Android中的Handler机制 - 黑马程序员技术交流社区

[size=1em][size=1em]public class HandlerTestActivity extends Activity {
[size=1em] private TextView tv;
[size=1em] private static final int UPDATE = 0;
[size=1em] private Handler handler = new Handler() {

[size=1em]       @Override
[size=1em]       public void handleMessage(Message msg) {
[size=1em]          // TODO 接收消息并且去更新UI线程上的控件内容
[size=1em]          if (msg.what == UPDATE) {
[size=1em]             // Bundle b = msg.getData();
[size=1em]             // tv.setText(b.getString("num"));
[size=1em]             tv.setText(String.valueOf(msg.obj));
[size=1em]          }
[size=1em]          super.handleMessage(msg);
[size=1em]       }
[size=1em] };

[size=1em] /** Called when the activity is first created. */
[size=1em] @Override
[size=1em] public void onCreate(Bundle savedInstanceState) {
[size=1em]       super.onCreate(savedInstanceState);
[size=1em]       setContentView(R.layout.main);
[size=1em]       tv = (TextView) findViewById(R.id.tv);

[size=1em]       new Thread() {
[size=1em]          @Override
[size=1em]          public void run() {
[size=1em]             // TODO 子线程中通过handler发送消息给handler接收，由handler去更新TextView的值
[size=1em]             try {
[size=1em]                   for (int i = 0; i < 100; i++) {
[size=1em]                      Thread.sleep(500);
[size=1em]                      Message msg = new Message();
[size=1em]                      msg.what = UPDATE;
[size=1em]                      // Bundle b = new Bundle();
[size=1em]                      // b.putString("num", "更新后的值：" + i);
[size=1em]                      // msg.setData(b);
[size=1em]                      msg.obj = "更新后的值：" + i;
[size=1em]                      handler.sendMessage(msg);
[size=1em]                   }
[size=1em]             } catch (InterruptedException e) {
[size=1em]                   e.printStackTrace();
[size=1em]             }
[size=1em]          }
[size=1em]       }.start();
[size=1em] }

[size=1em]}