Question

我的问题类似于this，但在android中。我试图从EditText上获取输入，并在按钮单击时将最终结果显示到TextView中。

我在尝试适应这三个答案时遇到了麻烦，OP说这三个答案都奏效了。

如何从TextView中获取值，然后在TextView中显示结果？

以下方法似乎可行，但输出为000，我想是因为在arrayList中没有存储任何东西

input = (Edittext)findViewById(R.id.et_input);
output = (TextView)findViewById(R.id.tv_output);
    ArrayList<Integer> myList = new ArrayList<Integer>();
            Scanner val = new Scanner(System.in); //can't figure out how to get user input from editText
            int x = 0;
            for (int i = 0; i < 3; i++) {
                x = val.nextInt();
                myList.add(x);
            }
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
                myList.sort(null);
            }

            for (int i = myList.size() - 1; i >= 0; i--) {
                answer += myList.get(i).toString();
            }


            send.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    output.setText(answer);
                }
            });

Answer 1

您可能可以执行以下操作：

@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    // use textview to display the result
    output = (TextView)findViewByIf(R.id.textview1);
    // use a button to activate sorting once you have the edittexts filled
    sortNumbersButton = (Button)findViewById(R.id.button);
    // use EditText(s) to get values from user
    input = (EditText)findViewById(R.id.edittext1);
    // set a listener for a button so that we can activate sorting
    sortNumbersButton.setOnClickListener(
        new View.OnClickListener()
        {
            public void onClick(View view)
            {
                // use a string array to store string values from input
                string[] strings = input.getText().toString().split(" ");
                // use the editText getText() method to pull values from UI
                int[] intArray = new int[] {Integer.parseInt(strings[0]),
                    Integer.parseInt(strings[1]),
                    Integer.parseInt(strings[2])};
                // sort the values in the array in ascending order
                Arrays.sort(intArray);
                // use stringbuilder to append string values for output
                StringBuilder sb = new StringBuilder();
                // loop backwards since it sorts in ascending order
                for (int i = 2; i > -1; i--) {
                    sb.append(intArray[i]);
                }
                // set the textview value of the sorted integers! and done
                output.setText(sb.toString());
            }
        });
}

Answer 2

这可以解决问题

在EditText中添加数字，并在每个数字之间用“”（空格）

    send.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String[] digits = input.getText().toString().split(" ");
            ArrayList<Integer> digitArray = new ArrayList<>();
            for (String digit : digits) {
                if (TextUtils.isDigitsOnly(digit))
                    digitArray.add(Integer.parseInt(digit));
            }
            Collections.sort(digitArray);
            StringBuilder largestPossibleNumber = new StringBuilder();
            for (int i = digitArray.size(); i > 0; i--) {
                largestPossibleNumber.append(digitArray.get(i - 1));
            }
            output.setText(largestPossibleNumber.toString());
        }
    });

不需要

ArrayList<Integer> myList = new ArrayList<Integer>();
        Scanner val = new Scanner(System.in); //can't figure out how to get user input from editText
        int x = 0;
        for (int i = 0; i < 3; i++) {
            x = val.nextInt();
            myList.add(x);
        }
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            myList.sort(null);
        }

        for (int i = myList.size() - 1; i >= 0; i--) {
            answer += myList.get(i).toString();
        }

更新如果您不想使用任何分隔符，请使用以下代码

        send.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String enteredText = input.getText().toString();
            ArrayList<Integer> digitArray = new ArrayList<>();
            for(int i = 0 ; i< enteredText.length(); i++) {
                if (TextUtils.isDigitsOnly(String.valueOf(enteredText.charAt(i))))
                    digitArray.add(Integer.parseInt(String.valueOf(enteredText.charAt(i))));
            }
            Collections.sort(digitArray);
            StringBuilder largestPossibleNumber = new StringBuilder();
            for (int i = digitArray.size(); i > 0; i--) {
                largestPossibleNumber.append(digitArray.get(i - 1));
            }
            output.setText(largestPossibleNumber.toString());
        }
    });

打印给定数字中的最大数字

2 个答案: