Handler，

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import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ProgressBar;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private ProgressBar timer;//声明水平进度条
    private int Time=10;//定义时间长度为60
    private int mProgressStatus=0;//定义初始完成进度为0；
    final int T_msg=0x11;//消息代码

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        timer=findViewById(R.id.timer);
        //启动进度条
        handler.sendEmptyMessage(T_msg);

    }

    Handler handler=new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            if(Time-mProgressStatus>0) {//倒计时设置判断，当前进度大于0
                mProgressStatus++;//进度+1
                timer.setProgress(Time-mProgressStatus);//更新组件进度
                sendEmptyMessageDelayed(T_msg,1000);//每一秒发送一次消息
            }else {
                Toast.makeText(MainActivity.this, "时间到", Toast.LENGTH_SHORT).show();
            }
        }
    };
}

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