TextWatcher计算

Question

        TextWatcher watch = new TextWatcher(){

            @Override
            public void afterTextChanged(Editable arg0) {
                // TODO Auto-generated method stub

            }

            @Override
            public void beforeTextChanged(CharSequence a, int arg1,
                    int arg2, int arg3) {
                // TODO Auto-generated method stub
                EditText et1 = (EditText)findViewById(arg1);
            final int before = Integer.parseInt(et1.getText().toString());

            }

            @Override
            public void onTextChanged(CharSequence a, int arg1,
                    int arg2, int arg3) {
                // TODO Auto-generated method stub

                    int id = 1000 + arg1;
                    EditText et2 = (EditText)findViewById(id);

                    int x = Integer.parseInt(a.toString());
                    int y = Integer.parseInt(et2.getText().toString());
                    int sum = (x / before) * y;



                }

我想根据编辑文本的前一个条目自动更新编辑文本，并将其显示在另一个编辑文本上。

例如,

我有两个编辑文本。一个用于calories，另一个用于grams。

如果我改变calories的值，grams也会相应地改变--

X是改变前的初始卡路里(在编辑文本1中)，y是改变时的卡路里(在编辑文本1中)，z是克值(在编辑文本2中)，

等式应该是：y/x * z

Answer 1

我想这会对你有帮助

package com.example.testandroid;

import android.app.Activity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.Menu;
import android.widget.EditText;

public class MainActivity extends Activity {

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

        EditText e1 = (EditText) findViewById(R.id.e1);
        final EditText e2 = (EditText) findViewById(R.id.e2);
        e1.addTextChangedListener(new TextWatcher() {

            @Override
            public void afterTextChanged(Editable s) {
                String value = s.toString();
                e2.setText(value);
            }

            @Override
            public void beforeTextChanged(CharSequence s, int start, int count,
                    int after) {

            }

            @Override
            public void onTextChanged(final CharSequence s, int start,
                    int before, int count) {

            }

        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

Answer 2

EditText ed1 = (EditText) findViewById(R.id.ed1);
    ed1.addTextChangedListener(new TextWatcher() {

        @Override
        public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {
            // TODO Auto-generated method stub

        }

        @Override
        public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
                int arg3) {
            // TODO Auto-generated method stub

        }

        @Override
        public void afterTextChanged(Editable ed) {

            EditText ed2 = (EditText) findViewById(R.id.ed2);
            ed2.setText(ed.toString());
        }
    });