Question

我试图制作一个按钮，当点击它时从一组卡中挑选一张随机卡并将其显示到ImageView中。要做到这一点，我有一个Card类的值和他们的id（可绘制的图像卡名称）。

public class Carte {

 int valeur;
 static String nomCarte;

 public Carte(int valeur, String nomImage) {

    valeur = this.valeur;
    nomCarte = this.nomCarte;
 }

 public static String getImageId() {
    return nomCarte;
 }
}

我将其中的52个初始化为tab []，当点击按钮绘制时，它从tab []中选择一个随机的，然后我尝试通过获取ID的ID来更改我的ImageView卡被选中并使用setImageResource但是它会让我的应用程序崩溃你能帮我吗？

这是我的mainActivity代码：

public class MainActivity extends AppCompatActivity {

protected Carte tab[];
protected ImageView imageCarte;
protected Button afficherCarte;

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

    imageCarte = (ImageView)  findViewById(R.id.imageCarte);

    tab = new Carte[]{new Carte(1, "c_1"), new Carte(1, "d_1"), new Carte(1, "h_1"), new Carte(1, "s_1"),
                    new Carte(2, "c_2"), new Carte(2, "d_2"), new Carte(2, "h_2"), new Carte(2, "s_2"),
                    new Carte(3, "c_2"), new Carte(3, "d_3"), new Carte(3, "h_3"), new Carte(3, "s_3"),
                    new Carte(4, "c_4"), new Carte(4, "d_4"), new Carte(4, "h_4"), new Carte(4, "s_4"),
                    new Carte(5, "c_5"), new Carte(5, "d_5"), new Carte(5, "h_5"), new Carte(5, "s_5"),
                    new Carte(6, "c_6"), new Carte(6, "d_6"), new Carte(6, "h_6"), new Carte(6, "s_6"),
                    new Carte(7, "c_7"), new Carte(7, "d_7"), new Carte(7, "h_7"), new Carte(7, "s_7"),
                    new Carte(8, "c_8"), new Carte(8, "d_8"), new Carte(8, "h_8"), new Carte(8, "s_8"),
                    new Carte(9, "c_9"), new Carte(9, "d_9"), new Carte(9, "h_9"), new Carte(9, "s_9"),
                    new Carte(10, "c_10"), new Carte(10, "d_10"), new Carte(10, "h_10"), new Carte(10, "s_10"),
                    new Carte(11, "c_11"), new Carte(11, "d_11"), new Carte(11, "h_11"), new Carte(11, "s_11"),
                    new Carte(12, "c_12"), new Carte(12, "d_12"), new Carte(12, "h_12"), new Carte(12, "s_12"),
                    new Carte(13, "c_13"), new Carte(13, "d_13"), new Carte(13, "h_13"), new Carte(13, "s_13"),};


    afficherCarte = (Button) findViewById(R.id.afficherCarte);
    afficherCarte.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Random r = new Random();
            int i1 = r.nextInt(53 - 1) + 1;
            int id = getResources().getIdentifier(tab[i1].getImageId(), "drawable", getPackageName());
            imageCarte.setImageResource(id);
        }
    });

}

}

Answer 1

您的构造函数是错误的，并且您在imageId上创建了一个静态字段，如果不删除它，它将始终是相同的ID。

 public Carte(int valeur, String nomImage) {
    valeur = this.valeur;
    nomCarte = this.nomCarte;
 }

您永远不会将方法参数存储到类字段中。你必须反过来使用它，如

this.valeur = valeur;
this.nomCarte = nomCarte;

因此，你的getter会返回null。除此之外，删除静态修饰符

 public String getImageId() {
    return nomCarte;
 }

setImageResource导致应用程序

1 个答案: