为什么从单个实例调用getColor时会发生NullPoInterException？

Question

Google Play崩溃日志：

Caused by: java.lang.NullPointerException: 
  at com.manager.loader.SkinManager.getColor (SkinManager.java:28)
  at base.util.ui.titlebar.BaseTitlebarFragmentActivity.getImmersiveColor (BaseTitlebarFragmentActivity.java:6)
  at base.util.ui.titlebar.BaseTitlebarFragmentActivity.onCreate (BaseTitlebarFragmentActivity.java)

活动：

public abstract class BaseTitlebarFragmentActivity extends FragmentActivity {

    public void onCreate(Bundle savedInstanceState) {
        setImmersive(getImmersiveColor());
        super.onCreate(savedInstanceState);
    }

    protected int getImmersiveColor(){
        return SkinManager.getInstance().getColor(R.color.v8_common_title_bg);
    }

SkinManager：

public class SkinManager implements ISkinLoader {

    private static final Object synchronizedLock = new Object();
    private static SkinManager instance;

    private SkinManager() { }

    public static SkinManager getInstance() {
        if (instance == null) {
            synchronized (synchronizedLock) {
                if (instance == null){
                    instance = new SkinManager();
                }
            }
        }
        return instance;
    }

    public int getColor(int resId){
        int originColor;
        if(mResources == null || isDefaultSkin){
            try {
                originColor = context.getResources().getColor(resId);
                return originColor;
            } catch (Exception e) {
            }
        }

        int trueColor = 0;
        try{
            trueColor = mResources.getColor(resId);
        }catch(Exception e){
            originColor = context.getResources().getColor(resId);
            trueColor = originColor;
        }
        
        return trueColor;
    }

App：

public class App extends BaseApplication {

    public void onCreate() {
        super.onCreate();
        initSkins();
    }

    private void initSkins() {
        AttrFactory.addSupportAttr("iiv_background_color", new IconicsImageViewBgColorAttr());
        AttrFactory.addSupportAttr("iiv_color", new IconicsImageViewColorAttr());
        AttrFactory.addSupportAttr("matProg_barColor", new ProgressWheelBarColorAttr());
        AttrFactory.addSupportAttr("progressDrawable", new ProgressBarDrawableAttr());
        AttrFactory.addSupportAttr("indeterminateDrawable", new ProgressBar2DrawableAttr());
        AttrFactory.addSupportAttr("button", new CheckBoxButtonDrawableAttr());

        SkinManager.getInstance().init(this);
        SkinManager.getInstance().setUpSkinFile();
        if (!ProcessManager.isMainProcess(getContext())) {
            SkinManager.getInstance().registerProcessSkinLoadReceiver();
        }
    }

Answer 1

尽管正如崩溃日志所示，这是不可能的，但我将重构GetColor，并查看：

    public int getColor(int resId){
        if(mResources == null || isDefaultSkin){
            try {
                int originColor = context.getResources().getColor(resId);
                return originColor;
            } catch (Exception ignored) {
            }
        }

        try{
            int trueColor = mResources.getColor(resId);
            return trueColor;
        } catch(Exception ignored) {
        }

        try {
            int originColor = context.getResources().getColor(resId);
            return originColor;
        } catch (Exception ignored) {
        }

        return 0;
    }