Question

我正在使用BufferedReader从String文件中获取.txt

 BufferedReader read = new BufferedReader(
new InputStreamReader(getAssets().open(name)));
    BufferedReader count = new BufferedReader(
new InputStreamReader(getAssets().open(name)));

    String line;
    String str =  null;

    while((line = count.readLine()) != null)
    {
        str += read.readLine() + "\n";

    }

我在String中显示TextView 但它显示的是null，而不是我的String

nullThis is file 1 而不是 This is file 1

我该如何解决这个问题？

Answer 1

试试这个！

BufferedReader read = new BufferedReader(
        new InputStreamReader(getAssets().open(name)));
BufferedReader count = new BufferedReader(
        new InputStreamReader(getAssets().open(name)));

String line;
String str = "";

while((line=count.readLine())!=null)

{
    str += read.readLine() + "\n";

}

Answer 2

您正在使用：

String str = null;

然后

str += read.readLine() + "\n";

哪个是

str = str + read.readLine() + "\n";

因此，在变量替换后，我们得到：

str = null + read.readLine() + "\n";

这意味着我们将其与null结合，有意产生"null"。

尝试其中一行（仅一个）：

String str = "";
String str = new String ();

Answer 3

您可以使用StringBuilder代替String。它具有更好的性能，因为String是不可变的。

[如果您希望它是线程安全的话，请使用StringBuffer 。

BufferedReader read = new BufferedReader(
new InputStreamReader(getAssets().open(name)));
    BufferedReader count = new BufferedReader(
new InputStreamReader(getAssets().open(name)));

    String line;
    StringBuilder str =  new StringBuilder();

    while((line = count.readLine()) != null)
    {
        str.append(read.readLine()).append("\n");
    }

Answer 4

将其初始化为

String str = "";

使用BufferedReader时，在字符串的开头添加Null

4 个答案: