java - Android:点击按钮后应用程序崩溃

Question

我是 android 新手，我使用 Android Studio 2.2 进行编码，我正在尝试构建我的第一个应用程序，基本上该应用程序现在没有做太多事情，然后在向 onClick 添加价格方法之后方法，每当我单击按钮时，应用程序就会崩溃。

下面我提供了错误消息和我自己的代码。

我从 android studio 收到的错误消息是从 logcat View 复制的:

10-06 09:46:00.338 30789-30789/com.example.abdulkarim.justjava E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.abdulkarim.justjava, PID: 30789
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
at android.view.View.performClick(View.java:4660)
at android.view.View$PerformClick.run(View.java:19445)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5603)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
at dalvik.system.NativeStart.main(Native Method)

 Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:4660) 
at android.view.View$PerformClick.run(View.java:19445) 
at android.os.Handler.handleCallback(Handler.java:733) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:146) 
at android.app.ActivityThread.main(ActivityThread.java:5603) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:515) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099) 
at dalvik.system.NativeStart.main(Native Method) 

 Caused by: android.content.res.Resources$NotFoundException: String resource ID #0x2
at android.content.res.Resources.getText(Resources.java:1431)
at android.support.v7.widget.ResourcesWrapper.getText(ResourcesWrapper.java:52)
at android.widget.TextView.setText(TextView.java:4954)
at com.example.abdulkarim.justjava.MainActivity.display(MainActivity.java:33)
at com.example.abdulkarim.justjava.MainActivity.submit(MainActivity.java:24)
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:515) 
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) 
at android.view.View.performClick(View.java:4660) 
at android.view.View$PerformClick.run(View.java:19445) 
at android.os.Handler.handleCallback(Handler.java:733) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:146) 
at android.app.ActivityThread.main(ActivityThread.java:5603) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:515) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099) 
at dalvik.system.NativeStart.main(Native Method) 
10-06 09:47:13.823 30789-30789/? I/Process: Sending signal. PID: 30789 SIG: 9

这是我的 MainActivity.java 代码

package com.example.abdulkarim.justjava;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
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);
    }

    /**
     * This method is called when the order button is clicked.
     */
    public void submit(View view){
        int numberOfCoffees = 2;
        display(numberOfCoffees);
        displayPrice(numberOfCoffees * 10);
    }

    /**
     * This method displays the given quantity on the screen
     */
    private void display(int number){
        TextView quantityTextView = (TextView) findViewById(R.id.quantity_text_view);
        quantityTextView.setText(number);
    }

    /**
     * This method displays the given price on the screen
     */
    private void displayPrice(int number){
        TextView priceTextView = (TextView) findViewById(R.id.price_text_view);
        priceTextView.setText(NumberFormat.getCurrencyInstance().format(number));
    }
}

这是我的 main_activity.xml 布局代码

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context="com.example.abdulkarim.justjava.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Quantity"
        android:textAllCaps="true"
        android:textSize="16sp"
        android:textColor="@android:color/darker_gray"
        android:layout_marginBottom="16dp"/>
    <TextView
        android:id="@+id/quantity_text_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="0"
        android:textSize="16sp"
        android:textColor="@android:color/black"
        android:layout_marginBottom="16dp"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Price"
        android:textAllCaps="true"
        android:textSize="16sp"
        android:textColor="@android:color/darker_gray"
        android:layout_marginBottom="16dp"/>
    <TextView
        android:id="@+id/price_text_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="$0"
        android:textSize="16sp"
        android:textColor="@android:color/black"
        android:layout_marginBottom="16dp"/>
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Order"
        android:textAllCaps="true"
        android:textSize="16sp"
        android:onClick="submit"/>
</LinearLayout>

请帮我找出代码中的错误。

Answer 1

你不能直接给你的Textview设置整数。只允许使用字符串，因此更新您的方法，它将起作用:

 /**
     * This method displays the given quantity on the screen
     */
    private void display(int number){
        TextView quantityTextView = (TextView) findViewById(R.id.quantity_text_view);
        quantityTextView.setText(number+"");
    }

    /**
     * This method displays the given price on the screen
     */
    private void displayPrice(int number){
        TextView priceTextView = (TextView) findViewById(R.id.price_text_view);
        priceTextView.setText(NumberFormat.getCurrencyInstance().format(number)+"");
    }