AlertDialog中的幾個按鈕的一個OnClickListener

我正在創建一個模擬滾動不同類型的骰子的應用程序。所有的骰子都通過一個AlertDialog按鈕來選擇。我想爲其中的6個按鈕使用一個OnClickListener，但是當我嘗試設置該偵聽器時，eclipse會拋出NullPointerException。AlertDialog中的幾個按鈕的一個OnClickListener

package edu.elon.cs.diceroller; 


import android.app.Activity; 
import android.app.AlertDialog; 
import android.os.Bundle; 
import android.view.LayoutInflater; 
import android.view.Menu; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
import android.widget.ListView; 
import android.widget.TextView; 


public class RollMenuActivity extends Activity { 

    private int diceAmount; 
    private int diceSides; 
    private boolean sum; 

    private Button addDiceButton; 
    private Button rollDiceButton; 
    private ListView diceListView; 

    private Button oneButton; 
    private Button twoButton; 
    private Button threeButton; 
    private Button fourButton; 
    private Button fiveButton; 
    private Button sixButton; 

    private Button d4; 
    private Button d6; 
    private Button d8; 
    private Button d12; 
    private Button d20; 

    private Button sumButton; 
    private Button top3Button; 
    private Button trimButton; 
    private Button avgButton; 
    private Button hiLoButton; 
    private Button loHiButton; 

    private TextView displayQuantity; 
    private TextView displayType; 
    private TextView displayArrange; 

    private OnClickListener addDiceListener = new OnClickListener() { 

     @Override 
     public void onClick(View aArg0) { 

      AlertDialog.Builder alert = new AlertDialog.Builder(
        RollMenuActivity.this); 
      LayoutInflater factory = LayoutInflater 
        .from(RollMenuActivity.this); 
      View layout = factory.inflate(R.layout.dice_select, null); 
      alert.setView(layout); 


      alert.show(); 

     } 
    }; 
    private OnClickListener rollDiceListener = new OnClickListener() { 

     @Override 
     public void onClick(View aV) { 
      // TODO Auto-generated method stub 

     } 

    }; 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.activity_roll_menu, menu); 
     return true; 
    } 

    private OnClickListener quantityListener = new OnClickListener(){ 

     @Override 
     public void onClick(View v) { 
      Button aButton = (Button) v; 
      String buttonNumber = aButton.getText().toString(); 
      diceAmount = Integer.parseInt(buttonNumber.trim()); 
      displayQuantity.setText(buttonNumber); 

     } 

    }; 

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

     addDiceButton = (Button) findViewById(R.id.adddicebutton); 
     rollDiceButton = (Button) findViewById(R.id.rolldicebutton); 
     diceListView = (ListView) findViewById(R.id.dicelistview); 

     addDiceButton.setOnClickListener(addDiceListener); 
     rollDiceButton.setOnClickListener(rollDiceListener); 

     oneButton = (Button) findViewById(R.id.button1); 
     twoButton = (Button) findViewById(R.id.button2); 
     threeButton = (Button) findViewById(R.id.button3); 
     fourButton = (Button) findViewById(R.id.button4); 
     fiveButton = (Button) findViewById(R.id.button5); 
     sixButton = (Button) findViewById(R.id.button6); 

     oneButton.setOnClickListener(quantityListener); 
     twoButton.setOnClickListener(quantityListener); 
     threeButton.setOnClickListener(quantityListener); 
     fourButton.setOnClickListener(quantityListener); 
     fiveButton.setOnClickListener(quantityListener); 
     sixButton.setOnClickListener(quantityListener); 


     displayQuantity = (TextView) findViewById(R.id.displayquantity); 

    } 
} 


<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" 
    tools:context=".RollMenuActivity" > 

    <ListView 
     android:id="@+id/dicelistview" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:layout_above="@+id/adddicebutton" > 

    </ListView> 

    <Button 
     android:id="@+id/rolldicebutton" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:layout_alignParentBottom="true" 
     android:layout_centerHorizontal="true" 
     android:text="Press or Shake to Roll Dice" 
     tools:ignore="HardcodedText" /> 

    <Button 
     android:id="@+id/adddicebutton" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:layout_above="@+id/rolldicebutton" 
     android:layout_alignParentLeft="true" 
     android:text="Add a Dice" 
     tools:ignore="HardcodedText" /> 

</RelativeLayout> 

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:id="@+id/diceselectlayout" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:orientation="vertical" > 

    <LinearLayout 
     android:id="@+id/linearLayout2" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_centerHorizontal="true" 
     android:layout_marginTop="34dp" > 

     <Button 
      android:id="@+id/button1" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="1" /> 

     <Button 
      android:id="@+id/buttond4" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="d4" /> 

     <Button 
      android:id="@+id/buttonsum" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text=" Sum " /> 
    </LinearLayout> 

    <LinearLayout 
     android:id="@+id/linearLayout1" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_below="@+id/linearLayout5" 
     android:layout_centerHorizontal="true" > 

     <Button 
      android:id="@+id/button5" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="5" /> 

     <Button 
      android:id="@+id/buttond20" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="d20" /> 

     <Button 
      android:id="@+id/buttonhilo" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="Hi-Lo" /> 
    </LinearLayout> 

    <TextView 
     android:id="@+id/textView2" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignParentTop="true" 
     android:layout_centerHorizontal="true" 
     android:text="Type" 
     android:textAppearance="?android:attr/textAppearanceMedium" /> 

    <TextView 
     android:id="@+id/textView1" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignLeft="@+id/linearLayout2" 
     android:layout_alignParentTop="true" 
     android:text="Quantity" 
     android:textAppearance="?android:attr/textAppearanceMedium" /> 

    <TextView 
     android:id="@+id/textView3" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignParentTop="true" 
     android:layout_alignRight="@+id/linearLayout2" 
     android:text="Arrange" 
     android:textAppearance="?android:attr/textAppearanceMedium" /> 

    <LinearLayout 
     android:id="@+id/linearLayout3" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignLeft="@+id/linearLayout2" 
     android:layout_below="@+id/linearLayout2" > 

     <Button 
      android:id="@+id/button2" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="2" /> 

     <Button 
      android:id="@+id/buttond6" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="d6" /> 

     <Button 
      android:id="@+id/buttontop3" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="Top 3" /> 
    </LinearLayout> 

    <LinearLayout 
     android:id="@+id/linearLayout4" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignLeft="@+id/linearLayout3" 
     android:layout_below="@+id/linearLayout3" > 

     <Button 
      android:id="@+id/button3" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="3" /> 

     <Button 
      android:id="@+id/buttond8" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="d8" /> 

     <Button 
      android:id="@+id/buttontrim" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="Trim " /> 
    </LinearLayout> 

    <LinearLayout 
     android:id="@+id/linearLayout5" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignLeft="@+id/linearLayout4" 
     android:layout_below="@+id/linearLayout4" > 

     <Button 
      android:id="@+id/button4" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="4" /> 

     <Button 
      android:id="@+id/buttond12" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="d12" /> 

     <Button 
      android:id="@+id/buttonavg" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text=" Avg. " /> 
    </LinearLayout> 

    <LinearLayout 
     android:id="@+id/linearLayout6" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_below="@+id/linearLayout1" 
     android:layout_centerHorizontal="true" > 

     <Button 
      android:id="@+id/button6" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="6" /> 

     <Button 
      android:id="@+id/button17" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text=" " /> 

     <Button 
      android:id="@+id/buttonlohi" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="Lo-Hi" /> 
    </LinearLayout> 

    <TextView 
     android:id="@+id/displayquantity" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignLeft="@+id/linearLayout5" 
     android:layout_below="@+id/linearLayout6" 
     android:layout_marginTop="17dp" 
     android:text=" " 
     android:textAppearance="?android:attr/textAppearanceMedium" /> 

    <TextView 
     android:id="@+id/displaytype" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignBottom="@+id/textView4" 
     android:layout_centerHorizontal="true" 
     android:text=" " 
     android:textAppearance="?android:attr/textAppearanceMedium" /> 

    <TextView 
     android:id="@+id/displayarrange" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignBaseline="@+id/textView5" 
     android:layout_alignBottom="@+id/textView5" 
     android:layout_alignRight="@+id/linearLayout2" 
     android:text=" " 
     android:textAppearance="?android:attr/textAppearanceMedium" /> 

</RelativeLayout>

來源

2013-05-19 user2399111

你在哪裏設置你的按鈕的onClick偵聽器在警報對話框..？ – Pragnani

你能顯示你得到的錯誤嗎？代碼中發生了什麼？ – EyalBellisha

如果沒有找到id，則docs指出findViewById返回null。我的猜測是一個（或多個）你的標籤不在AlertDialog上。發佈你的layout.xml和你的logcat ... http：//developer.android.com/reference/android/app/Activity.html#findViewById（int） – DigCamara

而不是創建持有實現OnClickListener和覆蓋OnClick方法OnClickListener實施，使用類的實例變量。

在onCreate分配對象的新實例的按鈕

了Android SDK的工作實例化onCreate在你的對象，而不是依賴於類的創建過程中實例化他們時，這是更好的做法。

編輯：我也修復了你的方法Integer.parseInteger。如果無法解析它，則拋出異常。

// Create Classes that implement OnClickListener 

private class OnAddDiceListener implements OnClickListener 
{ 
    public void onClick(View v) 
    { 
     LayoutInflater inflater = LayoutInflater.from(v.getContext()); 

     View layout = inflater.inflate(R.layout.dice_select, null); 

     Builder builder = new Builder(v.getContext()); 
     builder.setView(layout); 

     AlertDialog alert = builder.create(); 
     alert.show(); 
    } 
} 

private class OnRollDiceListener implements OnClickListener 
{ 
    public void onClick(View v) 
    { 

    } 
} 

private class OnQuantityListener implements OnClickListener 
{ 
    public void onClick(View v) 
    { 
     Button button = (Button) v; 

     try 
     { 
      diceAmount = Integer.parseInt(button.getText().toString()); 
     } 
     catch(NumberFormatException e) 
     { 
      diceAmount = 0; 
      e.printStackTrace(); 
     } 

     displayQuantity.setText(diceAmount); 
    } 
} 

@Override 
public boolean onCreateOptionsMenu(Menu menu) 
{ 
    // Inflate the menu; this adds items to the action bar if it is present. 
    getMenuInflater().inflate(R.menu.activity_roll_menu, menu); 
    return true; 
} 

@Override 
protected void onCreate(Bundle savedInstanceState) 
{ 
    super.onCreate(savedInstanceState); 

    setContentView(R.layout.activity_roll_menu); 

    addDiceButton = (Button) findViewById(R.id.adddicebutton); 
    rollDiceButton = (Button) findViewById(R.id.rolldicebutton); 
    diceListView = (ListView) findViewById(R.id.dicelistview); 

    // Since this is the onCreate method, instantiate the Listeners for the buttons 
    addDiceButton.setOnClickListener(new OnAddDiceListener()); 
    rollDiceButton.setOnClickListener(new OnRollDiceListener()); 

    oneButton = (Button) findViewById(R.id.button1); 
    twoButton = (Button) findViewById(R.id.button2); 
    threeButton = (Button) findViewById(R.id.button3); 
    fourButton = (Button) findViewById(R.id.button4); 
    fiveButton = (Button) findViewById(R.id.button5); 
    sixButton = (Button) findViewById(R.id.button6); 

    // Instantiate the OnQuantityListener 
    oneButton.setOnClickListener(new OnQuantityListener()); 
    twoButton.setOnClickListener(new OnQuantityListener()); 
    threeButton.setOnClickListener(new OnQuantityListener()); 
    fourButton.setOnClickListener(new OnQuantityListener()); 
    fiveButton.setOnClickListener(new OnQuantityListener()); 
    sixButton.setOnClickListener(new OnQuantityListener()); 

    displayQuantity = (TextView) findViewById(R.id.displayquantity); 
}

來源

2013-05-19 15:30:58 mrres1

AlertDialog中的幾個按鈕的一個OnClickListener

回答

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