Question

我正在尝试显示两个用户输入的结果 - 数字字段但是徒劳无功。它应该是实时发生的，即无需按任何按钮，结果应显示为字段数据更改，默认值为“零”。这里number1和number2是两个输入，grosstotal是number1 + number2的结果。请帮忙。

更新： 我已按照[@Jacky]的建议输入代码，但是一旦我尝试输入任何数字，app就会崩溃。尝试使用调试[从我在模拟器上进行数据输入的点]并且已经输入了它的结果，因为它可能有任何帮助。请帮助。

MainActivity：

package com.ck.cg;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

private EditText getnumber1;
private EditText getnumber2;
private TextView displaygrossTotal;


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

    getnumber1 = (EditText) findViewById(R.id.number1);
    getnumber2 = (EditText) findViewById(R.id.number2);
    displaygrossTotal = (TextView) findViewById(R.id.grossTotal);

    getQuantity.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
        }

        @Override
        public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
        }

        @Override
        public void afterTextChanged(Editable editable) {
            GetSum();
        }
    });

    getRate.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
        }

        @Override
        public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
        }

        @Override
        public void afterTextChanged(Editable editable) {
            GetSum();
        }
    });
}


private void GetSum() {
    int a = 0, b = 0, total;

    if (getnumber1.getText() != null && !getnumber1.getText().toString().equals("")) {
        try {
            a = Integer.parseInt(getnumber1.getText().toString());
        } catch (Exception e) {
            a = 0;
        }
    }

    if (getnumber2.getText() != null && !getnumber2.getText().toString().equals("")) {
        try {
            b = Integer.parseInt(getnumber2.getText().toString());
        } catch (Exception e) {
            b = 0;
        }
    }
    total = a + b;
    displaygrossTotal.setText(total);
}
}

xml：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.ck.cg.MainActivity">

<EditText
    android:id="@+id/number1"
    android:labelFor="@+id/number1"
    android:layout_width="90dp"
    android:layout_height="45dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:contentDescription="@string/number_1"
    android:ems="10"
    android:inputType="numberDecimal"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

<EditText
    android:id="@+id/number2"
    android:labelFor="@+id/number2"
    android:layout_width="90dp"
    android:layout_height="45dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:contentDescription="@string/number_2"
    android:ems="10"
    android:inputType="numberDecimal"
    app:layout_constraintStart_toEndOf="@+id/number1"
    app:layout_constraintTop_toTopOf="parent" />

<TextView
    android:id="@+id/grossTotal"
    android:layout_width="90dp"
    android:layout_height="45dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:contentDescription="@string/gross_total"
    app:layout_constraintStart_toEndOf="@+id/number2"
    app:layout_constraintTop_toTopOf="parent" />

<Button
    android:id="@+id/button"
    android:layout_width="50dp"
    android:layout_height="45dp"
    android:layout_marginEnd="8dp"
    android:layout_marginTop="8dp"
    android:text="+"
    android:textStyle="bold"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

调试：

W/ResourceType: No package identifier when getting value for resource number 0x00000001
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
              Process: com.ck.cg, PID: 6801
              android.content.res.Resources$NotFoundException: String resource ID #0x1
                  at android.content.res.Resources.getText(Resources.java:335)
                  at android.widget.TextView.setText(TextView.java:4555)
                  at com.ck.cg.MainActivity.GetSum(MainActivity.java:77)
                  at com.ck.cg.MainActivity.access$000(MainActivity.java:10)
                  at com.ck.cg.MainActivity$1.afterTextChanged(MainActivity.java:37)
                  at android.widget.TextView.sendAfterTextChanged(TextView.java:8203)
                  at android.widget.TextView$ChangeWatcher.afterTextChanged(TextView.java:10382)
                  at android.text.SpannableStringBuilder.sendAfterTextChanged(SpannableStringBuilder.java:1218)
                  at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:579)
                  at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:509)
                  at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:508)
                  at android.text.method.NumberKeyListener.onKeyDown(NumberKeyListener.java:121)
                  at android.widget.TextView.doKeyDown(TextView.java:6285)
                  at android.widget.TextView.onKeyDown(TextView.java:6075)
                  at android.view.KeyEvent.dispatch(KeyEvent.java:2688)
                  at android.view.View.dispatchKeyEvent(View.java:9960)
                  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1630)
                  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1630)
                  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1630)
                  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1630)
                  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1630)
                  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1630)
                  at com.android.internal.policy.DecorView.superDispatchKeyEvent(DecorView.java:405)
                  at com.android.internal.policy.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1798)
                  at android.app.Activity.dispatchKeyEvent(Activity.java:3021)
                  at android.support.v7.app.AppCompatActivity.dispatchKeyEvent(AppCompatActivity.java:534)
                  at android.support.v7.view.WindowCallbackWrapper.dispatchKeyEvent(WindowCallbackWrapper.java:58)
                  at android.support.v7.app.AppCompatDelegateImplBase$AppCompatWindowCallbackBase.dispatchKeyEvent(AppCompatDelegateImplBase.java:316)
                  at com.android.internal.policy.DecorView.dispatchKeyEvent(DecorView.java:319)
                  at android.view.ViewRootImpl$ViewPostImeInputStage.processKeyEvent(ViewRootImpl.java:4331)
                  at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4302)
                  at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3853)
                  at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3906)
                  at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3872)
                  at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3999)
                  at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3880)
                  at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4056)
                  at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3853)
                  at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3906)
                  at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3872)
                  at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3880)
                  at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3853)
                  at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:6246)
                  at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:6220)
                  at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:6181)
                  at android.view.ViewRootImpl$ViewRootHandler.handleMessage(ViewRootImpl.java:3651)
                  at android.os.Handler.dispatchMessage(Handler.java:102)
                  at android.os.Looper.loop(Looper.java:154)
                  at android.app.ActivityThread.main(ActivityThread.java:6119)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

Answer 1

对于之前的帖子感到抱歉，因为它会给你带来很多麻烦。经过审核，我不知道为什么我会给你TextWatcher给你答案，给你带来很多麻烦。这是MainActivity，简单OnClickListener：

    private EditText getnumber1;
    private EditText getnumber2;
    private TextView displaygrossTotal;
    private Button button;

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

        getnumber1 = (EditText) findViewById(R.id.number1);
        getnumber2 = (EditText) findViewById(R.id.number2);
        displaygrossTotal = (TextView) findViewById(R.id.grossTotal);
        button = (Button) findViewById(R.id.button);

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                int a = 0, b = 0, total;
                if (getnumber1.getText() != null && !getnumber1.getText().toString().equals("")) {
                    try {
                        a = Integer.parseInt(getnumber1.getText().toString());
                    } catch (Exception e) {
                        a = 0;
                    }
                }

                if (getnumber2.getText() != null && !getnumber2.getText().toString().equals("")) {
                    try {
                        b = Integer.parseInt(getnumber2.getText().toString());
                    } catch (Exception e) {
                        b = 0;
                    }
                }
                total = a + b;
                displaygrossTotal.setText(String.valueOf(total));
            }
        });
    }

在Android中实时显示用户输入的结果

1 个答案: