Question

我必须在scrollview中显示一个viewpager（pager行中图像下方的图像和文本）。我正在从网上下载图像，文本并在寻呼机行中显示。我在srollview中包含了viewpager以支持横向模式。

 <com.xxx.myapp.android.ui.CustomScrollView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:fadingEdge="none"
    android:fillViewport="true"
    android:gravity="center">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:descendantFocusability="blocksDescendants"
        android:orientation="vertical" >

        <android.support.v4.view.ViewPager
            android:id="@+id/viewPager"
            android:layout_width="match_parent"
            android:layout_height="800dp"
            android:layout_gravity="top"
            android:layout_marginTop="10dp" />  
    </LinearLayout>
</com.xxx.myapp.android.ui.CustomScrollView>

这是CustomScrollView。问题是如何根据子高度设置视图寻呼机高度，以便我可以滚动屏幕直到视图寻呼机项目结束。如果我将view pager height设置为wrapcontent，则viewpager中不会显示任何内容。如果我设置了800dp，那么我可以看到寻呼机项目，但屏幕上有不必要的滚动。我不希望我的滚动视图滚动超出寻呼机儿童的高度。请帮我。

Answer 1

要修复viewpager的高度，我们可以自定义viewpager类。

public class WrapContentViewPager extends ViewPager {

private int mCurrentPagePosition = 0;

public WrapContentViewPager(Context context) {
    super(context);
}

public WrapContentViewPager(Context context, AttributeSet attrs) {
    super(context, attrs);
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    try {
        View child = getChildAt(mCurrentPagePosition);
        if (child != null) {
            child.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
            int h = child.getMeasuredHeight();
            heightMeasureSpec = MeasureSpec.makeMeasureSpec(h, MeasureSpec.EXACTLY);
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}

public void reMeasureCurrentPage(int position) {
    mCurrentPagePosition = position;
    requestLayout();
}
}

这个reMeasureCurrentPage应该在viewpager上调用onPageSelected callback.and CustomScrollView是父视图。

Answer 2

mViewPager = new ViewPager(mContext) {
        @Override
        protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);

            View view = getChildAt(this.getCurrentItem());
            if (view != null) {
                view.measure(widthMeasureSpec, heightMeasureSpec);
            }
            setMeasuredDimension(getMeasuredWidth(), measureHeight(heightMeasureSpec, view));
        }

        private int measureHeight(int measureSpec, View view) {
            int result = 0;
            int specMode = MeasureSpec.getMode(measureSpec);
            int specSize = MeasureSpec.getSize(measureSpec);

            if (specMode == MeasureSpec.EXACTLY) {
                result = specSize;
            } else {
                // set the height from the base view if available
                if (view != null) {
                    result = view.getMeasuredHeight();
                }
                if (specMode == MeasureSpec.AT_MOST) {
                    result = Math.min(result, specSize);
                }
            }
            return result;
        }
    };

Answer 3

试试这种方式

<com.xxx.myapp.android.ui.CustomScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center"
    android:fadingEdge="none"
    android:fillViewport="true"
    android:gravity="center">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:descendantFocusability="blocksDescendants"
        android:orientation="vertical" >

        <android.support.v4.view.ViewPager
            android:id="@+id/viewPager"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_gravity="top"
            android:layout_marginTop="10dp" />  
    </LinearLayout>
</com.xxx.myapp.android.ui.CustomScrollView>

Answer 4

这是最好，最简单的解决方案：

1）在您自定义的ViewPager类中-

override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
    var heightMeasureSpec = heightMeasureSpec
    val mode = MeasureSpec.getMode(heightMeasureSpec)
    // Unspecified means that the ViewPager is in a ScrollView WRAP_CONTENT.
    // At Most means that the ViewPager is not in a ScrollView WRAP_CONTENT.
    if (mode == MeasureSpec.UNSPECIFIED || mode == MeasureSpec.AT_MOST) {
        // super has to be called in the beginning so the child views can be initialized.
        super.onMeasure(widthMeasureSpec, heightMeasureSpec)
        var height = 0
        for (i in 0 until childCount) {
            val child = getChildAt(i)
            child.measure(
                widthMeasureSpec,
                MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED)
            )
            val h = child.measuredHeight
            if (h > height) height = h
        }
        heightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY)
    }
    // super has to be called again so the new specs are treated as exact measurements
    super.onMeasure(widthMeasureSpec, heightMeasureSpec)
}

2）在将适配器设置为ViewPager时-

val viewPagerAdapter = ViewPagerAdapter(fragmentList, supportFragmentManager)
view_pager.adapter = viewPagerAdapter
view_pager.measure(LinearLayout.LayoutParams.MATCH_PARENT,LinearLayout.LayoutParams.WRAP_CONTENT)`
view_pager.currentItem = 0

Answer 5

将您的寻呼机行包装在CustomScrollView中，而不是将寻呼机包装在CustomScrollview中。并且不要像Piyush Gupath评论的那样修复Viewpager的高度。使用wrapcontent。

在android中的Scrollview中设置Viewpager高度

5 个答案: