Question

我有一个自定义列表视图 - 其中的对象来自自定义BaseAdapter。我还为滚动条创建了以下形状：

<?xml version="1.0" encoding="utf-8"?>
    <shape xmlns:android="http://schemas.android.com/apk/res/android" >   
    <solid android:color="#CC0a2b41"></solid>
    <corners android:radius="8dp" />
    <padding 
        android:top="20dp"
        android:left="5dp"
        android:right="5dp"/>
</shape>

但是现在滚动条粘在屏幕的右侧，我希望它略微向左，这样滚动条和屏幕边缘之间有一个小填充。无论我放在那里的值是什么，上述形状的填充属性似乎都无能为力。

我的列表视图，如果有帮助：

 <ListView
    android:id="@+id/mainMenuListView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_below="@+id/textView3"
    android:divider="@color/blue_border"
    android:dividerHeight="1px"
    android:scrollbarThumbVertical="@drawable/scroller"
    >

我在xml中尝试过scrollbarPositionStyles，但没有达到预期的效果 -

Answer 1

试试这个。您可以使用View.SCROLLBAR_POSITION_LEFT将任何视图的滚动条位置向左移动。

Answer 2

你也可以试试这个，至少2.2以上。

 import java.lang.reflect.Field;

 import android.annotation.SuppressLint;
 import android.content.Context;
 import android.graphics.Rect;
 import android.graphics.drawable.Drawable;
 import android.graphics.drawable.LayerDrawable;
 import android.util.AttributeSet;
 import android.util.Log;
 import android.view.View;
  import android.widget.ListView;


public class ListViewWithLeftScrollBar extends ListView {
private static final String LOG_TAG = ListViewWithLeftScrollBar.class.getSimpleName();
private static final boolean DEBUG = true;

private boolean patchInvalidate;

public ListViewWithLeftScrollBar(Context context) {
    super(context);
    moveVerticalScrollbarToTheLeft();
}

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

public ListViewWithLeftScrollBar(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    moveVerticalScrollbarToTheLeft();
}

@Override
public void invalidate(Rect r) {
    invalidate(r.left, r.top, r.right, r.bottom);
}

@Override
public void invalidate(int left, int top, int right, int bottom) {
    int width = right - left;
    if (DEBUG) log("invalidate original w:"+ getWidth() +" h:"+ getHeight()+"  rect:"+left+", "+top+", "+right+", "+bottom);
    if (patchInvalidate && right == getWidth() && top == 0 && bottom == getHeight() && width < 30) {
        // The above condition should ensure that ListView is VERY likely to be invalidating the scrollbar.
        // In fact ListView appears to not invalidate anything except the scrollbar, ever.
        left = 0;
        right = left + width;
        if (DEBUG) log("invalidate patched  w:"+ getWidth() +" h:"+ getHeight()+"  rect:"+left+", "+top+", "+right+", "+bottom);
    }
    super.invalidate(left, top, right, bottom);
}

private void moveVerticalScrollbarToTheLeft() {
    try {
        if (DEBUG) log("moveVerticalScrollbarToTheLeft: Trying API Level >=11");
        tryApiLevel11();
        if (DEBUG) log("moveVerticalScrollbarToTheLeft: API Level >=11 success");
    } catch (Throwable t1) {
        if (DEBUG) {
            log("moveVerticalScrollbarToTheLeft: API Level >=11 FAILED");
            t1.printStackTrace();
        }
        try {
            if (DEBUG) log("moveVerticalScrollbarToTheLeft: Trying hack for API Level <11");
            tryApiLevelPre11();
            patchInvalidate = true;
            if (DEBUG) log("moveVerticalScrollbarToTheLeft: API Level <11 hack success");
        } catch (Throwable t2) {
            if (DEBUG) {
                log("moveVerticalScrollbarToTheLeft: API Level <11 hack FAILED");
                t2.printStackTrace();
            }
        }
    }
}

@SuppressLint("NewApi")
private void tryApiLevel11() {
    setVerticalScrollbarPosition(View.SCROLLBAR_POSITION_LEFT);
}

private void tryApiLevelPre11() throws Exception {
    Class<?> viewClass = View.class;

    Field scrollCacheField = viewClass.getDeclaredField("mScrollCache");
    scrollCacheField.setAccessible(true);
    Object scrollCache = scrollCacheField.get(this);
    if (DEBUG) log("scrollCache: "+ scrollCache);

    Field scrollBarField = scrollCache.getClass().getDeclaredField("scrollBar");
    scrollBarField.setAccessible(true);
    Object scrollBar = scrollBarField.get(scrollCache);
    if (DEBUG) log("scrollBar: "+ scrollBar);

    Field verticalThumbField = scrollBar.getClass().getDeclaredField("mVerticalThumb");
    verticalThumbField.setAccessible(true);
    Object verticalThumb = verticalThumbField.get(scrollBar);
    if (DEBUG) log("verticalThumb: "+ verticalThumb);

    Drawable verticalThumbDrawable = (Drawable) verticalThumb;
    Drawable replacementVerticalThumbDrawable = new LayerDrawable(new Drawable[]{ verticalThumbDrawable }) {
        @Override
        public void setBounds(int left, int top, int right, int bottom) {
            if (DEBUG) log("setBounds original: "+left+", "+top+", "+right+", "+bottom);
            int width = right - left;
            left = 0;
            right = left + width;
            if (DEBUG) log("setBounds patched:  "+left+", "+top+", "+right+", "+bottom);
            super.setBounds(left, top, right, bottom);
        }       
    };
    verticalThumbField.set(scrollBar, replacementVerticalThumbDrawable);
}

private static void log(String msg) {
    Log.d(LOG_TAG, msg);
}
}

重新定位列表视图的滚动条

2 个答案: