NoSuchMethodException自定義搜索欄

Question

我創建了搜索欄類的擴展：

package com.simplemathgame; 

import android.content.Context; 
import android.widget.SeekBar; 
import android.widget.TextView; 

public class SeekBarPlus extends SeekBar { 
    private TextView numberOfDrills; 

    public SeekBarPlus(Context context) { 
     super(context); 
     // TODO Auto-generated constructor stub 
    } 

    public void onStartTrackingTouch(SeekBar seekBar) { 
     // TODO Auto-generated method stub 

    } 

    public void onStopTrackingTouch(SeekBar seekBar) { 
     // TODO Auto-generated method stub 

    } 

    public void onProgressChanged(SeekBar seekBar, int progress, 
      boolean fromUser) { 
     // TODO Auto-generated method stub 
     numberOfDrills.setText(progress); 
    } 

    public void setTextView(TextView textView){ 
     numberOfDrills = textView; 
    } 

} 

這裏是XML佈局文件：

<?xml version="1.0" encoding="utf-8"?> 
<TableLayout 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_height="fill_parent" 
    android:layout_width="fill_parent" 
    android:background="#000044"> 
    <TableRow 
     android:layout_marginTop="10dp" 
     android:gravity="center_vertical" > 
     <TextView 
      android:textColor="#FFFFFFFF" 
      android:textSize="16sp" 
      android:textStyle="bold" 
      android:text="Addition Drills:"/> 
    </TableRow> 
    <TableRow 
     android:layout_marginTop="5dp" 
     android:gravity="center_vertical" > 

     <com.simplemathgame.SeekBarPlus 
      android:id="@+id/add_seek_bar" 
      android:layout_width="20dp" 
      android:max="10" 
      android:layout_weight="0.8"/> 
     <TextView 
      android:id="@+id/add_drills_number" 
      android:textColor="#FFFFFFFF" 
      android:textSize="16sp" 
      android:textStyle="bold" 
      android:layout_weight="0.2" 
      android:gravity="center_horizontal" 
      android:text="0"/> 
    </TableRow> 
</TableLayout> 

這裏是logcat的：

12-19 19:52:48.457: D/dalvikvm(335): GC_EXTERNAL_ALLOC freed 46K, 53% free 2546K/5379K, external 1917K/2137K, paused 72ms 
12-19 19:52:51.617: D/AndroidRuntime(335): Shutting down VM 
12-19 19:52:51.617: W/dalvikvm(335): threadid=1: thread exiting with uncaught exception (group=0x40015560) 
12-19 19:52:51.647: E/AndroidRuntime(335): FATAL EXCEPTION: main 
12-19 19:52:51.647: E/AndroidRuntime(335): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.simplemathgame/com.simplemathgame.MainActivity}: android.view.InflateException: Binary XML file line #20: Error inflating class com.simplemathgame.SeekBarPlus 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647) 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.os.Handler.dispatchMessage(Handler.java:99) 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.os.Looper.loop(Looper.java:123) 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.app.ActivityThread.main(ActivityThread.java:3683) 
12-19 19:52:51.647: E/AndroidRuntime(335): at java.lang.reflect.Method.invokeNative(Native Method) 
12-19 19:52:51.647: E/AndroidRuntime(335): at java.lang.reflect.Method.invoke(Method.java:507) 
12-19 19:52:51.647: E/AndroidRuntime(335): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
12-19 19:52:51.647: E/AndroidRuntime(335): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
12-19 19:52:51.647: E/AndroidRuntime(335): at dalvik.system.NativeStart.main(Native Method) 
12-19 19:52:51.647: E/AndroidRuntime(335): Caused by: android.view.InflateException: Binary XML file line #20: Error inflating class com.simplemathgame.SeekBarPlus 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.view.LayoutInflater.createView(LayoutInflater.java:508) 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:570) 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.view.LayoutInflater.rInflate(LayoutInflater.java:623) 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.view.LayoutInflater.rInflate(LayoutInflater.java:626) 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.view.LayoutInflater.inflate(LayoutInflater.java:408) 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.view.LayoutInflater.inflate(LayoutInflater.java:320) 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.view.LayoutInflater.inflate(LayoutInflater.java:276) 
12-19 19:52:51.647: E/AndroidRuntime(335): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:207) 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.app.Activity.setContentView(Activity.java:1657) 
12-19 19:52:51.647: E/AndroidRuntime(335): at com.simplemathgame.MainActivity.onCreate(MainActivity.java:16) 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 
12-19 19:52:51.647: E/AndroidRuntime(335): ... 11 more 
12-19 19:52:51.647: E/AndroidRuntime(335): Caused by: java.lang.NoSuchMethodException: SeekBarPlus(Context,AttributeSet) 
12-19 19:52:51.647: E/AndroidRuntime(335): at java.lang.Class.getMatchingConstructor(Class.java:643) 
12-19 19:52:51.647: E/AndroidRuntime(335): at java.lang.Class.getConstructor(Class.java:472) 
12-19 19:52:51.647: E/AndroidRuntime(335): at android.view.LayoutInflater.createView(LayoutInflater.java:480) 
12-19 19:52:51.647: E/AndroidRuntime(335): ... 22 more 

我發現擴展的SeekBarPlus類有一個問題，但是不知道爲什麼。謝謝！

Answer 1

您尚未在自定義視圖類中指定完整的構造函數集。在你的特定情況下，SeekBarPlus(Context,AttributeSet)構造函數丟失。

自定義視圖類需要有這3個構造函數：

public SeekBarPlus(Context context) { 
    super(context); 
} 

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

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

如果您不需要它們，只需撥打super()如上圖所示。

Answer 2

你錯過了落實查看給出的另外兩個cunstructors：

// Constructor that is called when inflating a view from XML. 
View(Context context, AttributeSet attrs) 

// Perform inflation from XML and apply a class-specific base style. 
View(Context context, AttributeSet attrs, int defStyle)