SwipeRefreshLayout使用

1、用法

<android.support.v4.widget.SwipeRefreshLayout
    android:id="@+id/refreshClient"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_below="@+id/spinner1">
    <!-- 这里是一个子view，仅能有一个子view，一般为AbsListView -->
</android.support.v4.widget.SwipeRefreshLayout>

让Activity继承SwipeRefreshLayout.OnRefreshListener
然后refreshLayout.setOnRefreshListener(this);
即可监听刷新动作，只要在onRefresh()里执行刷新代码即可

博主在使用时发现SwipeRefreshLayout会占满剩余屏幕，且它的子view也是一样，可以看SwipeRefreshLayout源码的onMeasure和onLayout方法。如果想要使它的子view是适应内容高度的话，博主测试了下，跟ScrollView的做法是一样的，但是这样子的话AbsListView就不能滑动了，从而知道SwipeRefreshLayout跟ScrollView还是不同的，之后就试了下在AbsListView外面套一层ScrollView，这时候就能让AbsListView自适应内容高度且能上下滑动了。

public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        if (mTarget == null) {
            ensureTarget();
        }
        if (mTarget == null) {
            return;
        }
        mTarget.measure(MeasureSpec.makeMeasureSpec(
                getMeasuredWidth() - getPaddingLeft() - getPaddingRight(),
                MeasureSpec.EXACTLY), MeasureSpec.makeMeasureSpec(
                getMeasuredHeight() - getPaddingTop() - getPaddingBottom(), MeasureSpec.EXACTLY));
        mCircleView.measure(MeasureSpec.makeMeasureSpec(mCircleDiameter, MeasureSpec.EXACTLY),
                MeasureSpec.makeMeasureSpec(mCircleDiameter, MeasureSpec.EXACTLY));
        mCircleViewIndex = -1;
        // Get the index of the circleview.
        for (int index = 0; index < getChildCount(); index++) {
            if (getChildAt(index) == mCircleView) {
                mCircleViewIndex = index;
                break;
            }
        }
    }
    其中mCircleView就是那个刷新时出现的转圈圈的ImageView，而mTarget就是我们在布局文件里定义的SwipeRefreshLayout子View。可以看到mTarget和SwipeRefreshLayout的宽高是一致的，当然啦，不包括SwipeRefreshLayout的padding。

protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        final int width = getMeasuredWidth();
        final int height = getMeasuredHeight();
        if (getChildCount() == 0) {
            return;
        }
        if (mTarget == null) {
            ensureTarget();
        }
        if (mTarget == null) {
            return;
        }
        final View child = mTarget;
        final int childLeft = getPaddingLeft();
        final int childTop = getPaddingTop();
        final int childWidth = width - getPaddingLeft() - getPaddingRight();
        final int childHeight = height - getPaddingTop() - getPaddingBottom();
        child.layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
        int circleWidth = mCircleView.getMeasuredWidth();
        int circleHeight = mCircleView.getMeasuredHeight();
        mCircleView.layout((width / 2 - circleWidth / 2), mCurrentTargetOffsetTop,
                (width / 2 + circleWidth / 2), mCurrentTargetOffsetTop + circleHeight);
    }
    一开始博主有试过在这里让mTarget自适应内容高度，也成功了，结果就是不能滑动，跟上面的一个方法效果一样，所以最后只能选择再套一层ScrollView了。

这里只是android本身自带的刷新控件的使用，网上很多人把这个layout修改成下拉刷新，上拉加载的控件了，博主还没看过源码，水平较低，暂不知怎么实现。如果要实现，怎么的也要将SwipeRefreshLayout负责出来修改，同时也要把MaterialProgressDrawable和CircleImageView复制出来。