If else 条件和逻辑运算符

Question

这是我的代码，用于搜索调用 polyline 方法的 2 个地方。当我的 editext Tabaco - Malinao 正确调用方法时，与 Tabaco-Bacacay、Tabaco-Santo Domingo、Tabaco-Malilipot 相同。但是当我的 edittext 是 Malilipot-Santo Domingo, Santo Domingo-Bacacay 时，它总是要求第一个条件 (Tabaco-Malinao)不是他们自己的条件。

会不会是条件不对？或我正在使用的逻辑运算符？

我的理解是，先到先得，等号不对。 这可能是错误的。

String origin = etOrigin.getText().toString();
    String destination = etDestination.getText().toString();
            if (origin.equals("Tabaco") == destination.equals("Malinao") && origin.equals("Malinao") == destination.equals("Tabaco")) {
            ttom();
            Toast.makeText(getApplicationContext(), "tabaco malinao", Toast.LENGTH_SHORT).show();
        } else if (origin.equals("Tabaco") == destination.equals("Bacacay") && origin.equals("Bacacay") == destination.equals("Tabaco")) {
            ttob();
            Toast.makeText(getApplicationContext(), "tabaco bacacay", Toast.LENGTH_SHORT).show();
        } else if (origin.equals("Tabaco") == destination.equals("Santo Domingo") && origin.equals("Santo Domingo") == destination.equals("Tabaco")) {
            ttosto();
            Toast.makeText(getApplicationContext(), "tabaco sto domingo", Toast.LENGTH_SHORT).show();
        } else if (origin.equals("Tabaco") == destination.equals("Malilipot") && origin.equals("Malilipot") == destination.equals("Tabaco")) {
            ttomali();
            Toast.makeText(getApplicationContext(), "tabaco malilipot", Toast.LENGTH_SHORT).show();
        } else if (origin.equals("Malilipot") == destination.equals("Santo Domingo") && origin.equals("Santo Domingo") == destination.equals("Malilipot")) {
            malitosto();
            Toast.makeText(getApplicationContext(), "malilipot sto domingo", Toast.LENGTH_SHORT).show();
        } else if (origin.equals("Malilipot") == destination.equals("Bacacay") && origin.equals("Bacacay") == destination.equals("Malilipot")) {
            malitobac();
            Toast.makeText(getApplicationContext(), "malilipot bacacay", Toast.LENGTH_SHORT).show();
        } else if (origin.equals("Santo Domingo") == destination.equals("Bacacay") && origin.equals("Bacacay") == destination.equals("Santo Domingo")) {
            bactosto();
            Toast.makeText(getApplicationContext(), "sto domingo bacacay", Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(this, "Invalid input!", Toast.LENGTH_SHORT).show();
}

Answer 1

改变条件如下，在你的情况下，当你输入 Malilipot-Santo Domingo 根据第一个条件

if (origin.equals("Tabaco") == destination.equals("Malinao") && origin.equals("Malinao") == destination.equals("Tabaco"))

origin.equals("Tabaco") 是 false 并且 destination.equals("Malinao") 也是 false 然后 false == false 它变成 true 同样下一个条件

String origin = etOrigin.getText().toString();
        String destination = etDestination.getText().toString();
                if ((origin.equals("Tabaco") && destination.equals("Malinao")) ||( origin.equals("Malinao") == destination.equals("Tabaco"))) {
                ttom();
                Toast.makeText(getApplicationContext(), "tabaco malinao", Toast.LENGTH_SHORT).show();
            } else if ((origin.equals("Tabaco") && destination.equals("Bacacay")) || ( origin.equals("Bacacay") && destination.equals("Tabaco"))) {
                ttob();
                Toast.makeText(getApplicationContext(), "tabaco bacacay", Toast.LENGTH_SHORT).show();
            } else if ((origin.equals("Tabaco") && destination.equals("Santo Domingo")) ||( origin.equals("Santo Domingo") && destination.equals("Tabaco")) ){
                ttosto();
                Toast.makeText(getApplicationContext(), "tabaco sto domingo", Toast.LENGTH_SHORT).show();
            } else if ((origin.equals("Tabaco") && destination.equals("Malilipot") )||( origin.equals("Malilipot") && destination.equals("Tabaco"))) {
                ttomali();
                Toast.makeText(getApplicationContext(), "tabaco malilipot", Toast.LENGTH_SHORT).show();
            } else if ((origin.equals("Malilipot") && destination.equals("Santo Domingo") )||( origin.equals("Santo Domingo") && destination.equals("Malilipot"))){
                malitosto();
                Toast.makeText(getApplicationContext(), "malilipot sto domingo", Toast.LENGTH_SHORT).show();
            } else if ((origin.equals("Malilipot") && destination.equals("Bacacay")) ||( origin.equals("Bacacay") && destination.equals("Malilipot"))) {
                malitobac();
                Toast.makeText(getApplicationContext(), "malilipot bacacay", Toast.LENGTH_SHORT).show();
            } else if (origin.equals("Santo Domingo") && destination.equals("Bacacay") )||( origin.equals("Bacacay") && destination.equals("Santo Domingo"))) {
                bactosto();
                Toast.makeText(getApplicationContext(), "sto domingo bacacay", Toast.LENGTH_SHORT).show();
            } else {
                Toast.makeText(this, "Invalid input!", Toast.LENGTH_SHORT).show();
    }

Answer 2

逻辑错误，假设你有：

String origin = "Malilipot";

String destination = "Santo Domingo";

那么origin.equals("Tabaco")就是false destination.equals("Malinao") 也是 false .

因此 origin.equals("Tabaco") == destination.equals("Malinao") 产生 false == false 即 true，尽管它绝对不符合您认为的条件。

重构您的代码以仅使用 && (AND) 和 || (OR) 运算符：

if (origin.equals("Tabaco") == destination.equals("Malinao") && origin.equals("Malinao") == destination.equals("Tabaco"))

变成

if ((origin.equals("Tabaco") && destination.equals("Malinao")) || (origin.equals("Malinao") && destination.equals("Tabaco")))

Answer 3

这是第一种情况的解释...

String origin = "Malilipot";
    String destination = "Santo Domingo";
    if(origin.equals("Tabaco") == destination.equals("Malinao") && origin.equals("Malinao") == destination.equals("Tabaco"))

    origin.equals("Tabaco")  = false
    destination.equals("Malinao") = false
    origin.equals("Tabaco") == destination.equals("Malinao")
            false           ==      false 
            result will be  = true

    origin.equals("Malinao")  = false
    destination.equals("Tabaco") = false

    origin.equals("Malinao") == destination.equals("Tabaco")
                    false    ==       false

            result will be = true


    at your last condition will be if (true == true)
            it will be : true


    thats why its going in first condition

If else 条件和逻辑运算符

If else condition and logical operators

java

android

if-statement

logical-operators