BaseAdapter 上下文检索奇怪的行为答案

【问题标题】：BaseAdapter context retrieving strange behaviourBaseAdapter 上下文检索奇怪的行为
【发布时间】：2015-04-06 16:11:55
【问题描述】：

我一定遗漏了一些明显但无法找到的东西。

在下面的函数中，如果我尝试加载我的 Drawable 数组，我得到一个空指针异常，说 getResource 在空指针处被调用，而如果我直接传递 drawable 并在上下文的帮助下膨胀它，它工作正常。

我在这里做错了什么？请帮忙。

class MyDrawerAdapter extends BaseAdapter {
private Context context;
String[] drawerList;


public MyDrawerAdapter(Context context) {
    drawerList = context.getResources().getStringArray(R.array.Cat_array);
    this.context = context;

}
/*
Drawable[] drawableArr ={MrVector.inflate(context.getResources(),R.drawable.home),
        MrVector.inflate(context.getResources(),R.drawable.home),
        MrVector.inflate(context.getResources(),R.drawable.home),
        MrVector.inflate(context.getResources(),R.drawable.home),
        MrVector.inflate(context.getResources(),R.drawable.home),
        MrVector.inflate(context.getResources(),R.drawable.home),
        MrVector.inflate(context.getResources(),R.drawable.home),
        MrVector.inflate(context.getResources(),R.drawable.home),
        MrVector.inflate(context.getResources(),R.drawable.home),
        MrVector.inflate(context.getResources(),R.drawable.home),
        MrVector.inflate(context.getResources(),R.drawable.home),
        MrVector.inflate(context.getResources(),R.drawable.home),
        MrVector.inflate(context.getResources(),R.drawable.home),
        MrVector.inflate(context.getResources(),R.drawable.home),
        MrVector.inflate(context.getResources(),R.drawable.home)};
*/
@Override
public int getCount() {
    return drawerList.length;
}

@Override
public Object getItem(int position) {
    return null;
}

@Override
public long getItemId(int position) {
    return position;
}

@Override
public int getViewTypeCount() {
    return 3;
}

@Override
public int getItemViewType(int position) {
    if (position == 3 || position == 11) {
        return 1;
    }
    if (position == 4) {
        return 2;
    }
    return 0;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View row = null;
    LayoutInflater inflater = (LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
    if (getItemViewType(position) == 1) {
        if (convertView == null) {
            row = inflater.inflate(R.layout.divider, parent, false);
        } else {
            row = convertView;
        }
        row.setEnabled(false);
        row.setOnClickListener(null);
    }
    if (getItemViewType(position) == 0) {
        if (convertView == null) {
            row = inflater.inflate(R.layout.drawer_list_item, parent, false);
        } else {
            row = convertView;
        }
        TextView titletext = (TextView) row.findViewById(R.id.drawer_text);
        ImageView titleImage = (ImageView) row.findViewById(R.id.drawer_image);
        titletext.setText(drawerList[position]);
        //titleImage.setImageDrawable(drawableArr[position]);
        titleImage.setImageDrawable(MrVector.inflate(context.getResources(),R.drawable.home));
    }
    if (getItemViewType(position) == 2) {
        if (convertView == null) {
            row = inflater.inflate(R.layout.header_listview_menu, parent, false);
        } else {
            row = convertView;
        }
        row.setEnabled(false);
        row.setOnClickListener(null);
    }
    return row;
}

}

【问题讨论】：

问题一定出在调用代码上。
如何调用MyDrawerAdapter的构造函数？
@DavidJhons mMyDrawerAdapter = new MyDrawerAdapter(this);在我的 MainActivity 中。
也请贴日志猫
你能显示调用代码吗？类似问题stackoverflow.com/questions/29490118/…

标签： android baseadapter android-context

【解决方案1】：

这是我已经实施的解决方法，但如果有人可以提供帮助，我仍然希望得到答案。

class MyDrawerAdapter extends BaseAdapter {
private Context context;
String[] drawerList;    

public MyDrawerAdapter(Context context) {
    drawerList = context.getResources().getStringArray(R.array.Cat_array);
    this.context = context;

}

@Override
public int getCount() {
    return drawerList.length;
}

@Override
public Object getItem(int position) {
    return null;
}

@Override
public long getItemId(int position) {
    return position;
}

@Override
public int getViewTypeCount() {
    return 3;
}

@Override
public int getItemViewType(int position) {
    if (position == 3 || position == 11) {
        return 1;
    }
    if (position == 4) {
        return 2;
    }
    return 0;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View row = null;
    int layoutID = context.getResources().getIdentifier("icon_" + position, "drawable", context.getApplicationInfo().packageName);
    LayoutInflater inflater = (LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
    if (getItemViewType(position) == 1) {
        if (convertView == null) {
            row = inflater.inflate(R.layout.divider, parent, false);
        } else {
            row = convertView;
        }
        row.setEnabled(false);
        row.setOnClickListener(null);
    }
    if (getItemViewType(position) == 0) {
        if (convertView == null) {
            row = inflater.inflate(R.layout.drawer_list_item, parent, false);
        } else {
            row = convertView;
        }
        TextView titletext = (TextView) row.findViewById(R.id.drawer_text);
        ImageView titleImage = (ImageView) row.findViewById(R.id.drawer_image);
        titletext.setText(drawerList[position]);

        titleImage.setImageDrawable(MrVector.inflate(context.getResources(),layoutID));
    }
    if (getItemViewType(position) == 2) {
        if (convertView == null) {
            row = inflater.inflate(R.layout.header_listview_menu, parent, false);
        } else {
            row = convertView;
        }
        row.setEnabled(false);
        row.setOnClickListener(null);
    }
    return row;
}

}

【讨论】：