android - ImageButton を使用した OnClickListener

Question

複数の写真を表示する小さなアプリを作成したいと思います。クリックするとトーストが表示され、名前が表示されます。なぜすぐにクラッシュするのか本当にわかりません。LogCat は、Nullpointerexpection のようなことを言いますか?! どうぞよろしくお願いいたします。

  package com.example.housesgot;
  import android.os.Bundle;
  import android.annotation.SuppressLint;
  import android.app.Activity;
  import android.view.View;
  import android.view.View.OnClickListener;
  import android.widget.ImageButton;
  import android.widget.Toast;

  @SuppressLint("ShowToast")
  public class MainActivity extends Activity implements OnClickListener 
  {

      ImageButton  imageButton1,imageButton2,imageButton3,imageButton4,imageButton5,imageButton6;
      @Override
      protected void onCreate(Bundle savedInstanceState) 
      {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            imageButton1=(ImageButton)findViewById(R.drawable.house_baratheon);
            imageButton2=(ImageButton)findViewById(R.drawable.house_frey);
            imageButton3=(ImageButton)findViewById(R.drawable.house_greyjoy);
            imageButton4=(ImageButton)findViewById(R.drawable.house_lannister);
            imageButton5=(ImageButton)findViewById(R.drawable.house_stark);
            imageButton6=(ImageButton)findViewById(R.drawable.house_targaryen);
            imageButton1.setOnClickListener(this);
            imageButton2.setOnClickListener(this);
            imageButton3.setOnClickListener(this);
            imageButton4.setOnClickListener(this);
            imageButton5.setOnClickListener(this);
            imageButton6.setOnClickListener(this);
      }


    @SuppressLint("ShowToast")
    @Override
    public void onClick(View v) 
    {
        if(v==imageButton1){
            Toast.makeText(MainActivity.this, R.string.baratheon, Toast.LENGTH_LONG);}
        if(v==imageButton2){
            Toast.makeText(MainActivity.this, R.string.frey, Toast.LENGTH_LONG);}
        if(v==imageButton3){
            Toast.makeText(MainActivity.this, R.string.greyjoy, Toast.LENGTH_LONG);}
        if(v==imageButton4){
            Toast.makeText(MainActivity.this, R.string.lannister, Toast.LENGTH_LONG);}
        if(v==imageButton5){
            Toast.makeText(MainActivity.this, R.string.stark, Toast.LENGTH_LONG);}
        if(v==imageButton6){
            Toast.makeText(MainActivity.this, R.string.targaryen, Toast.LENGTH_LONG);}

     }
}

Answer 1

logcat を投稿していないため、コードを修正することはできませんが、実際の例を示すことができます。

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


      ImageButton ib1,ib2,ib3,ib4,ib5;

       //change your image ID's here
       ib1= (ImageButton) findViewById(R.id.go_to_lagan_screen);
       ib2= (ImageButton) findViewById(R.id.go_to_city);
       ib3= (ImageButton) findViewById(R.id.go_to_university);
       ib4= (ImageButton) findViewById(R.id.go_to_icon_screen);
       ib5= (ImageButton) findViewById(R.id.map_to_home_screen);


       ib1.setOnClickListener(new View.OnClickListener()
       {
          @Override
          public void onClick(View v)
          {
             //change the action here, a toast in your example
             Toast.makeText(MainActivity.this, MainActivity.this.getResources().getString(R.string.my_resource_string), Toast.LENGTH_LONG);

          }
       } );

       ib2.setOnClickListener((new View.OnClickListener()
       {
          @Override
          public void onClick(View v)
          {
             Intent intent1= new Intent (MapScreen.this, CityCentre.class);
             startActivity(intent1);
             //To change body of implemented methods use File | Settings | File Templates.
          }
       }));
       ib3.setOnClickListener((new View.OnClickListener()
       {
          @Override
          public void onClick(View v)
          {
             Intent intent2= new Intent (MapScreen.this, UniversityArea.class);
             startActivity(intent2);
             //To change body of implemented methods use File | Settings | File Templates.
          }
       }));
       ib4.setOnClickListener((new View.OnClickListener()
       {
          @Override
          public void onClick(View v)
          {
             Intent intent3= new Intent (MapScreen.this, TheIcons.class);
             startActivity(intent3);

             //To change body of implemented methods use File | Settings | File Templates.
          }
       }));
       ib5.setOnClickListener((new View.OnClickListener()
       {
          @Override
          public void onClick(View v)
          {
             Intent intent4= new Intent (MapScreen.this, MyActivity.class);
             startActivity(intent4);
             //To change body of implemented methods use File | Settings | File Templates.
          }
       }));
    }