Question

我正在从另一个活动（Activity1）开始一个活动（Activity2）。我正在Activity1的公共方法中显示进度对话框。当我从Activity2调用此方法时，会发生异常。

public class Activity1 extends Activity{

   private ProgressDialog progressDialog;

   public Activity1(){
   }

   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.layout_activity1);           
   }

   public void showDialog(){
      progressDialog = ProgressDialog.show(Activity1.this,
                "Please Wait");
      progressDialog.setProgressStyle(R.style.DialogStyle);
      progressDialog.setCancelable(true);
      progressDialog.setCanceledOnTouchOutside(true);
   }

   //On Clicking a button this method gets called
   private void nextActivity(){
      Intent intent = new Intent(Activity1.this, Activity2.class);
      startActivity(intent);
}

public class Activity2 extends Activity{
   private Activity1 activity1;

   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.layout_activity2);  
      activity1 = new Activity1();
      activity1.showDialog();         
   }
}

从Activity2调用Activity1＆lt; showDialog（）方法后，它在showDialog（）方法的以下行中给出了异常：

progressDialog = ProgressDialog.show（Activity1.this，＆＃34;请等待＆＃34;）;

我也尝试将ProgressDialog的对象设为静态但不起作用

Answer 1

这是在另一个Activity中访问该方法的错误方法。

最好的方法是添加Base Activity并在那里移动showDialog代码。您可以在Activity

中添加所有常见的Base Activity代码

像这样创建基本活动

  public class BaseActivity extends Activity {
      private ProgressDialog progressDialog;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        progressDialog = ProgressDialog.show(Activity1.this,
            "Please Wait");
   }

      public void showDialog(){
       progressDialog.setProgressStyle(R.style.DialogStyle);
       progressDialog.setCancelable(true);
       progressDialog.setCanceledOnTouchOutside(true);
       progressDialog.show();
  }

现在，您可以从所有必需的活动中扩展BaseActivity，并在需要时调用showDialog（）方法。

   public Activity2 extends BaseActivity {
        @Override
        protected void onCreate(Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);
           setContentView(R.layout.layout_activity2);
           // show the progress dialog
           showDialog();         
       }
   }

IIlegalStateException：onCreate（）[ProgressDialog]之前的活动不可用的系统服务

1 个答案: