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java - 不能改变整型变量的值

问题描述

@RequiresApi(api = Build.VERSION_CODES.O)
public class MainActivity extends AppCompatActivity {

        TextSwitcher textSwitcherage, textSwitcherGender;
        Button nextButton, previousButton, nextButton2, previousButton2;
        String[] age = {"U-4","Kid","Teen","Adult","Old"};
        String[] gender = {"Male","Female","Other"};
        TextView textView;
        Typeface typeface;

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

    public void defVars()
    {
        textSwitcherGender = findViewById(R.id.textSwitcherGender);
        textSwitcherage = findViewById(R.id.textSwitcherage);
        nextButton = findViewById(R.id.nextButton1);
        nextButton2 = findViewById(R.id.nextButton2);
        previousButton = findViewById(R.id.previousButton1);
        previousButton2 = findViewById(R.id.previousButton2);
        typeface = getResources().getFont(R.font.lettersforlearners);

        nextAndPreviousButtons(nextButton,previousButton,textSwitcherage,age,0);
        nextAndPreviousButtons(nextButton2, previousButton2, textSwitcherGender, gender,0);
    }

    public void nextAndPreviousButtons(Button buttonNext, Button buttonPrevious, final TextSwitcher textSwitcher, final String[] data, final Integer stringIndex)
    {
        buttonNext.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(stringIndex == data.length - 1)
                {
                    stringIndex = 0;
                    textSwitcher.setText(data[stringIndex]);
                }
                else
                {
                    textSwitcher.setText(data[++stringIndex]);
                }
            }
        });

        buttonPrevious.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(stringIndex==0)
                {
                    stringIndex = data.length-1;
                    textSwitcher.setText(data[stringIndex]);
                }
                else
                {
                    textSwitcher.setText(data[--stringIndex]);
                }
            }
        });

        textSwitcher.setFactory(new ViewSwitcher.ViewFactory() {
            @Override
            public View makeView() {
                textView = new TextView(MainActivity.this);
                textView.setTypeface(typeface);
                textView.setTextColor(Color.BLACK);
                textView.setTextSize(40);
                textView.setGravity(Gravity.CENTER_HORIZONTAL);
                return textView;
            }
        });

        textSwitcher.setText(data[stringIndex]);

    }
}

我有一个错误：

“错误：无法为最终变量 stringIndex 赋值”

我设置了stringIndex决赛，但仍然遇到了这个问题。我不知道。我必须为 stringIndex 定义整数变量吗？或者我应该删除 stringIndex final？我需要为每个函数定义单独的 stringIndex 变量

标签： javaandroid

解决方案

如果你声明final Integer stringIndex...，那么你就完成了！这就是保留字 final... 的概念和含义...是您无法在...之后重新分配的对象

public void nextAndPreviousButtons(Button buttonNext, Button buttonPrevious, 
   final TextSwitcher textSwitcher, final String[] data, Integer stringIndex)

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