在文件列表中选择文件，并把一个文件的内容显示在TextArea中

private FileDialog openFileDialog = new FileDialog(this,"Open File",FileDialog.LOAD);

else if(eventSource == openFile)
        {
            openFileDialog.show();
            fileName = openFileDialog.getDirectory()+openFileDialog.getFile();
            if(fileName != null)
              readFile(fileName);
        }

public void readFile(String fileName)

{

File file = new File(fileName);
FileReader readIn = new FileReader(file);
int size = (int)file.length();
int charsRead = 0;
char[] content = new char[size];
while(readIn.ready())
charsRead += readIn.read(content, charsRead, size - charsRead);
readIn.close();
textArea.setText(new String(content, 0, charsRead));

}