Android：如何更改從MainActivity接收數據的片段中的視圖

Question

我正在開發從藍牙設備接收數據以便在viewpager中片段化的應用程序。 我的應用程序的過程中它

1. MainActivity從藍牙設備接收數據

2. MainActivity的靜態字符串值改爲從藍牙設備中的數據

3. 片段在viewpager進度在MainActivity刷新數據作爲MainActivity的數據（已更改的整數）

4. 片段的進度條刷新數據並查看MainActivity的數據改變

   public class BalanceFragment extends Fragment{ 
   
   public static String data = "0"; 
   private String old = data; 
   
   private ProgressBar progressBar; 
   private TextView textView; 
   private Handler handler; 
   private MyThread myThread; 
   
   public BalanceFragment() { 
   
   } 
   
   @Override 
   public View onCreateView(LayoutInflater inflater, ViewGroup container, 
            Bundle savedInstanceState) { 
   
       return inflater.inflate(R.layout.fragment_balance, container, false); 
   } 
   
   @Override 
   public void onStop() { 
       try{ 
        myThread.stop(); 
       } catch (Exception e){ 
        e.printStackTrace(); 
       } 
   } 
   
   @Override 
   public void onViewCreated(View view, @Nullable Bundle savedInstanceState) { 
       super.onViewCreated(view, savedInstanceState); 
       progressBar = (ProgressBar) view.findViewById(R.id.progressBar); 
       textView = (TextView) view.findViewById(R.id.balanceProgressText); 
       myThread = new MyThread(); 
       myThread.run(); 
   } 
   
   @Override 
   public void onResume() { 
       myThread.run(); 
   } 
   
   class MyThread extends Thread{ 
       @Override 
       public void run() { 
        while(true) { 
         try { 
          this.sleep(5000); 
          MainActivity.println("test", "test"); 
         } catch (Exception e){ 
          e.printStackTrace(); 
         } 
         if (old != data){ 
          old = data; 
          progressBar.setProgress(Integer.valueOf(data)); 
          textView.setText(data); 
          progressBar.invalidate(); 
          textView.invalidate(); 
         } 
        } 
        } 
       } 
   } 
   

但是....當我啓動這個應用程序，查看被凍結...... 我不知道爲什麼我的應用程序被凍結

Answer 1

你可以創建界面片段進行溝通，例如：

public class TestActivity extends Activity { 

    interface DataCallback { 

     void onData(String data); 

    } 

    DataCallback callback; 

    @Override 
    protected void onResume() { 
     super.onResume(savedInstanceState); 

     SampleFragment fragment = SampleFragment.newInstance(); 
     callback = fragment.getCallback(); 
     getFragmentManager().beginTransaction().replace(R.id.container, fragment, "tag").commit() 

    } 

    public static class SampleFragment extends Fragment implements DataCallback { 

     public static SampleFragment newInstance() { 

      Bundle args = new Bundle(); 

      SampleFragment fragment = new SampleFragment(); 
      fragment.setArguments(args); 
      return fragment; 
     } 

     public DataCallback getCallback() { 
      return this; 
     } 

     @Override 
     public void onData(String data) { 
      //Update UI with data 
     } 
    } 

} 

每一個你的活動接收到一個新的數據時

你應該叫：

callback.onData(variableValue) 

並傳遞新數據。