由网友(搁浅)分享简介：package com.example.tictactoeshowgrid;import android.os.Bundle;import java.io.*;import android.widget.Toast;import android.content.*;import java.io....

            package com.example.tictactoeshowgrid;

            import android.os.Bundle;
            import java.io.*;
            import android.widget.Toast;
            import android.content.*;

            import java.io.FileInputStream;
            import java.io.FileNotFoundException;
            import java.io.FileOutputStream;
            import java.io.IOException;
            import java.util.Date;

            import android.content.Context;

                public class ImportOBJ {

                protected void onCreate(String filename) {
                    try
                    {
                        FileInputStream fis = openFileInput(filename);
                        BufferedReader reader = new BufferedReader(new InputStreamReader(fis));
                        String line = null, input="";
                        while ((line = reader.readLine()) != null)
                            input += line;
                        reader.close();
                        fis.close();
                        //toast("File successfully loaded.");
                        //return input;
                    }
                    catch (Exception ex)
                    {
                        //toast("Error loading file: " + ex.getLocalizedMessage());
                        //return "";
                    }
                }
            }

我在看文件I / O为Android的一个例子。我很奇怪，为什么openFileInput快到了一个错误作为一个未定义的功能。我在想，也许我错过了一个进口？如果没有，那么就必须有一些其他的问题。

I am looking at an example of File I/O for Android. I am wondering why openFileInput is coming up with an error as being an undefined function. I was thinking that maybe I missed an import? If not then there must be some other problem.

在此先感谢...

推荐答案

在非活性类访问 openFileInput 方法，你将需要传递活动上下文给它发送上下文采用参数化方法或使用 ImportOBJ 类的构造函数为：

for accessing openFileInput method in non Activity class you will need to pass Activity Context to it by sending Context using parametrized method or using ImportOBJ class constructor as:

protected void onCreate(String filename,Context context) {
   try
     {
         FileInputStream fis = context.openFileInput(filename);  
         //...your code here...      
     }
   catch (Exception ex)
     {

     }
}

和从活动传球方面为：

ImportOBJ obj_import=new ImportOBJ();
obj_import.onCreate(<File_Name_Here>,Your_Current_Activity_Name.this);