分享一个可下拉刷新的ScrollView

原理：就是动态改变ScrollView header的margin实现

主要的代码：

http://blog.csdn.net/swust_chenpeng/article/details/39289721

代码其实还是比较容易，但是但是，自己还是花了很多时间，脑袋瓜不够灵活呀...

下面是ScrollViewHeader的代码：

public class ScrollViewHeader extends RelativeLayout {

    public final static int STATE_NORMAL = 0;

    public final static int STATE_READY = 1;

    public final static int STATE_REFRESHING = 2;

    private final int ROTATE_ANIM_DURATION = 180;

    private int topMargin = 0;

    private int state = STATE_NORMAL;

    private TextView refreshTv = null;

    private TextView refreshTimeTv = null;

    private ProgressBar refreshProgress = null;

    private ImageView refreshArrow = null;

    private Animation animationUp = null;

    private Animation animationDown = null;

    public ScrollViewHeader(Context context) {

        super(context);

        // TODO Auto-generated constructor stub

        if(!isInEditMode())

            initView(context);

    }

    public ScrollViewHeader(Context context, AttributeSet attrs) {

        super(context, attrs);

        // TODO Auto-generated constructor stub

        if(!isInEditMode())

            initView(context);

    }

    public ScrollViewHeader(Context context, AttributeSet attrs, int defStyle) {

        super(context, attrs, defStyle);

        // TODO Auto-generated constructor stub

        if(!isInEditMode())

            initView(context);

    }

    /**

     * 初始化相关的view

     */

    public void initView(Context context) {

        animationDown = new RotateAnimation(-180f, 0, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);

        animationDown.setDuration(ROTATE_ANIM_DURATION);

        animationDown.setFillAfter(true);

        animationUp = new RotateAnimation(0, -180f, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);

        animationUp.setDuration(ROTATE_ANIM_DURATION);

        animationUp.setFillAfter(true);

        setPadding(10, 25, 10, 25);

        View view = LayoutInflater.from(context).inflate(R.layout.scrollview_header, this, true);

        refreshTv = (TextView) view.findViewById(R.id.refresh_text);

        refreshTimeTv = (TextView) view.findViewById(R.id.refresh_time);

        refreshProgress = (ProgressBar) view.findViewById(R.id.refresh_progress);

        refreshArrow = (ImageView) view.findViewById(R.id.refresh_arrow);

    }

    /**

     * 设置scrollviewHeader的状态

     * @param state

     */

    public void setState(int state) {

        if(this.state == state) {

            return ;

        }

        switch (state) {

        case STATE_NORMAL:

            refreshTv.setText("下拉刷新");

            refreshArrow.setVisibility(View.VISIBLE);

            refreshProgress.setVisibility(View.INVISIBLE);

            if(this.state == STATE_READY) {

                refreshArrow.startAnimation(animationDown);

            } else if(this.state == STATE_REFRESHING) {

                refreshArrow.clearAnimation();

            }

            break;

        case STATE_READY:

            refreshTv.setText("松开刷新");

            refreshArrow.setVisibility(View.VISIBLE);

            refreshProgress.setVisibility(View.INVISIBLE);

            refreshArrow.startAnimation(animationUp);

            break;

        case STATE_REFRESHING:

            refreshTv.setText("正在加载...");

            refreshProgress.setVisibility(View.VISIBLE);

            refreshArrow.clearAnimation();

            refreshArrow.setVisibility(View.INVISIBLE);

            break;

        default:

            break;

        }

        this.state = state;

    }

    /**

     * 更新header的margin

     * @param margin

     */

    public void updateMargin(int margin) {

        //这里用Linearlayout的原因是Headerview的父控件是scrollcontainer是一个linearlayout

        LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) this.getLayoutParams();

        params.topMargin = margin;

        topMargin = margin;

        setLayoutParams(params);

    }

    /**

     * 获取header的margin

     * @return

     */

    public int getTopMargin() {

        return topMargin;

    }

}  

header的布局文件，scrollview_header

<?xml version="1.0" encoding="utf-8"?>

<merge xmlns:android="http://schemas.android.com/apk/res/android" >

    <LinearLayout

        android:id="@+id/refresh_des"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_centerInParent="true"

        android:gravity="center"

        android:orientation="vertical" >

        <TextView

            android:id="@+id/refresh_text"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:text="下拉刷新" />

        <TextView

            android:id="@+id/refresh_time"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:text="5分钟前更新" />

    </LinearLayout>

    <ProgressBar

        android:id="@+id/refresh_progress"

        android:layout_width="30dip"

        android:layout_height="30dip"

        android:layout_centerVertical="true"

        android:layout_marginRight="10dip"

        android:layout_toLeftOf="@id/refresh_des"

        android:visibility="invisible" />

    <ImageView

        android:id="@+id/refresh_arrow"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_centerVertical="true"

        android:layout_marginRight="10dip"

        android:layout_toLeftOf="@id/refresh_des"

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

</merge>  

好了，相关的源码就只有3个文件...