Question

可能重复：
  Generating random number in a range with Java
  How can I generate random number in specific range in Android?

这是我的情景来自Mainactivity;单击按钮我想生成1到4的随机数根据输出，我想写一个if-else，它将调用4个不同的活动

因此，点击，如果生成4，则调用活动4 下一次可以生成1并且应该调用活动1 等等....

有人可以帮我解释一下这段代码吗？

Answer 1

   public void test1(){
    Random r = new Random();
    int index = r.nextInt(4)+1;

    Intent intent = null;

    switch(index){
    case 1:  intent = new Intent(this, Activity1.class);
        break;
    case 2:  intent = new Intent(this, Activity2.class);
        break;
    case 3:  intent = new Intent(this, Activity3.class);
        break;
    case 4:  intent = new Intent(this, Activity4.class);
        break;
    default:
     Log.e("ERROR", "");
            return;
    }
    if(intent != null){
       this.startActivity(intent);
    }
   }

Answer 2

myBtn.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {
            // TODO Auto-generated method stub

            Random r = new Random();
            int index = r.nextInt(4)+1;

            Intent intent;

            if (index == 4) {
                intent = new Intent(Activity.this, Activity4.class); 
            }
            else if (index == 3) {
                intent = new Intent(Activity.this, Activity3.class); 
            }
            else if (index == 2) {
            intent = new Intent(Activity.this, Activity2.class); 
            }
            else 
            intent = new Intent(Activity.this, Activity1.class);                    

            startActivity(intent);                
         }
    });

Android代码 - 调用活动的随机数生成

2 个答案: