[英]Strange issue with writing/reading ArrayList to a file
我在我的活動中有這個代碼:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_top_jokes_body);
final GlobalsHolder globals = (GlobalsHolder)getApplication();
TextView text = (TextView) findViewById(R.id.txtJoke);
text.setText(globals.getList().get(globals.clickedPosition));
ArrayList<String> jokeBodyList = new ArrayList<String>();
jokeBodyList.addAll(readFromFile());
jokeBodyList.add(text.getText().toString());
System.out.println("List content(jokeBodyList): " + jokeBodyList.toString());
writeToFile(jokeBodyList);
System.out.println("The file content(new)" + readFromFile().toString());
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.top_jokes_body, menu);
return true;
}
/* Write content to a file */
private void writeToFile(ArrayList<String> list) {
FileOutputStream fos;
if(list != null){
try {
fos = openFileOutput("jokesBody2.bjk",Context.MODE_PRIVATE);
ObjectOutputStream out = new ObjectOutputStream(fos);
out.writeObject(list.toString());
out.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}else{
try {
fos = openFileOutput("jokesBody2.bjk",Context.MODE_PRIVATE);
ObjectOutputStream out = new ObjectOutputStream(fos);
out.writeObject("");
out.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/* Read file's content */
private ArrayList<String> readFromFile() {
File file = new File("jokesBody.bjk");
String ret = "";
ArrayList<String> list = new ArrayList<String>();
try {
InputStream inputStream = openFileInput(file.toString());
if (inputStream != null) {
InputStreamReader inputStreamReader = new InputStreamReader(
inputStream);
BufferedReader bufferedReader = new BufferedReader(
inputStreamReader);
String receiveString = "";
StringBuilder stringBuilder = new StringBuilder();
while ((receiveString = bufferedReader.readLine()) != null) {
list.add(receiveString);
}
inputStream.close();
ret = stringBuilder.toString();
}
} catch (FileNotFoundException e) {
Log.e("log activity", "File not found: " + e.toString());
} catch (IOException e) {
Log.e("log activity", "Can not read file: " + e.toString());
}
return list;
}
主要思想是將文件的內容傳遞給ArrayList
然后將另一個值添加到同一個ArrayList
,然后將列表寫回teh文件。 我正在使用兩種方法來讀寫文件,問題是寫入和讀取有問題。 我的意思是這兩張照片
System.out.println("List content(jokeBodyList): " + jokeBodyList.toString());
System.out.println("The file content(new)" + readFromFile().toString());
正在回歸一些奇怪的價值觀 這是輸出:
02-13 09:10:22.482: I/System.out(2286): List content(jokeBodyList): [����tT[���sr�java.util.ArrayListx����a��I�sizexp���w���, t�����sr�java.util.ArrayListx����a��I�sizexp���w��� t��t��t��t�.joke 13joke 12Joke 8 ,joke 14 ,joke 13 ,Joke 9t� ,Joke 9t� ,Joke 8t�t� ,Ceco's joket� ,joke 13xt� ,joke 12x, ,joke 12], joke 10]
02-13 09:10:22.542: I/System.out(2286): The file content(new)[����tT[���sr�java.util.ArrayListx����a��I�sizexp���w���, t�����sr�java.util.ArrayListx����a��I�sizexp���w��� t��t��t��t�.joke 13joke 12Joke 8 ,joke 14 ,joke 13 ,Joke 9t� ,Joke 9t� ,Joke 8t�t� ,Ceco's joket� ,joke 13xt� ,joke 12x, ,joke 12]]
即使文本文件為空,也會發生這種情況。 我錯過了什么? 我知道它真的很小,但我找不到它。
out.writeObject(list.toString());
完全錯了! 使用out.writeObject(list);
這就是ObjectOutputStream
的用途。
閱讀是另一種方式:
ObjectInputStream ois = new ObjectInputStream( new FileInputStream( file ) );
yourArrayList = (ArrayList)ois.readObject();
ois.close();
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