Android(安卓)StaggeredGrid 加下拉刷新功能 PullToRefresh

https://github.com/etsy/AndroidStaggeredGrid 用的github上面提供瀑布流，继承于abslistview，回收机制不错，并且提供了OnScrollListener来监听滑动时间。

然后想加一个下拉刷新功能，下面分享一下研究的最终结果。

Java代码：

package com.xxx.waterfall;import android.annotation.TargetApi;import android.content.Context;import android.os.Build.VERSION;import android.os.Build.VERSION_CODES;import android.os.Bundle;import android.util.AttributeSet;import android.view.View;import com.handmark.pulltorefresh.library.OverscrollHelper;import com.handmark.pulltorefresh.library.PullToRefreshBase;import com.handmark.pulltorefresh.library.R;public class PullToRefreshStaggeredGridView extends PullToRefreshBase<StaggeredGridView> {    private static final OnRefreshListener<StaggeredGridView> defaultOnRefreshListener = new OnRefreshListener<StaggeredGridView>() {        @Override        public void onRefresh(PullToRefreshBase<StaggeredGridView> refreshView) {        }    };    public PullToRefreshStaggeredGridView(Context context) {        super(context);        /**         * Added so that by default, Pull-to-Refresh refreshes the page         */        setOnRefreshListener(defaultOnRefreshListener);    }    public PullToRefreshStaggeredGridView(Context context, AttributeSet attrs) {        super(context, attrs);        /**         * Added so that by default, Pull-to-Refresh refreshes the page         */        setOnRefreshListener(defaultOnRefreshListener);    }    public PullToRefreshStaggeredGridView(Context context, Mode mode) {        super(context, mode);        /**         * Added so that by default, Pull-to-Refresh refreshes the page         */        setOnRefreshListener(defaultOnRefreshListener);    }    public PullToRefreshStaggeredGridView(Context context, Mode mode, AnimationStyle style) {        super(context, mode, style);        /**         * Added so that by default, Pull-to-Refresh refreshes the page         */        setOnRefreshListener(defaultOnRefreshListener);    }    @Override    public final Orientation getPullToRefreshScrollDirection() {        return Orientation.VERTICAL;    }    @Override    protected StaggeredGridView createRefreshableView(Context context, AttributeSet attrs) {        StaggeredGridView gridView;        if (VERSION.SDK_INT >= VERSION_CODES.GINGERBREAD) {            gridView = new InternalStaggeredGridViewSDK9(context, attrs);        } else {            gridView = new StaggeredGridView(context, attrs);        }        gridView.setId(R.id.gridview);        return gridView;    }    @Override    protected boolean isReadyForPullStart() {        boolean result = false;        View v = getRefreshableView().getChildAt(0);        if (getRefreshableView().getFirstVisiblePosition() == 0) {            if (v != null) {                // getTop() and getBottom() are relative to the ListView,                // so if getTop() is negative, it is not fully visible                boolean isTopFullyVisible = v.getTop() >= 0;                result = isTopFullyVisible;            }        }        return result;    }    @Override    protected boolean isReadyForPullEnd() {        boolean result = false;        int last = getRefreshableView().getChildCount() - 1;        View v = getRefreshableView().getChildAt(last);        int firstVisiblePosition = getRefreshableView().getFirstVisiblePosition();        int visibleItemCount = getRefreshableView().getChildCount();        int itemCount = getRefreshableView().getAdapter().getCount();        if (firstVisiblePosition + visibleItemCount >= itemCount) {            if (v != null) {                boolean isLastFullyVisible = v.getBottom() <= getRefreshableView().getHeight();                result = isLastFullyVisible;            }        }        return result;    }    @Override    protected void onPtrRestoreInstanceState(Bundle savedInstanceState) {        super.onPtrRestoreInstanceState(savedInstanceState);    }    @Override    protected void onPtrSaveInstanceState(Bundle saveState) {        super.onPtrSaveInstanceState(saveState);    }    @TargetApi(9)    final class InternalStaggeredGridViewSDK9 extends StaggeredGridView {        // WebView doesn't always scroll back to it's edge so we add some        // fuzziness        static final int OVERSCROLL_FUZZY_THRESHOLD = 2;        // WebView seems quite reluctant to overscroll so we use the scale        // factor to scale it's value        static final float OVERSCROLL_SCALE_FACTOR = 1.5f;        public InternalStaggeredGridViewSDK9(Context context, AttributeSet attrs) {            super(context, attrs);        }        @Override        protected boolean overScrollBy(int deltaX, int deltaY, int scrollX, int scrollY, int scrollRangeX, int scrollRangeY, int maxOverScrollX, int maxOverScrollY, boolean isTouchEvent) {            final boolean returnValue = super.overScrollBy(deltaX, deltaY, scrollX, scrollY, scrollRangeX, scrollRangeY, maxOverScrollX, maxOverScrollY, isTouchEvent);// Does all of the hard work...            OverscrollHelper.overScrollBy(PullToRefreshStaggeredGridView.this, deltaX, scrollX, deltaY, getScrollRange(), isTouchEvent);            return returnValue;        }        /**         * Taken from the AOSP ScrollView source         */        private int getScrollRange() {            int scrollRange = 0;            if (getChildCount() > 0) {                View child = getChildAt(0);                scrollRange = Math.max(0, child.getHeight() - (getHeight() - getPaddingBottom() - getPaddingTop()));            }            return scrollRange;        }    }}

XML代码：

    <com.xxx.waterfall.PullToRefreshStaggeredGridView        android:id="@+id/HomePullToRefreshStaggerdGridView"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:background="@null"        android:cacheColorHint="#00000000"        android:fadingEdge="none"        android:overScrollMode="never"        android:scrollbars="none"        app:column_count="2"        app:item_margin="2dp"        ptr:ptrMode="both" >    </com.xxx.waterfall.PullToRefreshStaggeredGridView>

Java Activity:

package com.xxx.activity; import com.handmark.pulltorefresh.library.PullToRefreshBase;import com.handmark.pulltorefresh.library.PullToRefreshBase.Mode;import com.handmark.pulltorefresh.library.PullToRefreshBase.OnRefreshListener;import com.handmark.pulltorefresh.library.PullToRefreshBase.OnRefreshListener2;public class HomeFragment extends DFFragment implements OnRefreshListener<StaggeredGridView>, AbsListView.OnScrollListener {     /**下来刷新**/    private PullToRefreshStaggeredGridView mPullToRefreshStaggerdGridView;    private StaggeredGridView gv       private void initView() {        mPullToRefreshStaggerdGridView = (PullToRefreshStaggeredGridView) parentView.findViewById(R.id.HomePullToRefreshStaggerdGridView);                 mPullToRefreshStaggerdGridView.setMode(Mode.PULL_FROM_END);        mPullToRefreshStaggerdGridView.setOnRefreshListener(new OnRefreshListener<StaggeredGridView>() {            @Override            public void onRefresh(PullToRefreshBase<StaggeredGridView> refreshView) { 
　　　　　　　　//刷新
            }        });mPullToRefreshStaggerdGridView.setMode(Mode.BOTH);        mPullToRefreshStaggerdGridView.setOnRefreshListener(listener);        gv=mPullToRefreshStaggerdGridView.getRefreshableView();          Gv.setAdapter(waterfallAdapter);        Gv.setOnScrollListener(this);    }    @Override    public void onScrollStateChanged(final AbsListView view, final int scrollState) {    }    @Override    public void onScroll(final AbsListView view, final int firstVisibleItem, final int visibleItemCount, final int totalItemCount) {        if (!mHasRequestedMore) {            int lastInScreen = firstVisibleItem + visibleItemCount;            if (lastInScreen >= totalItemCount) {                 //加载事件                onLoadMoreItems();            }        }    }    private boolean mHasRequestedMore;    private void onLoadMoreItems() {        //加载事件。。。        mHasRequestedMore = false;    }     }

然后就可以用了，是不是很爽~~

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