“字段可以转换为局部变量”。设置Android ActionBar颜色时出现错误消息 [英] "Field can be converted to a local variable" message appearing when setting Android ActionBar colour

问题描述

在设置操作栏的颜色后，中的 actionBarColor 私有字符串actionBarColor =＃B36305; 获取突出显示黄色，并出于某种原因返回警告。可以做些什么来消除这个警告？

After setting the colour of the Action Bar, actionBarColor in private String actionBarColor = "#B36305"; gets highlighted yellow and a warning is returned for some reason. What can be done to get rid of this warning?

字段可以转换为局部变量

Field can be converted to a local variable

public class MainActivity extends AppCompatActivity {

    private String actionBarColor = "#B36305";

    private int getFactorColor(int color, float factor) {
        float[] hsv = new float[3];
        Color.colorToHSV(color, hsv);
        hsv[2] *= factor;
        color = Color.HSVToColor(hsv);
        return color;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.fragment_activity_main);

        ActionBar actionBar = getSupportActionBar();
        if(actionBar != null) {
            actionBar.setBackgroundDrawable(new ColorDrawable(Color.parseColor(actionBarColor)));
        }
    }
}

推荐答案

警告告诉你的是 actionBarColor 不应该是全局变量（即字段），因为它只在一个方法中使用（的onCreate ）。这是一个很好的建议：你应该总是最小化变量的范围，因为它提高了可读性并减少了编程错误的可能性。

What the warning is telling you is that actionBarColor shouldn't be a global variable (i.e. a field), because it's only used in one method (onCreate). This is good advice: you should always minimize the scope of your variables, because it improves readability and reduces possibilities for programming errors.

要摆脱警告，修复通过在 onCreate 中声明变量来解决问题：

To get rid of the warning, fix the problem by declaring the variable within onCreate:

final String actionBarColor = "#B36305";

if(actionBar != null) {
    actionBar.setBackgroundDrawable(
        new ColorDrawable(Color.parseColor(actionBarColor)));
}

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