解决ViewPager根据试图动态调整高度

淡淡的烟草味﹌ 2023-07-07 08:22 22阅读 0赞

两个问题

1.在使用ViewPager组件设置高度为wrap\_content布局时，会出现View不显示的问题；

2.在使用WrapContentViewPager时，pager的子页面高度一致，导致页面内容少的view出现空白；

解决第一个问题，直接下载WrapContentViewPager到项目中使用即可。但是会出现第二个问题；原因是，在WrapContentViewPager中复写OnMeasure方法，使用的高度是子页面中最大的高度，所以页面内容少的view会出现空白

解决第二个问题，动态改变pager的高度即可

/**
     * ViewPager DynamicHeight解决方案
     */
    public class DynamicHeightViewPager extends ViewPager {
    
    
        /**
         * Constructor
         *
         * @param context the context
         */
        public DynamicHeightViewPager(Context context) {
            super(context);
        }
    
        /**
         * Constructor
         *
         * @param context the context
         * @param attrs   the attribute set
         */
        public DynamicHeightViewPager(Context context, AttributeSet attrs) {
            super(context, attrs);
        }
    
        //    @Override
    //    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    //        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    //
    //        // find the first child view
    //        View view = getChildAt(0);
    //        if (view != null) {
    //            // measure the first child view with the specified measure spec
    //            view.measure(widthMeasureSpec, heightMeasureSpec);
    //        }
    //
    //        setMeasuredDimension(getMeasuredWidth(), measureHeight(heightMeasureSpec, view));
    //    }
        /**
         * 解决pager中视图高度不一致的情况 动态更改pager高度
         * @param widthMeasureSpec
         * @param heightMeasureSpec
         */
        @Override
        protected void onMeasure(final int widthMeasureSpec, int heightMeasureSpec) {
            int index = getCurrentItem();
            int height = 0;
            View v = getChildAt(index);
            if (v != null) {
                v.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
                height = v.getMeasuredHeight();
            }
            heightMeasureSpec = MeasureSpec.makeMeasureSpec(height + 80, MeasureSpec.EXACTLY);
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
            final ViewPager pager = this;
            pager.addOnPageChangeListener(new SimpleOnPageChangeListener() {
                private int position;
                private int oldPositon;
    
                @Override
                public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
                    this.position = position;
                }
    
                @Override
                public void onPageScrollStateChanged(int state) {
                    if (state == 2) {
                        requestLayout();
                    }
                }
    
            });
        }
    }