如何解决滚动条滑出屏幕的问题

cnaaa8 2014-11-26 05:57:32

动态移动ScrollView中某个item的位置，如何解决滚动条滑出屏幕的问题

xml文件





<LinearLayout 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"

    tools:context="com.example.scrollview.MainActivity" >



    <com.example.scrollview.ObservableScrollView

        android:id="@+id/sv"

        android:layout_width="match_parent"

        android:layout_height="match_parent" >



        <LinearLayout

            android:layout_width="match_parent"

            android:layout_height="match_parent"

            android:orientation="vertical" >



            <ImageView

                android:layout_width="match_parent"

                android:layout_height="wrap_content"

                android:src="@drawable/sj" />



            <TextView

                android:id="@+id/yidong"

                android:layout_width="wrap_content"

                android:layout_height="wrap_content"

                android:background="#FFFFFF"

                android:text="移动的标题" />



            <ImageView

                android:layout_width="match_parent"

                android:layout_height="wrap_content"

                android:src="@drawable/sj" />



            <TextView

                android:layout_width="wrap_content"

                android:layout_height="wrap_content"

                android:text="其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n其让\r\n" />



            <TextView

                android:layout_width="wrap_content"

                android:layout_height="wrap_content"

                android:text="其让啦啦啦" />

        </LinearLayout>

    </com.example.scrollview.ObservableScrollView>



</LinearLayout>

main文件





package com.example.scrollview;



import android.app.Activity;

import android.os.Bundle;

import android.util.Log;

import android.view.View;

import android.widget.TextView;





public class MainActivity extends Activity {

	

	int[] location = new int[2];

	int[] locationSv = new int[2];

	private TextView yidong;

	private ObservableScrollView sv;

	

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        sv = (ObservableScrollView) findViewById(R.id.sv);

        yidong = (TextView) findViewById(R.id.yidong);

        

        sv.setScrollViewListener(new ScrollViewListener() {

			

			@Override

			public void onScrollChanged(ObservableScrollView scrollView, int x, int y,

					int oldx, int oldy) {

				// TODO Auto-generated method stub

				yidong.getLocationOnScreen(location);

				sv.getLocationOnScreen(locationSv);

				sv.top=(location[1]-locationSv[1]);

				//sv.v=yidong;

			}

		});

    }





}

接口文件



package com.example.scrollview;



public interface ScrollViewListener {

	void onScrollChanged(ObservableScrollView scrollView, int x, int y, int oldx, int oldy);  

}

自定义 ScrollView文件



package com.example.scrollview;

  

import android.content.Context;

import android.graphics.Canvas;

import android.util.AttributeSet;

import android.view.View;

import android.widget.ScrollView;

  

public class ObservableScrollView extends ScrollView {  

  

    private ScrollViewListener scrollViewListener = null;  

    public int top=Integer.MAX_VALUE;

    public View v;

    

    public ObservableScrollView(Context context) {  

        super(context);  

    }  

  

    public ObservableScrollView(Context context, AttributeSet attrs,  

            int defStyle) {  

        super(context, attrs, defStyle);  

    }  

  

    public ObservableScrollView(Context context, AttributeSet attrs) {  

        super(context, attrs);  

    }  

  

    public void setScrollViewListener(ScrollViewListener scrollViewListener) {  

        this.scrollViewListener = scrollViewListener;  

    }  

    

    @Override

    protected void dispatchDraw(Canvas canvas) {

    	// TODO Auto-generated method stub

    	super.dispatchDraw(canvas);

    	

    	if(top<=0 && v!=null){

    		int pLeft = getPaddingLeft();

    		int pTop = getPaddingTop();

    		canvas.translate(pLeft, pTop - top);

    		//smoothScrollTo(pLeft, pTop - top);

    		drawChild(canvas, v, getDrawingTime());

    	}

    	

    }

  

    @Override  

    protected void onScrollChanged(int x, int y, int oldx, int oldy) {  

        super.onScrollChanged(x, y, oldx, oldy);  

        if (scrollViewListener != null) {  

            scrollViewListener.onScrollChanged(this, x, y, oldx, oldy);  

        }  

    }  

  

}