自定义ScrollView+自定义滚动条

主题思路就是，通过scrollView的onScrollChanged的事件，去设置重绘cursor...  当然也可以直接用ScrollTo

先看主界面UserNoticeActivity

这里面有个自定义的控件，很简单。。。

package com.example.demo;import android.annotation.SuppressLint;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.widget.RelativeLayout;import android.widget.TextView;import java.io.InvalidClassException;public class UserNoticeActivity extends Activity  {CustomeUserNoticeScrollView user_notice_scroll;CustomeUserNoticeCursor user_notice_cursor;RelativeLayout start_virtual;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.user_notice);initRes();user_notice_scroll.setCursor(user_notice_cursor);}@SuppressLint("WrongViewCast")private void initRes() {user_notice_scroll = (CustomeUserNoticeScrollView) findViewById(R.id.user_notice_scroll);user_notice_cursor = (CustomeUserNoticeCursor) findViewById(R.id.user_notice_cursor);}}

CustomeUserNoticeScrollView

package com.example.demo;import android.content.Context;import android.util.AttributeSet;import android.util.Log;import android.widget.ScrollView;public class CustomeUserNoticeScrollView extends ScrollView {CustomeUserNoticeCursor cursor;private float noticeScrollViewTotleHeight;private float noticeScrollViewVisibleHeight;private Context context;public CustomeUserNoticeScrollView(Context context) {this(context, null);}public CustomeUserNoticeScrollView(Context context, AttributeSet attrs,int defStyle) {super(context, attrs, defStyle);this.context = context;}public CustomeUserNoticeScrollView(Context context, AttributeSet attrs) {this(context, attrs, 0);}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {super.onMeasure(widthMeasureSpec, heightMeasureSpec);noticeScrollViewTotleHeight = this.getChildAt(0).getMeasuredHeight();noticeScrollViewVisibleHeight = this.getHeight();// 3683 900Log.i("TAG", "totle:" + noticeScrollViewTotleHeight + ",visible"+ noticeScrollViewVisibleHeight);}@Overrideprotected void onScrollChanged(int l, int t, int oldl, int oldt) {super.onScrollChanged(l, t, oldl, oldt);float currentScrollY = this.getScrollY();float proportionTotalHeight = currentScrollY/ (noticeScrollViewTotleHeight - noticeScrollViewVisibleHeight);float cursorMoveY = proportionTotalHeight* (noticeScrollViewVisibleHeight - dp2px(context, 30));Log.i("TAG", "currentScrollY:" + currentScrollY+ ",proportionVisibleHeight--" + cursorMoveY);// cursor.scrollTo(0, -(int) proportionVisibleHeight);cursor.SetOffSet(cursorMoveY);}public void setCursor(CustomeUserNoticeCursor user_notice_cursor) {this.cursor = user_notice_cursor;}public static int dp2px(Context context, float dpValue) {float scale = context.getResources().getDisplayMetrics().density;return (int) (dpValue * scale + 0.5f);}}

CustomeUserNoticeCursor

package com.example.demo;import android.content.Context;import android.graphics.Canvas;import android.graphics.Paint;import android.graphics.RectF;import android.util.AttributeSet;import android.util.Log;import android.view.View;public class CustomeUserNoticeCursor extends View {Paint mPaint;private Context context;private float userNoticeCursorWidth;public CustomeUserNoticeCursor(Context context, AttributeSet attrs,int defStyle) {super(context, attrs, defStyle);this.context = context;initRes();}private void initRes() {mPaint = new Paint();mPaint.setColor(getResources().getColor(R.color.contentPressColor));mPaint.setStyle(Paint.Style.FILL);mPaint.setAntiAlias(true);userNoticeCursorWidth = dp2px(context, 24);}public CustomeUserNoticeCursor(Context context, AttributeSet attrs) {this(context, attrs, 0);}public CustomeUserNoticeCursor(Context context) {this(context, null);}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);RectF rect3 = new RectF(userNoticeCursorWidth / 4, cursorMoveY,userNoticeCursorWidth / 4 * 2, cursorMoveY + dp2px(context, 30));canvas.drawRoundRect(rect3, 10, 10, mPaint);}private float cursorMoveY;public void SetOffSet(float cursorMoveY) {this.cursorMoveY = cursorMoveY;Log.i("TAG", ",proportionVisibleHeight:" + cursorMoveY);invalidate();}//public static int dp2px(Context context, float dpValue) {float scale = context.getResources().getDisplayMetrics().density;return (int) (dpValue * scale + 0.5f);}}

user_notice.xml

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:background="#7A000000"    android:orientation="vertical" >        <LinearLayout             android:layout_centerInParent="true"            android:layout_width="300dp"            android:layout_height="300dp"            android:background="@color/white"            android:orientation="horizontal" >            <com.example.demo.CustomeUserNoticeScrollView                android:id="@+id/user_notice_scroll"                android:layout_width="0dp"                android:layout_height="fill_parent"                android:layout_weight="1"                android:scrollbars="none" >                <TextView                    android:layout_width="fill_parent"                    android:layout_height="fill_parent"                    android:lineSpacingExtra="6dp"                    android:text="@string/user_notice"                    android:textColor="#333333"                    android:textSize="16dp" />            </com.example.demo.CustomeUserNoticeScrollView>            <com.example.demo.CustomeUserNoticeCursor                android:id="@+id/user_notice_cursor"                android:layout_width="24dp"                android:layout_height="300dp"                android:layout_gravity="center"                android:gravity="center_horizontal|top" >            </com.example.demo.CustomeUserNoticeCursor>        </LinearLayout></RelativeLayout>

还有那些测试数据。。。。。随便写点就行了