one Object and remove it from another Object?
无论我尝试过什么，我仍然会遇到错误，而且我认为它是函数之间的处理。
TypeError: Error #1009: Cannot access a property or method of a null object reference.
at Classes::GuessingGames/selfClearingEvents()
at Classes::GuessingGames/loseGame()
at Classes::GuessingGames/evaluateGuessing()
at Classes::GuessingGames/enterKeyGuess()
这是为删除事件侦听器而创建的函数
public function selfClearingEvents(){
// Remove Event Listeners
stGame.removeEventListener(MouseEvent.CLICK, startGame);
inStruc.removeEventListener(MouseEvent.CLICK, instructions);
// Remove Timer Listeners
myTimer.stop();
myTimer.removeEventListener (TimerEvent.TIMER_COMPLETE, timerComplete);
myTimer.removeEventListener(TimerEvent.TIMER, timerHandler);
// Remove Other Keyboard and MouseListeners
input_txt.removeEventListener(KeyboardEvent.KEY_DOWN, enterKeyGuess); // event.charCode === 13
guess_btn.removeEventListener(MouseEvent.CLICK, enterMouseGuess);
}
这是我的完整代码
package Classes {
import flash.display.MovieClip;
import flash.events.MouseEvent;
import flash.events.KeyboardEvent;
// Import Timer Utilities
import flash.utils.Timer;
import flash.text.TextField;
import flash.events.TimerEvent;
import flash.display.Stage;
public class GuessingGames extends MovieClip {
// Create Vars for Game
var randNum = 0;
var maxNum = 10; // Max number we will be guessing
var numOfGuesses = 4; // Give Max Number of Guesses
var myGuess; // Setup Variable for Guess
var myTimer:Timer;
var seconds = 00;
var minutes = 2;
var score = 0;
//var input_txt:TextField; // Create the Text field
public function GuessingGames() {
// stop the playhead first thing
stop();
//trace("HelloWorld"); //test to see whats working
// Add Functionality to Buttons
// ----------------------------------------------------
stGame.addEventListener(MouseEvent.CLICK, startGame);
inStruc.addEventListener(MouseEvent.CLICK, instructions);
} // End Guessing Games
// Button Functions
// Functions for Buttons
// ----------------------------------------------------------------------
public function startGame(event:MouseEvent):void {
// frame 10 is the game start
gotoAndStop(10);
gameStarting();
}
public function instructions(event:MouseEvent):void {
// frame 5 is the instructions
gotoAndStop(5);
trace("Instuctions");
}
public function clearInput(event:MouseEvent):void {
input_txt.text="";
input_txt.removeEventListener(MouseEvent.CLICK, clearInput);
}
// Game Logic
//-----------------------------------------------------
private function gameStarting(){
// Game Started
trace("game started");
randomNumber(); // Make the Number
theTimer();
// Keeping score
score = 0; // reset the score
score_txt.text = score; // show it on the board
// Track the Number of Guesses and Display them to the User
guess_txt.text = numOfGuesses;
// Setup Input
input_txt.restrict="0-9"; //Restrict to numbers 0 - 9
input_txt.text="__"; //Clears the input text field.
input_txt.addEventListener(MouseEvent.CLICK, clearInput);
// Add Event Listener for Enter Guess
// Add to types EnterKey, and MouseEvent
input_txt.addEventListener(KeyboardEvent.KEY_DOWN, enterKeyGuess); // event.charCode === 13
guess_btn.addEventListener(MouseEvent.CLICK, enterMouseGuess);
// Setup a feedback message spot
// ==================
var beginningText = "Start by choosing a number 1-10... Lead your team to a TouchDown by guessing the Number.";
message_txt.text = beginningText;
}
// Create the Random Number
private function randomNumber(){
randNum = Math.ceil(Math.random() * maxNum);
}
// Keyboard Event Checking Guess
// --------------------------------------------
public function enterKeyGuess(event:KeyboardEvent){
// if the key is ENTER
if(event.charCode === 13){
// Do Something
//trace("entered Keyboard Guess");
evaluateGuessing();
}
}
// Mouse Event Checking Guess
// --------------------------------------------
public function enterMouseGuess(event:MouseEvent):void {
// Do Something
//trace("entered Mouse Guess");
evaluateGuessing();
}
// Store and Check Guesses
// ---------------------------------------------
public function evaluateGuessing(){
myGuess = input_txt.text; // Store Guess
// Evaluating The Guesses
// ---------------------------------
// Check to make sure guess is in the parameters
if(myGuess > 10 || myGuess <= 0) {
message_txt.text = "Flag On The Play -- Please pick a number between 1 and 10";
} else {
if (myGuess > randNum && myGuess ) { // Check Guess Lose
message_txt.text = "Incomplete Pass! You overthrew your reciever. ";
numOfGuesses--; // Remove a Guess
} else if (myGuess < randNum) { // Check Guess Lose
message_txt.text = "Tackled short of your goal.";
numOfGuesses--; // Remove a Guess
} else{
// Check Guess Win
message_txt.text = "TOUCHDOWN!! Number " + randNum + ".";
score++;
score_txt.text = score;
// reset the random number
randomNumber();
// reset the Number of Guesses
numOfGuesses = 4;
} // end eval
}// end else
// Adjust the Text on Scoreboard always
guess_txt.text = numOfGuesses;
if(numOfGuesses === 0) {
loseGame();
}
}
// Create a Timer
// --------------------------------------------
public function theTimer(){
myTimer = new Timer(1000, 120);
myTimer.start();
timeText.text = "2:00"; // Displaying The Clock
myTimer.addEventListener (TimerEvent.TIMER_COMPLETE, timerComplete);
myTimer.addEventListener(TimerEvent.TIMER, timerHandler);
}
public function timerHandler(e:TimerEvent): void {
if(seconds > 00) {
seconds-=1;
} else {
if (minutes > 0){ minutes-=1; seconds = 59; }
}
timeText.text = minutes+":"+(seconds >= 10? seconds : "0"+seconds);
trace("Current Count: " + myTimer.currentCount);
}
private function timerComplete(e:TimerEvent) {
//trace("Timer is Done");
if(score === 0) {
loseGame();
} else {
winGame();
}
}
// Winning or Losing Game
// ---------------------------------------------
public function winGame(){
trace("Yea You won!");
myTimer.stop();
gotoAndStop(15); // Frame 15 Shows the Win Screen
}
public function loseGame(){
trace("You Lost Idiot");
selfClearingEvents();
gotoAndStop(20); // Frame 20 Shows the Lose Screen
}
public function selfClearingEvents(){
// Remove Event Listeners
stGame.removeEventListener(MouseEvent.CLICK, startGame);
inStruc.removeEventListener(MouseEvent.CLICK, instructions);
// Remove Timer Listeners
myTimer.stop();
myTimer.removeEventListener (TimerEvent.TIMER_COMPLETE, timerComplete);
myTimer.removeEventListener(TimerEvent.TIMER, timerHandler);
// Remove Other Keyboard and MouseListeners
input_txt.removeEventListener(KeyboardEvent.KEY_DOWN, enterKeyGuess); // event.charCode === 13
guess_btn.removeEventListener(MouseEvent.CLICK, enterMouseGuess);
}
}
}
我大胆猜测 stGame 和 inStruc 是 MovieClip 实例，您已将它们放在主时间轴上，但在第 10 帧中不可用是调用 selfClearingEvents 方法的框架。这解释了为什么当您尝试调用 removeEventListener 时会出现空对象引用错误。
如果游戏开始后不再需要这些实例，您可以尝试在此时移除监听器：
private function gameStarting(){
// Remove Event Listeners
stGame.removeEventListener(MouseEvent.CLICK, startGame);
inStruc.removeEventListener(MouseEvent.CLICK, instructions);
// Rest of game start code
}
所以我一直在努力改造我早年在学校制作的一个简单的猜谜游戏。基本上我已经弄清楚了，但是我似乎总是遗漏了一些东西，那就是在游戏结束时删除事件监听器和计时器，这样用户就可以开始一个新的会话，如果他们想这样做的话。
在研究这个问题时，我找不到任何关于相同信息的内容。除了这个链接，但它仍然没有多大帮助。
Can I create EventListener in AS3 from one Object and remove it from another Object?
无论我尝试过什么，我仍然会遇到错误，而且我认为它是函数之间的处理。
TypeError: Error #1009: Cannot access a property or method of a null object reference.
at Classes::GuessingGames/selfClearingEvents()
at Classes::GuessingGames/loseGame()
at Classes::GuessingGames/evaluateGuessing()
at Classes::GuessingGames/enterKeyGuess()
这是为删除事件侦听器而创建的函数
public function selfClearingEvents(){
// Remove Event Listeners
stGame.removeEventListener(MouseEvent.CLICK, startGame);
inStruc.removeEventListener(MouseEvent.CLICK, instructions);
// Remove Timer Listeners
myTimer.stop();
myTimer.removeEventListener (TimerEvent.TIMER_COMPLETE, timerComplete);
myTimer.removeEventListener(TimerEvent.TIMER, timerHandler);
// Remove Other Keyboard and MouseListeners
input_txt.removeEventListener(KeyboardEvent.KEY_DOWN, enterKeyGuess); // event.charCode === 13
guess_btn.removeEventListener(MouseEvent.CLICK, enterMouseGuess);
}
这是我的完整代码
package Classes {
import flash.display.MovieClip;
import flash.events.MouseEvent;
import flash.events.KeyboardEvent;
// Import Timer Utilities
import flash.utils.Timer;
import flash.text.TextField;
import flash.events.TimerEvent;
import flash.display.Stage;
public class GuessingGames extends MovieClip {
// Create Vars for Game
var randNum = 0;
var maxNum = 10; // Max number we will be guessing
var numOfGuesses = 4; // Give Max Number of Guesses
var myGuess; // Setup Variable for Guess
var myTimer:Timer;
var seconds = 00;
var minutes = 2;
var score = 0;
//var input_txt:TextField; // Create the Text field
public function GuessingGames() {
// stop the playhead first thing
stop();
//trace("HelloWorld"); //test to see whats working
// Add Functionality to Buttons
// ----------------------------------------------------
stGame.addEventListener(MouseEvent.CLICK, startGame);
inStruc.addEventListener(MouseEvent.CLICK, instructions);
} // End Guessing Games
// Button Functions
// Functions for Buttons
// ----------------------------------------------------------------------
public function startGame(event:MouseEvent):void {
// frame 10 is the game start
gotoAndStop(10);
gameStarting();
}
public function instructions(event:MouseEvent):void {
// frame 5 is the instructions
gotoAndStop(5);
trace("Instuctions");
}
public function clearInput(event:MouseEvent):void {
input_txt.text="";
input_txt.removeEventListener(MouseEvent.CLICK, clearInput);
}
// Game Logic
//-----------------------------------------------------
private function gameStarting(){
// Game Started
trace("game started");
randomNumber(); // Make the Number
theTimer();
// Keeping score
score = 0; // reset the score
score_txt.text = score; // show it on the board
// Track the Number of Guesses and Display them to the User
guess_txt.text = numOfGuesses;
// Setup Input
input_txt.restrict="0-9"; //Restrict to numbers 0 - 9
input_txt.text="__"; //Clears the input text field.
input_txt.addEventListener(MouseEvent.CLICK, clearInput);
// Add Event Listener for Enter Guess
// Add to types EnterKey, and MouseEvent
input_txt.addEventListener(KeyboardEvent.KEY_DOWN, enterKeyGuess); // event.charCode === 13
guess_btn.addEventListener(MouseEvent.CLICK, enterMouseGuess);
// Setup a feedback message spot
// ==================
var beginningText = "Start by choosing a number 1-10... Lead your team to a TouchDown by guessing the Number.";
message_txt.text = beginningText;
}
// Create the Random Number
private function randomNumber(){
randNum = Math.ceil(Math.random() * maxNum);
}
// Keyboard Event Checking Guess
// --------------------------------------------
public function enterKeyGuess(event:KeyboardEvent){
// if the key is ENTER
if(event.charCode === 13){
// Do Something
//trace("entered Keyboard Guess");
evaluateGuessing();
}
}
// Mouse Event Checking Guess
// --------------------------------------------
public function enterMouseGuess(event:MouseEvent):void {
// Do Something
//trace("entered Mouse Guess");
evaluateGuessing();
}
// Store and Check Guesses
// ---------------------------------------------
public function evaluateGuessing(){
myGuess = input_txt.text; // Store Guess
// Evaluating The Guesses
// ---------------------------------
// Check to make sure guess is in the parameters
if(myGuess > 10 || myGuess <= 0) {
message_txt.text = "Flag On The Play -- Please pick a number between 1 and 10";
} else {
if (myGuess > randNum && myGuess ) { // Check Guess Lose
message_txt.text = "Incomplete Pass! You overthrew your reciever. ";
numOfGuesses--; // Remove a Guess
} else if (myGuess < randNum) { // Check Guess Lose
message_txt.text = "Tackled short of your goal.";
numOfGuesses--; // Remove a Guess
} else{
// Check Guess Win
message_txt.text = "TOUCHDOWN!! Number " + randNum + ".";
score++;
score_txt.text = score;
// reset the random number
randomNumber();
// reset the Number of Guesses
numOfGuesses = 4;
} // end eval
}// end else
// Adjust the Text on Scoreboard always
guess_txt.text = numOfGuesses;
if(numOfGuesses === 0) {
loseGame();
}
}
// Create a Timer
// --------------------------------------------
public function theTimer(){
myTimer = new Timer(1000, 120);
myTimer.start();
timeText.text = "2:00"; // Displaying The Clock
myTimer.addEventListener (TimerEvent.TIMER_COMPLETE, timerComplete);
myTimer.addEventListener(TimerEvent.TIMER, timerHandler);
}
public function timerHandler(e:TimerEvent): void {
if(seconds > 00) {
seconds-=1;
} else {
if (minutes > 0){ minutes-=1; seconds = 59; }
}
timeText.text = minutes+":"+(seconds >= 10? seconds : "0"+seconds);
trace("Current Count: " + myTimer.currentCount);
}
private function timerComplete(e:TimerEvent) {
//trace("Timer is Done");
if(score === 0) {
loseGame();
} else {
winGame();
}
}
// Winning or Losing Game
// ---------------------------------------------
public function winGame(){
trace("Yea You won!");
myTimer.stop();
gotoAndStop(15); // Frame 15 Shows the Win Screen
}
public function loseGame(){
trace("You Lost Idiot");
selfClearingEvents();
gotoAndStop(20); // Frame 20 Shows the Lose Screen
}
public function selfClearingEvents(){
// Remove Event Listeners
stGame.removeEventListener(MouseEvent.CLICK, startGame);
inStruc.removeEventListener(MouseEvent.CLICK, instructions);
// Remove Timer Listeners
myTimer.stop();
myTimer.removeEventListener (TimerEvent.TIMER_COMPLETE, timerComplete);
myTimer.removeEventListener(TimerEvent.TIMER, timerHandler);
// Remove Other Keyboard and MouseListeners
input_txt.removeEventListener(KeyboardEvent.KEY_DOWN, enterKeyGuess); // event.charCode === 13
guess_btn.removeEventListener(MouseEvent.CLICK, enterMouseGuess);
}
}
}
我大胆猜测 stGame 和 inStruc 是 MovieClip 实例，您已将它们放在主时间轴上，但在第 10 帧中不可用是调用 selfClearingEvents 方法的框架。这解释了为什么当您尝试调用 removeEventListener 时会出现空对象引用错误。
如果游戏开始后不再需要这些实例，您可以尝试在此时移除监听器：
private function gameStarting(){
// Remove Event Listeners
stGame.removeEventListener(MouseEvent.CLICK, startGame);
inStruc.removeEventListener(MouseEvent.CLICK, instructions);
// Rest of game start code
}