Question

我想知道如何在android中随机选择一个按钮。例如，有4个按钮，我希望应用程序从它们中随机选择一个按钮并对其执行一些操作。这是我的代码：

Button start;
ImageButton btn1, btn2, btn3, btn4, btn5;
Random random = new Random();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_memory);
    start = (Button)findViewById(R.id.button1);
    start.setOnClickListener(this);
    btn1 = (ImageButton)findViewById(R.id.imageButton1);
    btn2 = (ImageButton)findViewById(R.id.imageButton2);
    btn3 = (ImageButton)findViewById(R.id.imageButton3);
    btn4 = (ImageButton)findViewById(R.id.imageButton4);

}

ImageButton[] all= {btn1, btn2, btn3, btn4};

@Override
public void onClick(View v) {
    if (v == start)
    {
        btn5 = all[random.nextInt(all.length)];
        btn5.setBackgroundColor(Color.RED);
    }
}

如果我改变它，它可以完美地工作但是它只会是btn1而不是随机选择。

@Override
public void onClick(View v) {
    if (v == start)
    {
        btn5 = btn1;
        btn5.setBackgroundColor(Color.RED);
    }
}

Answer 1

您需要将此行放在onCreate()方法中：

all= {btn1, btn2, btn3, btn4};

现在：

ImageButton[] all= {btn1, btn2, btn3, btn4};

它在所有按钮为空的承包商时间运行。在onCreate中，您为新变量分配按钮，但这不会改变ImageButton。另外你可以写道：

ImageButton[0] = (ImageButton)findViewById(R.id.imageButton1);
ImageButton[1] = (ImageButton)findViewById(R.id.imageButton2);
ImageButton[2] = (ImageButton)findViewById(R.id.imageButton3);
ImageButton[3] = (ImageButton)findViewById(R.id.imageButton4);

Answer 2

all必须设置后设置btn1等：否则它将是null的数组。

    btn1 = (ImageButton)findViewById(R.id.imageButton1);
    btn2 = (ImageButton)findViewById(R.id.imageButton2);
    btn3 = (ImageButton)findViewById(R.id.imageButton3);
    btn4 = (ImageButton)findViewById(R.id.imageButton4);
    all= {btn1, btn2, btn3, btn4}; //here
}

ImageButton[] all; //not here

Answer 3

How do I generate random integers within a specific range in Java?

检查以上引用以生成随机数，然后使用

switch(number)
{
case 1:
button.performClick()

.....
}

Answer 4

这样做

 ImageButton[] all= {btn1, btn2, btn3, btn4};

 Random rand = new Random();
 ImageButton randomBtn = all[rand.nextInt(all.length)];

Answer 5

我目前运行的代码如下：

    Button start;
    ImageButton btn1, btn2, btn3, btn4, btn5;
    Random random;

    int[] all;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        random = new Random();

        start = (Button)findViewById(R.id.button1);

        start.setOnClickListener(this);

        btn1 = (ImageButton)findViewById(R.id.ImageButton01);
        btn2 = (ImageButton)findViewById(R.id.ImageButton02);
        btn3 = (ImageButton)findViewById(R.id.ImageButton03);
        btn4 = (ImageButton)findViewById(R.id.ImageButton04);

        all = new int[]{R.id.ImageButton01,R.id.ImageButton02,R.id.ImageButton03,R.id.ImageButton04};
    }



    @Override
    public void onClick(View v) {
        if (v.getId() == R.id.button1)
        {
            int id = all[random.nextInt(all.length)];
            findViewById(id).setBackgroundColor(Color.BLACK);
        }
    }

如何在android中随机选择按钮？

5 个答案: