無法啓動活動 - 二進制XML文件行，錯誤膨脹類

Question

我完全不熟悉Android，並在做家庭作業。我正在使用Android Studio 0.8.11。我試過搜索，但沒有找到合適的答案。

我會很感激任何幫助與破譯錯誤信息：

package com.mken.csd_homework5; 

import android.app.Activity; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.os.Bundle; 
import android.text.Layout; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.widget.TextView; 

import org.w3c.dom.Text; 


public class random_circles_activity extends Activity { 
    com.mken.csd_homework5.DrawView dv; 

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

DrawCircle.java

package com.mken.csd_homework5; 

import android.view.View; 
import android.content.Context; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.view.View; 

public class DrawCircle extends View 
{ 
    public DrawCircle(Context con) 
    { 
     super(con); 
    } 
} 

activity_random_circles_activity.xml

<RelativeLayout 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:paddingLeft="@dimen/activity_horizontal_margin" 
    android:paddingRight="@dimen/activity_horizontal_margin" 
    android:paddingTop="@dimen/activity_vertical_margin" 
    android:paddingBottom="@dimen/activity_vertical_margin" 
    tools:context=".random_circles_activity"> 

    <com.mken.csd_homework5.DrawCircle 
     android:id="@+id/dcCustom" 
     android:layout_width="fill_parent" 
     android:layout_height="wrap_content" 
    /> 

    <Button 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="New Button" 
     android:id="@+id/button" 
     android:layout_alignParentBottom="true" 
     android:layout_alignParentLeft="true" 
     android:layout_alignParentStart="true" /> 

    <Button 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="New Button" 
     android:id="@+id/button2" 
     android:layout_alignBottom="@+id/button" 
     android:layout_alignParentRight="true" 
     android:layout_alignParentEnd="true" /> 
</RelativeLayout> 

錯誤的logcat：

10-01 02:11:35.120: E/AndroidRuntime(2910): Process: com.mken.csd_homework5, PID: 2910 
10-01 02:11:35.120: E/AndroidRuntime(2910): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mken.csd_homework5/com.mken.csd_homework5.random_circles_activity}: android.view.InflateException: Binary XML file line #18: Error inflating class com.mken.csd_homework5.DrawCircle 
10-01 02:11:35.120: E/AndroidRuntime(2910): Caused by: android.view.InflateException: Binary XML file line #18: Error inflating class com.mken.csd_homework5.DrawCircle 
10-01 02:11:35.120: E/AndroidRuntime(2910): at com.mken.csd_homework5.random_circles_activity.onCreate(random_circles_activity.java:22) 

Answer 1

這可能不是答案，但我想向你展示一些代碼。我猜你需要在你的自定義DrawCircle類中設置屬性集的構造函數：

 public DrawCircle(Context context) 
    { 
     super(context); 

    } 
    public DrawCircle(Context context, AttributeSet attrs) 
    { 
     super(context, attrs); 

    } 
    public DrawCircle(Context context, AttributeSet attrs, int defStyle) { 
     super(context, attrs, defStyle); 

    }