有没有办法通过键从哈希图中随机选择值？

Question

假设我有两个ImageButtons，一个HashMap，drawable(resources)中的图片作为一个值放在这个HashMap中。我需要使用 Randomizer 按键从 HashMap 中随机选择一个值，然后将此值（即图片）分配给 ImageButton 作为背景。例如，如果点击第一个按钮，第二个按钮的背景将随机改变。

这是我已有的：

public class MainActivity extends Activity {

  final Resources res = getResources();
  final Random random = new Random();

  final ImageButton imgButt1 = (ImageButton) findViewById(R.id.imageButton1);
  final ImageButton imgButt2 = (ImageButton) findViewById(R.id.imageButton2);

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

    Drawable coub1 = res.getDrawable(R.drawable.coub1);
    Drawable coub2 = res.getDrawable(R.drawable.coub2);
    Drawable coub3 = res.getDrawable(R.drawable.coub3);
    Drawable coub4 = res.getDrawable(R.drawable.coub4);
    Drawable coub5 = res.getDrawable(R.drawable.coub5);
    Drawable coub6 = res.getDrawable(R.drawable.coub6);
    Drawable coub7 = res.getDrawable(R.drawable.coub7);
    Drawable coub8 = res.getDrawable(R.drawable.coub8);
    Drawable coub9 = res.getDrawable(R.drawable.coub9);
    Drawable coub10 = res.getDrawable(R.drawable.coub10);

    final Map<Integer,Object> someHashMap = new HashMap<Integer,Object>();
    someHashMap.put(1, coub1);
    someHashMap.put(2, coub2);
    someHashMap.put(3, coub3);
    someHashMap.put(4, coub4);
    someHashMap.put(5, coub5);
    someHashMap.put(6, coub6);
    someHashMap.put(7, coub7);
    someHashMap.put(8, coub8);
    someHashMap.put(9, coub9);
    someHashMap.put(10, coub1);

    imgButt1.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

            Object[] values = someHashMap.values().toArray();
            Object randomValue = values[random.nextInt(values.length)];
            int drawableID = values.;
            imgButt2.setBackgroundResource(drawableID);
        }
    });

    imgButt2.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

            Object[] values = someHashMap.values().toArray();
            Object randomValue = values[random.nextInt(values.length)];
            int drawableID = myImages.getResourceId(randomInt, -1);
            imgButt1.setBackgroundResource(drawableID);
        }
    });
  }
}

Answer 1

您可以随机选择一个键，方法是将一个 Map 的所有键放入一个列表（或数组）中，然后从该列表（或数组）中随机选择一个索引

List<Integer> keys = new ArrayList<Integer>(someHashMap.keys());
Integer randomKey = keys.get(random.nextInt(keys.size()));
Object randomValue = someHashMap.get(randomKey);

Answer 2

您可以完全放弃 Map，而只使用 int 个值的数组。

int[] ids = {R.drawable.coub1, R.drawable.coub2, R.drawable.coub3, R.drawable.coub4, 
             R.drawable.coub5, R.drawable.coub6, R.drawable.coub7, R.drawable.coub8, 
             R.drawable.coub9, R.drawable.coub10};
// Then, when you need a random Drawable 
Drawable drawable = res.getDrawable(ids[random.nextInt(ids.length)]);

有没有办法通过键从哈希图中随机选择值？

Is there a way to randomly choose value from hashmap by key?

java

random

android

hashmap