项目学习资料

Posted 2022-12-09 lxn_李小牛

概述

从今天开始总结一下，项目中学到的一些东西，方便学习。

1.避免从从安装页面打开app后退出后台，再点击桌面icon，多出一个任务栈

在启动页的onCreate方法中做判断

  @Override
    protected void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        // 避免第一次安装成功，直接点击"打开"后，再点HOME置后台，再点桌面icon，导制存在2个任务栈问题
        if ((getIntent().getFlags() & Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT) != 0) 
            finish();
            return;
        

2.时间转化

//将小数分钟转化为xx小时和xx分,比如10.00分钟
    public String getTime(double minute)
        BigDecimal bigDecimal = new BigDecimal(minute * 60 * 1000);
        long time = bigDecimal.longValue();
        SimpleDateFormat format = new SimpleDateFormat("HH:mm", Locale.getDefault());
        //解决8个小时误差问题
        format.setTimeZone(TimeZone.getTimeZone("GMT+0"));
        return format.format(new Date(time));
    

3.在当前时间的基础上加上10分钟(当前时间格式为yyyy-MM-dd HH:mm:ss)

public void getTime2(String text)
    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    Date date = null;
    try 
        date = format.parse(text);
        format.setLenient(false);
     catch (ParseException e) 
        e.printStackTrace();
    
    Calendar calendar = Calendar.getInstance();
    Date upcarTime = new Date(date.getTime() + 60 *  10000);
    calendar.setTime(upcarTime);
    int hour = calendar.get(Calendar.HOUR_OF_DAY);
    int minute = calendar.get(Calendar.MINUTE);
    String str = String.valueOf(minute);
    if (minute >=0 && minute <= 9) 
        str = "0" + str;
    
    System.out.println(String.format(Locale.getDefault(),getString(R.string.arrive_time),hour,str));

4.重写onTouchEvent提示要调用performClick方法

正确写法如下

  @Override
    public boolean onTouchEvent(MotionEvent ev) 
        switch (ev.getAction()) 
            case MotionEvent.ACTION_DOWN:
             break;
            case MotionEvent.ACTION_UP:
                performClick();
                break;
        
        return super.onTouchEvent(ev);
    

    @Override
    public boolean performClick() 
        super.performClick();
        return true;
    

5.给View设置enable为false的情况下，无法执行点击事件，可以把事件放在onTouch里执行，onTouch同样会有警告

5.防止Button重复点击和ViewPager滑动过快

  // 检测以避免重复多次点击
    private static long lastClickTime;
    public static boolean isFastDoubleClick() 
        long time = System.currentTimeMillis();
        long timeD = time - lastClickTime;
        if ( 0 < timeD && timeD < 500) 
            return true;
        
        lastClickTime = time;
        return false;
    

    // 检测以避免快速滑动
    private static long lastScrollTime;
    public static boolean isFastScroll() 
        long time = System.currentTimeMillis();
        long timeD = time - lastScrollTime;
        if ( 0 < timeD && timeD < 800) 
            return true;
        
        lastScrollTime = time;
        return false;
    

6.设置View的bottomMargin

public void setMarginBottom(int marginBottom) 
        RelativeLayout.LayoutParams layoutParams = (LayoutParams) getLayoutParams();
        layoutParams.setMargins(layoutParams.leftMargin, layoutParams.topMargin, layoutParams.rightMargin, marginBottom + SizeUtils.dp2px(getContext(), 10));