ArrayAdapter源码

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/* * Copyright (C) 2006 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * *      http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */package qianlong.qlmobile.ui;import android.content.Context;import android.util.Log;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.Filter;import android.widget.Filterable;import android.widget.TextView;import java.util.ArrayList;import java.util.Arrays;import java.util.Collection;import java.util.List;import java.util.Comparator;import java.util.Collections;/** * A ListAdapter that manages a ListView backed by an array of arbitrary * objects.  By default this class expects that the provided resource id references * a single TextView.  If you want to use a more complex layout, use the constructors that * also takes a field id.  That field id should reference a TextView in the larger layout * resource. * * However the TextView is referenced, it will be filled with the toString() of each object in * the array. You can add lists or arrays of custom objects. Override the toString() method * of your objects to determine what text will be displayed for the item in the list. * * To use something other than TextViews for the array display, for instance, ImageViews, * or to have some of data besides toString() results fill the views, * override {@link #getView(int, View, ViewGroup)} to return the type of view you want. */public class ArrayAdapter<T> extends BaseAdapter implements Filterable {    /**     * Contains the list of objects that represent the data of this ArrayAdapter.     * The content of this list is referred to as "the array" in the documentation.     */    private List<T> mObjects;    /**     * Lock used to modify the content of {@link #mObjects}. Any write operation     * performed on the array should be synchronized on this lock. This lock is also     * used by the filter (see {@link #getFilter()} to make a synchronized copy of     * the original array of data.     */    private final Object mLock = new Object();    /**     * The resource indicating what views to inflate to display the content of this     * array adapter.     */    private int mResource;    /**     * The resource indicating what views to inflate to display the content of this     * array adapter in a drop down widget.     */    private int mDropDownResource;    /**     * If the inflated resource is not a TextView, {@link #mFieldId} is used to find     * a TextView inside the inflated views hierarchy. This field must contain the     * identifier that matches the one defined in the resource file.     */    private int mFieldId = 0;    /**     * Indicates whether or not {@link #notifyDataSetChanged()} must be called whenever     * {@link #mObjects} is modified.     */    private boolean mNotifyOnChange = true;    private Context mContext;    private ArrayList<T> mOriginalValues;    private ArrayFilter mFilter;    private LayoutInflater mInflater;    /**     * Constructor     *     * @param context The current context.     * @param textViewResourceId The resource ID for a layout file containing a TextView to use when     *                 instantiating views.     */    public ArrayAdapter(Context context, int textViewResourceId) {        init(context, textViewResourceId, 0, new ArrayList<T>());    }    /**     * Constructor     *     * @param context The current context.     * @param resource The resource ID for a layout file containing a layout to use when     *                 instantiating views.     * @param textViewResourceId The id of the TextView within the layout resource to be populated     */    public ArrayAdapter(Context context, int resource, int textViewResourceId) {        init(context, resource, textViewResourceId, new ArrayList<T>());    }    /**     * Constructor     *     * @param context The current context.     * @param textViewResourceId The resource ID for a layout file containing a TextView to use when     *                 instantiating views.     * @param objects The objects to represent in the ListView.     */    public ArrayAdapter(Context context, int textViewResourceId, T[] objects) {        init(context, textViewResourceId, 0, Arrays.asList(objects));    }    /**     * Constructor     *     * @param context The current context.     * @param resource The resource ID for a layout file containing a layout to use when     *                 instantiating views.     * @param textViewResourceId The id of the TextView within the layout resource to be populated     * @param objects The objects to represent in the ListView.     */    public ArrayAdapter(Context context, int resource, int textViewResourceId, T[] objects) {        init(context, resource, textViewResourceId, Arrays.asList(objects));    }    /**     * Constructor     *     * @param context The current context.     * @param textViewResourceId The resource ID for a layout file containing a TextView to use when     *                 instantiating views.     * @param objects The objects to represent in the ListView.     */    public ArrayAdapter(Context context, int textViewResourceId, List<T> objects) {        init(context, textViewResourceId, 0, objects);    }    /**     * Constructor     *     * @param context The current context.     * @param resource The resource ID for a layout file containing a layout to use when     *                 instantiating views.     * @param textViewResourceId The id of the TextView within the layout resource to be populated     * @param objects The objects to represent in the ListView.     */    public ArrayAdapter(Context context, int resource, int textViewResourceId, List<T> objects) {        init(context, resource, textViewResourceId, objects);    }    /**     * Adds the specified object at the end of the array.     *     * @param object The object to add at the end of the array.     */    public void add(T object) {        if (mOriginalValues != null) {            synchronized (mLock) {                mOriginalValues.add(object);                if (mNotifyOnChange) notifyDataSetChanged();            }        } else {            mObjects.add(object);            if (mNotifyOnChange) notifyDataSetChanged();        }    }    /**     * Adds the specified Collection at the end of the array.     *     * @param collection The Collection to add at the end of the array.     */    public void addAll(Collection<? extends T> collection) {        if (mOriginalValues != null) {            synchronized (mLock) {                mOriginalValues.addAll(collection);                if (mNotifyOnChange) notifyDataSetChanged();            }        } else {            mObjects.addAll(collection);            if (mNotifyOnChange) notifyDataSetChanged();        }    }    /**     * Adds the specified items at the end of the array.     *     * @param items The items to add at the end of the array.     */    public void addAll(T ... items) {        if (mOriginalValues != null) {            synchronized (mLock) {                for (T item : items) {                    mOriginalValues.add(item);                }                if (mNotifyOnChange) notifyDataSetChanged();            }        } else {            for (T item : items) {                mObjects.add(item);            }            if (mNotifyOnChange) notifyDataSetChanged();        }    }    /**     * Inserts the specified object at the specified index in the array.     *     * @param object The object to insert into the array.     * @param index The index at which the object must be inserted.     */    public void insert(T object, int index) {        if (mOriginalValues != null) {            synchronized (mLock) {                mOriginalValues.add(index, object);                if (mNotifyOnChange) notifyDataSetChanged();            }        } else {            mObjects.add(index, object);            if (mNotifyOnChange) notifyDataSetChanged();        }    }    /**     * Removes the specified object from the array.     *     * @param object The object to remove.     */    public void remove(T object) {        if (mOriginalValues != null) {            synchronized (mLock) {                mOriginalValues.remove(object);            }        } else {            mObjects.remove(object);        }        if (mNotifyOnChange) notifyDataSetChanged();    }    /**     * Remove all elements from the list.     */    public void clear() {        if (mOriginalValues != null) {            synchronized (mLock) {                mOriginalValues.clear();            }        } else {            mObjects.clear();        }        if (mNotifyOnChange) notifyDataSetChanged();    }    /**     * Sorts the content of this adapter using the specified comparator.     *     * @param comparator The comparator used to sort the objects contained     *        in this adapter.     */    public void sort(Comparator<? super T> comparator) {        Collections.sort(mObjects, comparator);        if (mNotifyOnChange) notifyDataSetChanged();    }    /**     * {@inheritDoc}     */    @Override    public void notifyDataSetChanged() {        super.notifyDataSetChanged();        mNotifyOnChange = true;    }    /**     * Control whether methods that change the list ({@link #add},     * {@link #insert}, {@link #remove}, {@link #clear}) automatically call     * {@link #notifyDataSetChanged}.  If set to false, caller must     * manually call notifyDataSetChanged() to have the changes     * reflected in the attached view.     *     * The default is true, and calling notifyDataSetChanged()     * resets the flag to true.     *     * @param notifyOnChange if true, modifications to the list will     *                       automatically call {@link     *                       #notifyDataSetChanged}     */    public void setNotifyOnChange(boolean notifyOnChange) {        mNotifyOnChange = notifyOnChange;    }    private void init(Context context, int resource, int textViewResourceId, List<T> objects) {        mContext = context;        mInflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);        mResource = mDropDownResource = resource;        mObjects = objects;        mFieldId = textViewResourceId;    }    /**     * Returns the context associated with this array adapter. The context is used     * to create views from the resource passed to the constructor.     *     * @return The Context associated with this adapter.     */    public Context getContext() {        return mContext;    }    /**     * {@inheritDoc}     */    public int getCount() {        return mObjects.size();    }    /**     * {@inheritDoc}     */    public T getItem(int position) {        return mObjects.get(position);    }    /**     * Returns the position of the specified item in the array.     *     * @param item The item to retrieve the position of.     *     * @return The position of the specified item.     */    public int getPosition(T item) {        return mObjects.indexOf(item);    }    /**     * {@inheritDoc}     */    public long getItemId(int position) {        return position;    }    /**     * {@inheritDoc}     */    public View getView(int position, View convertView, ViewGroup parent) {        return createViewFromResource(position, convertView, parent, mResource);    }    private View createViewFromResource(int position, View convertView, ViewGroup parent,            int resource) {        View view;        TextView text;        if (convertView == null) {            view = mInflater.inflate(resource, parent, false);        } else {            view = convertView;        }        try {            if (mFieldId == 0) {                //  If no custom field is assigned, assume the whole resource is a TextView                text = (TextView) view;            } else {                //  Otherwise, find the TextView field within the layout                text = (TextView) view.findViewById(mFieldId);            }        } catch (ClassCastException e) {            Log.e("ArrayAdapter", "You must supply a resource ID for a TextView");            throw new IllegalStateException(                    "ArrayAdapter requires the resource ID to be a TextView", e);        }        T item = getItem(position);        if (item instanceof CharSequence) {            text.setText((CharSequence)item);        } else {            text.setText(item.toString());        }        return view;    }    /**     * <p>Sets the layout resource to create the drop down views.</p>     *     * @param resource the layout resource defining the drop down views     * @see #getDropDownView(int, android.view.View, android.view.ViewGroup)     */    public void setDropDownViewResource(int resource) {        this.mDropDownResource = resource;    }    /**     * {@inheritDoc}     */    @Override    public View getDropDownView(int position, View convertView, ViewGroup parent) {        return createViewFromResource(position, convertView, parent, mDropDownResource);    }    /**     * Creates a new ArrayAdapter from external resources. The content of the array is     * obtained through {@link android.content.res.Resources#getTextArray(int)}.     *     * @param context The application's environment.     * @param textArrayResId The identifier of the array to use as the data source.     * @param textViewResId The identifier of the layout used to create views.     *     * @return An ArrayAdapter<CharSequence>.     */    public static ArrayAdapter<CharSequence> createFromResource(Context context,            int textArrayResId, int textViewResId) {        CharSequence[] strings = context.getResources().getTextArray(textArrayResId);        return new ArrayAdapter<CharSequence>(context, textViewResId, strings);    }    /**     * {@inheritDoc}     */    public Filter getFilter() {        if (mFilter == null) {            mFilter = new ArrayFilter();        }        return mFilter;    }    /**     * <p>An array filter constrains the content of the array adapter with     * a prefix. Each item that does not start with the supplied prefix     * is removed from the list.</p>     */    private class ArrayFilter extends Filter {        @Override        protected FilterResults performFiltering(CharSequence prefix) {            FilterResults results = new FilterResults();            if (mOriginalValues == null) {                synchronized (mLock) {                    mOriginalValues = new ArrayList<T>(mObjects);                }            }            if (prefix == null || prefix.length() == 0) {                synchronized (mLock) {                    ArrayList<T> list = new ArrayList<T>(mOriginalValues);                    results.values = list;                    results.count = list.size();                }            } else {                String prefixString = prefix.toString().toLowerCase();                final ArrayList<T> values = mOriginalValues;                final int count = values.size();                final ArrayList<T> newValues = new ArrayList<T>(count);                for (int i = 0; i < count; i++) {                    final T value = values.get(i);                    final String valueText = value.toString().toLowerCase();                    // First match against the whole, non-splitted value                    if (valueText.startsWith(prefixString)) {                        newValues.add(value);                    } else {                        final String[] words = valueText.split(" ");                        final int wordCount = words.length;                        for (int k = 0; k < wordCount; k++) {                        if (words[k].startsWith(prefixString)) {//源码 ,匹配开头                                newValues.add(value);                                break;                            }                        }                    }                }                results.values = newValues;                results.count = newValues.size();            }            return results;        }        @Override        protected void publishResults(CharSequence constraint, FilterResults results) {            //noinspection unchecked            mObjects = (List<T>) results.values;            if (results.count > 0) {                notifyDataSetChanged();            } else {                notifyDataSetInvalidated();            }        }    }}
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