Android 中ProgressDialog进度条对话框的使用(使用子线程模拟更新进度)

public class MainActivity extends AppCompatActivity implements View.OnClickListener{
 private int iPos = 0; //初始化进度条的进度值
 private ProgressDialog progressDialog; //声明进度条对话框的对象
 private Button btn_progressDialog; //声明Button按钮对象
 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    btn_progressDialog = findViewById(R.id.btn_progressDialog);
        btn_progressDialog.setOnClickListener(this);
}
@Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.btn_progressDialog:
                progressDialog = new ProgressDialog(this);
                progressDialog.setTitle("正在加载"); //设置进度条的标题
                progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL); //设置对话框样式为带有水平进度条的对话框
                progressDialog.setMax(100); //设置进度条的最大值为100
                progressDialog.setMessage("具体内容");  //设置具体的内容
                progressDialog.show(); //显示对话框
                //开启一个子线程模拟进度条更新进度
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        while (progressDialog.getMax() - iPos > 0) {
                            iPos++;
                            progressDialog.setProgress(iPos);
                            try {
                                Thread.sleep(50);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }
                        }
                        progressDialog.dismiss(); //进度完成时对话框关闭
                        iPos=0;
                    }
                }).start();
                break;
        }
    }
    }