handler与asynctask对比
package async_demo;import com.exercise.R;import com.exercise.R.layout;import com.exercise.R.menu;import android.os.AsyncTask;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.app.Activity;import android.view.Menu;import android.view.View;import android.view.View.OnClickListener;import android.widget.ProgressBar;import android.widget.TextView;public class AsyncTask_Handler extends Activity { TextView asynctask_textView; TextView handler_textview; MyHandler handler;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.async_task);asynctask_textView=(TextView) findViewById(R.id.asynctask_textview);asynctask_textView.setOnClickListener(new OnClickListener(){@Overridepublic void onClick(View v) {// TODO Auto-generated method stubAsynctask task=new Asynctask();task.execute();}});handler_textview=(TextView) findViewById(R.id.handler_textview);handler_textview.setOnClickListener(new OnClickListener(){@Overridepublic void onClick(View v) {// TODO Auto-generated method stubhandler=new MyHandler();MyThread mt=new MyThread();new Thread(mt).start();}});}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.async_task, menu);return true;} class Asynctask extends AsyncTask<String, ProgressBar, String>{@Overrideprotected String doInBackground(String... params) {// TODO Auto-generated method stubString text="AsynacTask_Change";return text;}@Overrideprotected void onCancelled(String result) {// TODO Auto-generated method stubsuper.onCancelled(result);}@Overrideprotected void onPostExecute(String result) {// TODO Auto-generated method stubasynctask_textView.setText(result);//在asynctask中修改UI}@Overrideprotected void onProgressUpdate(ProgressBar... values) {// TODO Auto-generated method stubsuper.onProgressUpdate(values);} } class MyHandler extends Handler{@Overridepublic void handleMessage(Message msg) {// TODO Auto-generated method stubsuper.handleMessage(msg); if (msg.what==1010){ Bundle b=msg.getData(); String textString =b.getString("text"); AsyncTask_Handler.this.handler_textview.setText(textString);//在handler中修改ui };} } class MyThread implements Runnable{@Overridepublic void run() {// TODO Auto-generated method stubMessage msg=new Message();Bundle bundle=new Bundle();bundle.putString("text","Change" );msg.setData(bundle);msg.what=1010;AsyncTask_Handler.this.handler.sendMessage(msg);} }}?