常用的方法、知识（三）

来源：互联网发布：淘宝我的下单截图编辑：程序博客网时间：2024/05/17 21:01

1、Fragment中写onTouchevent，监听Fragment的触碰事件，主要用于滚屏监听隐藏显示某个控件：

首先在Fragment的父Activity中写一个回调接口：

public interface MyTouchListener {        public void onTouchEvent(MotionEvent event);    }    // 保存MyTouchListener接口的列表    private ArrayList<MyTouchListener> myTouchListeners = new ArrayList<MainActivity.MyTouchListener>();    /**     * 提供给Fragment通过getActivity()方法来注册自己的触摸事件的方法     * @param listener     */    public void registerMyTouchListener(MyTouchListener listener) {        myTouchListeners.add(listener);    }    /**     * 提供给Fragment通过getActivity()方法来取消注册自己的触摸事件的方法     * @param listener     */    public void unRegisterMyTouchListener(MyTouchListener listener) {        myTouchListeners.remove( listener );    }    /**     * 分发触摸事件给所有注册了MyTouchListener的接口     */    @Override    public boolean dispatchTouchEvent(MotionEvent ev) {        for (MyTouchListener listener : myTouchListeners) {            listener.onTouchEvent(ev);        }        return super.dispatchTouchEvent(ev);    }

然后在Fragment中，其中在触碰事件中，判断是上滑动还是下滑动，从而做一个悬浮按钮的显示、隐藏：

 //Fragment的OnTouchevent，滚动隐藏显示备忘录图标        MainActivity.MyTouchListener myTouchListener = new MainActivity.MyTouchListener() {            @Override            public void onTouchEvent(MotionEvent event) {                if (event.getAction() == MotionEvent.ACTION_DOWN) {                    y1 = event.getY();                }                if (event.getAction() == MotionEvent.ACTION_UP) {                    y2 = event.getY();                    if (y1 - y2 > 50) {                        //向上滑动                        if (fabReportMemo.getVisibility() == View.VISIBLE) {                            fabReportMemo.setVisibility(View.GONE);                            fabReportMemo.setAnimation(BaseMethod.HideAnimation(getContext()));                        }                    } else if (y2 - y1 > 50) {                        //向下滑动                        if (fabReportMemo.getVisibility() == View.GONE) {                            fabReportMemo.setVisibility(View.VISIBLE);                            fabReportMemo.setAnimation(BaseMethod.ShowAnimation(getContext()));                        }                    }                }                // 处理手势事件            }        };        // 将myTouchListener注册到分发列表        ((MainActivity) this.getActivity()).registerMyTouchListener(myTouchListener);

2、双击标题栏，布局滚动到顶部：

  int count = 0;  long firClick,secClick; //双击标题栏回到顶部        llReportTitle.setOnTouchListener(new View.OnTouchListener() {            @Override            public boolean onTouch(View v, MotionEvent event) {                if (MotionEvent.ACTION_DOWN == event.getAction()) {                    count++;                    if (count == 1) {                        firClick = System.currentTimeMillis();                    } else if (count == 2) {                        secClick = System.currentTimeMillis();                        if (secClick - firClick < 1000) {                            svReport.smoothScrollTo(0, 0);                            if (fabReportMemo.getVisibility() == View.GONE) {                                fabReportMemo.setVisibility(View.VISIBLE);                                fabReportMemo.setAnimation(BaseMethod.ShowAnimation(getContext()));                            }                        }                        count = 0;                        firClick = 0;                        secClick = 0;                    }                }                return true;            }        });

3、双击退出程序（新写法）：

private long exitTime = 0;    public void doExitApp() {        if ((System.currentTimeMillis() - exitTime) > 2000) {            Toast.makeText(this, R.string.press_again_exit_app, Toast.LENGTH_SHORT).show();            exitTime = System.currentTimeMillis();        } else {            finish();        }    }    @Override    public void onBackPressed() {                doExitApp();    }

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