Handler发送Message

用Handler更新UI

 package activity.cyq.handlermessage;

 import android.content.res.Resources;
 import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
 import android.os.Handler;
 import android.os.Message;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.widget.Button;
 import android.widget.ImageView;
 import android.widget.TextView;
 import android.widget.Toast;

 public class MainActivity extends AppCompatActivity {
     private TextView textView;
     private Button button;
     private ImageView imageView;

     private int[] iamgeId = new int[]{R.drawable.aaa1, R.drawable.aaa3, R.drawable.image1};

     private Handler handler = new Handler(new Handler.Callback() {
         @Override
         public boolean handleMessage(Message msg) {
             Toast.makeText(MainActivity.this, "这是Handler的回掉函数", Toast.LENGTH_SHORT).show();
             /*如果返回true则终止handler()的执行 ，可用于对message内容进行判断，今儿决定是否继续对messsage的处理*/
             return false;
         }
     }) {
         @Override
         public void handleMessage(Message msg) {
             super.handleMessage(msg);
             textView.setText(msg.arg1 + "" + msg.arg2);
             imageView.setImageBitmap((Bitmap) msg.obj);
         }
     };

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         textView = (TextView) findViewById(R.id.textView);
         button = (Button) findViewById(R.id.button);
         imageView = (ImageView) findViewById(R.id.imageView);
         /*通过handler.post(Runnable)方法根性UI*/
         new Thread() {
             @Override
             public void run() {
                 super.run();
                 /*创建一个Bitmap对象*/
                 Resources res = getResources();
                 Bitmap bmp = BitmapFactory.decodeResource(res, R.drawable.aaa1);
                 /*发送Message*/
                 Message message = new Message();
                 message.arg1 = 123;
                 message.arg2 = 245;
                 message.obj = bmp;
                 /* arg1 arg2 是int类型数据 obj为object类型数据 */
                 handler.sendMessage(message);
             }
         }.start();

     }

 }