[英]Android read / write text files
問題很簡單:我的班上有那些方法的人。 這將數據保存在一個文本文件中:
//Store the data in a text file
public void saveScores(String testo, TextView text) {
try {
FileOutputStream fileout = getActivity().openFileOutput("flagQuiz.txt", getActivity().MODE_PRIVATE);
OutputStreamWriter outputWriter=new OutputStreamWriter(fileout);
outputWriter.write(testo);
outputWriter.close();
text.setText(testo);
} catch (Exception e) {
e.printStackTrace();
}
}
相反,此方法從文本文件讀取數據。
//Load data from text file
public void loadScores() {
try {
FileInputStream fileIn = getActivity().openFileInput("flagQuiz.txt");
InputStreamReader InputRead= new InputStreamReader(fileIn);
char[] inputBuffer= new char[100];
String s="";
int charRead;
while ((charRead=InputRead.read(inputBuffer))>0) {
String readstring=String.copyValueOf(inputBuffer,0,charRead);
s +=readstring;
}
InputRead.close();
} catch (Exception e) {
e.printStackTrace();
}
}
據我所知,第一種方法效果很好,因為它不會引發異常,而且text.setText(testo);
不會引發異常text.setText(testo);
工作正常。
問題
應用程序打開(onCreate)時,我無法讀取文本文件。
如您所見,這里有一個空指針異常,這意味着我想文件沒有保存,或者我可能為InputStream輸入了錯誤的路徑。
有什么建議嗎? 我將在內部存儲器上寫這個很小的文本文件。
完整的日志可以在這里找到: link 。
下面的代碼將從簡歷上的.txt文件讀取數據。
public class MainActivity extends Activity {
private final static String NOTES = "notes.txt";
private EditText editText;
private Button Btn;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editText = (EditText) findViewById(R.id.editor);
Btn = (Button) findViewById(R.id.close);
Btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
finish();
}
});
}
public void onResume(){ //this method will read data from .txt file
super.onResume();
try {
InputStream in = openFileInput(NOTES);
if (in != null) {
InputStreamReader tmp = new InputStreamReader(in);
BufferedReader reader = new BufferedReader(tmp);
String str;
StringBuffer buf = new StringBuffer();
while ((str = reader.readLine()) != null) {
buf.append(str + "\n");
}
in.close();
editText.setText(buf.toString());
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (Throwable t) {
Toast.makeText(this, "Exception: " + t.toString(), Toast.LENGTH_LONG).show();
}
}
使用OpenFileInput
的示例:
FileInputStream in = openFileInput("filename.txt");
InputStreamReader inputStreamReader = new InputStreamReader(in);
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
StringBuilder sb = new StringBuilder();
String line;
while ((line = bufferedReader.readLine()) != null) {
sb.append(line);
}
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