Question

我已经扩展了ScrollView类来创建一个类，以便可以监听onScroll事件。但它说我扩展的课程无法找到。我已经尝试了给出的选项，但似乎都没有。这是XML的代码

   <com.example.random.ScrollViewExt
   android:id="@+id/scrollview1"
   xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent">

   <LinearLayout android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:orientation="vertical"
   android:paddingBottom="@dimen/activity_vertical_margin"
   android:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
   android:paddingTop="@dimen/activity_vertical_margin" >

   <TextView
    android:id="@+id/text1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/hello_world" />

    </LinearLayout>
    </com.example.random.ScrollViewExt>

以下是自定义类的代码。

    package com.example.random;

    import android.widget.ScrollView;
    import android.content.Context;
     import android.util.AttributeSet;


    public class ScrollViewExt extends ScrollView {
        private ScrollViewListener scrollViewListener = null;
        public ScrollViewExt(Context context) {
              super(context);
         }

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

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

         public void setScrollViewListener(ScrollViewListener scrollViewListener) {
             this.scrollViewListener = scrollViewListener;
        } 

        @Override
         protected void onScrollChanged(int l, int t, int oldl, int oldt) {
            super.onScrollChanged(l, t, oldl, oldt);
             if (scrollViewListener != null) {
                 scrollViewListener.onScrollChanged(this, l, t, oldl, oldt);
              }
          }
     }

关于我能做什么的任何想法？

Answer 1

在XML文件中使用<ScrollView></ScrollView>，然后将对象强制转换为ScrollViewExt以便处理其侦听器

<ScrollView
   android:id="@+id/scrollview1"
   xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent">

   <LinearLayout android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:orientation="vertical"
   android:paddingBottom="@dimen/activity_vertical_margin"
   android:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
   android:paddingTop="@dimen/activity_vertical_margin" >

   <TextView
    android:id="@+id/text1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/hello_world" />

    </LinearLayout>
</ScrollView>

侦听器的接口

public interface ScrollViewListener {
    void onScrollChanged(ScrollViewExt scrollView, 
                         int x, int y, int oldx, int oldy);
}

然后让活动类实现之前创建的接口，然后：

scroll = (ScrollViewExt) findViewById(R.id.scrollView1);
scroll.setScrollViewListener(this);

另外

@Override
public void onScrollChanged(ScrollViewExt scrollView, int x, int y, int oldx, int oldy) {
    // We take the last son in the scrollview
    View view = (View) scrollView.getChildAt(scrollView.getChildCount() - 1);
    int diff = (view.getBottom() - (scrollView.getHeight() + scrollView.getScrollY()));

    // if diff is zero, then the bottom has been reached
    if (diff == 0) {
        // do stuff
    }
}

Android - ＆＃34;找不到以下类： - （更改为com.example.random.ScrollViewExt，修复构建路径，编辑XML，创建类）＆＃34;

1 个答案: