android edittext addchangelistener

Question

我有一个应用程序要求用户输入他/她吃的量。我使用的输入字段是EditText。我想要发生的是当编辑文本发生变化时，它应该计算（即将金额乘以卡路里，如2面包量等于8卡路里。所以答案应该是16卡路里。）

但我无法让它发挥作用。请看看我尝试过的内容：

更新：

public class Bread_White extends Activity implements OnClickListener, OnItemSelectedListener {

Spinner sp;
Button calories, save, back, home;
String selected, strCalories;
TextView tv;
EditText etAmount;

int total;

RadioGroup rgMeal;
//RadioButton breakfast, ms, lunch, as, dinner, es;

String[] classes = {
        "Cornbread",
        "French Bread",
        "French Toast",
        "French Toast, low fat",
        "Italian Bread",
        "Wheat Bread",
        "Wheat Bread, low calories",
        "Wheat Bread, whole wheat"
};

//put how much calorie each food item has in this array
int[] intCalories = {188, 185, 126, 149, 81, 66, 46, 89};

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.food_vegetable);

    initControls();

}

private void initControls() {
    // TODO Auto-generated method stub

    // RadioGroup 
    rgMeal = (RadioGroup) findViewById (R.id.rgSelectMeal);

    sp = (Spinner) findViewById (R.id.spFoodVegetable);
    save = (Button) findViewById (R.id.btFoodVegetableSave);
    calories = (Button) findViewById (R.id.btFoodVegetableCalories);
    back = (Button) findViewById (R.id.tabs_back);
    home = (Button) findViewById (R.id.tabs_home);
    tv = (TextView) findViewById (R.id.txtMenuHeader);
    etAmount = (EditText) findViewById (R.id.etAmount);
    tv.setText(R.string.whitebread);

    ArrayAdapter<String> array =
            new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, classes);
    sp.setAdapter(array);
    sp.setOnItemSelectedListener(this);

    back.setOnClickListener(this);
    home.setOnClickListener(this);
    save.setOnClickListener(this);

}

public void onClick(View v) {
    // TODO Auto-generated method stub

    switch( v.getId() ){
    case R.id.btFoodVegetableSave:
        String mealname = selected;

        String serving = calories.getText().toString();
        int i = Integer.parseInt(serving.replaceAll("[\\D]", ""));

        //int amount = Integer.valueOf(etAmount.getText().toString());
        //int answer  = amount * i;
        String strAnswer = String.valueOf(i);
        //calories.setText(strAnswer);

        SimpleDateFormat sdf = new SimpleDateFormat("MM-dd-yyyy");
        String strDate = sdf.format(new Date());

        if ( ( mealname.isEmpty() || strAnswer.isEmpty() ) ){

            // call for custom toast
            viewErrorToast();
        }

        else {

        boolean didItWork = true;

        try{

            int checkedRadioButton = rgMeal.getCheckedRadioButtonId();

            switch( checkedRadioButton ){
            case R.id.rbBreakfast:
                BreakFastLog bfLog = new BreakFastLog(Bread_White.this);
                bfLog.open();
                bfLog.createEntry(mealname, strAnswer, strDate);
                bfLog.close();
                break;
            case R.id.rbMorningSnack:
                MorningSnackLog msLog = new MorningSnackLog(Bread_White.this);
                msLog.open();
                msLog.createEntry(mealname, strAnswer, strDate);
                msLog.close();
                break;
            case R.id.rbLunch:
                LunchLog lunchLog = new LunchLog(Bread_White.this);
                lunchLog.open();
                lunchLog.createEntry(mealname, strAnswer, strDate);
                lunchLog.close();
                break;
            case R.id.rbAfternoonSnack:
                AfternoonSnackLog asLog = new AfternoonSnackLog(Bread_White.this);
                asLog.open();
                asLog.createEntry(mealname, strAnswer, strDate);
                asLog.close();
                break;
            case R.id.rbDinner:
                DinnerLog dinnerLog = new DinnerLog(Bread_White.this);
                dinnerLog.open();
                dinnerLog.createEntry(mealname, strAnswer, strDate);
                dinnerLog.close();
                break;
            case R.id.rbEveningSnack:
                EveningSnackLog esLog = new EveningSnackLog(Bread_White.this);
                esLog.open();
                esLog.createEntry(mealname, strAnswer, strDate);
                esLog.close();
                break;
            }


            }
            catch(Exception e){
                didItWork = false;
                viewErrorToast();
            }finally{
                if (didItWork){
                    viewBMRSavedToast();
                }

            }
        } // end of if else statement
        break;
    case R.id.tabs_back:
        finish();
        break;
    case R.id.tabs_home:
        Intent home = new Intent(this, IHealthFirstActivity.class);
        home.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        startActivity(home); 
        break;
    }
}

private void viewBMRSavedToast() {
    // TODO Auto-generated method stub
    Toast.makeText(getBaseContext(), "Successful", Toast.LENGTH_SHORT).show();
}

private void viewErrorToast() {
    // TODO Auto-generated method stub
    Toast.makeText(getBaseContext(), "Error", Toast.LENGTH_SHORT).show();
}

public void onItemSelected(AdapterView<?> parent, View arg1, int position,
        long arg3) {
    // TODO Auto-generated method stub
    selected = parent.getItemAtPosition(position).toString();


    int amount = Integer.valueOf(etAmount.getText().toString());
    total = amount * intCalories[position];
    calories.setText(strCalories);

    TextWatcher watcher = new TextWatcher(){
        public void afterTextChanged(Editable s) {
            //your business logic after text is changed
             strCalories = total + " calories";
             calories.setText(strCalories);
        }
        public void beforeTextChanged(CharSequence s, int start, int count, int after){
            //your business logic before text is changed
        }

        public void onTextChanged(CharSequence s, int start, int before, int count){
            //your business logic while text has changed
        }
    };

    etAmount.addTextChangedListener(watcher);



}

public void onNothingSelected(AdapterView<?> arg0) {
    // TODO Auto-generated method stub

}

}

请帮忙解决这个问题。感谢。

Answer 1

卡路里视图定义在哪里？你也许想做最后的决定。你能改一下这个问题吗？我无法找到这个问题：）

Answer 2

将 selectedPos 声明为类级别变量

int selectedPos = 0;

public void afterTextChanged(Editable s) {
        //your business logic after text is changed

         int cal = intCalories[selectedPos];
         total = (Integer.parseInt(s.toString)) * cal;

         calories.setText(total + " calories");
    }

在定义的变量中设置微调器的选定位置。

快乐编码：）