使用Scroller仿QQ刷新

来源：互联网发布：java报文加密编辑：程序博客网时间：2024/05/16 12:34
最近突然对QQ的刷新感兴趣，就自己试做了下，目前还差图片的变换以及速度的改变。
package com.luoxf.drag.view;import android.content.Context;import android.graphics.Point;import android.os.Handler;import android.os.Message;import android.util.AttributeSet;import android.util.Log;import android.view.MotionEvent;import android.view.VelocityTracker;import android.view.View;import android.view.ViewConfiguration;import android.view.ViewTreeObserver;import android.view.WindowManager;import android.widget.LinearLayout;import android.widget.RelativeLayout;import android.widget.Scroller;import android.widget.TextView;import com.luoxf.drag.R;import com.nineoldandroids.view.ViewHelper;/** * Created by luoxf on 2015/10/27. */public class PullRelativeLayout extends RelativeLayout{    private final int REFRESHING = 1;    private final String TAG = PullRelativeLayout.class.getSimpleName();    private int screenHeight;    private int screenWidth;    private Context mContext;    private Scroller mScroller;    private int mLastX;    private int mLastY;    private int touchSlop; //最小滑动距离    private boolean isNeedToUp;    private View refreshContent; //刷新内容    private int refreshContentHeight; //刷新高度    private View content;    private TextView refreshText; //刷新文本    private View refreshIcon; //刷新图标    private Handler handler;    private VelocityTracker velocityTracker; // 速度捕捉器    public PullRelativeLayout(Context context) {        super(context);        initView(context);    }    public PullRelativeLayout(Context context, AttributeSet attrs) {        super(context, attrs);        initView(context);    }    public PullRelativeLayout(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        initView(context);    }    private void initView(Context context) {        this.mContext = context;        this.mScroller = new Scroller(context);        touchSlop = ViewConfiguration.get(context).getScaledTouchSlop();        WindowManager wm = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);        Point point = new Point();        wm.getDefaultDisplay().getSize(point);        screenWidth = point.x;        screenHeight = point.y;        handler = new Handler() {            public void handleMessage(Message msg){                super.handleMessage(msg);                switch (msg.what) {                    //正在刷新                    case REFRESHING:                        if(refreshText.getText().toString().equals(mContext.getString(R.string.refresh_three))) {                            smoothScrollTo(0, refreshContentHeight);                        }                        break;                }            }        };    }    @Override    protected void onFinishInflate() {        super.onFinishInflate();        refreshContent = findViewById(R.id.refresh_content);        content = findViewById(R.id.content);        refreshText = (TextView) findViewById(R.id.refresh_text);        refreshIcon = findViewById(R.id.refresh_icon);        refreshContent.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {            @Override            public void onGlobalLayout() {                refreshContent.getViewTreeObserver().removeGlobalOnLayoutListener(this);                refreshContentHeight = refreshContent.getHeight();                mScroller.setFinalY(refreshContentHeight);                LinearLayout.LayoutParams layoutParams = (LinearLayout.LayoutParams) getLayoutParams();                layoutParams.height = getHeight() + refreshContentHeight;                layoutParams.width = getWidth();                setLayoutParams(layoutParams);            }        });    }    @Override    public boolean onInterceptTouchEvent(MotionEvent ev) {        boolean intercepted = false;        int x = (int) ev.getX();        int y = (int) ev.getY();        final int action = ev.getAction();        switch (action) {            case MotionEvent.ACTION_DOWN:                velocityTracker = VelocityTracker.obtain();                intercepted = false;                break;            case MotionEvent.ACTION_MOVE:                int deltaY = y - mLastY;                //子view需要                if(mScroller.getFinalY() == refreshContentHeight && (deltaY < 0 || content.getScrollY() != 0)) {                    return false;                } else {                    return true;                }            case MotionEvent.ACTION_UP:                intercepted = false;                break;        }        mLastX = x;        mLastY = y;        return intercepted;    }    //调用此方法滚动到目标位置    public void smoothScrollTo(int fx, int fy) {        int dx = fx - mScroller.getFinalX();        int dy = fy - mScroller.getFinalY();        smoothScrollBy(dx, dy);    }    //调用此方法设置滚动的相对偏移    public void smoothScrollBy(int dx, int dy) {        //设置mScroller的滚动偏移量        mScroller.startScroll(mScroller.getFinalX(), mScroller.getFinalY(), dx, dy);        invalidate();//这里必须调用invalidate()才能保证computeScroll()会被调用，否则不一定会刷新界面，看不到滚动效果    }    @Override    public void computeScroll() {        //先判断mScroller滚动是否完成        if (mScroller.computeScrollOffset()) {            //这里调用View的scrollTo()完成实际的滚动            scrollTo(mScroller.getCurrX(), mScroller.getCurrY());            //必须调用该方法，否则不一定能看到滚动效果            postInvalidate();        }    }    @Override    public boolean onTouchEvent(MotionEvent event) {        int x = (int) event.getX();        int y = (int) event.getY();        switch (event.getAction()) {            case MotionEvent.ACTION_MOVE:                velocityTracker.computeCurrentVelocity(1000);                int deltaY = y - mLastY;                //改变刷新图标和文字                if(mScroller.getFinalY() <= 0) {                    ViewHelper.setRotation(refreshIcon, 180);                    refreshText.setText(mContext.getString(R.string.refresh_two));                } else {                    ViewHelper.setRotation(refreshIcon, 180);                    refreshText.setText(mContext.getString(R.string.refresh_first));                }                //滑到顶部                if(mScroller.getFinalY() - deltaY > refreshContentHeight) {                    smoothScrollTo(0, refreshContentHeight);                    isNeedToUp = false;                }                //下滑大于屏幕三分之一                else if(mScroller.getFinalY() - deltaY < -screenHeight / 3) {                    smoothScrollTo(0, -screenHeight / 3);                    isNeedToUp = true;                } else {                    smoothScrollBy(0, -deltaY);                    isNeedToUp = true;                }                break;            case MotionEvent.ACTION_UP:                //自动滑到顶部                if(isNeedToUp) {                    //正在刷新                    if(mScroller.getFinalY() <= 0) {                        smoothScrollTo(0, 0);                        refreshText.setText(mContext.getString(R.string.refresh_three));                        new Thread(new Runnable() {                            @Override                            public void run() {                                try {                                    Thread.sleep(1000);                                    handler.sendEmptyMessage(REFRESHING);                                } catch (InterruptedException e) {                                    e.printStackTrace();                                }                            }                        }).start();                    } else {                        smoothScrollTo(0, refreshContentHeight);                    }                }                //清除速度                velocityTracker.clear();                velocityTracker.recycle();                break;            default:                break;        }        mLastX = x;        mLastY = y;        return true;    }}
效果图如下：
接下来边学习边修改，努力。
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