转于:http://blog.csdn.net/luckyjda/article/details/8601517
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在Android开发过程中,常需要更新界面的UI。而更新UI是要主线程来更新的,即UI线程更新。如果在主线线程之外的线程中直接更新页面显示常会报错。抛出异常:android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
只有原始创建这个视图层次(view hierachy)的线程才能修改它的视图(view)
话不多说,贴出下面的代码
方法一:
在Activity.onCreate(Bundle savedInstanceState)中创建一个Handler类的实例, 在这个Handler实例的handleMessage回调函数中调用更新界面显示的函数。
界面:
- <span style="font-size:14px;">public class MainActivity extends Activity {
- private EditText UITxt;
- private Button updateUIBtn;
- private UIHandler UIhandler;
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_main);
- UITxt = (EditText)findViewById(R.id.ui_txt);
- updateUIBtn = (Button)findViewById(R.id.update_ui_btn);
- updateUIBtn.setOnClickListener(new View.OnClickListener() {
- public void onClick(View v) {
- // TODO Auto-generated method stub
- UIhandler = new UIHandler();
- UIThread thread = new UIThread();
- thread.start();
- }
- });
- }
- @Override
- public boolean onCreateOptionsMenu(Menu menu) {
- getMenuInflater().inflate(R.menu.activity_main, menu);
- return true;
- }
- private class UIHandler extends Handler{
- @Override
- public void handleMessage(Message msg) {
- // TODO Auto-generated method stub
- super.handleMessage(msg);
- Bundle bundle = msg.getData();
- String color = bundle.getString("color");
- UITxt.setText(color);
- }
- }
- private class UIThread extends Thread{
- @Override
- public void run() {
- try {
- Thread.sleep(3000);
- } catch (InterruptedException e) {
- // TODO Auto-generated catch block
- e.printStackTrace();
- }
- Message msg = new Message();
- Bundle bundle = new Bundle();
- bundle.putString("color", "黄色");
- msg.setData(bundle);
- MainActivity.this.UIhandler.sendMessage(msg);
- }
- }
- }</span>
更新后:
方法二:利用Activity.runOnUiThread(Runnable)把更 新ui的代码创建在Runnable中,然后在需要更新ui时,把这个Runnable对象传给 Activity.runOnUiThread(Runnable)。 这样Runnable对像就能在ui程序中被调用。如果当前线程是UI线程,那么行动是立即执行。如果当前线程不是UI线程,操作是发布到事件队列的UI 线程
- FusionField.currentActivity.runOnUiThread(new Runnable()
- {
- public void run()
- {
- Toast.makeText(getApplicationContext(), , "Update My UI",
- Toast.LENGTH_LONG).show();
- }
- });