Android.widget textView to android.widget.button

Question

저는 Android가 처음이에요. 그러나 나는 내가 굵은 글씨의 코드를 추가 할 때마다이 작은 응용 프로그램을 구축을 위해 노력하고있다 :

d = (Button) findViewById (R.id.tvDis); 

응용 프로그램 충돌 나는이 줄을 제거하면 모든 것이 잘 작동합니다. 나는 안드로이드 2.2 API 8 버전과 넥서스 에뮬레이터에서 이것을 실행 중이다.

package com.maximusstudios.numtowords; 

import android.os.Bundle; 
import android.app.Activity; 
import android.view.Menu; 
import android.view.View; 
import android.widget.Button; 
import android.widget.TextView; 


public class MainActivity extends Activity { 
/**Called when the activity is first created.*/ 
    int counter; 
    Button add, sub; 
    TextView d; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     counter = 0; 
     add = (Button) findViewById (R.id.bAdd); 
     **d = (Button) findViewById (R.id.tvDis);** 
     sub = (Button) findViewById(R.id.bSub); 
     add.setOnClickListener(new View.OnClickListener() { 

      @Override 
      public void onClick(View v) { 
       // TODO Auto-generated method stub 
       counter++; 

      } 
     }); 
sub.setOnClickListener(new View.OnClickListener() { 

      @Override 
      public void onClick(View v) { 
       // TODO Auto-generated method stub 
       counter--; 
      } 
     }); 

    } 

    @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_main, menu); 
     return true; 
    } 

} 

XML 코드 :

<?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:orientation="vertical" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    tools:context=".MainActivity" > 

    <TextView 
     android:layout_width="fill_parent" 
     android:layout_height="wrap_content" 
     android:text="Your Total is 0" 
     android:textSize="20dp" 
     android:layout_gravity="center" 
     android:gravity="center" 
     android:id="@+id/tvDis" 

     /> 

    <Button 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="Add one" 
     android:layout_gravity="center" 
     android:textSize="20dp" 
     android:id="@+id/bAdd" 
     /> 
    <Button 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="Add one" 
     android:layout_gravity="center" 
     android:textSize="20dp" 
     android:id="@+id/bSub" 
     /> 

</LinearLayout> 

오류 목록 :

02-10 18:00:21.452: D/AndroidRuntime(910): Shutting down VM 
02-10 18:00:21.452: W/dalvikvm(910): threadid=1: thread exiting with uncaught exception (group=0x4001d800) 
02-10 18:00:21.472: E/AndroidRuntime(910): FATAL EXCEPTION: main 
02-10 18:00:21.472: E/AndroidRuntime(910): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.maximusstudios.numtowords/com.maximusstudios.numtowords.MainActivity}: java.lang.ClassCastException: android.widget.TextView 
02-10 18:00:21.472: E/AndroidRuntime(910): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663) 
02-10 18:00:21.472: E/AndroidRuntime(910): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679) 
02-10 18:00:21.472: E/AndroidRuntime(910): at android.app.ActivityThread.access$2300(ActivityThread.java:125) 
02-10 18:00:21.472: E/AndroidRuntime(910): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033) 
02-10 18:00:21.472: E/AndroidRuntime(910): at android.os.Handler.dispatchMessage(Handler.java:99) 
02-10 18:00:21.472: E/AndroidRuntime(910): at android.os.Looper.loop(Looper.java:123) 
02-10 18:00:21.472: E/AndroidRuntime(910): at android.app.ActivityThread.main(ActivityThread.java:4627) 
02-10 18:00:21.472: E/AndroidRuntime(910): at java.lang.reflect.Method.invokeNative(Native Method) 
02-10 18:00:21.472: E/AndroidRuntime(910): at java.lang.reflect.Method.invoke(Method.java:521) 
02-10 18:00:21.472: E/AndroidRuntime(910): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
02-10 18:00:21.472: E/AndroidRuntime(910): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
02-10 18:00:21.472: E/AndroidRuntime(910): at dalvik.system.NativeStart.main(Native Method) 
02-10 18:00:21.472: E/AndroidRuntime(910): Caused by: java.lang.ClassCastException: android.widget.TextView 
02-10 18:00:21.472: E/AndroidRuntime(910): at com.maximusstudios.numtowords.MainActivity.onCreate(MainActivity.java:23) 
02-10 18:00:21.472: E/AndroidRuntime(910): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
02-10 18:00:21.472: E/AndroidRuntime(910): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627) 
02-10 18:00:21.472: E/AndroidRuntime(910): ... 11 more 

Answer 1

변경

d = (TextView) findViewById (R.id.tvDis); 

에 대한 귀하의 캐스팅이 잘못되었습니다. 코드를 사용하여 (Button)을 수행하면 findViewById()에 의해 반환되는 TextView을 Button으로 캐스팅하려고합니다. 호환되지 않는 형식으로 인해 작동하지 않습니다.

Answer 2

당신은 TextView로 D를 정의하고

d = (TextView) findViewById (R.id.tvDis); 

당신이 얻고있는 오류되어야 Button

에 캐스팅하려고 내가 당신의 질문에 나타났습니다 ClassCastException