当我在android中按下home按钮时,活动重新启动
当我通过TaskManager打开活动时,我的活动恐怕会重新启动 我的DefaultHttpClient对象被视为一个新对象,所以这里我失去了 会议 我试图重写onSaveInstanceState()方法,但没有用当我在android中按下home按钮时,活动重新启动,android,android-activity,Android,Android Activity,当我通过TaskManager打开活动时,我的活动恐怕会重新启动 我的DefaultHttpClient对象被视为一个新对象,所以这里我失去了 会议 我试图重写onSaveInstanceState()方法,但没有用 @Override protected void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); // the UI component
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState); // the UI component values are saved here.
}
如何摆脱这个…您可以对Android应用程序进行子类化:您可以在那里初始化HttpClient并保存引用 使用
activity.getApplication()
如果会话使用cookie,则可能需要持久cookie存储(如数据库或共享首选项):
import java.io.ByteArrayInputStream;
导入java.io.ByteArrayOutputStream;
导入java.io.ObjectInputStream;
导入java.io.ObjectOutputStream;
导入java.util.Date;
导入java.util.List;
导入java.util.concurrent.ConcurrentHashMap;
导入java.util.concurrent.CopyOnWriteArrayList;
导入org.apache.http.client.CookieStore;
导入org.apache.http.cookie.cookie;
导入android.content.Context;
导入android.content.SharedReferences;
导入android.text.TextUtils;
/**
*实现Apache HttpClient的持久cookie存储
*{@link CookieStore}接口。Cookie已存储并将保留在服务器上
*应用程序会话之间的用户设备,因为它们已序列化且
*存储在{@link SharedPreferences}中。
*
*/
公共类PersistentCookieStore实现CookieStore{
私有静态最终字符串COOKIE\u PREFS=“CookiePrefsFile”;
私有静态最终字符串COOKIE\u NAME\u STORE=“NAME”;
私有静态最终字符串COOKIE\u NAME\u PREFIX=“COOKIE\ux”;
私有最终ConcurrentHashMap cookies;
私人最终共享参考cookiePrefs;
/**
*构造一个持久的cookie存储。
*/
公共PersistentCookieStore(上下文){
cookiePrefs=context.getSharedReferences(COOKIE\u PREFS,0);
cookies=新的ConcurrentHashMap();
//将以前存储的任何cookie加载到存储中
String storedCookieNames=cookiePrefs.getString(COOKIE\u NAME\u STORE,
无效);
if(storedCookieNames!=null){
字符串[]cookieNames=TextUtils.split(storedCookieNames,“,”);
for(字符串名称:cookieNames){
String encodedCookie=cookiePrefs.getString(COOKIE\u NAME\u前缀
+名称(空);
如果(encodedCookie!=null){
Cookie decodedCookie=解码Cookie(encodedCookie);
if(decodedCookie!=null){
cookies.put(名称、解码cookie);
}
}
}
//清除过期的饼干
clearExpired(新日期());
}
}
@凌驾
公共同步的void addCookie(Cookie Cookie){
字符串名称=cookie.getName()+cookie.getDomain();
//将cookie保存到本地存储中,或在过期时删除
如果(!cookie.isExpired(new Date())){
cookies.put(名称、cookie);
}否则{
删除(名称);
}
//将cookie保存到持久存储中
SharedPreferences.Editor prefsWriter=cookiePrefs.edit();
prefsWriter.putString(COOKIE\u NAME\u存储,
TextUtils.join(“,”,cookies.keySet());
prefsWriter.putString(COOKIE\u NAME\u PREFIX+NAME,
encodeCookie(新的SerializableCookie(cookie));
prefsWriter.commit();
}
@凌驾
公共同步无效清除(){
//从持久存储中清除cookie
SharedPreferences.Editor prefsWriter=cookiePrefs.edit();
for(字符串名称:cookies.keySet()){
prefsWriter.remove(COOKIE\u NAME\u PREFIX+NAME);
}
删除(COOKIE\u NAME\u存储);
prefsWriter.commit();
//清除本地商店的cookies
cookies.clear();
}
@凌驾
公共同步布尔clearExpired(日期){
布尔clearedAny=false;
SharedPreferences.Editor prefsWriter=cookiePrefs.edit();
对于(ConcurrentHashMap.Entry:cookies.entrySet()){
字符串名称=entry.getKey();
Cookie Cookie=entry.getValue();
如果(cookie.isExpired(日期)){
//清除本地商店的cookies
删除(名称);
//从持久存储中清除cookie
prefsWriter.remove(COOKIE\u NAME\u PREFIX+NAME);
//我们至少清除了一个
clearedAny=true;
}
}
//更新持久存储中的名称
如果(清除任何){
prefsWriter.putString(COOKIE\u NAME\u存储,
TextUtils.join(“,”,cookies.keySet());
}
prefsWriter.commit();
返回clearedAny;
}
@凌驾
公共同步列表getCookies(){
返回新的CopyOnWriteArrayList(cookies.values());
}
//
//Cookie序列化/反序列化
//
受保护的同步字符串编码cookie(SerializableCookie cookie){
ByteArrayOutputStream os=新建ByteArrayOutputStream();
试一试{
ObjectOutputStream outputStream=新的ObjectOutputStream(os);
outputStream.writeObject(cookie);
}捕获(例外e){
返回null;
}
返回byteArrayToHexString(os.toByteArray());
}
受保护的同步Cookie解码Cookie(字符串cookieStr){
字节[]字节=hexStringToByteArray(cookieStr);
ByteArrayInputStream is=新的ByteArrayInputStream(字节);
Cookie=null;
试一试{
ObjectInputStream ois=新ObjectInputStream(is);
cookie=((SerializableCookie)ois.readObject()).getCookie();
}捕获(例外e){
e、 printStackTrace();
}
返回cookie;
}
//使用so
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Date;
import java.util.List;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;
import org.apache.http.client.CookieStore;
import org.apache.http.cookie.Cookie;
import android.content.Context;
import android.content.SharedPreferences;
import android.text.TextUtils;
/**
* A persistent cookie store which implements the Apache HttpClient
* {@link CookieStore} interface. Cookies are stored and will persist on the
* user's device between application sessions since they are serialized and
* stored in {@link SharedPreferences}.
* <p>
*/
public class PersistentCookieStore implements CookieStore {
private static final String COOKIE_PREFS = "CookiePrefsFile";
private static final String COOKIE_NAME_STORE = "names";
private static final String COOKIE_NAME_PREFIX = "cookie_";
private final ConcurrentHashMap<String, Cookie> cookies;
private final SharedPreferences cookiePrefs;
/**
* Construct a persistent cookie store.
*/
public PersistentCookieStore(Context context) {
cookiePrefs = context.getSharedPreferences(COOKIE_PREFS, 0);
cookies = new ConcurrentHashMap<String, Cookie>();
// Load any previously stored cookies into the store
String storedCookieNames = cookiePrefs.getString(COOKIE_NAME_STORE,
null);
if (storedCookieNames != null) {
String[] cookieNames = TextUtils.split(storedCookieNames, ",");
for (String name : cookieNames) {
String encodedCookie = cookiePrefs.getString(COOKIE_NAME_PREFIX
+ name, null);
if (encodedCookie != null) {
Cookie decodedCookie = decodeCookie(encodedCookie);
if (decodedCookie != null) {
cookies.put(name, decodedCookie);
}
}
}
// Clear out expired cookies
clearExpired(new Date());
}
}
@Override
public synchronized void addCookie(Cookie cookie) {
String name = cookie.getName() + cookie.getDomain();
// Save cookie into local store, or remove if expired
if (!cookie.isExpired(new Date())) {
cookies.put(name, cookie);
} else {
cookies.remove(name);
}
// Save cookie into persistent store
SharedPreferences.Editor prefsWriter = cookiePrefs.edit();
prefsWriter.putString(COOKIE_NAME_STORE,
TextUtils.join(",", cookies.keySet()));
prefsWriter.putString(COOKIE_NAME_PREFIX + name,
encodeCookie(new SerializableCookie(cookie)));
prefsWriter.commit();
}
@Override
public synchronized void clear() {
// Clear cookies from persistent store
SharedPreferences.Editor prefsWriter = cookiePrefs.edit();
for (String name : cookies.keySet()) {
prefsWriter.remove(COOKIE_NAME_PREFIX + name);
}
prefsWriter.remove(COOKIE_NAME_STORE);
prefsWriter.commit();
// Clear cookies from local store
cookies.clear();
}
@Override
public synchronized boolean clearExpired(Date date) {
boolean clearedAny = false;
SharedPreferences.Editor prefsWriter = cookiePrefs.edit();
for (ConcurrentHashMap.Entry<String, Cookie> entry : cookies.entrySet()) {
String name = entry.getKey();
Cookie cookie = entry.getValue();
if (cookie.isExpired(date)) {
// Clear cookies from local store
cookies.remove(name);
// Clear cookies from persistent store
prefsWriter.remove(COOKIE_NAME_PREFIX + name);
// We've cleared at least one
clearedAny = true;
}
}
// Update names in persistent store
if (clearedAny) {
prefsWriter.putString(COOKIE_NAME_STORE,
TextUtils.join(",", cookies.keySet()));
}
prefsWriter.commit();
return clearedAny;
}
@Override
public synchronized List<Cookie> getCookies() {
return new CopyOnWriteArrayList<Cookie>(cookies.values());
}
//
// Cookie serialization/deserialization
//
protected synchronized String encodeCookie(SerializableCookie cookie) {
ByteArrayOutputStream os = new ByteArrayOutputStream();
try {
ObjectOutputStream outputStream = new ObjectOutputStream(os);
outputStream.writeObject(cookie);
} catch (Exception e) {
return null;
}
return byteArrayToHexString(os.toByteArray());
}
protected synchronized Cookie decodeCookie(String cookieStr) {
byte[] bytes = hexStringToByteArray(cookieStr);
ByteArrayInputStream is = new ByteArrayInputStream(bytes);
Cookie cookie = null;
try {
ObjectInputStream ois = new ObjectInputStream(is);
cookie = ((SerializableCookie) ois.readObject()).getCookie();
} catch (Exception e) {
e.printStackTrace();
}
return cookie;
}
// Using some super basic byte array <-> hex conversions so we don't have
// to rely on any large Base64 libraries. Can be overridden if you like!
protected synchronized String byteArrayToHexString(byte[] b) {
StringBuffer sb = new StringBuffer(b.length * 2);
for (byte element : b) {
int v = element & 0xff;
if (v < 16) {
sb.append('0');
}
sb.append(Integer.toHexString(v));
}
return sb.toString().toUpperCase();
}
protected synchronized byte[] hexStringToByteArray(String s) {
int len = s.length();
byte[] data = new byte[len / 2];
for (int i = 0; i < len; i += 2) {
data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4) + Character
.digit(s.charAt(i + 1), 16));
}
return data;
}
}
android:launchMode="singleInstance"
android:alwaysRetainTaskState="true"
if (!isTaskRoot()) {
final Intent intent = getIntent();
final String action = intent.getAction();
if (intent.hasCategory(Intent.CATEGORY_LAUNCHER) && action != null && action.equals(Intent.ACTION_MAIN)) {
finish();//Launcher Activity is not the root. So,finish it instead of launching
return;
}
}