Question

我有一个地图对象，键/值定义为美国州/首都（例如德克萨斯/奥斯汀）

当用户键入状态时我需要返回Capital，当用户输入类型时，我会返回状态

我编写了以下代码，但它仅适用于Capital - ＆gt;国家比较。

对于什么是错误的任何想法？

public class StatesCapitals extends AppCompatActivity {

    Map<String, String> capitals = new HashMap<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_states_capitals);

        String text = "US_states"; //text file in the assets folder

        byte[] buffer = null;

        InputStream is;
        try {
            is = getAssets().open(text);
            int size = is.available(); //size of the file in bytes
            buffer = new byte[size]; //declare the size of the byte array with size of the file
            is.read(buffer); //read file
            is.close(); //close file

        } catch (IOException e) {
            e.printStackTrace();

        }

        // Store text file data in the string variable
        String str_data = new String(buffer);

        //Split using the delimiter ":" to the all elements
        String[] stateCapsArray = str_data.split(":");
        //Iterate over the array
        for(int i=0;i<stateCapsArray.length-1;i++) {
            //Skip each other element as we are collecting 2 elements at a time
            if(i%2 == 0) {
                String state = stateCapsArray[i];
                String capital = stateCapsArray[i+1];
                capitals.put(state, capital);
            }
        }

Toast.makeText(getBaseContext(), capitals.toString(), Toast.LENGTH_LONG).show();

    }

    public void doit(View v)
    {
        TextView result=(TextView)findViewById(R.id.textViewResult);
        EditText et=(EditText)findViewById(R.id.editText);
        String input=et.getText().toString();
        Toast.makeText(getBaseContext(), "Input: "+input, Toast.LENGTH_LONG).show();

        Iterator entries = capitals.entrySet().iterator();
        while (entries.hasNext()) {
            Map.Entry entry = (Map.Entry) entries.next();
            String key = (String)entry.getKey();
            String value = (String)entry.getValue();
            if (input.equals(key))
            {result.setText("The Capital of "+key+" is: "+value);}
            else if (input.equals(value)) {result.setText("The State of: "+value+" is: "+key);}
        }

    }

}

Answer 1

看起来问题出在循环中：

str_data

如果state1:capital1:state2:capital2:state3:...包含for (int i = 0; i < stateCapsArray.length; i += 2) { String state = stateCapsArray[i]; String capital = stateCapsArray[i+1]; capitals.put(state, capital); }之类的信息，那么您的循环应该遍历它：

主要变化是2在每次迭代时都会DB[:school_districts].select(:code).group_and_count(:code).reverse_order(:count)前进。

在Map对象中查找键/值并返回相应的值/键

1 个答案: