Android 中不用线程如何实现倒计时

package test.demo.countdowntest;import android.os.Bundle;import android.os.CountDownTimer;import android.support.v7.app.AppCompatActivity;import android.view.View;import android.widget.Button;import android.widget.ProgressBar;import android.widget.Toast;public class MainActivity extends AppCompatActivity implements View.OnClickListener{  private Button bt1, bt2, bt3;  private ProgressBar pb1, pb2, pb3;  private MyCount mc1,mc2, mc3;  private boolean mc1Click = false;  private boolean mc2Click = false;  private boolean mc3Click = false;  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    bt1 = ((Button) findViewById(R.id.bt1));    bt2 = ((Button) findViewById(R.id.bt2));    bt3 = ((Button) findViewById(R.id.bt3));    bt1.setOnClickListener(this);    bt2.setOnClickListener(this);    bt3.setOnClickListener(this);    pb1 = ((ProgressBar) findViewById(R.id.pb1));    pb2 = ((ProgressBar) findViewById(R.id.pb2));    pb3 = ((ProgressBar) findViewById(R.id.pb3));    mc1 = new MyCount(30000, 1000);    mc1.setPb(bt1, pb1);    mc2 = new MyCount(30000, 1000);    mc2.setPb(bt2, pb2);    mc3 = new MyCount(30000, 1000);    mc3.setPb(bt3, pb3);  }  @Override  public void onClick(View view) {    switch (view.getId()) {      case R.id.bt1:        if (mc1Click) {          mc1.cancel();          pb1.setVisibility(View.GONE);          mc1Click = false;        } else {          pb1.setVisibility(View.VISIBLE);          mc1.start();          mc1Click = true;        }        break;      case R.id.bt2:        if (mc2Click) {          pb2.setVisibility(View.GONE);          mc2.cancel();          mc2Click = false;        } else {          pb2.setVisibility(View.VISIBLE);          mc2.start();          mc2Click = true;        }        break;      case R.id.bt3:        if (mc3Click) {          pb3.setVisibility(View.GONE);          mc3.cancel();          mc3Click = false;        } else {          pb3.setVisibility(View.VISIBLE);          mc3.start();          mc3Click = true;        }        break;    }  }  /*定义一个倒计时的内部类*/  class MyCount extends CountDownTimer {    Button mBt;    ProgressBar mPb;    public MyCount(long millisInFuture, long countDownInterval) {      super(millisInFuture, countDownInterval);    }    public void setPb(Button bt, ProgressBar pb) {      mBt = bt;      mPb = pb;    }    @Override    public void onFinish() {      mPb.setVisibility(View.GONE);    }    @Override    public void onTick(long millisUntilFinished) {      mBt.setText("请等待30秒(" + millisUntilFinished / 1000 + ")...");      Toast.makeText(MainActivity.this, millisUntilFinished / 1000 + "", Toast.LENGTH_LONG).show();    }  }}

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  xmlns:tools="http://schemas.android.com/tools"  android:id="@+id/activity_main"  android:layout_width="match_parent"  android:layout_height="match_parent"  android:paddingBottom="@dimen/activity_vertical_margin"  android:paddingLeft="@dimen/activity_horizontal_margin"  android:paddingRight="@dimen/activity_horizontal_margin"  android:paddingTop="@dimen/activity_vertical_margin"  android:orientation="vertical"  tools:context="cn.sh.changxing.countdowntest.MainActivity">  <LinearLayout    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:orientation="horizontal">    <Button      android:id="@+id/bt1"      android:layout_width="0dp"      android:layout_height="wrap_content"      android:layout_weight="1"      android:text="测试启动1"/>    <ProgressBar      android:id="@+id/pb1"      style="?android:attr/progressBarStyleSmall"      android:layout_width="wrap_content"      android:layout_height="wrap_content"      android:layout_gravity="center"      android:indeterminate="true"/>  </LinearLayout>  <LinearLayout    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:orientation="horizontal">    <Button      android:id="@+id/bt2"      android:layout_width="0dp"      android:layout_height="wrap_content"      android:layout_weight="1"      android:text="测试启动2"/>    <ProgressBar      android:id="@+id/pb2"      style="?android:attr/progressBarStyleSmall"      android:layout_width="wrap_content"      android:layout_height="wrap_content"      android:layout_gravity="center"      android:indeterminate="true"/>  </LinearLayout>  <LinearLayout    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:orientation="horizontal">    <Button      android:id="@+id/bt3"      android:layout_width="0dp"      android:layout_height="wrap_content"      android:layout_weight="1"      android:text="测试启动3"/>    <ProgressBar      android:id="@+id/pb3"      style="?android:attr/progressBarStyleSmall"      android:layout_width="wrap_content"      android:layout_height="wrap_content"      android:layout_gravity="center"      android:indeterminate="true"/>  </LinearLayout></LinearLayout>