我为离线概念创建了一个Android应用程序。当互联网连接的数据可以通过服务器同步时。
我的平板电脑拥有超过5.7GB的内存空间。当我从服务器同步数据时，它报告错误为内存不足。
我认为数据存储位置已更改，其存储在其他位置。有谁能解决这个问题？我想在清单文件中进行一些修改。
public class sync extends Activity implements OnClickListener {
private static String url = "Json URL";
// Button
Button chktosync, logout_menu;
private ProgressDialog pd;
DBAdapter db = new DBAdapter(this);
JSONArray contacts = null;
JSONArray cropdetails = null;
JSONArray biodetails = null;
String land, area, sf, land_id;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.sync);
logout_menu = (Button) findViewById(R.id.logout_menu);
logout_menu.setOnClickListener(this);
chktosync = (Button) findViewById(R.id.chktosync);
chktosync.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
pd = ProgressDialog.show(sync.this, "Synchronizing", "Synchronizing...");
new Thread() {
public void run() {
try {
processThread();
pestanddisease();
bioparam();
} catch (Exception e) {
Log.e("tag", e.getMessage());
}
// dismiss the progress dialog
pd.dismiss();
}
}.start();
}
});
}
private void processThread() {
// Creating JSON Parser instance
JSONParser jParser = new JSONParser();
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(url);
try {
// Getting Array of Contacts
contacts = json.getJSONArray(loginPage.code);
db.open();
// looping through All Contacts
for (int i = 0; i < contacts.length(); i++) {
JSONObject c = contacts.getJSONObject(i);
// Storing each json item in variable
String farmerid = c.getString("farmerid");
String farmername = c.getString("farmername");
String farmer_fathername = c.getString("farmer_fathername");
String farmer_mobilenumber = c.getString("farmer_mobilenumber");
String districtname = c.getString("districtname");
String blockname = c.getString("blockname");
String villagename = c.getString("villagename");
db.insertFarmer(farmerid, farmername,
farmer_fathername, farmer_mobilenumber,
districtname, blockname, villagename);
//land details
JSONArray Land = c.getJSONArray("land_details");
for (int l = 0; l < Land.length(); l++) {
JSONObject s = Land.getJSONObject(l);
String survey_no = s.getString("survey_no");
String area = s.getString("area");
String land_type = s.getString("land_type");
String patternref = s.getString("patternref");
String crop_matrix_id = s.getString("crop_matrix");
land_id = s.getString("land_id");
String season1_crop = s.getString("season1_crop");
String season2_crop = s.getString("season2_crop");
String season3_crop = s.getString("season3_crop");
db.insertlanddetails(farmerid, survey_no, area, land_type, patternref, land_id, crop_matrix_id, season1_crop, season2_crop, season3_crop);
}
db.close();
}
catch (JSONException e)
{
e.printStackTrace();
}
}
public void pestanddisease()
{
/// Creating JSON Parser instance
JSONParser jParser = new JSONParser();
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(pestdisease);
try
{
// Getting Array of Contacts
cropdetails = json.getJSONArray("CropDetails");
db.open();
for (int i = 0; i < cropdetails.length(); i++) {
JSONObject s = cropdetails.getJSONObject(i);
String cropname = s.getString("crop");
String pest = s.getString("pest_name");
String disease = s.getString("disease_name");
db.insertcrop_pest_details(cropname, pest);
db.insertcrop_disease_details(cropname, disease);
}
db.close();
} catch (JSONException e) {
e.printStackTrace();
}
}
}
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONObject getJSONFromUrl(String url) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
BufferedReader reader;
try {
reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),1048576);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null)
{
line=reader.readLine();
sb.append(line + "\n");
}
is.close();
json = sb.toString();
Log.e("JSON", json);
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
08-28 02:06:59.199: E/dalvikvm-heap(304): Out of memory on a 9513056-byte allocation.
08-28 02:06:59.446: E/AndroidRuntime(304): Uncaught handler: thread Thread-9 exiting due to uncaught exception
08-28 02:06:59.732: E/AndroidRuntime(304): java.lang.OutOfMemoryError
08-28 02:06:59.732: E/AndroidRuntime(304): at java.lang.AbstractStringBuilder.enlargeBuffer(AbstractStringBuilder.java:97)
08-28 02:06:59.732: E/AndroidRuntime(304): at java.lang.AbstractStringBuilder.append0(AbstractStringBuilder.java:131)
08-28 02:06:59.732: E/AndroidRuntime(304): at java.lang.StringBuilder.append(StringBuilder.java:271)
08-28 02:06:59.732: E/AndroidRuntime(304): at java.io.BufferedReader.readLine(BufferedReader.java:413)
08-28 02:06:59.732: E/AndroidRuntime(304): at com.login.JSONParser.getJSONFromUrl(JSONParser.java:55)
08-28 02:06:59.732: E/AndroidRuntime(304): at com.login.sync.processThread(sync.java:76)
08-28 02:06:59.732: E/AndroidRuntime(304): at com.login.sync.access$1(sync.java:70)
08-28 02:06:59.732: E/AndroidRuntime(304): at com.login.sync$1$1.run(sync.java:57)
08-28 02:07:00.416: I/dalvikvm(304): threadid=7: reacting to signal 3
08-28 02:07:00.416: E/dalvikvm(304): Unable to open stack trace file '/data/anr/traces.txt': Permission denied
答案 0 :(得分：0)
所以OutOfMemoryError并不意味着你的文件系统容量不足，这意味着你的内存已经用完了下载缓冲区。
在您的情况下，您需要更改JSONObject.getJSONFromUrl(URL)以管理文件系统上的下载缓冲区，而不是内存。这是一个例子：
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpUriRequest request = new HttpGet(url);
HttpResponse response = httpClient.execute(request);
HttpEntity resEntity = response.getEntity();
InputStream is = null;
FileOutputStream fos = null;
try {
if (resEntity == null)
throw new IllegalArgumentException("HTTP entity should not be null.");
is = resEntity.getContent();
if (is == null) return 0;
// Create parent folder to avoid IOException
if (!mBinaryFile.getParentFile().exists())
mBinaryFile.getParentFile().mkdirs();
fos = new FileOutputStream(mBinaryFile, mDownloadedLength!=0);
byte[] tmp = new byte[8192];
int bufLength;
while((bufLength = is.read(tmp)) != -1) {
fos.write(tmp, 0, bufLength);
}
return mBinaryFile.length();
} catch (IOException e) {
throw new ServerConnectionException(R.string.error_network_error,
"Download file "+mBinaryFile.getName()+" failed.", e);
} finally {
Utils.closeStream(is);
Utils.closeStream(fos);
}
在这种情况下，只需要8KB内存，因此可以解决OOM问题。但是你的问题将转向如何从文件系统中读取JSON数据。只需读取您需要的数据以避免OutOfMemoryError，并在完成后立即释放内存。
答案 1 :(得分：0)
Json解析器工作正常。无需将其更改为文件。错误的原因是JSON没有正确使用。我在服务器端做了一些修改。现在它的工作正常。在同步数据之前，请确保JSON是否有效。谢谢您的支持......