仅使用 Context 而不是 Activity 实例显示对话框

问题描述

如果我使用 Activity 实例，我可以显示对话框，但是当我使用 Context 或 Application Context 实例时，对话框没有显示.

I could show dialog if I uses an Activity instance but when I uses Context or Application Context instance Dialog is not showing.

AlertDialog.Builder builder = new AlertDialog.Builder(activity);
            builder.setTitle(title);
            builder.setMessage(msg);

            if (null != positiveLabel) {
                builder.setPositiveButton(positiveLabel, new DialogInterface.OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {

                        dialog.cancel();
                        if (null != listener) {
                            listener.onOk();
                        }
                    }
                });
            }

            if (null != negativeLable) {
                builder.setNegativeButton(negativeLable, new DialogInterface.OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {

                        dialog.cancel();
                        if (null != listener) {
                            listener.onCancel();
                        }
                    }
                });
            }

            builder.create().show();

你能不能给我一个解决方案来显示对话框而不使用 Activity 实例

Can you please give me a solution to show dialog without using Activity instance

推荐答案

这个问题也是我最近遇到的问题，没有Activity实例就不能创建对话框.getApplicationContext() 调用也不起作用.我这样做的方法是从一个活动调用创建对话框的方法，并传递this"，即对该活动的引用作为参数.

The problem is something I faced recently too, you cant create a dialog without and activity instance. getApplicationContext() call doesn't work too. The way I did this is to make the call to a method that creates the dialog, from an activity, and pass "this" i.e. the reference to that activity as a parameter.

如果您打算重用此代码，作为可重用组件或作为在多个位置创建对话框的机制，请创建一个基本活动类并在其中包含此方法，并根据需要在子类活动中使用它.

If you are going to reuse this code, as a reusable component or as a mechanism to create dialogs at multiple places, create a base activity class and have this method in there, and use it in sub-classed activities as needed.

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