回调函数的使用

Posted 2022-12-09 小筱萌

1.定义接口

package com.app.util;

public interface ZYJCallBack 
   public void dataResult( String resultString ) ;
   
   public void progress( Integer progress ) ;
   
   public void start() ;

2.实体

package com.app.util;
import android.os.AsyncTask;

public class ZYJAsyncTask  extends AsyncTask< String , Integer , String >  

    ZYJCallBack zyjCallBack ;

    //开始
    @Override
    protected void onPreExecute() 
        super.onPreExecute();
        zyjCallBack.start();
    

    /**
     * 特别注意：publishProgress( 10  );  
     * 这一句一定要写，否则 onProgressUpdate() ,这个方法不会被回调
     */
    @Override
    protected String doInBackground(String... params) 
        publishProgress( 10  );   
        publishProgress( 20  );
        publishProgress( 50  );
        publishProgress( 100  );
        return "哈哈哈，操作完成了" ;
    

    //onProgressUpdate方法用于更新进度信息  
    @Override  
    protected void onProgressUpdate(Integer... progresses)   
        zyjCallBack.progress( progresses[0] );
      

    @Override
    protected void onPostExecute(String result) 
        super.onPostExecute(result);
        zyjCallBack.dataResult( result );
    

    public void setCallBackListener(ZYJCallBack zyjCallBack)
        this.zyjCallBack = zyjCallBack ;
    

3.回调

package com.android10;
import com.app.util.ZYJAsyncTask;
import com.app.util.ZYJCallBack;

import android.app.Activity;
import android.os.Bundle;

public class MainActivity extends Activity 

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

        ZYJAsyncTask zyjAsyncTask = new ZYJAsyncTask() ;
        zyjAsyncTask.setCallBackListener( new ZYJCallBack() 
            
            @Override
            public void start() 
                System.out.println("ssss开始了" ) ;
            
            
            @Override
            public void progress(Integer progress) 
                System.out.println("ssss进度为： " + progress ) ;
            
            
            @Override
            public void dataResult(String resultString) 
                System.out.println("ssss结果是：" + resultString  ) ;
            
        );
        
        zyjAsyncTask.execute( "" ) ;