大家都知道由于性能要求，android要求只能在UI线程中更新UI，要想在其他线程中更新UI，大致有4种方式，下面分别使用四种方式来更新一个TextView。
1.使用Handler消息传递机制
package com.example.runonuithreadtest; import android.app.Activity; import android.os.Bundle; import android.os.Handler; import android.widget.TextView; public class MainActivity extends Activity { private TextView tv; Handler handler = new Handler() { public void handleMessage(android.os.Message msg) { if(msg.what==0x123) { tv.setText("更新后的TextView"); } }; }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); tv = (TextView) findViewById(R.id.tv); new MyThread().start(); } class MyThread extends Thread { @Override public void run() { //延迟两秒更新 try { Thread.sleep(2000); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } handler.sendEmptyMessage(0x123); } } }
2. 使用AsyncTask异步任务（更新UI的操作只能在onPostExecute(String result)方法中）
package com.example.runonuithreadtest; import android.app.Activity; import android.os.AsyncTask; import android.os.Bundle; import android.widget.TextView; public class MainActivity extends Activity { private TextView tv; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); tv = (TextView) findViewById(R.id.tv); new Yibu().execute(); } class Yibu extends AsyncTask<String, String, String> { @Override protected String doInBackground(String... params) { try { Thread.sleep(2000); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } return null; } @Override protected void onPostExecute(String result) { // TODO Auto-generated method stub tv.setText("更新后的TextView"); } } }
3. 使用runOnUiThread(action)方法
package com.example.runonuithreadtest; import android.app.Activity; import android.os.Bundle; import android.widget.TextView; public class MainActivity extends Activity { private TextView tv; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); tv = (TextView) findViewById(R.id.tv); new MyThread().start(); } class MyThread extends Thread { @Override public void run() { runOnUiThread(new Runnable() { @Override public void run() { // TODO Auto-generated method stub try { //延迟两秒更新 Thread.sleep(2000); } catch (InterruptedException e) { e.printStackTrace(); } tv.setText("更新后的TextView"); } }); } } }
4. 使用Handler的post(Runnabel r)方法
package com.example.runonuithreadtest; import android.app.Activity; import android.os.Bundle; import android.os.Handler; import android.widget.TextView; public class MainActivity extends Activity { private TextView tv; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); tv = (TextView) findViewById(R.id.tv); Handler handler = new Handler(); handler.post(new Runnable(){ @Override public void run() { try { //延迟两秒更新 Thread.sleep(2000); } catch (InterruptedException e) { e.printStackTrace(); } tv.setText("更新后的TextView"); } }); } }
以上就是四种Android异步更新UI的方式，希望对大家的学习有所帮助。
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