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Android Java：將else-if轉換為switch

[英]Android Java: Convert else-if to switch

 原文  2020-04-09 00:05:28  5   2    java/ android/ performance/ android-studio/ if-statement

問題描述

我使用 else-if 語句來檢查 Boolean 值，並且由於使用 else-if，它會導致性能不佳。

出於這個原因，我正在考慮將 else-if 語句轉換為 switch 語句，以便我想聽聽您對它進行適當轉換的建議。

這是我的 else-if 語句

public class Config_Monday_0 {
private Context mContext;

public Config_Monday_0(Context context){
    this.mContext = context;
}

public int monday_0(TextView mon_1, TextView mon_2, TextView mon_3, TextView mon_4, TextView mon_5,
                     TextView mon_6, TextView mon_7, TextView mon_8, TextView mon_9, TextView mon_10,
                     TextView mon_11, TextView mon_12, TextView mon_13, TextView mon_14, TextView mon_15,
                     TextView mon_16, TextView mon_17, TextView mon_18, TextView mon_19, TextView mon_20,
                     TextView mon_21, TextView mon_22, TextView mon_23, TextView mon_24){

    Schedule_Boolean_Monday_0 schedule_boolean_monday0 = new Schedule_Boolean_Monday_0(mContext);
    DatabaseTimetable databaseTimetable = new DatabaseTimetable(mContext);

    int start_time;
    int end_time;

    //Database 0 AM is not used
    if (!schedule_boolean_monday0.Monday_0_1() && !schedule_boolean_monday0.Monday_0_2() && !schedule_boolean_monday0.Monday_0_3() && !schedule_boolean_monday0.Monday_0_4() && !schedule_boolean_monday0.Monday_0_5() &&
            !schedule_boolean_monday0.Monday_0_6() && !schedule_boolean_monday0.Monday_0_7()&& !schedule_boolean_monday0.Monday_0_8() && !schedule_boolean_monday0.Monday_0_9() && !schedule_boolean_monday0.Monday_0_10() &&
            !schedule_boolean_monday0.Monday_0_11() && !schedule_boolean_monday0.Monday_0_12() && !schedule_boolean_monday0.Monday_0_13() && !schedule_boolean_monday0.Monday_0_14() && !schedule_boolean_monday0.Monday_0_15() &&
            !schedule_boolean_monday0.Monday_0_16() && !schedule_boolean_monday0.Monday_0_17()&& !schedule_boolean_monday0.Monday_0_18() && !schedule_boolean_monday0.Monday_0_19() && !schedule_boolean_monday0.Monday_0_20() &&
            !schedule_boolean_monday0.Monday_0_21() && !schedule_boolean_monday0.Monday_0_22() && !schedule_boolean_monday0.Monday_0_23() && !schedule_boolean_monday0.Monday_0_24()){
        return 0;
    }
    //0 am - 1 hr.
    else if (schedule_boolean_monday0.Monday_0_1() && !schedule_boolean_monday0.Monday_0_2() && !schedule_boolean_monday0.Monday_0_3() && !schedule_boolean_monday0.Monday_0_4() && !schedule_boolean_monday0.Monday_0_5() &&
            !schedule_boolean_monday0.Monday_0_6() && !schedule_boolean_monday0.Monday_0_7()&& !schedule_boolean_monday0.Monday_0_8() && !schedule_boolean_monday0.Monday_0_9() && !schedule_boolean_monday0.Monday_0_10() &&
            !schedule_boolean_monday0.Monday_0_11() && !schedule_boolean_monday0.Monday_0_12() && !schedule_boolean_monday0.Monday_0_13() && !schedule_boolean_monday0.Monday_0_14() && !schedule_boolean_monday0.Monday_0_15() &&
            !schedule_boolean_monday0.Monday_0_16() && !schedule_boolean_monday0.Monday_0_17()&& !schedule_boolean_monday0.Monday_0_18() && !schedule_boolean_monday0.Monday_0_19() && !schedule_boolean_monday0.Monday_0_20() &&
            !schedule_boolean_monday0.Monday_0_21() && !schedule_boolean_monday0.Monday_0_22() && !schedule_boolean_monday0.Monday_0_23() && !schedule_boolean_monday0.Monday_0_24()){
        start_time = 0;
        end_time = 1;
        schedule_boolean_monday0.Monday_0_1();
        mon_1.setText(databaseTimetable.Monday_Title(start_time, end_time));
        mon_1.setTextColor(Color.parseColor(databaseTimetable.Monday_Text_Color(start_time, end_time)));
        mon_1.setBackgroundColor(Color.parseColor(databaseTimetable.Monday_Text_BG_Color(start_time, end_time)));
        return 1;
    }
    //0 am - 2 hr.
    else if (!schedule_boolean_monday0.Monday_0_1() && schedule_boolean_monday0.Monday_0_2() && !schedule_boolean_monday0.Monday_0_3() && !schedule_boolean_monday0.Monday_0_4() && !schedule_boolean_monday0.Monday_0_5() &&
            !schedule_boolean_monday0.Monday_0_6() && !schedule_boolean_monday0.Monday_0_7()&& !schedule_boolean_monday0.Monday_0_8() && !schedule_boolean_monday0.Monday_0_9() && !schedule_boolean_monday0.Monday_0_10() &&
            !schedule_boolean_monday0.Monday_0_11() && !schedule_boolean_monday0.Monday_0_12() && !schedule_boolean_monday0.Monday_0_13() && !schedule_boolean_monday0.Monday_0_14() && !schedule_boolean_monday0.Monday_0_15() &&
            !schedule_boolean_monday0.Monday_0_16() && !schedule_boolean_monday0.Monday_0_17()&& !schedule_boolean_monday0.Monday_0_18() && !schedule_boolean_monday0.Monday_0_19() && !schedule_boolean_monday0.Monday_0_20() &&
            !schedule_boolean_monday0.Monday_0_21() && !schedule_boolean_monday0.Monday_0_22() && !schedule_boolean_monday0.Monday_0_23() && !schedule_boolean_monday0.Monday_0_24()){
        start_time = 0;
        end_time = 2;
        schedule_boolean_monday0.Monday_0_2();
        mon_1.setText(databaseTimetable.Monday_Title(start_time, end_time));
        mon_1.setTextColor(Color.parseColor(databaseTimetable.Monday_Text_Color(start_time, end_time)));
        mon_1.setBackgroundColor(Color.parseColor(databaseTimetable.Monday_Text_BG_Color(start_time, end_time)));
        mon_2.setBackgroundColor(Color.parseColor(databaseTimetable.Monday_Text_BG_Color(start_time, end_time)));
        return 2;
    }
    //0 am - 3 hr.
    else if (!schedule_boolean_monday0.Monday_0_1() && !schedule_boolean_monday0.Monday_0_2() && schedule_boolean_monday0.Monday_0_3() && !schedule_boolean_monday0.Monday_0_4() && !schedule_boolean_monday0.Monday_0_5() &&
            !schedule_boolean_monday0.Monday_0_6() && !schedule_boolean_monday0.Monday_0_7()&& !schedule_boolean_monday0.Monday_0_8() && !schedule_boolean_monday0.Monday_0_9() && !schedule_boolean_monday0.Monday_0_10() &&
            !schedule_boolean_monday0.Monday_0_11() && !schedule_boolean_monday0.Monday_0_12() && !schedule_boolean_monday0.Monday_0_13() && !schedule_boolean_monday0.Monday_0_14() && !schedule_boolean_monday0.Monday_0_15() &&
            !schedule_boolean_monday0.Monday_0_16() && !schedule_boolean_monday0.Monday_0_17()&& !schedule_boolean_monday0.Monday_0_18() && !schedule_boolean_monday0.Monday_0_19() && !schedule_boolean_monday0.Monday_0_20() &&
            !schedule_boolean_monday0.Monday_0_21() && !schedule_boolean_monday0.Monday_0_22() && !schedule_boolean_monday0.Monday_0_23() && !schedule_boolean_monday0.Monday_0_24()){
        start_time = 0;
        end_time = 3;
        schedule_boolean_monday0.Monday_0_3();
        mon_1.setText(databaseTimetable.Monday_Title(start_time, end_time));
        mon_1.setTextColor(Color.parseColor(databaseTimetable.Monday_Text_Color(start_time, end_time)));
        mon_1.setBackgroundColor(Color.parseColor(databaseTimetable.Monday_Text_BG_Color(start_time, end_time)));
        mon_2.setBackgroundColor(Color.parseColor(databaseTimetable.Monday_Text_BG_Color(start_time, end_time)));
        mon_3.setBackgroundColor(Color.parseColor(databaseTimetable.Monday_Text_BG_Color(start_time, end_time)));
        return 3;
    }

    return 99;
    }
}

這是一個 class 表示 Boolean 變量

public class Schedule_Boolean_Monday_0 {

    private Context mContext;
    private DatabaseTimetable databaseTimetable;

    public Schedule_Boolean_Monday_0(Context context){
        this.mContext = context;
    }

    public Boolean Monday_0_1(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,1);
        return !result.equals("");
    }

    public Boolean Monday_0_2(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,2);
        return !result.equals("");
    }

    public Boolean Monday_0_3(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,3);
        return !result.equals("");
    }

    public Boolean Monday_0_4(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,4);
        return !result.equals("");
    }

    public Boolean Monday_0_5(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,5);
        return !result.equals("");
    }

    public Boolean Monday_0_6(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,6);
        return !result.equals("");
    }

    public Boolean Monday_0_7(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,7);
        return !result.equals("");
    }

    public Boolean Monday_0_8(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,8);
        return !result.equals("");
    }

    public Boolean Monday_0_9(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,9);
        return !result.equals("");
    }

    public Boolean Monday_0_10(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,10);
        return !result.equals("");
    }

    public Boolean Monday_0_11(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,11);
        return !result.equals("");
    }

    public Boolean Monday_0_12(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,12);
        return !result.equals("");
    }

    public Boolean Monday_0_13(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,13);
        return !result.equals("");
    }

    public Boolean Monday_0_14(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,14);
        return !result.equals("");
    }

    public Boolean Monday_0_15(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,15);
        return !result.equals("");
    }

    public Boolean Monday_0_16(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,16);
        return !result.equals("");
    }

    public Boolean Monday_0_17(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,17);
        return !result.equals("");
    }

    public Boolean Monday_0_18(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,18);
        return !result.equals("");
    }

    public Boolean Monday_0_19(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,19);
        return !result.equals("");
    }

    public Boolean Monday_0_20(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,20);
        return !result.equals("");
    }

    public Boolean Monday_0_21(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,21);
        return !result.equals("");
    }

    public Boolean Monday_0_22(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,22);
        return !result.equals("");
    }

    public Boolean Monday_0_23(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,23);
        return !result.equals("");
    }

    public Boolean Monday_0_24(){
        databaseTimetable = new DatabaseTimetable(mContext);
        String result = databaseTimetable.Monday_Title(0,0);
        return !result.equals("");
    }
}

在每個 if/else-if arguments 中有 24 個 Boolean 變量。 我認為轉換為切換方法可能會為我的應用帶來更好的性能，如果您有任何想法，我想聽聽您的建議。

2 個解決方案

解決方案1
 0  2020-04-09 00:12:23

您的問題不是if語句， if語句盡可能高效。 您的問題是為每個變量訪問訪問數據庫，這是您應該處理的問題。

如果我是你，我會讀一遍所有 boolean 變量，然后使用這些值來實現你想要實現的任何邏輯。 要點是， READ ONCE AND CACHE ALL YOU CAN 。

解決方案2
 0  2020-04-09 00:36:03

編寫好代碼的核心原則之一是避免重復。 就您而言，我認為嘗試遵守這一原則可能會有所幫助。

為了擴展 Lenik 的答案，我認為您最好先將整個if語句包含在首先檢查Monday_0_4到Monday_0_24的檢查中。 像這樣的東西：

if( !schedule_boolean_monday0.Monday_0_4() && !schedule_boolean_monday0.Monday_0_5() &&  
    !schedule_boolean_monday0.Monday_0_6() && !schedule_boolean_monday0.Monday_0_7()&& 
    !schedule_boolean_monday0.Monday_0_8() && !schedule_boolean_monday0.Monday_0_9() && 
    !schedule_boolean_monday0.Monday_0_10() && !schedule_boolean_monday0.Monday_0_11() && 
    !schedule_boolean_monday0.Monday_0_12() && !schedule_boolean_monday0.Monday_0_13() && 
    !schedule_boolean_monday0.Monday_0_14() && !schedule_boolean_monday0.Monday_0_15() && 
    !schedule_boolean_monday0.Monday_0_16() && !schedule_boolean_monday0.Monday_0_17()&& 
    !schedule_boolean_monday0.Monday_0_18() && !schedule_boolean_monday0.Monday_0_19() && 
    !schedule_boolean_monday0.Monday_0_20() && !schedule_boolean_monday0.Monday_0_21() && 
    !schedule_boolean_monday0.Monday_0_22() && !schedule_boolean_monday0.Monday_0_23() && 
    !schedule_boolean_monday0.Monday_0_24() ) {
    //your existing if statement here, but with the checks for Monday_0_4 through Monday_0_24 removed from each one
}

其次，只是為了更好的代碼，並記住我可能不完全理解您的代碼，我認為您最好將數據庫檢查重新設計為以下內容：

public Boolean Monday_0(int hour){
    databaseTimetable = new DatabaseTimetable(mContext);
    String result = databaseTimetable.Monday_Title(0,hour);
    return !result.equals("");
}

您還可以通過以下方式進一步簡化代碼：

  • 在 if 語句outside放置一個返回值，返回end_time 。 end_time應初始化為 -1，這將作為“錯誤”返回值的兩倍（而不是 99）。
  • 也將它們移到 if 之外，因為無論哪個條件為真，它們都會被調用：（您需要另一個嵌套的 if 以確保在 Monday_0_1 為假時不會調用它）
mon_1.setText(databaseTimetable.Monday_Title(start_time, end_time));
mon_1.setTextColor(Color.parseColor(databaseTimetable.Monday_Text_Color(start_time, end_time)));
mon_1.setBackgroundColor(Color.parseColor(databaseTimetable.Monday_Text_BG_Color(start_time, end_time)));
  • 使用我之前提到的改進的數據庫檢查，使用for循環執行檢查

希望這可以幫助！

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