Question

是的，所以我的问题是我有18个微调器包含43个选项供用户选择。我希望每个选项都能更改不同页面上的链接，以便用户查看有关该选项的pdf。我有共享首选项来分享选择，我现在正在实现我的if / else if语句，但如果我使用if / else语句，我将为每个微调器最终得到43，然后每个微调器为43最后我需要实现700多条if语句，并且必须有一种更简单的方法来实现我不知道的想法。这是一个代码示例：

if (spinnerValue == 1)
    {
        TextView textView =(TextView)findViewById(R.id.textViewWeb1);
        textView.setClickable(true);
        textView.setMovementMethod(LinkMovementMethod.getInstance());
        String text = "<a href='http://qualifications.pearson.com/content/dam/pdf/BTEC-Nationals/Information-Technology/2010/Specification/Unit-1-Communication-and-Employability-Skills-for-IT.pdf'>Unit 1: Communication and Employability Skills for IT</a>";
        textView.setText(Html.fromHtml(text));
    }
    else if (spinnerValue == 2){
        TextView textView =(TextView)findViewById(R.id.textViewWeb1);
        textView.setClickable(true);
        textView.setMovementMethod(LinkMovementMethod.getInstance());
        String text = "<a href='http://qualifications.pearson.com/content/dam/pdf/BTEC-Nationals/Information-Technology/2010/Specification/Unit-2-Computer-Systems.pdf'>Unit 2: Computer Systems</a>";
        textView.setText(Html.fromHtml(text));
    }
    else if (spinnerValue == 3){
        TextView textView =(TextView)findViewById(R.id.textViewWeb1);
        textView.setClickable(true);
        textView.setMovementMethod(LinkMovementMethod.getInstance());
        String text = "<a href='http://qualifications.pearson.com/content/dam/pdf/BTEC-Nationals/Information-Technology/2010/Specification/Unit-3-Information-Systems.pdf'>Unit 3: Information Systems</a>";
        textView.setText(Html.fromHtml(text));
    }

所以在这结束时，将有43个if（spinnervalue == 1到43）和18个微调器值。我是java和android工作室的新手，所以任何帮助或指导或许对此进行解释都非常感激。

编辑：我的if语句可以工作，但也可以切换，但我仍然需要实现43次if / switch语句18次。有什么办法我可以做一些事情 - 如果（spinnervalue 1到18 == 1） - 那么这将允许我写一次43个案例并让它适用于所有微调器值（1 - 18）

Answer 1

以下是我对此的第一个想法：

String[] fileNames = new String[] {
 //Put your filenames here in order
}

然后在你当前的代码中：

if(spinnerValue<=fileNames.length) { //Make sure the value is valid
    TextView textView =(TextView)findViewById(R.id.textViewWeb1);
    textView.setClickable(true);
    textView.setMovementMethod(LinkMovementMethod.getInstance());
    String text = "<a href='http://qualifications.pearson.com/content/dam/pdf/BTEC-Nationals/Information-Technology/2010/Specification/"+fileNames[spinnerValue-1]+".pdf'>"+fileNames[spinnerValue-1].replaceAll("-"," ")+"</a>";
    textView.setText(Html.fromHtml(text));
}

不确定这是否是最有效的方式，但请尝试考虑如何动态设置html。

Answer 2

由于唯一的区别是字符串，并且您使用的是连续值1-43，因此最简单的是文本数组。

请记住，数组是从零开始的。

private static final String[] SPINNER_TEXTS = {
    /*1*/"<a href='http://qualifications.pearson.com/content/dam/pdf/BTEC-Nationals/Information-Technology/2010/Specification/Unit-1-Communication-and-Employability-Skills-for-IT.pdf'>Unit 1: Communication and Employability Skills for IT</a>",
    /*2*/"<a href='http://qualifications.pearson.com/content/dam/pdf/BTEC-Nationals/Information-Technology/2010/Specification/Unit-2-Computer-Systems.pdf'>Unit 2: Computer Systems</a>",
    /*3*/"<a href='http://qualifications.pearson.com/content/dam/pdf/BTEC-Nationals/Information-Technology/2010/Specification/Unit-3-Information-Systems.pdf'>Unit 3: Information Systems</a>"
};

TextView textView =(TextView)findViewById(R.id.textViewWeb1);
textView.setClickable(true);
textView.setMovementMethod(LinkMovementMethod.getInstance());
textView.setText(Html.fromHtml(SPINNER_TEXTS[spinnerValue - 1]));

Answer 3

很多都可以重构 - 例如

    TextView textView =(TextView)findViewById(R.id.textViewWeb1);
    textView.setClickable(true);
    textView.setMovementMethod(LinkMovementMethod.getInstance());
    String text = "";
    switch(spinnerValue) {
        case 1:
            text = "<a href='http://qualifications.pearson.com/content/dam/pdf/BTEC-Nationals/Information-Technology/2010/Specification/Unit-1-Communication-and-Employability-Skills-for-IT.pdf'>Unit 1: Communication and Employability Skills for IT</a>";
            break;
        case 2:
            text = "<a href='http://qualifications.pearson.com/content/dam/pdf/BTEC-Nationals/Information-Technology/2010/Specification/Unit-2-Computer-Systems.pdf'>Unit 2: Computer Systems</a>";
            break;
    }
    textView.setText(Html.fromHtml(text));

但我并不相信这是最好的方法。我可能会创建一个地图（或一个数组，因为它只是键的数值）的微调值 - ＆gt; URL并使用它来填充链接。需要更少的代码行，并且将来可以扩展更多！

Answer 4

您可以创建这样的映射表：

    Map<Integer, String> spinnerValueToLinkMapping = new HashMap<Integer, String> {{
        put(1, "<a href='http://qualifications.pearson.com/content/dam/pdf/BTEC-Nationals/Information-Technology/2010/Specification/Unit-1-Communication-and-Employability-Skills-for-IT.pdf'>Unit 1: Communication and Employability Skills for IT</a>");
        put(2, "<a href='http://qualifications.pearson.com/content/dam/pdf/BTEC-Nationals/Information-Technology/2010/Specification/Unit-2-Computer-Systems.pdf'>Unit 2: Computer Systems</a>");
        put(3, "<a href='http://qualifications.pearson.com/content/dam/pdf/BTEC-Nationals/Information-Technology/2010/Specification/Unit-3-Information-Systems.pdf'>Unit 3: Information Systems</a>");
    }}

然后使用以下代码检索所需的链接：

    TextView textView =(TextView)findViewById(R.id.textViewWeb1);
        textView.setClickable(true);
        textView.setMovementMethod(LinkMovementMethod.getInstance());
        String text = spinnerValueToLinkMapping.get(spinnerValue);
        textView.setText(Html.fromHtml(text));

有了这个，你最终会得到易于支持的映射表和DRY代码

为同一件事做多个if语句的简单方法

4 个答案: