为什么我的if语句在此for循环中不起作用？

Question

题：

我正在设计一个小型的Android应用程序，当您按下看起来像特定乐器的imageButton时会播放声音（音符），并且可以在6个imageButtons中最多播放10个音符。 它将音符编号存储在数组中，并将元素设置为特定编号。 这部分似乎工作正常

该应用程序具有一项功能，可让您播放最近播放的内容。 由于某种原因，它只会播放前一个音符10次-似乎不了解新的数组值，因此它总是挂在for循环中的第一个if语句上。 我需要它来读取新的数组值，以便可以播放用户在给定乐器上演奏的内容。

码：

public void drum1button(View view) { //This code snippet works as expected
    if (studio.drumCount < 10){
        new Thread(drum.drum1).start();
        drum.drums[studio.drumCount] = 0;
        Toast.makeText(getApplicationContext(),studio.drumCount + " drum.drums[studio.drumCount] = " + drum.drums[studio.drumCount],2).show();

        studio.drumCount++;
    }
    else {
    Toast.makeText(getApplicationContext(),"Record limit reached. Head to the studio!",5).show();
    }
}


public void drum2button(View view) {
if (studio.drumCount < 10){
    new Thread(drum.drum2).start();
    drum.drums[studio.drumCount] = 1;
    Toast.makeText(getApplicationContext(),studio.drumCount + " drum.drums[studio.drumCount] = " + drum.drums[studio.drumCount],2).show();

    studio.drumCount++;

}
else {
Toast.makeText(getApplicationContext(),"Record limit reached. Head to the studio!",5).show();
}
}


public void drum3button(View view) {
    if (studio.drumCount <10 ) {
    new Thread(drum.drum3).start();
    drum.drums[studio.drumCount] = 2;
    Toast.makeText(getApplicationContext(),studio.drumCount + " drum.drums[studio.drumCount] = " + drum.drums[studio.drumCount],2).show();

    studio.drumCount++;
    }
    else {
    Toast.makeText(getApplicationContext(),"Record limit reached. Head to the studio!",5).show();
    }

}

public void drum4button(View view) {
    if (studio.drumCount < 10) {
    new Thread(drum.drum4).start();
    drum.drums[studio.drumCount] = 3;
    Toast.makeText(getApplicationContext(),studio.drumCount + " drum.drums[studio.drumCount] = " + drum.drums[studio.drumCount],2).show();

    studio.drumCount++;
    }
    else {
    Toast.makeText(getApplicationContext(),"Record limit reached. Head to the studio!",5).show();
    }
}

public void drum5button(View view) {
    if (studio.drumCount < 10) {
    new Thread(drum.drum5).start();
    drum.drums[studio.drumCount] = 4;
    Toast.makeText(getApplicationContext(),studio.drumCount + " drum.drums[studio.drumCount] = " + drum.drums[studio.drumCount],2).show();

    studio.drumCount++;
    }

    else {
    Toast.makeText(getApplicationContext(),"Record limit reached. Head to the studio!",5).show();
    }
}

public void drum6button(View view) {
    if (studio.drumCount < 10){
    new Thread(drum.drum6).start();
    drum.drums[studio.drumCount] = 5;
    Toast.makeText(getApplicationContext(),studio.drumCount + " drum.drums[studio.drumCount] = " + drum.drums[studio.drumCount],2).show();

    studio.drumCount++;
    }
    else {
        Toast.makeText(getApplicationContext(),"Record limit reached. Head to the studio!",5).show();

    }
}

---

Runnable drumPlayback = new Runnable() {

    public void run() {
    for (int i = 0; i < 10; i++) { //(was i = 10, typo in formatting when //pasting. Still does not work with i = 0
        //handler.postDelayed(drumPlayback, 5000);

        try {Thread.sleep(1000);} catch(Exception e) {}
         if (drum.drums[i] == 0) { 
          new Thread(drum.drum1).start(); //this is the only one that plays

          }
          if (drum.drums[i] == 1) { 
          new Thread(drum.drum2).start(); 
          } 
         if (drum.drums[i] == 2) { 
          new Thread(drum.drum3).start(); 
          } 
           if (drum.drums[i] == 3) { 
          new Thread(drum.drum4).start(); 
          } 
           if (drum.drums[i] == 4) { 
          new Thread(drum.drum5).start(); 
          } 
           if (drum.drums[i] == 5) {
          new Thread(drum.drum6).start(); 
                    }
                }
            }
    };

Answer 1

循环条件是i < 10但是您使用10初始化i。因此循环将永远不会开始。