How to set a maximum height with wrap content in a

问题:

In android, how can you create a scroll view that's got a max height, and wrap contents, basically it wraps the content vertically, but has a maximum height?

I tried

<ScrollView 
     android:id="@+id/scrollView1"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
         android:maxHeight="200dp"
     android:layout_alignParentBottom="true" >

    <LinearLayout
        android:id="@+id/maincontainer"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

    </LinearLayout>
</ScrollView>

But this isn't working?

回答1:

you can add this to any view (override onMeasure in a class inherited from a view)

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    if (maxHeight > 0){
        int hSize = MeasureSpec.getSize(heightMeasureSpec);
        int hMode = MeasureSpec.getMode(heightMeasureSpec);

        switch (hMode){
            case MeasureSpec.AT_MOST:
                heightMeasureSpec = MeasureSpec.makeMeasureSpec(Math.min(hSize, maxHeight), MeasureSpec.AT_MOST);
                break;
            case MeasureSpec.UNSPECIFIED:
                heightMeasureSpec = MeasureSpec.makeMeasureSpec(maxHeight, MeasureSpec.AT_MOST);
                break;
            case MeasureSpec.EXACTLY:
                heightMeasureSpec = MeasureSpec.makeMeasureSpec(Math.min(hSize, maxHeight), MeasureSpec.EXACTLY);
                break;
        }
    }

    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}

回答2:

I've extended ScrollView and added code to implement this feature:

https://gist.github.com/JMPergar/439aaa3249fa184c7c0c

I hope that be useful.

回答3:

You can do it programmatically.

 private static class OnViewGlobalLayoutListener implements ViewTreeObserver.OnGlobalLayoutListener {
    private final static int maxHeight = 130;
    private View view;

    public OnViewGlobalLayoutListener(View view) {
        this.view = view;
    }

    @Override
    public void onGlobalLayout() {
        if (view.getHeight() > maxHeight)
            view.getLayoutParams().height = maxHeight;
    }
}

And add listener to the view:

view.getViewTreeObserver()
                  .addOnGlobalLayoutListener(new OnViewGlobalLayoutListener(view));

Listener will call method onGlobalLayout(), when view height will be changed.

回答4:

for set scrollview height you must use 2 linerlayout inside together and then set scrool view as them child then set middle linerlayout layout:height for limit scrollview height.

回答5:

Here you can set height of your Scrollview like this -:

<ScrollView 
 android:id="@+id/scrollView1"
 android:layout_width="match_parent"
 android:layout_height="200dp"
 android:layout_alignParentBottom="true" >

           <LinearLayout
            android:id="@+id/maincontainer"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">

           </LinearLayout>
</ScrollView>