Question

如何在android中使用后台线程更新进度条？它还会改变进度条的进度。请帮忙。

AndroidVogue

Answer 1

我使用AsyncTask完成了类似的任务。 AsyncTask有方法onProgressUpdate(Integer)，您可以通过调用doInBackground()来调用每次迭代，例如每次在publishProgress()期间完成进度。

有关详细信息，请参阅docs。

Answer 2

Thread t=new Thread()
{
public void run()
{
while(some condition)
{
sleep(1000);
Message myMessage = new Message();
myMessage.obj = "success";
handler.sendMessage(myMessage);
}
}
};


private Handler handler=new Handler()
    {
        @Override
        public void handleMessage(Message msg)
        {
            String result=(String)msg.obj;
                     if(result.equals("success")
                     {
                     //update progress bar here
                      }

                 }
        };

Answer 3

private ProgressBar pgb;
private TextView textview;
private int progressBarStatus = 0;
private Handler progressBarbHandler = new Handler();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_next);
    pgb = (ProgressBar) findViewById(R.id.progressBar2) ;
}

public void load_bar(View view)
{
    pgb.setMax(100);
    pgb.setProgress(0);

    new Thread(new Runnable() {
        @Override
        public void run() {
            for (progressBarStatus = 0; progressBarStatus <= 100; progressBarStatus++) {

                progressBarbHandler.post(new Runnable() {
                    public void run() {
                        pgb.setProgress(progressBarStatus);
                    }
                });


                try {
                    Thread.sleep(50);
                } catch (Exception ex) {
                }
            }
        }
    }).start();
}

Answer 4

  // this is demonstrate how to update progress bar from a thread 
  private ProgressBar pgb;  //  is a progressBar named with pgb 
  private int progressBarStatus = 0;// is a variable named progressBarStatus and initialize by 0
  // in  onCreate  method find the ui component view horizontal prograssbar named progressBar2  


 public void load_bar(View view) // is a button OnClick
// and i am using a thread with for loop to demonstrate a task and variable progressBarStatus  as status 

  pgb = (ProgressBar) findViewById(R.id.progressBar2) ;// find view by id 

  pgb.setMax(100); // at this point we the maximum value of a progress bar to make it full like we make 100 pices of it 

  pgb.setProgress(0); // initialize the progress bar with 0 % progress

    // progress bar handler that update the status of progress bar . without handler we cant update progress bar from thread 

   progressBarbHandler.post(new Runnable() {
                public void run() {
                    pgb.setProgress(progressBarStatus);
                }

Answer 5

使用handler，此处理程序将更新进度条你要做的是： 1）从你的线程向处理程序发送消息 2）更新处理程序中的进度条

Answer 6

使用Thread可以做到这一点，只需在oncreate方法中调用函数

public void loadProgressbar()
{
    progressBar.setMax(100);
    progressBar.setProgress(0);

    new Thread(new Runnable() {
        @Override
        public void run() {
            for (progress = 0; progress <= 100; progress++) {

                handler.post(new Runnable() {
                    public void run() {
                        progressBar.setProgress(progress);
                    }
                });


                try {
                    Thread.sleep(50);
                } catch (Exception ex) {
                }
            }
        }
    }).start();
}

如何使用Thread更新进度条

6 个答案: