Question

您好我找到了创建文件并在其中添加字符串的方法

public void generateNoteOnSD(Context context, String sFileName, String sBody) {
try {
    File root = new File(Environment.getExternalStorageDirectory(), "Notes");
    if (!root.exists()) {
        root.mkdirs();
    }
    File gpxfile = new File(root, sFileName);
    FileWriter writer = new FileWriter(gpxfile);
    writer.append(sBody);
    writer.flush();
    writer.close();
    Toast.makeText(context, "Saved", Toast.LENGTH_SHORT).show();
} catch (IOException e) {
    e.printStackTrace();
}
}

我的问题是如何调用此方法？我试过这样的事情

 protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    String FILENAME = "hello_file";
    String string = "hello world!";
    generateNoteOnSD(Context ,FILENAME,string);
}

我不理解Context上下文部分

Answer 1

如果您参加活动

，则需要致电getApplicationContext()

generateNoteOnSD(getApplicationContext(),FILENAME,string);

Answer 2

使用

generateNoteOnSD(YoureActivity.this,FILENAME,string);

Answer 3

protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 String FILENAME = "hello_file";
 String string = "hello world!";
 generateNoteOnSD(YourActivityName.this ,FILENAME,string);
}

Answer 4

如果您使用Fragment，那么

generateNoteOnSD(getContext(),FILENAME,string);

如果是活动就像这样

generateNoteOnSD(YourActivityName.this,FILENAME,string);

如何使用Context上下文调用方法

4 个答案: