Android Studio运行时错误（按钮）
[英]Runtime Error with Android Studio (Button)
问题描述
I would be so, so grateful if you can help me with this problem. 
如果您能帮助我解决这个问题，我将非常感激。
I am learning android development with Android Basics on Udacity. 我正在使用Udacity上的Android Basics学习android开发。 I am at User Input: Lesson 8. The apps have been downloading to my phone fine so far but now the app (JustJava) crashes when I press the only button in it. 我在用户输入中：第8课。到目前为止，应用程序可以很好地下载到我的手机上，但是现在当我按其中的唯一按钮时，该应用程序（JustJava）崩溃了。 There are no serious (red) errors showing on Android Studio. Android Studio上没有显示严重（红色）错误。
I have reviewed logcat but cannot understand it except that the button (onClick) is the problem. 我已经查看了logcat，但除了按钮（onClick）是问题之外，无法理解它。 I have no idea how to fix it. 我不知道如何解决它。
This keeps appearing in red in logcat every few seconds: E/TZ_CCM_SERVER: Only 'CCM' are supported 这会每隔几秒钟在logcat中始终显示为红色：E / TZ_CCM_SERVER：仅支持“ CCM”
Here is the full error log relating my runtime crash: 这是有关我的运行时崩溃的完整错误日志：
07-09 10:51:17.638 18253-18253/com.example.android.justjava E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.android.justjava, PID: 18253 java.lang.IllegalStateException: Could not execute method for android:onClick at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:389) at android.view.View.performClick(View.java:5697) at android.widget.TextView.performClick(TextView.java:10826) at android.view.View$PerformClick.run(View.java:22526) at android.os.Handler.handleCallback(Handler.java:739) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:158) at android.app.ActivityThread.main(ActivityThread.java:7224) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120) Caused by: java.lang.reflect.InvocationTargetException at java.lang.reflect.Metho
EDIT: MainActivity / java code: 编辑：MainActivity / Java代码：
package com.example.android.justjava;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.TextView;
import java.text.NumberFormat;
/**
* This app displays an order form to order coffee.
*/
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 submitOrder(View view) {
int coffeeNumber = 3;
display(coffeeNumber);
displayPrice(coffeeNumber * 5);
}
/**
* This method displays the given quantity value 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));
}
}
XML Code: XML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:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="16dp"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:paddingTop="16dp"
android:orientation="vertical"
tools:context=".MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Quantity"
android:fontFamily="sans-serif-light"
android:textColor="@android:color/black"
android:padding="10dp"
android:textAllCaps="true"
android:layout_marginBottom="16dp"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="0"
android:textSize="16sp"
android:fontFamily="sans-serif-light"
android:textColor="@android:color/black"
android:padding="10dp"
android:id="@+id/quantity_text_view"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Price"
android:fontFamily="sans-serif-light"
android:textColor="@android:color/black"
android:padding="10dp"
android:textAllCaps="true"
android:layout_marginBottom="16dp"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="€0"
android:textSize="16sp"
android:fontFamily="sans-serif-light"
android:textColor="@android:color/black"
android:padding="10dp"
android:layout="@+id/price_text_view"
/>
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:text="Order"
android:onClick="submitOrder"
/>
</LinearLayout>
3 个解决方案
解决方案1
0 2018-07-09 10:10:39
I have just Called TextView in global, then initialized in onCreate and then using wherever we need. 我刚刚在全局中调用了TextView ，然后在onCreate进行了初始化，然后在需要的地方使用它。
Just replace this edited java class, 只需替换此已编辑的Java类，
public class MainActivity extends AppCompatActivity {
TextView priceTextView, quantityTextView ;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
quantityTextView = (TextView) findViewById(R.id.quantity_text_view);
priceTextView = (TextView) findViewById(R.id.price_text_view);
}
/**
* This method is called when the order button is clicked.
*/
public void submitOrder(View view) {
int coffeeNumber = 3;
display(coffeeNumber);
displayPrice(coffeeNumber * 5);
}
/**
* This method displays the given quantity value on the screen.
*/
private void display(int number) {
quantityTextView.setText("" + number);
}
/**
* This method displays the given price on the screen.
*/
private void displayPrice(int number) {
priceTextView.setText(NumberFormat.getCurrencyInstance().format(number));
}
}
解决方案2
0 2018-07-09 15:20:35
Check your activity_main.xml in this layout you does not have a TextView with that id price_text_view. 在此布局中检查您的activity_main.xml，您没有一个ID为price_text_view的TextView。 Just define a TextView with that id and your App will not crash anymore and you can go Forward to the next chapter ;) 只需使用该ID定义一个TextView，您的应用就不会崩溃，您可以继续下一章;）
<TextView
android:id="@+id/price_text_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
I think you just made a silly misstake. 我认为您只是犯了一个愚蠢的错误。 I saw you're using layout insteed of id ^^ 我看到您使用的是ID ^^的布局指示
解决方案3
0 2018-07-10 04:14:13
Change your xml like below 如下更改您的xml
<?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:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="16dp"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:paddingTop="16dp"
android:orientation="vertical"
tools:context=".MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Quantity"
android:fontFamily="sans-serif-light"
android:textColor="@android:color/black"
android:padding="10dp"
android:textAllCaps="true"
android:layout_marginBottom="16dp"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="0"
android:textSize="16sp"
android:fontFamily="sans-serif-light"
android:textColor="@android:color/black"
android:padding="10dp"
android:id="@+id/quantity_text_view"/>
<TextView
android:id="@+id/price_text_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Price"
android:fontFamily="sans-serif-light"
android:textColor="@android:color/black"
android:padding="10dp"
android:textAllCaps="true"
android:layout_marginBottom="16dp"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="€0"
android:textSize="16sp"
android:fontFamily="sans-serif-light"
android:textColor="@android:color/black"
android:padding="10dp"
android:layout="@+id/price_text_view"
/>
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:text="Order"
android:onClick="submitOrder"
/>
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