android fileinputstream 2g,android FileInputStream崩溃

我是一个为android开发的业余程序员。我现在只是尝试了解基础知识，但是我有一个错误，我不知道为什么。android FileInputStream崩溃

我正在创建一个具有保存和加载按钮的活动，它使用fileOutputStream和fileInputStream来完成此任务。

我遇到的问题是，如果我第一次使用该活动时点击加载按钮，我的应用程序崩溃。任何人都可以帮助我如何跳过加载部分，如果该文件尚未创建？我应该在我的if语句中使用什么。

由于一吨，这是我的代码：

import android.app.Activity;

import android.content.Context;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.EditText;

import android.widget.TextView;

public class InternalData extends Activity implements OnClickListener {

String FILENAME = "InternalString";

EditText sharedData;

TextView dataResults;

FileOutputStream fos;

String d;

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

setContentView(R.layout.sharedpreferences);

Button save = (Button) findViewById(R.id.bSave);

Button load = (Button) findViewById(R.id.bLoad);

sharedData = (EditText) findViewById(R.id.etSharedPrefs);

dataResults = (TextView) findViewById(R.id.tvLoadSharedPrefs);

save.setOnClickListener(this);

load.setOnClickListener(this);

try {

fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);

} catch (FileNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

public void onClick(View v) {

// TODO Auto-generated method stub

switch (v.getId()) {

case R.id.bSave:

d = sharedData.getText().toString();

try {

fos.write(d.getBytes());

fos.close();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

break;

case R.id.bLoad:

FileInputStream fis = null;

try {

if (openFileInput(FILENAME) != null){

fis = openFileInput(FILENAME);

byte[] data = new byte[fis.available()];

while(fis.read(data) != -1){

String readData = new String(data);

dataResults.setText(readData);

}}

} catch (FileNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}finally{

try {

fis.close();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

break;

}

}

}

感谢您的帮助卢卡斯，我已经更新了我的代码，我在想，如果你可以看看它在确保我使用的AsyncTask正常。再次感谢！

public class InternalData extends Activity implements OnClickListener {

String FILENAME = "InternalString";

EditText sharedData;

TextView dataResults;

FileOutputStream fos;

String d;

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

setContentView(R.layout.sharedpreferences);

Button save = (Button) findViewById(R.id.bSave);

Button load = (Button) findViewById(R.id.bLoad);

sharedData = (EditText) findViewById(R.id.etSharedPrefs);

dataResults = (TextView) findViewById(R.id.tvLoadSharedPrefs);

save.setOnClickListener(this);

load.setOnClickListener(this);

}

public void onClick(View v) {

// TODO Auto-generated method stub

switch (v.getId()) {

case R.id.bSave:

d = sharedData.getText().toString();

try {

fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);

fos.write(d.getBytes());

fos.close();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

break;

case R.id.bLoad:

AsyncTask dat = new loadInternalData().execute(FILENAME);

break;

}

}

public class loadInternalData extends AsyncTask {

@Override

protected String doInBackground(String... params) {

// TODO Auto-generated method stub

FileInputStream fis = null;

String collected = null;

try {

fis = openFileInput(FILENAME);

byte[] data = new byte[fis.available()];

while (fis.read(data) != -1){

collected = new String(data);

}

} catch (FileNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}finally{

try {

fis.close();

return collected;

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

return collected;

}

@Override

protected void onPostExecute(String result)

{

super.onPostExecute(result);

Log.i("InteralStorage", "onPostExecute(): " + result);

dataResults.setText(result);

}

}

}

2011-07-16

travis