【发布时间】：2017-10-23 18:22:37
【问题描述】：
每当我在设备上运行应用程序时单击增量按钮，我的应用程序就会意外强制 这是我的 activity_main.xml 代码
<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_height="match_parent"
android:layout_width="match_parent"
tools:context=".MainActivity"
>
<RelativeLayout
android:padding="20dp"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:orientation="vertical"
android:gravity="center_vertical"
>
<EditText
android:id="@+id/name_text_field"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Name"
android:inputType="textCapWords"
></EditText>
<TextView
android:layout_centerVertical="true"
android:id="@+id/heading1"
style="@style/HeaderTextStyle"
android:text="Toppings"
android:layout_below="@id/name_text_field"
/>
<CheckBox
android:layout_below="@id/heading1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/whipped_cream"
android:textSize="16sp"
android:paddingLeft="24dp"
android:layout_marginTop="20dp"
android:text="Whipped Cream"
/>
<CheckBox
android:layout_marginTop="20dp"
android:layout_below="@id/whipped_cream"
android:id="@+id/chocolate"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="chocolate"
android:textSize="16sp"
android:paddingLeft="24dp"
/>
<TextView
android:layout_below="@id/chocolate"
android:id="@+id/quantity_text_view"
style="@style/HeaderTextStyle"
android:text="Quantity"
android:layout_marginBottom="20dp"
/>
<Button
android:layout_below="@id/quantity_text_view"
android:id="@+id/decrement_button"
android:layout_width="48dp"
android:layout_height="48dp"
android:onClick="decrement"
android:text="-"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="48dp"
android:paddingLeft="10dp"
android:layout_below="@id/quantity_text_view"
android:paddingRight="10dp"
android:textSize="15sp"
android:layout_toRightOf="@id/decrement_button"
android:id="@+id/initial_qty"
android:gravity="center_vertical"
android:text="1"
/>
<Button
android:layout_toRightOf="@id/initial_qty"
android:layout_below="@id/quantity_text_view"
android:id="@+id/increment_button"
android:onClick="increment"
android:layout_width="48dp"
android:layout_height="48dp"
android:text="+"
/>
<Button
android:id="@+id/submit_button"
android:layout_marginTop="20dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="order"
android:onClick="submitOrder"
android:gravity="center_vertical"
android:layout_below="@id/decrement_button"
/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:gravity="center_vertical"
android:id="@+id/order_summary_text_view"
android:textAllCaps="true"
android:textStyle="bold"
android:textSize="16sp"
android:layout_below="@id/submit_button"
/>
</RelativeLayout>
</ScrollView>
这是我的 MainActivity.java 文件
package com.orton.birthdaycard;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.Editable;
import android.util.Log;
import android.view.View;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.TextView;
import java.text.NumberFormat;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
int quantity=1;
private void increment(View view)
{
if(quantity==100)
return;
else
quantity++;
displayQuantity(quantity);
}
private void decrement(View view)
{
if(quantity==1)
return;
else
quantity--;
displayQuantity(quantity);
}
private void displayQuantity(int qty)
{
TextView quantityTextView=(TextView) findViewById(R.id.initial_qty);
quantityTextView.setText(String.valueOf(quantity));
Log.v("MainActivity","the quantity is " + quantity);
}
int basePrice;
private int calculatePrice(boolean hasWhippedCream,boolean hasChocolate)
{
basePrice = 5;
if(hasWhippedCream==true)
basePrice += 1;
if(hasChocolate==true)
basePrice +=2 ;
return basePrice=basePrice*quantity;
}
String priceMessage="";
private void submitOrder(View view)
{
EditText nameField = (EditText) findViewById(R.id.name_text_field);
String name = nameField.getText().toString();
CheckBox whippedCream = (CheckBox) findViewById(R.id.whipped_cream);
boolean hasWhippedCream = whippedCream.isChecked();
CheckBox chocolate = (CheckBox) findViewById(R.id.chocolate);
boolean hasChocolate = chocolate.isChecked();
int price=calculatePrice(hasWhippedCream,hasChocolate);
String orderSummary=createOrderSummary(name,price,hasWhippedCream,hasChocolate);
displayMessage(orderSummary);
}
private void displayMessage(String orderSummary)
{
TextView summary= (TextView) findViewById(R.id.order_summary_text_view);
summary.setText(""+orderSummary);
}
private String createOrderSummary(String name, int price, boolean hasWhippedCream, boolean hasChocolate)
{
String priceMessage = "Name :" + name;
if(hasWhippedCream)
priceMessage += "\nWhipped Cream Added" ;
if(hasChocolate)
priceMessage += "\nChocolate Added" ;
priceMessage+="\nQuantity : "+quantity;
priceMessage+="\nTotal : $"+price;
priceMessage+="Thank You!" ;
return priceMessage;
}
}
这是调试报告 05-23 22:14:45.695 29736-29736/com.orton.birthdaycard E/AndroidRuntime: 致命例外: main 进程：com.orton.birthdaycard，PID：29736 java.lang.IllegalStateException：无法在父或祖先上下文中找到方法增量（视图），用于在视图类 android.support.v7.widget.AppCompatButton 上定义的 android:onClick 属性，id 为“increment_button” 在 android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:327) 在 android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:284) 在 android.view.View.performClick(View.java:5612) 在 android.view.View$PerformClick.run(View.java:22285) 在 android.os.Handler.handleCallback(Handler.java:751) 在 android.os.Handler.dispatchMessage(Handler.java:95) 在 android.os.Looper.loop(Looper.java:154) 在 android.app.ActivityThread.main(ActivityThread.java:6123) 在 java.lang.reflect.Method.invoke（本机方法） 在 com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867) 在 com.android.internal.os.ZygoteInit.main(ZygoteInit.java:757)
【问题讨论】：
-
为按钮点击声明的方法必须是公开的
标签： android