尝试记录按键长度时要调用什么功能？ （处理）对

Question

例如，如果我想记录我按下了b键并想记录按住它的时间长度，我该怎么做？

Answer 1

加工超级简单。请查看keyPressed()和keyReleased()。

// create a variable to store the time
int t = 0;

void setup() {
  // whatever you need to do here
}

void draw() {
  // do other stuff here
}

// when 'b' key is pressed, store the current
// time in milliseconds since the program started
void keyPressed() {
  if (key == 'b') {
    t = millis();    
  }
}

// when the 'b' key is released, subtract the start
// time from the current time to get the duration
void keyReleased() {
  if (key == 'b') {
    t = millis() - t;
    println("b key held for " + t + " milliseconds");
  } 
}

Answer 2

这是可能的方法之一：

import java.util.HashMap;
import java.util.Map;
import processing.core.PApplet;
import processing.event.KeyEvent;

// this map holds currently pressed keys
private Map<Character, Record> map = new HashMap<Character, Record>();

public void setup() {
...
}

public void draw() {
...
}

@Override
public void keyPressed(KeyEvent event) {
    char key = event.getKey();

    // only if map doesn't hold this key yet
    if (!map.containsKey(key)) {

        // create new record with this key and start timestamp
        Record record = new Record(key, millis());
        map.put(key, record);
    }
}

@Override
public void keyReleased(KeyEvent event) {
    char key = event.getKey();

    // retrieve record for this key
    Record record = map.get(key);

    // store release timestamp (milliseconds from program startup)
    record.releaseTime = millis();

    map.remove(key);

    // now record has full info
    println(key + ", time: " + (record.releaseTime - record.pressedTime));
}

class Record {
    char key;
    long pressedTime;
    long releaseTime;

    Record(char key, long pressedTime) {
        this.key = key;
        this.pressedTime = pressedTime;
    }
}

希望这会有所帮助......