活動與構造

Question

，我要開始我與構造 我想通過對象的數組活動不使用偏好的唯一解決的一個問題是使用構造

public class ApresConnextionActivity extends Activity { 

    public Bts[] listeBts; 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     super.setContentView(R.layout.apresconnect); 
     final Button btsButton = (Button) findViewById(R.id.btbts); 
     //boutonbts 
     btsButton.setOnClickListener(new OnClickListener() { 
      @Override 
      public void onClick(View v) {    

       Log.w("myApp",""+listeBts.length); 
       BtsBoutonActivity btba = new BtsBoutonActivity(listeBts);     
       Intent i = new Intent(getApplicationContext(), btba.getClass()); 
       startActivity(i); 

      } 
     }); 
     new JSONParseBts().execute(); 
    } 
    public class JSONParseBts extends AsyncTask<String, String, JSONObject> { ... } 

} 



public class BtsBoutonActivity extends Activity { 
    Bts[] listeBts; 
    cellule[] listecellule; 
    int i,xx=0; 

    public BtsBoutonActivity(Bts[] listeBts2) { 
     this.listeBts=listeBts2; 
    } 

    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     super.setContentView(R.layout.btsbouton); 
     //Log.w("myApp",""+listeBts.length); 
    final Button[] b = new Button[listeBts.length]; 
     LinearLayout ll3 = (LinearLayout)findViewById(R.id.linearLayout2); // Btn 

      for(i = 0; i < listeBts.length; i++){ 
       //Log.w("myApp",listeBts[i].toString()); 
     b[i] = new Button(BtsBoutonActivity.this); 
     b[i].setText(listeBts[i].getNombts()); 
     xx =listeBts[i].getIdbts(); 
     Log.w("myApp",""+xx); 
     b[i].setId(xx); 
     ll3.addView(b[i]); 

     final Button btbts = (Button) findViewById(xx); 
     btbts.setOnClickListener(new OnClickListener() { 
    public void onClick(View v) { 

    Toast saved_message=Toast.makeText(BtsBoutonActivity.this,btbts.getText()+" "+btbts.getId(),1); 
      saved_message.show();       


      }}); 

      } 
    } 


} 

05-09 20:14:31.121: E/AndroidRuntime(596): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{pfe.essat.com/pfe.essat.com.BtsBoutonActivity}: java.lang.InstantiationException: can't instantiate class pfe.essat.com.BtsBoutonActivity; no empty constructor 

這是對一個問題聲明在文件清單也許！ 預先感謝您

Answer 1

您不能在Android中手動實例化活動，因此不要使用構造函數在活動之間傳遞數據。

有關如何在活動之間正確傳遞對象列表的信息，請參閱this thread。

Answer 2

您不能使用構造函數將數據從一個活動傳遞到另一個活動。你需要使用意圖。

intent = new Intent(this, Timer.class); 
//add the data you want to pass to the other activity here... 
intent.putExtra("EXTRA_DATA", data); 
startActivity(intent); //or use startActivityForResult to check if activity really exists 

http://developer.android.com/training/basics/firstapp/starting-activity.html您可以在此鏈接中找到更多信息。這是以一種非常清晰易懂的方式解釋的。