Android - What is difference between progressDialo

问题:

I mean, what is difference between return value of ProgressDialog static method show() and the non-static method show of an instance of that class?

Is there any reason to prefer this strategy

ProgressDialog pd = new ProgressDialog(mActivity);
pd.setTitle(mTitle);
pd.setMessage(mMessage);
pd.show();

to this:

ProgressDialog pd = ProgressDialog.show(mActivity,mTitle,mMessage);

for a particular situation?

回答1:

In my opinion, the "correct" method would depend on your usage. The static show( ... ) methods are performing the same steps you are:

public static ProgressDialog show(Context context, CharSequence title,
        CharSequence message) {
    return show(context, title, message, false);
}

public static ProgressDialog show(Context context, CharSequence title,
        CharSequence message, boolean indeterminate) {
    return show(context, title, message, indeterminate, false, null);
}

public static ProgressDialog show(Context context, CharSequence title,
        CharSequence message, boolean indeterminate, boolean cancelable) {
    return show(context, title, message, indeterminate, cancelable, null);
}

public static ProgressDialog show(Context context, CharSequence title,
        CharSequence message, boolean indeterminate,
        boolean cancelable, OnCancelListener cancelListener) {
    ProgressDialog dialog = new ProgressDialog(context);
    dialog.setTitle(title);
    dialog.setMessage(message);
    dialog.setIndeterminate(indeterminate);
    dialog.setCancelable(cancelable);
    dialog.setOnCancelListener(cancelListener);
    dialog.show();
    return dialog;
}

You can see that any calls to the static show methods with parameters just ends up constructing a ProgressDialog and will call the instance method show().

Using the static show( ... ) methods just make it convenient for you to display a basic ProgressDialog using one line of code.

回答2:

writing it with capital p is the correct way to go since the method show is static

ProgressDialog.show(mActivity,mTitle,mMessage);

see the doc here

Is there any reason to prefer this strategy??

the reason why is the best way to go is that static methods should always be accessed in a static way