Question

我已按照this和that个回答，我还找到了this个链接。

我使用这些资源进行试验＆amp;错误。现在，我的自定义ViewPager成功衡量了其内容，但只显示了第一个。仅供参考，我的ViewPager包含一些复杂的视图，例如ExpendableListView - 这就是为什么这些资源中的代码都没有完美运行，我需要自己修改代码。

我有4个片段（内容），所以我使用pager.setOffscreenPageLimit(3);

这是我的自定义ViewPager：

public class CustomViewPager extends ViewPager{

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

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

    @Override
    public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        boolean wrapHeight = MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.AT_MOST;

        final View tab = getChildAt(0);
        int width = getMeasuredWidth();
        int tabHeight = tab.getMeasuredHeight();

        if (wrapHeight) {
            // Keep the current measured width.
            widthMeasureSpec = MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY);
        }

        int fragmentHeight = measureFragment(((Fragment) getAdapter().instantiateItem(this, getCurrentItem())).getView());
        heightMeasureSpec = MeasureSpec.makeMeasureSpec(tabHeight + fragmentHeight + (int)TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 50, getResources().getDisplayMetrics()), MeasureSpec.AT_MOST);

        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }

    public int measureFragment(View view) {
        if (view == null)
            return 0;

        view.measure(0, 0);
        return view.getMeasuredHeight();
    }
}

这是我的CustomPagerTabStrip：

int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2,MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, expandSpec);
android.view.ViewGroup.LayoutParams params =  getLayoutParams();
params.height = getMeasuredHeight();

这是我的XML：

        <RelativeLayout
            android:id="@+id/relativePager"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" >

            <com.xxx.yyy.util.CustomViewPager
                android:id="@+id/detailPager"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" >

                <com.xxx.yyy.util.CustomPagerTabStrip
                    android:id="@+id/detailTab"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:background="#161C28"
                    android:textColor="#FFFFFF" />
            </com.xxx.yyy.util.CustomViewPager>

        </RelativeLayout>

示例案例：

如果第一个片段的高度为100px，那么所有其他片段将保持在100px。因此，如果第二个片段的高度为130px，则将其切割为100px。

当我尝试调试时，我onMeasure上的CustomViewPager在创建Activity时总是被调用4次，但所有这些都只读取了第一个片段。在此之后，onMeasure 永远再次被调用，即使我从一个片段更改（向左/向右滑动）到另一个片段。

请帮帮我，我花了很多时间让这件事工作。只要问我是否需要更多信息，感谢您的时间。

Answer 1

嗨Blaze发现有些东西用完了，以下解决方案对我有用。

它包括自定义滚动视图和自定义视图寻呼机。目的自定义视图寻呼机是根据子节点的高度动态计算高度，其高度设置为最初包装内容，滚动视图的目的是处理触摸事件，如果用户垂直滚动屏幕，它将即使滚动也不会通过触摸，因此用户可以滚动页面。

自定义滚动视图

public class CustomScrollView extends ScrollView {

private GestureDetector mGestureDetector;

public CustomScrollView(Context context, AttributeSet attrs) {
    super(context, attrs);
    mGestureDetector = new GestureDetector(context, new YScrollDetector());
    setFadingEdgeLength(0);
}

@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
    return super.onInterceptTouchEvent(ev)
            && mGestureDetector.onTouchEvent(ev);
}

// Return false if we're scrolling in the x direction
class YScrollDetector extends SimpleOnGestureListener {
    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2,
            float distanceX, float distanceY) {
        return (Math.abs(distanceY) > Math.abs(distanceX));
    }
}
}

自定义视图寻呼机

public class CustomPager extends ViewPager{

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

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

@Override
public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);

    boolean wrapHeight = MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.AT_MOST;

    final View tab = getChildAt(0);
    int width = getMeasuredWidth();
    int tabHeight = tab.getMeasuredHeight();

    if (wrapHeight) {
        // Keep the current measured width.
        widthMeasureSpec = MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY);
    }

    int fragmentHeight = measureFragment(((Fragment) getAdapter().instantiateItem(this, getCurrentItem())).getView());
    heightMeasureSpec = MeasureSpec.makeMeasureSpec(tabHeight + fragmentHeight + (int)TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 50, getResources().getDisplayMetrics()), MeasureSpec.AT_MOST);

    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}

public int measureFragment(View view) {
    if (view == null)
        return 0;

    view.measure(0, 0);
    return view.getMeasuredHeight();
}
}

布局文件

<com.example.demo2.activity.widget.CustomScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >

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

    <TextView
        style="@style/text"
        android:text="Text 1" />

    <View style="@style/text_divider" />

    <TextView
        style="@style/text"
        android:text="Text 2" />


        <com.example.demo2.activity.widget.CustomPager
          android:id="@+id/myViewPager"
          android:layout_width="match_parent"
          android:layout_height="wrap_content" />

    <View style="@style/text_divider" />

    <TextView
        style="@style/text"
        android:text="Text 4" />

    <View style="@style/text_divider" />

    <TextView
        style="@style/text"
        android:text="Text 5" />

    <View style="@style/text_divider" />

    <TextView
        style="@style/text"
        android:text="Text 6" />

    <View style="@style/text_divider" />

    <TextView
        style="@style/text"
        android:text="Text 7" />

    <View style="@style/text_divider" />

    <TextView
        style="@style/text"
        android:text="Text 8" />

    <View style="@style/text_divider" />

    <TextView
        style="@style/text"
        android:text="Text 9" />

    <View style="@style/text_divider" />

    <TextView
        style="@style/text"
        android:text="Text 10" />
</LinearLayout>

<强>活动

public class MainActivity extends FragmentActivity {



@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    MyPagerAdapter pageAdapter = new MyPagerAdapter(getSupportFragmentManager());
    ViewPager pager = (ViewPager)findViewById(R.id.myViewPager);
    pager.setAdapter(pageAdapter);

}



}

片段适配器

不同高度的碎片被添加到viewpager，FragmentBlue，Green等只是片段用于添加到viewpager你可以使用自己的片段，有一点要记住的是他们的外部布局应该是相同的，在我的情况下我使用了衬垫所有

的布局

public class MyPagerAdapter extends FragmentPagerAdapter {

private List<Fragment> fragments;

public MyPagerAdapter(FragmentManager fm) {
    super(fm);
    this.fragments = new ArrayList<Fragment>();
    fragments.add(new FragmentBlue());
    fragments.add(new FragmentGreen());
    fragments.add(new FragmentPink());
    fragments.add(new FragmentRed());
}

@Override
public Fragment getItem(int position) {
    return fragments.get(position);
}

@Override
public int getCount() {
    return fragments.size();
}
}

Answer 2

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

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

int getMeasureExactly(View child, int widthMeasureSpec) {
    child.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
    int height = child.getMeasuredHeight();
    return MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);
}

@Override
public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    boolean wrapHeight = MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.AT_MOST;

    final View tab = getChildAt(0);
    if (tab == null) {
        return;
    }

    int width = getMeasuredWidth();
    if (wrapHeight) {
        // Keep the current measured width.
        widthMeasureSpec = MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY);
    }
    Fragment fragment = ((Fragment) getAdapter().instantiateItem(this, getCurrentItem()));
    heightMeasureSpec = getMeasureExactly(fragment.getView(), widthMeasureSpec);

    //Log.i(Constants.TAG, "item :" + getCurrentItem() + "|height" + heightMeasureSpec);
    // super has to be called again so the new specs are treated as
    // exact measurements.
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}

动态高度不起作用的Viewpager（始终使用第一个片段的高度）

2 个答案: