Expandable Gridview With View Recycling In Android

January 25, 2024 Post a Comment

I am trying to implement a android activity where I have sections of items (for example car brands and their models). I want to be able to display the items in a grid (e.g. fixed t

Solution 1:

Here's my reinvented wheel (A lot of code is copy-pasted from AOSP's GridView).

package ua.snuk182.expandablegrid;

import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.TypedArray;
import android.database.DataSetObserver;
import android.util.AttributeSet;
import android.util.Log;
import android.view.Gravity;
import android.view.View;
import android.view.ViewDebug;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.LinearLayout;

publicclassExpandableGridViewextendsExpandableListView {

    /**
     * Disables stretching.
     * 
     * @see #setStretchMode(int)
     */publicstaticfinalintNO_STRETCH=0;
    /**
     * Stretches the spacing between columns.
     * 
     * @see #setStretchMode(int)
     */publicstaticfinalintSTRETCH_SPACING=1;
    /**
     * Stretches columns.
     * 
     * @see #setStretchMode(int)
     */publicstaticfinalintSTRETCH_COLUMN_WIDTH=2;
    /**
     * Stretches the spacing between columns. The spacing is uniform.
     * 
     * @see #setStretchMode(int)
     */publicstaticfinalintSTRETCH_SPACING_UNIFORM=3;

    /**
     * Creates as many columns as can fit on screen.
     * 
     * @see #setNumColumns(int)
     */publicstaticfinalintAUTO_FIT= -1;

    privateintmNumColumns= AUTO_FIT;

    privateintmHorizontalSpacing=0;
    privateint mRequestedHorizontalSpacing;
    privateintmVerticalSpacing=0;
    privateintmStretchMode= STRETCH_COLUMN_WIDTH;
    privateint mColumnWidth;
    privateint mRequestedColumnWidth;
    privateint mRequestedNumColumns;

    publicExpandableGridView(Context context) {
        this(context, null);
    }

    publicExpandableGridView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    publicExpandableGridView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        TypedArraya= context.obtainStyledAttributes(attrs,
                R.styleable.ExpandableGridView, defStyle, 0);

        inthSpacing= a.getDimensionPixelOffset(
                R.styleable.ExpandableGridView_horizontalSpacing, 0);
        setHorizontalSpacing(hSpacing);

        intvSpacing= a.getDimensionPixelOffset(
                R.styleable.ExpandableGridView_verticalSpacing, 0);
        setVerticalSpacing(vSpacing);

        intindex= a.getInt(R.styleable.ExpandableGridView_stretchMode, STRETCH_COLUMN_WIDTH);
        if (index >= 0) {
            setStretchMode(index);
        }

        intcolumnWidth= a.getDimensionPixelOffset(R.styleable.ExpandableGridView_columnWidth, -1);
        if (columnWidth > 0) {
            setColumnWidth(columnWidth);
        }

        intnumColumns= a.getInt(R.styleable.ExpandableGridView_numColumns, 1);
        setNumColumns(numColumns);

        //I haven't dealt with gravity yet, so this is commented for now.../*index = a.getInt(R.styleable.ExpandableGridView_gravity, -1);
        if (index >= 0) {
            setGravity(index);
        }*/

        a.recycle();
    }

    @OverridepublicvoidsetAdapter(ExpandableListAdapter adapter) {
        super.setAdapter(newExpandableGridInnerAdapter(adapter));
    }

    /**
     * Set the amount of horizontal (x) spacing to place between each item
     * in the grid.
     *
     * @param horizontalSpacing The amount of horizontal space between items,
     * in pixels.
     *
     * @attr ref android.R.styleable#GridView_horizontalSpacing
     */publicvoidsetHorizontalSpacing(int horizontalSpacing) {
        if (horizontalSpacing != mRequestedHorizontalSpacing) {
            mRequestedHorizontalSpacing = horizontalSpacing;
            requestLayout();
        }
    }

    /**
     * Returns the amount of horizontal spacing currently used between each item in the grid.
     *
     * <p>This is only accurate for the current layout. If {@link #setHorizontalSpacing(int)}
     * has been called but layout is not yet complete, this method may return a stale value.
     * To get the horizontal spacing that was explicitly requested use
     * {@link #getRequestedHorizontalSpacing()}.</p>
     *
     * @return Current horizontal spacing between each item in pixels
     *
     * @see #setHorizontalSpacing(int)
     * @see #getRequestedHorizontalSpacing()
     *
     * @attr ref android.R.styleable#GridView_horizontalSpacing
     */publicintgetHorizontalSpacing() {
        return mHorizontalSpacing;
    }

    /**
     * Returns the requested amount of horizontal spacing between each item in the grid.
     *
     * <p>The value returned may have been supplied during inflation as part of a style,
     * the default GridView style, or by a call to {@link #setHorizontalSpacing(int)}.
     * If layout is not yet complete or if GridView calculated a different horizontal spacing
     * from what was requested, this may return a different value from
     * {@link #getHorizontalSpacing()}.</p>
     *
     * @return The currently requested horizontal spacing between items, in pixels
     *
     * @see #setHorizontalSpacing(int)
     * @see #getHorizontalSpacing()
     *
     * @attr ref android.R.styleable#GridView_horizontalSpacing
     */publicintgetRequestedHorizontalSpacing() {
        return mRequestedHorizontalSpacing;
    }

    /**
     * Set the amount of vertical (y) spacing to place between each item
     * in the grid.
     *
     * @param verticalSpacing The amount of vertical space between items,
     * in pixels.
     *
     * @see #getVerticalSpacing()
     *
     * @attr ref android.R.styleable#GridView_verticalSpacing
     */publicvoidsetVerticalSpacing(int verticalSpacing) {
        if (verticalSpacing != mVerticalSpacing) {
            mVerticalSpacing = verticalSpacing;
            requestLayout();
        }
    }

    /**
     * Returns the amount of vertical spacing between each item in the grid.
     *
     * @return The vertical spacing between items in pixels
     *
     * @see #setVerticalSpacing(int)
     *
     * @attr ref android.R.styleable#GridView_verticalSpacing
     */publicintgetVerticalSpacing() {
        return mVerticalSpacing;
    }

    /**
     * Control how items are stretched to fill their space.
     *
     * @param stretchMode Either {@link #NO_STRETCH},
     * {@link #STRETCH_SPACING}, {@link #STRETCH_SPACING_UNIFORM}, or {@link #STRETCH_COLUMN_WIDTH}.
     *
     * @attr ref android.R.styleable#GridView_stretchMode
     */publicvoidsetStretchMode(int stretchMode) {
        if (stretchMode != mStretchMode) {
            mStretchMode = stretchMode;
            requestLayout();
        }
    }

    publicintgetStretchMode() {
        return mStretchMode;
    }

    /**
     * Set the width of columns in the grid.
     *
     * @param columnWidth The column width, in pixels.
     *
     * @attr ref android.R.styleable#GridView_columnWidth
     */publicvoidsetColumnWidth(int columnWidth) {
        if (columnWidth != mRequestedColumnWidth) {
            mRequestedColumnWidth = columnWidth;
            requestLayout();
        }
    }

    /**
     * Return the width of a column in the grid.
     *
     * <p>This may not be valid yet if a layout is pending.</p>
     *
     * @return The column width in pixels
     *
     * @see #setColumnWidth(int)
     * @see #getRequestedColumnWidth()
     *
     * @attr ref android.R.styleable#GridView_columnWidth
     */publicintgetColumnWidth() {
        return mColumnWidth;
    }

    /**
     * Return the requested width of a column in the grid.
     *
     * <p>This may not be the actual column width used. Use {@link #getColumnWidth()}
     * to retrieve the current real width of a column.</p>
     *
     * @return The requested column width in pixels
     *
     * @see #setColumnWidth(int)
     * @see #getColumnWidth()
     *
     * @attr ref android.R.styleable#GridView_columnWidth
     */publicintgetRequestedColumnWidth() {
        return mRequestedColumnWidth;
    }

    /**
     * Set the number of columns in the grid
     *
     * @param numColumns The desired number of columns.
     *
     * @attr ref android.R.styleable#GridView_numColumns
     */publicvoidsetNumColumns(int numColumns) {
        if (numColumns != mRequestedNumColumns) {
            mRequestedNumColumns = numColumns;
            requestLayout();
        }
    }

    /**
     * Get the number of columns in the grid. 
     * Returns {@link #AUTO_FIT} if the Grid has never been laid out.
     *
     * @attr ref android.R.styleable#GridView_numColumns
     * 
     * @see #setNumColumns(int)
     */@ViewDebug.ExportedProperty
    publicintgetNumColumns() {  
        return mNumColumns;
    }

    public ExpandableListAdapter getInnerAdapter() {
        return ((ExpandableGridInnerAdapter)getExpandableListAdapter()).mInnerAdapter;
    }

    privatebooleandetermineColumns(int availableSpace) {
        finalintrequestedHorizontalSpacing= mRequestedHorizontalSpacing;
        finalintstretchMode= mStretchMode;
        finalintrequestedColumnWidth= mRequestedColumnWidth;
        booleandidNotInitiallyFit=false;

        if (mRequestedNumColumns == AUTO_FIT) {
            if (requestedColumnWidth > 0) {
                // Client told us to pick the number of columns
                mNumColumns = (availableSpace + requestedHorizontalSpacing) /
                        (requestedColumnWidth + requestedHorizontalSpacing);
            } else {
                // Just make up a number if we don't have enough info
                mNumColumns = 2;
            }
        } else {
            // We picked the columns
            mNumColumns = mRequestedNumColumns;
        }

        if (mNumColumns <= 0) {
            mNumColumns = 1;
        }

        switch (stretchMode) {
        case NO_STRETCH:
            // Nobody stretches
            mColumnWidth = requestedColumnWidth;
            mHorizontalSpacing = requestedHorizontalSpacing;
            break;

        default:
            intspaceLeftOver= availableSpace - (mNumColumns * requestedColumnWidth) -
                    ((mNumColumns - 1) * requestedHorizontalSpacing);

            if (spaceLeftOver < 0) {
                didNotInitiallyFit = true;
            }

            switch (stretchMode) {
            case STRETCH_COLUMN_WIDTH:
                // Stretch the columns
                mColumnWidth = requestedColumnWidth + spaceLeftOver / mNumColumns;
                mHorizontalSpacing = requestedHorizontalSpacing;
                break;

            case STRETCH_SPACING:
                // Stretch the spacing between columns
                mColumnWidth = requestedColumnWidth;
                if (mNumColumns > 1) {
                    mHorizontalSpacing = requestedHorizontalSpacing + 
                        spaceLeftOver / (mNumColumns - 1);
                } else {
                    mHorizontalSpacing = requestedHorizontalSpacing + spaceLeftOver;
                }
                break;

            case STRETCH_SPACING_UNIFORM:
                // Stretch the spacing between columns
                mColumnWidth = requestedColumnWidth;
                if (mNumColumns > 1) {
                    mHorizontalSpacing = requestedHorizontalSpacing + 
                        spaceLeftOver / (mNumColumns + 1);
                } else {
                    mHorizontalSpacing = requestedHorizontalSpacing + spaceLeftOver;
                }
                break;
            }

            break;
        }
        return didNotInitiallyFit;
    }

    @OverrideprotectedvoidonMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        intwidthMode= MeasureSpec.getMode(widthMeasureSpec);
        intwidthSize= MeasureSpec.getSize(widthMeasureSpec);

        if (widthMode == MeasureSpec.UNSPECIFIED) {
            if (mColumnWidth > 0) {
                widthSize = mColumnWidth + getPaddingLeft() + getPaddingRight();
            } else {
                widthSize = getPaddingLeft() + getPaddingRight();
            }
            widthSize += getVerticalScrollbarWidth();
        }

        intchildWidth= widthSize - getPaddingLeft() - getPaddingRight();
        determineColumns(childWidth);
    }

    privateclassExpandableGridInnerAdapterimplementsExpandableListAdapter {

        privatefinal ExpandableListAdapter mInnerAdapter;

        privateExpandableGridInnerAdapter(ExpandableListAdapter adapter) {
            this.mInnerAdapter = adapter;
        }

        @OverridepublicintgetGroupCount() {
            return mInnerAdapter.getGroupCount();
        }

        @OverridepublicintgetChildrenCount(int groupPosition) {
            intrealCount= mInnerAdapter.getChildrenCount(groupPosition);

            int count;
            if (mNumColumns != AUTO_FIT) {
                count = realCount > 0 ? (realCount + mNumColumns - 1) / mNumColumns : 0;
            } else {
                count = realCount;
            }   

            return count;
        }

        @Overridepublic Object getGroup(int groupPosition) {
            return mInnerAdapter.getGroup(groupPosition);
        }

        @Overridepublic Object getChild(int groupPosition, int childPosition) {
            return mInnerAdapter.getChild(groupPosition, childPosition);
        }

        @OverridepubliclonggetGroupId(int groupPosition) {
            return mInnerAdapter.getGroupId(groupPosition);
        }

        @OverridepubliclonggetChildId(int groupPosition, int childPosition) {
            return0;
        }

        @OverridepublicbooleanhasStableIds() {
            returnfalse;
        }

        @Overridepublic View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
            return mInnerAdapter.getGroupView(groupPosition, isExpanded, convertView, parent);
        }

        @SuppressLint("InlinedApi")@Overridepublic View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
            LinearLayoutrow= (LinearLayout) (convertView != null ? convertView : newLinearLayout(getContext()));

            if (row.getLayoutParams() == null) {
                row.setLayoutParams(newAbsListView.LayoutParams(AbsListView.LayoutParams.MATCH_PARENT, AbsListView.LayoutParams.WRAP_CONTENT, AbsListView.ITEM_VIEW_TYPE_IGNORE));
                row.setPadding(0, mVerticalSpacing / 2, 0, mVerticalSpacing / 2);
                row.setGravity(Gravity.CENTER_HORIZONTAL);
            }

            intgroupChildrenCount= mInnerAdapter.getChildrenCount(groupPosition);

            intindex=0;
            for (int i=mNumColumns * childPosition; i<(mNumColumns * (childPosition + 1)); i++, index++) {
                View child;

                ViewcachedChild= index < row.getChildCount() ? row.getChildAt(index) : null;

                if (i<groupChildrenCount) {                 
                    if (cachedChild != null && cachedChild.getTag() == null) {
                        ((ViewGroup)cachedChild.getParent()).removeView(cachedChild);
                        cachedChild = null;
                    }

                    child = mInnerAdapter.getChildView(groupPosition, i, i == (groupChildrenCount - 1), cachedChild, parent);
                    child.setTag(mInnerAdapter.getChild(groupPosition, i));
                } else {
                    if (cachedChild != null && cachedChild.getTag() != null) {
                        ((ViewGroup)cachedChild.getParent()).removeView(cachedChild);
                        cachedChild = null;
                    }

                    child = newView(getContext());
                    child.setTag(null);
                }

                if (!(child.getLayoutParams() instanceof LinearLayout.LayoutParams)) {
                    LinearLayout.LayoutParams params;
                    if (child.getLayoutParams() == null) {
                        params = newLinearLayout.LayoutParams(mColumnWidth, LayoutParams.WRAP_CONTENT, 1);
                    } else {
                        params = newLinearLayout.LayoutParams(mColumnWidth, child.getLayoutParams().height, 1);
                    }

                    child.setLayoutParams(params);
                }

                child.setPadding(mHorizontalSpacing / 2, 0, mHorizontalSpacing / 2, 0);

                if (index == row.getChildCount()) {
                    row.addView(child, index);
                } else {
                    child.invalidate();
                }
            }

            return row;
        }

        @OverridepublicbooleanisChildSelectable(int groupPosition, int childPosition) {
            returnfalse;
        }

        @OverridepublicvoidregisterDataSetObserver(DataSetObserver observer) {
            mInnerAdapter.registerDataSetObserver(observer);
        }

        @OverridepublicvoidunregisterDataSetObserver(DataSetObserver observer) {
            mInnerAdapter.unregisterDataSetObserver(observer);
        }

        @OverridepublicbooleanareAllItemsEnabled() {
            return mInnerAdapter.areAllItemsEnabled();
        }

        @OverridepublicbooleanisEmpty() {
            return mInnerAdapter.isEmpty();
        }

        @OverridepublicvoidonGroupExpanded(int groupPosition) {
            mInnerAdapter.onGroupExpanded(groupPosition);
        }

        @OverridepublicvoidonGroupCollapsed(int groupPosition) {
            mInnerAdapter.onGroupCollapsed(groupPosition);
        }

        /*@Override
        public long getCombinedChildId(long groupId, long childId) {
            return mInnerAdapter.getCombinedChildId(groupId, childId);
        }

        @Override
        public long getCombinedGroupId(long groupId) {
            return mInnerAdapter.getCombinedGroupId(groupId);
        }*/publiclonggetCombinedChildId(long groupId, long childId) {
            return0x8000000000000000L | ((groupId & 0x7FFFFFFF) << 32) | (childId & 0xFFFFFFFF);
        }

        publiclonggetCombinedGroupId(long groupId) {
            return (groupId & 0x7FFFFFFF) << 32;
        }
    }
}

Corresponding attrs.xml.

<?xml version="1.0" encoding="utf-8"?><resources><declare-styleablename="ExpandableGridView"><attrname="horizontalSpacing"format="dimension" /><attrname="verticalSpacing"format="dimension" /><attrname="stretchMode"><enumname="none"value="0"/><enumname="spacingWidth"value="1" /><enumname="columnWidth"value="2" /><enumname="spacingWidthUniform"value="3" /></attr><attrname="columnWidth"format="dimension" /><attrname="numColumns"format="integer"min="0"><enumname="auto_fit"value="-1" /></attr></declare-styleable></resources>

Solution 2:

instead of using multiple expandable gridviews you could use this library https://github.com/TonicArtos/StickyGridHeaders, in which you can put one adapter with one gridView (the custom StickyGridHeadersView), and manage the different headers with specific view handlers for each kind of header/grid-element

Baca Juga

Solution 3:

You can use this example of Expandable RecyclerView . It provides an Expandable RecyclerView with group items that can be individually expanded to show its children in a two-dimensional scrolling grid. Each grid item can be selected.

friednshipgoneforlife

Expandable Gridview With View Recycling In Android

Solution 1:

Solution 2:

Solution 3:

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