我认为这是有效但现在不行，只是想下载然后打开下载 iv添加了一些coe
public class MainActivity extends Activity {
String entityString = null;
String storyObj = "";
Object json = null;
HttpEntity entity = null;
InputStream is = null;
Integer responseInteger = null;
//external storage check
boolean storageAvailable = false;
boolean storageWriteable = false;
String state = Environment.getExternalStorageState();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button downloadBtn = (Button) findViewById(R.id.downloadButton);
downloadBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
saveToExternal();
}
});
Button loadBtn = (Button) findViewById(R.id.loadButton);
loadBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
loadExternal();
}
});
//end of onCreate()
}
public void saveToExternal(){
TextView test = (TextView) findViewById(R.id.textView);
try{
//connects to mySQL
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost("http://10.0.2.2/textures_story_list.php");
HttpResponse response = client.execute(post);
//captures the response
entity = response.getEntity();
InputStream entityStream = entity.getContent();
StringBuilder entityStringBuilder = new StringBuilder();
byte [] buffer = new byte[1024];
int bytesReadCount;
while ((bytesReadCount = entityStream.read(buffer)) > 0) {
entityStringBuilder.append(new String(buffer, 0, bytesReadCount));
}
entityString = entityStringBuilder.toString();
//responseInteger = Integer.valueOf(entityString);
}catch(Exception e) {
Log.e("log_tag", "Error in http connection "+e.toString());
}
//writes as String from entityString to external memory
//first check storage state
try{
if (Environment.MEDIA_MOUNTED.equals(state)){
storageAvailable = storageWriteable = true;
} else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)){
storageAvailable = true;
storageWriteable = false;
} else storageAvailable = storageWriteable = false;
if(storageAvailable && storageWriteable) {
File extFile = new File(Environment.getExternalStorageDirectory(), "/android/data/com.game/story.json");
FileOutputStream out = new FileOutputStream(extFile);
out.write(entityString.getBytes());
out.flush();
out.close();
}
}catch(Exception e) {
Log.e("log_tag", "Error saving string "+e.toString());
}
//end of saveJson()
}
public void loadExternal(){
TextView test = (TextView) findViewById(R.id.textView);
//loads the files
try{
FileInputStream fileInput = openFileInput("/android/data/com.game/story.json");
BufferedReader inputReader = new BufferedReader(new InputStreamReader(fileInput, "UTF-8"), 8);
StringBuilder strBuilder = new StringBuilder();
String line = null;
while ((line = inputReader.readLine()) != null) {
strBuilder.append(line + "\n");
}
fileInput.close();
storyObj = strBuilder.toString();
}catch(IOException e){
Log.e("log_tag", "Error building string "+e.toString());
}
try{
JSONArray jArray = new JSONArray(storyObj);
String storyNames = "";
for(int i = 0;i<jArray.length();i++){
storyNames += jArray.getJSONObject(i).getString("story_name") +"\n";
}
test.setText(storyNames);
}catch(JSONException e) {
Log.e("log_tag", "Error returning string "+e.toString());
}
return;
//and of openJson()
}
//end of class body
}
错误说它没有文件story.json有没有人知道我缺少什么代码来解决这个问题？我的错误现在是
Error saving string java.io.FileNotFoundException: /mnt/sdcard/android/data/com.game/story.json (No such file or directory)
答案 0 :(得分：1)
类似的东西：
..........
String content = loadFromHttp();
savedToExternal(content, "story.json");
String res = loadFromExternal("story.json");
..........
private void savedToExternal(String content, String fileName) {
FileOutputStream fos = null;
Writer out = null;
try {
File file = new File(getAppRootDir(), fileName);
fos = new FileOutputStream(file);
out = new OutputStreamWriter(fos, "UTF-8");
out.write(content);
out.flush();
} catch (Throwable e){
e.printStackTrace();
} finally {
if(fos!=null){
try {
fos.close();
} catch (IOException ignored) {}
}
if(out!= null){
try {
out.close();
} catch (IOException ignored) {}
}
}
}
private String loadFromExternal(String fileName) {
String res = null;
File file = new File(getAppRootDir(), fileName);
if(!file.exists()){
Log.e("", "file " +file.getAbsolutePath()+ " not found");
return null;
}
FileInputStream fis = null;
BufferedReader inputReader = null;
try {
fis = new FileInputStream(file);
inputReader = new BufferedReader(new InputStreamReader(fis, "UTF-8"));
StringBuilder strBuilder = new StringBuilder();
String line;
while ((line = inputReader.readLine()) != null) {
strBuilder.append(line + "\n");
}
res = strBuilder.toString();
} catch(Throwable e){
if(fis!=null){
try {
fis.close();
} catch (IOException ignored) {}
}
if(inputReader!= null){
try {
inputReader.close();
} catch (IOException ignored) {}
}
}
return res;
}
public File getAppRootDir() {
File appRootDir;
boolean externalStorageAvailable;
boolean externalStorageWriteable;
String state = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(state)) {
externalStorageAvailable = externalStorageWriteable = true;
} else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
externalStorageAvailable = true;
externalStorageWriteable = false;
} else {
externalStorageAvailable = externalStorageWriteable = false;
}
if (externalStorageAvailable && externalStorageWriteable) {
appRootDir = getExternalFilesDir(null);
} else {
appRootDir = getDir("appRootDir", MODE_PRIVATE);
}
if (!appRootDir.exists()) {
appRootDir.mkdir();
}
return appRootDir;
}
............
答案 1 :(得分：0)
好的，让我们再试一次，完整代码：
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button downloadBtn = (Button) findViewById(R.id.downloadButton);
downloadBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
saveToExternal();
}
});
Button loadBtn = (Button) findViewById(R.id.loadButton);
loadBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
loadExternal();
}
});
//end of onCreate()
}
public void saveToExternal(){
String content = loadFromNet();
save(content, "story.json");
}
public void loadExternal(){
TextView test = (TextView) findViewById(R.id.textView);
String res = load("story.json");
test.setText(res);
}
private String loadFromNet(){
String result = null;
try{
//connects to mySQL
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost("http://10.0.2.2/textures_story_list.php");
HttpResponse response = client.execute(post);
//captures the response
HttpEntity entity = response.getEntity();
InputStream entityStream = entity.getContent();
StringBuilder entityStringBuilder = new StringBuilder();
byte [] buffer = new byte[1024];
int bytesReadCount;
while ((bytesReadCount = entityStream.read(buffer)) > 0) {
entityStringBuilder.append(new String(buffer, 0, bytesReadCount));
}
result = entityStringBuilder.toString();
//responseInteger = Integer.valueOf(entityString);
}catch(Exception e) {
Log.e("log_tag", "Error in http connection "+e.toString());
}
return result;
}
private void save(String content, String fileName) {
FileOutputStream fos = null;
Writer out = null;
try {
File file = new File(getAppRootDir(), fileName);
fos = new FileOutputStream(file);
out = new OutputStreamWriter(fos, "UTF-8");
out.write(content);
out.flush();
} catch (Throwable e){
e.printStackTrace();
} finally {
if(fos!=null){
try {
fos.close();
} catch (IOException ignored) {}
}
if(out!= null){
try {
out.close();
} catch (IOException ignored) {}
}
}
}
private String load(String fileName) {
String res = null;
File file = new File(getAppRootDir(), fileName);
if(!file.exists()){
Log.e("", "file " +file.getAbsolutePath()+ " not found");
return null;
}
FileInputStream fis = null;
BufferedReader inputReader = null;
try {
fis = new FileInputStream(file);
inputReader = new BufferedReader(new InputStreamReader(fis, "UTF-8"));
StringBuilder strBuilder = new StringBuilder();
String line;
while ((line = inputReader.readLine()) != null) {
strBuilder.append(line + "\n");
}
res = strBuilder.toString();
} catch(Throwable e){
if(fis!=null){
try {
fis.close();
} catch (IOException ignored) {}
}
if(inputReader!= null){
try {
inputReader.close();
} catch (IOException ignored) {}
}
}
return res;
}
public File getAppRootDir() {
File appRootDir;
boolean externalStorageAvailable;
boolean externalStorageWriteable;
String state = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(state)) {
externalStorageAvailable = externalStorageWriteable = true;
} else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
externalStorageAvailable = true;
externalStorageWriteable = false;
} else {
externalStorageAvailable = externalStorageWriteable = false;
}
if (externalStorageAvailable && externalStorageWriteable) {
appRootDir = getExternalFilesDir(null);
} else {
appRootDir = getDir("appRootDir", MODE_PRIVATE);
}
if (!appRootDir.exists()) {
appRootDir.mkdir();
}
return appRootDir;
}