Android中的常用控件之进度条（ProgressBar）

public class MainActivity extends AppCompatActivity {
 
    private int p=0;//当前进度
    private ProgressBar pb_main_download;//进度条
    private TextView tv_main_desc;//显示文本的控件
    private MyHandler myHandler=new MyHandler();//新写的Handler类
 
    public class MyHandler extends Handler{
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            int code=msg.what;//接受处理码
            switch (code){
                case 1:
                    p++;
                    pb_main_download.setProgress(p);//给进度条的当前进度赋值
                    tv_main_desc.setText(p+"%");//显示当前进度为多少
                    break;
            }
        }
    }
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        //根据ID找到进度条
        pb_main_download=findViewById(R.id.pb_main_download);
        //根据ID找到显示文本的控件
        tv_main_desc=findViewById(R.id.tv_main_desc);
    }
 
    //点击Download按钮所调用的方法
    public void download(View view) {
        if(0==p){//如果当前进度为0
            new myThread().start();//开启线程
        }
    }
 
    public class myThread extends Thread{
        @Override
        public void run() {
            super.run();
            while(true){
                try {
                    Thread.sleep(100);//使线程休眠0.1秒
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
 
                if(p==100){//当前进度等于总进度时退出循环
                    p=0;
                    break;
                }
 
                Message msg=new Message();
                msg.what=1;
                myHandler.sendMessage(msg);//发送处理码
            }
        }
    }
}