在 Adapter class 的 getView 中获取 java.lang.NullPointerException 而在 App 运行 中获取 java.lang.NullPointerException

Getting java.lang.NullPointerException in getView of Adapter class while running the App

我正在尝试在自定义 ListView 的 SQLite 数据库中显示我的 table 中的行,为此我创建了一个 ProductAdapter class。 运行 应用程序时出现错误 以下是错误

07-31 14:31:42.548    1968-1968/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.NullPointerException
            at com.sling.freshecomart.ProductAdapter.getView(ProductAdapter.java:54)

下面是行 ProductAdapter.java:54

convertView = mInflater.inflate(R.layout.item,null);

ProductAdapter class 是

public class ProductAdapter extends BaseAdapter {

    private LayoutInflater mInflater;
    private LayoutInflater inflater=null;

    public ProductAdapter(List<Product> list, Activity a) {
        this.mProductList = list;
        this.activity=a;
        inflater = (LayoutInflater) this.activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }


    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        final ViewItem item;

        if (convertView == null) {
            convertView = mInflater.inflate(R.layout.item,null);

        .......

        } 
    }
}

请帮助并提前致谢

改变

 convertView = mInflater.inflate(R.layout.item,null);

 convertView = inflater.inflate(R.layout.item,null);

因为mInflater=null