android.content.Context vs android.app.Activity

时间:2012-05-25 07:14:13

标签: android android-activity android-asynctask android-context

我想将当前活动的引用传递给不扩展Activity的类的方法。我需要对活动活动使用此引用,以便我可以使用getWindow().addFlags(LayoutParams.FLAG_KEEP_SCREEN_ON);

我使用类中的这些setter方法将当前上下文和活动传递给类对象:

public class VersionCheck {

    public Context context;
    public Activity activity;

    //---------------------------------------------------------------------------------------------------------
    //set the current context
    //---------------------------------------------------------------------------------------------------------
    public void setContext(Context context) {

        this.context = context;
    }

    //---------------------------------------------------------------------------------------------------------
    //set the current activity
    //---------------------------------------------------------------------------------------------------------
    public void setActivity(Activity activity) {

        this.activity = activity;
    }   

对活动的引用用于类中的AsyncTask(下面的摘录):

//---------------------------------------------------------------------------------------------------------
//asynchronous task to check if there is a newer version of the app available
//---------------------------------------------------------------------------------------------------------
private class UpdateCheckTask extends AsyncTask<String, Void, String> {

HttpClient httpclient;
HttpPost httppost;
HttpResponse response;
InputStream inputStream;
byte[] data;
StringBuffer buffer;

protected void onPreExecute ()
{
    VersionCheck vc = new VersionCheck();

    //do not lock screen or drop connection to server on login
        activity.getWindow().addFlags(LayoutParams.FLAG_KEEP_SCREEN_ON);

        //initiate progress dialogue to block user input during initial data retrieval
        ProcessingDialog = ProgressDialog.show(context, "Please Wait", "Checking for Updates", true,false);
}

    @Override
    protected String doInBackground(String... currentVersion) 
    {

如何获取对Activity的引用,以便将其传递给setActivity(Activity)方法?我使用myActivity.this作为上下文的参考。活动是否相同?

1 个答案:

答案 0 :(得分:3)

是的,活动.................

会是一样的

http://developer.android.com/reference/android/app/Activity.html

见这里上下文是Activity的超类......

java.lang.Object

   ↳    android.content.Context

       ↳    android.content.ContextWrapper

           ↳    android.view.ContextThemeWrapper

               ↳    android.app.Activity