基本上，我正在开发一个包含 4 个选项卡的选项卡活动的应用程序，并且我正在使用 actvityGroup 来管理活动和 backKeypressed() 方法。
当我的应用程序首次启动时，它会向服务器发送一个请求并显示进度条（使用 AsyncTask），如下图所示。
在此之后，我的完整 UI 显示为
它在按钮“GO”的单击事件上加载新的活动（代码如下）
btnGo.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent bookSearchResultActivityIntent = new Intent();
bookSearchResultActivityIntent
.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
bookSearchResultActivityIntent.setClass(getParent(),
BookSearchResultActivity.class);
bookSearchResultActivityIntent.putExtra("LANG", language);
bookSearchResultActivityIntent.putExtra("SEARCH_KEYWORDS",
edTxt_SearchField.getText().toString());
MyActivityGroup activityStack = (MyActivityGroup) getParent();
activityStack.push("BooksSearchActivity",
bookSearchResultActivityIntent);
这也是我的 ActivtyGroup.java 代码
public class MyActivityGroup extends ActivityGroup {
private Stack<String> stack;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (stack == null) {
stack = new Stack<String>();
}
push("1stStackActivity", new Intent(this, Home.class));
}
@Override
public void finishFromChild(Activity child) {
pop();
}
@Override
public void onBackPressed() {
pop();
}
public void push(String id, Intent intent) {
Window window = getLocalActivityManager().startActivity(id,
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP));
if (window != null) {
stack.push(id);
setContentView(window.getDecorView());
}
}
public void pop() {
if (stack.size() == 1) {
finish();
}
LocalActivityManager manager = getLocalActivityManager();
manager.destroyActivity(stack.pop(), true);
if (stack.size() > 0) {
Intent lastIntent = manager.getActivity(stack.peek()).getIntent()
.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
Window newWindow = manager.startActivity(stack.peek(), lastIntent);
setContentView(newWindow.getDecorView());
}
}
}
好的，现在我的问题是当我按下 backKey(); 它应该来到以前的活动。
- 是的，它涉及上一个活动，但它再次向服务器发送请求并再次显示进度条并加载，直到服务器发送响应。这浪费了我的时间。
- 我只想加载 HomeTab 一次（当我玩应用程序时）。不是一次又一次
我也在添加
setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
在开始活动时
还在 menifest.xml 文件中添加了以下代码
android:configChanges="键盘|keyboardHidden|方向"
但还没有工作。
这是我的主页选项卡的代码（它在 onCreate 方法中将请求发送到服务器）
public class Home extends Activity {
/** Called when the activity is first created. */
static final String URL = "http://www.shiaislamiclibrary.com/requesthandler.ashx";
static final String KEY_ITEM = "Book"; // parent node
static final String KEY_BOOKAUTHOR = "BookAuthor";
static final String KEY_BOOKDATEPUBLISHED = "DatePublished";
static final String KEY_BOOKTITLE = "BookTitle";
static final String KEY_BOOKCODE = "BookCode";
static final String KEY_BOOKIMAGE = "BookImage";
String searchLang;
String searchKeywords;
LayoutInflater inflater = null;
ArrayList<String> BookTitle = new ArrayList<String>();
ArrayList<String> BookCoverPhotos = new ArrayList<String>();
ArrayList<String> BookAuther = new ArrayList<String>();
ArrayList<String> BookPublishDate = new ArrayList<String>();
ArrayList<String> ImageByte = new ArrayList<String>();
ArrayList<Bitmap> bitmapArray = new ArrayList<Bitmap>();
Context ctx = this;
Activity act = this;
Context context = Home.this;
URL bookImageURL = null;
Bitmap bitMapImage = null;
Button btnGo;
Spinner spnrLanguage;
Spinner spnrBrowseBy;
String language;
EditText edTxt_SearchField;
GridView gridView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// setContentView(R.layout.home_activity);
View viewToLoad = LayoutInflater.from(this.getParent()).inflate(
R.layout.home_activity, null);
this.setContentView(viewToLoad);
gridView = (GridView) findViewById(R.id.gridview);
spnrLanguage = (Spinner) findViewById(R.id.spnrLanguage);
spnrBrowseBy = (Spinner) findViewById(R.id.spnrBrowseBy);
edTxt_SearchField = (EditText) findViewById(R.id.EditTxt_Search);
btnGo = (Button) findViewById(R.id.btn_GO);
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
// checking for availbe internet Connection
if (cm.getActiveNetworkInfo() != null
&& cm.getActiveNetworkInfo().isAvailable()
&& cm.getActiveNetworkInfo().isConnected()) {
new UIThread().execute(URL, "Imam Ali");
}
gridView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int pos,
long arg3) {
Toast.makeText(context, BookTitle.get(pos), Toast.LENGTH_SHORT)
.show();
Intent bookSearchResultActivityIntent = new Intent();
bookSearchResultActivityIntent.setClass(getParent(),
BookOverView.class);
bookSearchResultActivityIntent.putExtra("BITMAP",
bitmapArray.get(pos));
bookSearchResultActivityIntent.putExtra("BOOK_TITLE",
BookTitle.get(pos));
bookSearchResultActivityIntent.putExtra("BOOK_AUTHOR",
BookAuther.get(pos));
bookSearchResultActivityIntent.putExtra("BOOK_PUBLISH_DATE",
BookPublishDate.get(pos));
MyActivityGroup activityStack = (MyActivityGroup) getParent();
activityStack.push("BookOverViewActivity",
bookSearchResultActivityIntent);
}
});
// //////////////////// Spinners handler/////////////////////////
ArrayAdapter<String> adapterLanguage = new ArrayAdapter<String>(
context, android.R.layout.simple_spinner_item, getResources()
.getStringArray(R.array.spnr_language_array));
ArrayAdapter<String> adapterBrowseBy = new ArrayAdapter<String>(
context, android.R.layout.simple_spinner_item, getResources()
.getStringArray(R.array.spnr_browse_array));
spnrLanguage.setAdapter(adapterLanguage);
spnrBrowseBy.setAdapter(adapterBrowseBy);
spnrLanguage.setOnItemSelectedListener(new OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> arg0, View arg1, int pos,
long arg3) {
Toast.makeText(getParent(),
spnrLanguage.getItemAtPosition(pos) + "",
Toast.LENGTH_SHORT).show();
language = spnrLanguage.getItemAtPosition(pos).toString();
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
}
});
spnrBrowseBy.setOnItemSelectedListener(new OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> arg0, View arg1, int pos,
long arg3) {
Toast.makeText(context,
spnrBrowseBy.getItemAtPosition(pos) + "",
Toast.LENGTH_SHORT).show();
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
}
});
// ////////////////////Search Button Handler/////////////////
btnGo.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if (!edTxt_SearchField.getText().toString().equals("")) {
Intent bookSearchResultActivityIntent = new Intent();
bookSearchResultActivityIntent
.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
bookSearchResultActivityIntent.setClass(getParent(),
BookSearchResultActivity.class);
bookSearchResultActivityIntent.putExtra("LANG", language);
bookSearchResultActivityIntent.putExtra("SEARCH_KEYWORDS",
edTxt_SearchField.getText().toString());
MyActivityGroup activityStack = (MyActivityGroup) getParent();
activityStack.push("BooksSearchActivity",
bookSearchResultActivityIntent);
} else {
Toast.makeText(context, "Search Field Empty",
Toast.LENGTH_SHORT).show();
}
}
});
}
private class UIThread extends AsyncTask<String, Integer, String> {
ProgressDialog progressDialog;
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
progressDialog = ProgressDialog.show(getParent(),
"Acumlating Books from server...",
"This may Take a few seconds.\nPlease Wait...");
}
@Override
protected String doInBackground(String... params) {
String URL = params[0];
String searchKeywords = params[1];
XMLParser parser = new XMLParser();
String XMLString = parser.getXmlFromUrl(URL, searchKeywords,
searchLang);
// Log.i("XML Response", XMLString);
Document doc = parser.getDomElement(XMLString);
NodeList nl = doc.getElementsByTagName(KEY_ITEM);
// looping through all item nodes <item>
for (int i = 0; i < nl.getLength(); i++) {
Element e = (Element) nl.item(i);
BookTitle.add(parser.getValue(e, KEY_BOOKTITLE));
BookCoverPhotos.add("http://shiaislamicbooks.com/books_Snaps/"
+ parser.getValue(e, KEY_BOOKCODE) + "/1_thumb.jpg");
BookAuther.add(parser.getValue(e, KEY_BOOKAUTHOR));
BookPublishDate.add(parser.getValue(e, KEY_BOOKDATEPUBLISHED));
Log.i("URLs", BookCoverPhotos.toString());
}
for (int i = 0; i < BookAuther.size(); i++) {
try {
bookImageURL = new URL(BookCoverPhotos.get(i));
} catch (MalformedURLException e) {
e.printStackTrace();
Log.i("URL", "ERROR at image position" + i + "");
}
try {
bitMapImage = BitmapFactory.decodeStream(bookImageURL
.openConnection().getInputStream());
bitmapArray.add(bitMapImage);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.i("BITMAP", "ERROR" + i);
}
}
return null;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
progressDialog.dismiss();
ImageAdapter adapter = new ImageAdapter(getBaseContext(), act);
gridView.setAdapter(adapter);
}
}
public class ImageAdapter extends BaseAdapter {
public ImageAdapter(Context c) {
context = c;
}
// ---returns the number of images---
public int getCount() {
// return imageIDs.length;
return bitmapArray.size();
// return 6;
}
public ImageAdapter(Context ctx, Activity act) {
inflater = (LayoutInflater) act
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
// ---returns the ID of an item---
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
// ---returns an ImageView view---
public View getView(int position, View convertView, ViewGroup parent) {
// ImageView bmImage;
final ViewHolder holder;
View vi = convertView;
if (convertView == null) {
vi = inflater.inflate(R.layout.grid_style, parent, false);
holder = new ViewHolder();
holder.txt_BooksTitle = (TextView) vi
.findViewById(R.id.txt_BookTitle);
holder.img_BookCoverPhoto = (ImageView) vi
.findViewById(R.id.imgBookCover);
vi.setTag(holder);
} else {
holder = (ViewHolder) vi.getTag();
}
holder.txt_BooksTitle.setText(BookTitle.get(position) + "");
holder.img_BookCoverPhoto.setImageBitmap(bitmapArray.get(position));
return vi;
}
}
class ViewHolder {
TextView txt_BooksTitle;
ImageView img_BookCoverPhoto;
}
}
- 请看看我的活动小组课，告诉我该怎么做。提前致谢