Question

我的问题是我无法在onclickfoodimage（）函数中使用food1（食物类对象，其中存储所选食物的价值）对象的值我在onCreate（）中初始化的（onClickFoodImage是单击图像时调用的方法）

FoodActivity Class

public class FoodActivity extends Activity {
public static  final String EXTRA_MESSAGE2="message";
Food food1;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Intent intent=getIntent();
int Foodno=intent.getExtras().getInt(EXTRA_MESSAGE2);
food1=Food.food[Foodno];
ImageView image=(ImageView)findViewById(R.id.imageView3);
image.setImageResource(food1.getFoodImageId());

}
public final void onclickfoodimage()
{
TextView textview=(TextView)findViewById(R.id.textView4);
textview.setText(food1.getFoodName());
TextView textView=(TextView)findViewById(R.id.textView5);
textView.setText(food1.getFoodDescription());
}
}

包含食物的食物类食物1是对象的数据

public class Food {
String foodName,foodDescription;
int foodImageId;
static Food food[]={new Food("Dosa","A South Indian Dish",R.drawable.dosa),new Food("Paneer","A Famous And Delicious Dish made from Paneer",R.drawable.paneer)};
Food(String name,String description,int id)
{
    this.foodName=name;
    this.foodDescription=description;
    foodImageId=id;
}
String getFoodName()
{
    return foodName;
}
String getFoodDescription()
{
    return foodDescription;
}
int getFoodImageId()
{
    return foodImageId;
}
public String toString()
{
    return foodName;
}

}

Answer 1

当您点击ImageView时，似乎 onclickfoodimage（）没有被调用，我在这里为您开发了一个完整的程序，我没有对此进行测试，希望这对您有用。

MainActivity.java ，启动FoodActivity.java

public class MainActivity extends AppCompatActivity {

public static  final String EXTRA_MESSAGE2="message";
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Intent intent = new Intent(this , FoodActivity.class).putExtra(EXTRA_MESSAGE2,1);
    startActivity(intent);
}

}

FoodActivity.java：

    public class FoodActivity extends Activity {
    public static  final String EXTRA_MESSAGE2="message";
    Food food1;
    static ArrayList<Food> foodArray = new ArrayList<>();
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        foodArray.add(new Food("Dosa","A South Indian Dish",R.drawable.dosa)) ;
        foodArray.add(new Food("Paneer","A Famous And Delicious Dish made from Paneer",R.drawable.paneer)) ;

        Intent intent=getIntent();
        int Foodno=intent.getExtras().getInt(EXTRA_MESSAGE2);
        food1=foodArray.get(Foodno);
        ImageView image=(ImageView)findViewById(R.id.imageView3);
        image.setImageResource(food1.getFoodImageId());

    }
    public final void onclickfoodimage(View v)
    {
        TextView textview4 =(TextView)findViewById(R.id.textView4);
        textview4.setText(food1.getFoodName());

        TextView textView5 = (TextView)findViewById(R.id.textView5);
        textView5.setText(food1.getFoodDescription());
    }
}

Food.java：

    public class Food {
    String foodName,foodDescription;
    int foodImageId;

    Food(String name,String description,int id)
    {
        this.foodName=name;
        this.foodDescription=description;
        foodImageId=id;
    }
    String getFoodName()
    {
        return foodName;
    }
    String getFoodDescription()
    {
        return foodDescription;
    }
    int getFoodImageId()
    {
        return foodImageId;
    }
    public String toString()
    {
        return foodName;
    }

}

<强> activity_main.xml中

    <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.shishupalshakya.accessstringvariable.MainActivity">

    <TextView
        android:id="@+id/textView4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!" />

    <TextView
        android:id="@+id/textView5"
        android:layout_below="@+id/textView4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!" />

    <ImageView
        android:id="@+id/imageView3"
        android:layout_below="@+id/textView5"
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:src="@mipmap/ic_launcher"
        android:onClick="onclickfoodimage"
        />

</RelativeLayout>

注意：不要忘记在AndroidManifest.xml文件中注册FoodActivity.java。

只需用上面的代码替换您的代码。

在android中同一类的方法之间共享变量

1 个答案: