public class MainActivity extends AppCompatActivity {
  private Button bt;
  private TextView tv;
  public ProgressDialog myDialog;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    bt=(Button)findViewById(R.id.button);
    tv=(TextView)findViewById(R.id.text);
    bt.setOnClickListener(new myOnClickListener());
  }
  private class myOnClickListener implements View.OnClickListener{
    @Override
    public void onClick(View v) {
      final CharSequence strDialogTitle=getString(R.string.app_about);
      final CharSequence strDialogBody=getString(R.string.app_msg);
      //显示对话框
      myDialog=ProgressDialog.show(MainActivity.this,strDialogTitle,strDialogBody,true);
      tv.setText(R.string.result);
      //创建一个空线程模拟运行
      new Thread(){
        public void run(){
          try{
            //设置线程睡眠3秒
            sleep(3000);
          }catch (Exception e){
            e.printStackTrace();
          }
          finally {
            //删除所创建的myDialog对象
            myDialog.dismiss();
          }
        }
      }.start();//开始运行线程
    }
  }
}