标签：android http io color ar sp java for div
直接在UI线程中开启子线程来更新TextView显示的内容，运行程序我们会发现，如下错 误：android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.翻译过来就是：只有创建这个控件的线程才能去更新该控件的内容。
既然android给我们提供了Handler机制来解决这样的问题，请看如下代码：
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public class HandlerTestActivity extends Activity { private TextView tv; private static final int UPDATE = 0; private Handler handler = new Handler() { @Override public void handleMessage(Message msg) { // TODO 接收消息并且去更新UI线程上的控件内容 if (msg.what == UPDATE) { // Bundle b = msg.getData(); // tv.setText(b.getString("num")); tv.setText(String.valueOf(msg.obj)); } super.handleMessage(msg); } }; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); tv = (TextView) findViewById(R.id.tv); new Thread() { @Override public void run() { // TODO 子线程中通过handler发送消息给handler接收，由handler去更新TextView的值 try { for (int i = 0; i < 100; i++) { Thread.sleep(500); Message msg = new Message(); msg.what = UPDATE; // Bundle b = new Bundle(); // b.putString("num", "更新后的值：" + i); // msg.setData(b); msg.obj = "更新后的值：" + i; handler.sendMessage(msg); } } catch (InterruptedException e) { e.printStackTrace(); } } }.start(); }} |
我们就通过Handler机制来处理了子线程去更新UI线程控件问题，Andrid开发中要经常用到这种机制。
标签：android http io color ar sp java for div
原文地址：http://www.cnblogs.com/pinksnow520/p/4101032.html
