android - 当一个 Activity 加载其他 Activity 时添加进度条

Question

这是我的 Activity oncreate() 方法。我设置了一个带有对话窗口的肯定按钮ok。 当我点击它时，它会导航 UI Activity staticDisplay.class。我想在对话框窗口中单击“确定”后设置一个进度条，直到加载下一个 Activity 。

public void onCreate(Bundle savedInstanceState) {
    Log.d(TAG, "ACTIVITY ONCREATE");
    super.onCreate(savedInstanceState);
    // setContentView(R.layout.dialog);
    setContentView(R.layout.main);

    if (Registration.isRunning == false) {

        TextView title = new TextView(this);
        title.setText("DM2");
        title.setBackgroundColor(Color.DKGRAY);
        title.setPadding(10, 10, 10, 10);
        title.setGravity(Gravity.CENTER);
        title.setTextColor(Color.WHITE);
        title.setTextSize(20);
        /* alert message */
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setCustomTitle(title);

        builder.setMessage(R.string.app_description).setPositiveButton(
                "Ok", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) {
                        if (Registration.isRunning == false) {

                            startService(new Intent(
                                    getApplicationContext(),
                                    Registration.class));
                        }
                        staticInfo();
                        if (Registration.ruid == null)
                            Registration.ruid = uId;

                        startActivity(new Intent(getApplicationContext(),
                                StatisticDisplay.class));
                    }
                });
        AlertDialog alert = builder.create();
        alert.show();
    } else {
        startActivity(new Intent(getApplicationContext(),
                StatisticDisplay.class));
    }
}

创建方法上的StaticDisplay.class

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.statdisplay);


    usage_btn = (Button) findViewById(R.id.appstat);
    usage_btn.setOnClickListener(this);
    setting_btn = (Button) findViewById(R.id.setting);
    setting_btn.setOnClickListener(this);
}

Answer 1

您可以使用 AsyncTask 来完成后台进程并显示进度对话框，如下所示，

调用该类

        new Task().execute(CurrentActivity.this);  

在任务类中:

        private class Task extends AsyncTask<Void, Void, Void> 
             { 
                 ProgressDialog dialog;
                 Context context;
                public Task(Context context)
                { 
                  this.context=context;
                   //constructor for this class
                }
               protected void onPreExecute() {            
                 //create the progress dialog as 
                   dialog=new ProgressDialog(context);
              } 
             protected Void doInBackground(Void... JSONArray) { 

           //Place your background process code     

            }

            protected void onPostExecute(Void unused) {
                 //dismiss the progressdialog 
                dialog.dismiss();
           } 
       }