Question

我想从不同的类更新我的UI。我熟悉runOnUiThread()方法，但不知道如何在这种情况下实现它？

public class UploadAct extends MainActivity {

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

    //my code and functions would go here
}

然后，我的UploadData类

public class UploadData extends UploadAct {
    public void doSomethig(){
        printThis("I want to print this message to the UI");
    }

    public void printThis(String messsage) {
        final String mess = message;
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                Toast.makeText(getApplicationContext(),mess,Toast.LENGTH_LONG).show();
                // I want this to display on the main thread
                txt_upload.setText(mess);// and this also
        }
    });
}

}

Answer 1

使用BroadcastReceiver

// define a Broadcast Intent Action in String resources
<string name="broadcast_id">MY_BROADCAST_ID</string>

// register receiver in constructor/onCreate()
MyBroadcastReceiver myBroadcastReceiver = new MyBroadcastReceiver();
IntentFilter myIntentFilter = new IntentFilter();
myIntentFilter.addAction(context.getString(R.string.broadcast_id));
context.registerReceiver(myBroadcastReceiver, myIntentFilter);

// place your BroadcastReceiver in MainActivity, your UploadData class
public class MyBroadcastReceiver extends BroadcastReceiver {

    public MyBroadcastReceiver(){
        super();
    }
    @Override public void onReceive(Context context, Intent intent) {

        Log.d(TAG, "Broadcast received");
        if(intent.getAction() != null && intent.getAction().equals(context.getString(R.string.broadcast_id)) ){
            // do something
        }
    }
}

// send Broadcasts from where you want to act, your UploadAct class.
Intent intent = new Intent();
intent.setAction(context.getString(R.string.broadcast_id));
context.sendBroadcast(intent);
Log.d(TAG, "Broadcast sent.");

// you can unregister this receiver in onDestroy() method
context.unregisterReceiver(myBroadcastReceiver);

Answer 2

您还可以使用界面将UI更新为监听器。

首先，创建一个界面

public interface UpdateTextListener {
    void updateText(String data);
}

然后，在UploadData类中调用其方法

 public class UploadData extends UploadAct {

     UpdateTextListener listener;

     public void doSomethig(){
         listener.updateText("data to be loaded");
     }
 }

然后，通过聆听此方法更新您的UploadAct

public class UploadAct extends MainActivity  implements UpdateTextListener {

     @Override
     public void updateText(String  data) {
         textview.setText(data);
     }
}

Answer 3

首先 - 没有像某类课程那样的东西。有些活动可以处理UI小部件（ex TextView）。如果要从UploadData类对UI进行一些更改，则必须以某种方式传递给此类。可能是构造函数：

public class UploadData extends UploadAct{
private TextView txt_upload;

public UploadData(TextView tv)
{
      txt_upload = tv;
}
public void doSomethig(){
printThis("I want to print this message to the UI")
}

 public void printThis(String messsage) {
    final String mess = message;
    runOnUiThread(new Runnable() {
        @Override
        public void run() {
                       Toast.makeText(getApplicationContext(),mess,Toast.LENGTH_LONG).show();// I want this to display on the main thread
            txt_upload.setText(mess);// and this also
        }
    });
}
}

我假设您在MainActivity中创建了DataUpload。

Answer 4

每个人都使用这么多的图书馆，因为他们在Android中忘记了内置函数：）

确保使用AsyncTask并不困难，除此之外它还提供doInBackground功能，它具有https://developer.android.com/reference/android/os/AsyncTask.html#publishProgress(Progress...)功能，您所要求的功能。

只需创建一个扩展AsyncTask并覆盖1-2函数的类（UploadTask）。

如何与来自不同类的UI进行交互

4 个答案: