0

我有这样的枚举类：

public enum Names {

Logo1(R.drawable.adese,"Adese"),
Logo2(R.drawable.afra,"Afra");

private int resource;
private String description;
private Names(int resource, String description){
    this.description = description;
}

public boolean isCorrect(String input){
return input.equals(description);
}
}

我想从活动中的可绘制对象中获取枚举的名称。换句话说，当我为某个方法提供 R.drawable.adese 时，我想获得 Logo1。而当我提供 R.drawable.afra 时，我想得到 Logo2 等等。我怎样才能做到这一点？

在我的活动中

Names name;
.
.
.
id = R.drawable.adese;
name = Names.forDrawable(id);
    check.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {

            a=name.isCorrect(text.getText().toString());
            if(a==true){
            Intent intent = new Intent(LogoActivity.this, LevelSelectionActivity.class);
            startActivity(intent);
        }
        }
        });

活动中声明了检查按钮等，我没有写在这里缩短。

我收到错误消息：

03-03 12:16:27.125: E/AndroidRuntime(6091): FATAL EXCEPTION: main
03-03 12:16:27.125: E/AndroidRuntime(6091): java.lang.NullPointerException
03-03 12:16:27.125: E/AndroidRuntime(6091):     at         com.example.turkishlogoquiz.LogoActivity$1.onClick(LogoActivity.java:57)
03-03 12:16:27.125: E/AndroidRuntime(6091):     at android.view.View.performClick(View.java:4223)
03-03 12:16:27.125: E/AndroidRuntime(6091):     at android.view.View$PerformClick.run(View.java:17275)
03-03 12:16:27.125: E/AndroidRuntime(6091):     at android.os.Handler.handleCallback(Handler.java:615)
03-03 12:16:27.125: E/AndroidRuntime(6091):     at android.os.Handler.dispatchMessage(Handler.java:92)
03-03 12:16:27.125: E/AndroidRuntime(6091):     at android.os.Looper.loop(Looper.java:137)
-03 12:16:27.125: E/AndroidRuntime(6091):   at android.app.ActivityThread.main(ActivityThread.java:4898)
03-03 12:16:27.125: E/AndroidRuntime(6091):     at java.lang.reflect.Method.invokeNative(Native Method)
03-03 12:16:27.125: E/AndroidRuntime(6091):     at java.lang.reflect.Method.invoke(Method.java:511)
03-03 12:16:27.125: E/AndroidRuntime(6091):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1008)
03-03 12:16:27.125: E/AndroidRuntime(6091):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:775)
03-03 12:16:27.125: E/AndroidRuntime(6091):     at dalvik.system.NativeStart.main(Native Method)
4

1 回答 1

2

只需创建一个静态方法，该方法将返回一个Names可绘制资源的值。

public enum Names {
    Logo1(R.drawable.adese,"Adese"),
    Logo2(R.drawable.afra,"Afra");

    private int resource;
    private String description;

    private Names(int resource, String description) {
        this.resource = resource;
        this.description = description;         
    }

    public boolean isCorrect(String input){
        return input.equals(description);
    }

    public static Names forDrawable(int resourceId) {
        for (final Names name : Names.values()) {
            if (name.resource == resourceId) {
                return name;
            }
        }

        return null;
    }
}
于 2013-03-03T10:05:01.250 回答