Question

我正在尝试在ImageView上使用switch语句并分配一个String值，因此在我的onClick函数中，我可以根据单击的ImageView执行某些功能，并根据单击的ImageView使用String值。很抱歉有不好的解释，下面是代码示例。

ChooseLevelActivity.java

public class ChooseLevelActivity extends Activity implements View.OnClickListener {

    ImageView level001, level002, level003, level004, level005;
    String level_selected;

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

        level001 = (ImageView) findViewById(R.id.level001);
        level002 = (ImageView) findViewById(R.id.level002);
        level003 = (ImageView) findViewById(R.id.level003);
        level004 = (ImageView) findViewById(R.id.level004);
        level005 = (ImageView) findViewById(R.id.level005);

        // Array of ImageView
        final ImageView[] levelsArray = {level001, level002, level003, level004, level005};

        for(int i = 0; i < 5; i++) {
            levelsArray[i].setOnClickListener(this);
        }
    }

    @Override
    public void onClick(View v) {

        /* Switch statement to change the value of String level_selected
         * depending on which ImageView is clicked.
         * but an error "Constant expression required" shows up
         * What am I missing? How to use the switch on ImageView ?
         */
        switch (v) {
            case level001:
                level_selected = "level001";
                break;
            case level002:
                level_selected = "level002";
                break;
        }

        // Some function that uses the String level_selected

    }
}

Answer 1

为什么不使用已经不变的View的id，而不是比较v本身？

switch (v.getId()) {
    case R.id.level001:
        level_selected = "level001";
         break;
    case R.id.level002:
         level_selected = "level002";
         break;
}

ImageView上的Android Studio开关语句

1 个答案: