使用扩展BaseAdapter的自定义适配器刷新ListView(Refresh ListView with custom adapter that extends BaseAdapter)

 我正在使用ListView ，它由扩展BaseAdapter自定义适配器填充。 使用AsyncTask从外部服务器获取数据， AsyncTask onPostExecute方法调用ListActivity上的方法，该方法将适配器设置为显示数据 
 
 ListView还实现OnScrollListener以在滚动时获取数据并添加到底部。 
 
 我有一个带有自定义视图的ActionBar （ Toolbar ），其中包含EditText字段和单击Button ，同样，调用相同的AsyncTask以从Toolbar传递查询值来获取新数据。 
 
 问题是，当单击工具栏上的按钮时，我希望ListView填充全新数据替换旧值，而是在列表底部附加新数据（就像调用OnClickListener ）。 
 
 我检查了Link1 ， Link2，但似乎都没有帮助 
 
 当然主要的打击是使用NotifyDataSetChange ，我也使用它但不值得。 
 
 我的方法来设置适配器 
 
public void setBusinesses(ArrayList<BusinessListData> businesses) {

    imgFetcher = new BusinessListIconTask(this);
    layoutInflator = LayoutInflater.from(this);
    if (this.businesses == null || adapter == null) {
        this.businesses = new ArrayList<>();
        adapter = new BusinessListDataAdapter(this, imgFetcher,
                layoutInflator, this.businesses);
        businessList.setAdapter(adapter);
    }
    this.businesses.addAll(businesses);
    adapter.notifyDataSetChanged();

    /* Activates when scrolling to bottom of list */
    businessList.setOnScrollListener(new OnScrollListener() {
        public int currentScrollState;
        public int currentFirstVisibleItem;
        public int currentVisibleItemCount;
        public int totalItemCount;
        public int lastItem;
        boolean isLoading = false;

        public void onScrollStateChanged(AbsListView view, int scrollState) {
            this.currentScrollState = scrollState;
            this.isScrollCompleted();

        }

        @Override
        public void onScroll(AbsListView view, int firstVisibleItem,
                             int visibleItemCount, int totalItemCount) {
            this.currentFirstVisibleItem = firstVisibleItem;
            this.currentVisibleItemCount = visibleItemCount;
            this.totalItemCount = totalItemCount;
            this.lastItem = firstVisibleItem + visibleItemCount;
        }

        private void isScrollCompleted() {
            if (this.lastItem == this.totalItemCount) {
                /*** In this way I detect if there's been a scroll which has completed ***/
                if (!isLoading) {
                    isLoading = true;
                    getScrollData(metroTxt, metroLoc, metroId);
                }
            } else {
                businessList.removeFooterView(footerView);
            }
        }
    });

}
 
 使用搜索字段设置自定义工具栏 
 
void showCustomView(String metroTxt, String metroLoc, String metroId) {
    LayoutInflater mInflater = LayoutInflater.from(this);

    if (mCustomView == null)
        mCustomView = mInflater.inflate(R.layout.custom_action_bar, null);
    mToolbar.removeView(mCustomView);
    mToolbar.addView(mCustomView);
    Log.d("I'm inside custom view", "txt" + metroTxt);
    abKeyword = (CustomAutoCompleteTextView) mCustomView
            .findViewById(R.id.ab_keyword);
    abLocation = (CustomAutoCompleteTextView) mCustomView
            .findViewById(R.id.ab_location);
    ab_search = (Button) mCustomView
            .findViewById(R.id.ab_search);
    abKeyword.append(metroTxt);

    abLocation.setVisibility(View.GONE);
    ab_search.setVisibility(View.GONE);

    abKeyword.setOnFocusChangeListener(new View.OnFocusChangeListener() {
        @Override
        public void onFocusChange(View v, boolean hasFocus) {

            if (hasFocus || !abKeyword.getText().toString().isEmpty() || !abLocation.getText().toString().isEmpty()) {
                abLocation.setVisibility(View.VISIBLE);
                ab_search.setVisibility(View.VISIBLE);
            } else {
                abLocation.setVisibility(View.GONE);
                ab_search.setVisibility(View.GONE);
            }
        }
    });
    abKeyword.addTextChangedListener(new TextWatcher() {

        public void afterTextChanged(Editable editable) {
            // TODO Auto-generated method stub

        }

        public void beforeTextChanged(CharSequence s, int start, int count,
                                      int after) {
            // TODO Auto-generated method stub
        }

        public void onTextChanged(CharSequence s, int start, int before,
                                  int count) {

            String newText = s.toString();

            BusinessInfoSuggestionTask autocompleteTask = new BusinessInfoSuggestionTask(BusinessResultListActivity.this);
            String acType = "keyword";

            if (s.length() >= 1) {
                abLocation.setVisibility(View.VISIBLE);
                ab_search.setVisibility(View.VISIBLE);
                autocompleteTask.execute(newText, acType, cActivity);

            } else {
                abLocation.setVisibility(View.GONE);
                ab_search.setVisibility(View.GONE);
            }

        }

    });
    ab_search.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            InputMethodManager inputMethodManager = (InputMethodManager) getSystemService(INPUT_METHOD_SERVICE);
            inputMethodManager.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(), 0);
            String abKey = abKeyword.getText().toString();
            String abLoc = abLocation.getText().toString();
            String abId = "";
            getBusinesses(abKey, abLoc, abId);
            Log.d("I'm clicked", "button on toolbar clicked");
        }
    });

}
 
 从服务器获取数据的方法 
 
/* Get Businesses data from server */
private void getBusinesses(String metroTxt, String metroLoc, String metroId) {
    // TODO Auto-generated method stub
    String first = "first";
    BusinessListApiTask spTask = new BusinessListApiTask(
            BusinessResultListActivity.this);
    try {
        spTask.execute(metroTxt, metroLoc, metroId, first);
    } catch (Exception e) {
        spTask.cancel(true);
    }
}

/* Fetch more data on scroll */
private void getScrollData(String metroTxt, String metroLoc, String metroId) {
    // TODO Auto-generated method stub
    String first = "next";
    BusinessListApiTask spTask = new BusinessListApiTask(
            BusinessResultListActivity.this);
    try {
        spTask.execute(metroTxt, metroLoc, metroId, first); //Call AsyncTask to fetch data from server
    } catch (Exception e) {
        spTask.cancel(true);
    }
}

I'm using ListView which is populated by custom adapter that extends BaseAdapter. Data is fetched from external server with AsyncTask and onPostExecute method of AsyncTask calls a method on ListActivity that sets adapter to display data
 
ListView also implements OnScrollListener to fetch data on scroll and add to bottom.
 
I've an ActionBar (Toolbar) with custom view which contains EditText fields and Button on click of which, again, same AsyncTask is called to fetch new data with query values passed from Toolbar. 
 
Problem is, when button on toolbar is clicked I want the ListView to be populated with entirely new data replacing the old values but instead new data is appended at the bottom of list ( as if OnClickListener is called).
 
I checked Link1, Link2 but none seem to help 
 
And of course main strike would be to use NotifyDataSetChange and I'm using that too but not worth it.
 
My method to set adapter
 
public void setBusinesses(ArrayList<BusinessListData> businesses) {

    imgFetcher = new BusinessListIconTask(this);
    layoutInflator = LayoutInflater.from(this);
    if (this.businesses == null || adapter == null) {
        this.businesses = new ArrayList<>();
        adapter = new BusinessListDataAdapter(this, imgFetcher,
                layoutInflator, this.businesses);
        businessList.setAdapter(adapter);
    }
    this.businesses.addAll(businesses);
    adapter.notifyDataSetChanged();

    /* Activates when scrolling to bottom of list */
    businessList.setOnScrollListener(new OnScrollListener() {
        public int currentScrollState;
        public int currentFirstVisibleItem;
        public int currentVisibleItemCount;
        public int totalItemCount;
        public int lastItem;
        boolean isLoading = false;

        public void onScrollStateChanged(AbsListView view, int scrollState) {
            this.currentScrollState = scrollState;
            this.isScrollCompleted();

        }

        @Override
        public void onScroll(AbsListView view, int firstVisibleItem,
                             int visibleItemCount, int totalItemCount) {
            this.currentFirstVisibleItem = firstVisibleItem;
            this.currentVisibleItemCount = visibleItemCount;
            this.totalItemCount = totalItemCount;
            this.lastItem = firstVisibleItem + visibleItemCount;
        }

        private void isScrollCompleted() {
            if (this.lastItem == this.totalItemCount) {
                /*** In this way I detect if there's been a scroll which has completed ***/
                if (!isLoading) {
                    isLoading = true;
                    getScrollData(metroTxt, metroLoc, metroId);
                }
            } else {
                businessList.removeFooterView(footerView);
            }
        }
    });

}
 
setting custom toolbar with search fields
 
void showCustomView(String metroTxt, String metroLoc, String metroId) {
    LayoutInflater mInflater = LayoutInflater.from(this);

    if (mCustomView == null)
        mCustomView = mInflater.inflate(R.layout.custom_action_bar, null);
    mToolbar.removeView(mCustomView);
    mToolbar.addView(mCustomView);
    Log.d("I'm inside custom view", "txt" + metroTxt);
    abKeyword = (CustomAutoCompleteTextView) mCustomView
            .findViewById(R.id.ab_keyword);
    abLocation = (CustomAutoCompleteTextView) mCustomView
            .findViewById(R.id.ab_location);
    ab_search = (Button) mCustomView
            .findViewById(R.id.ab_search);
    abKeyword.append(metroTxt);

    abLocation.setVisibility(View.GONE);
    ab_search.setVisibility(View.GONE);

    abKeyword.setOnFocusChangeListener(new View.OnFocusChangeListener() {
        @Override
        public void onFocusChange(View v, boolean hasFocus) {

            if (hasFocus || !abKeyword.getText().toString().isEmpty() || !abLocation.getText().toString().isEmpty()) {
                abLocation.setVisibility(View.VISIBLE);
                ab_search.setVisibility(View.VISIBLE);
            } else {
                abLocation.setVisibility(View.GONE);
                ab_search.setVisibility(View.GONE);
            }
        }
    });
    abKeyword.addTextChangedListener(new TextWatcher() {

        public void afterTextChanged(Editable editable) {
            // TODO Auto-generated method stub

        }

        public void beforeTextChanged(CharSequence s, int start, int count,
                                      int after) {
            // TODO Auto-generated method stub
        }

        public void onTextChanged(CharSequence s, int start, int before,
                                  int count) {

            String newText = s.toString();

            BusinessInfoSuggestionTask autocompleteTask = new BusinessInfoSuggestionTask(BusinessResultListActivity.this);
            String acType = "keyword";

            if (s.length() >= 1) {
                abLocation.setVisibility(View.VISIBLE);
                ab_search.setVisibility(View.VISIBLE);
                autocompleteTask.execute(newText, acType, cActivity);

            } else {
                abLocation.setVisibility(View.GONE);
                ab_search.setVisibility(View.GONE);
            }

        }

    });
    ab_search.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            InputMethodManager inputMethodManager = (InputMethodManager) getSystemService(INPUT_METHOD_SERVICE);
            inputMethodManager.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(), 0);
            String abKey = abKeyword.getText().toString();
            String abLoc = abLocation.getText().toString();
            String abId = "";
            getBusinesses(abKey, abLoc, abId);
            Log.d("I'm clicked", "button on toolbar clicked");
        }
    });

}
 
Methods to fetch data from server
 
/* Get Businesses data from server */
private void getBusinesses(String metroTxt, String metroLoc, String metroId) {
    // TODO Auto-generated method stub
    String first = "first";
    BusinessListApiTask spTask = new BusinessListApiTask(
            BusinessResultListActivity.this);
    try {
        spTask.execute(metroTxt, metroLoc, metroId, first);
    } catch (Exception e) {
        spTask.cancel(true);
    }
}

/* Fetch more data on scroll */
private void getScrollData(String metroTxt, String metroLoc, String metroId) {
    // TODO Auto-generated method stub
    String first = "next";
    BusinessListApiTask spTask = new BusinessListApiTask(
            BusinessResultListActivity.this);
    try {
        spTask.execute(metroTxt, metroLoc, metroId, first); //Call AsyncTask to fetch data from server
    } catch (Exception e) {
        spTask.cancel(true);
    }
}

原文：https://stackoverflow.com/questions/28715238