我找到了这个例子http://android-codes-examples.blogspot.com/2011/11/show-or-hide-soft-keyboard-on-opening.html。在alert.show()之前添加以下代码。

InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
imm.toggleSoftInput(InputMethodManager.SHOW_FORCED,0);

如果有人想:

不能从Activity类型对非静态方法getSystemService(String)进行静态引用

尝试向getSystemService调用添加上下文。

So

InputMethodManager imm = 
(InputMethodManager) context.getSystemService(Context.INPUT_METHOD_SERVICE);
imm.toggleSoftInput(InputMethodManager.SHOW_FORCED,0);

你可以在创建对话框后立即请求软键盘(在SDK - r20上测试)

// create dialog
final AlertDialog dialog = ...; 

// request keyboard   
dialog.getWindow().setSoftInputMode (WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);

试着使用:

editText.requestFocus();
InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
imm.toggleSoftInput(InputMethodManager.SHOW_FORCED, InputMethodManager.HIDE_IMPLICIT_ONLY);

最初的问题涉及对话框和我的EditText是常规视图。无论如何，我认为这对你们大多数人也适用。所以这是对我有效的方法(上面建议的最高评价的方法对我没有任何作用)。下面是一个自定义的EditView，它可以做到这一点(子类化不是必需的，但我发现这对我的目的很方便，因为我还想在视图可见时捕获焦点)。

This is actually largely the same as the tidbecks answer. I actually didn't notice his answer at all as it had zero up votes. Then I was about to just comment his post, but it would have been too long, so I ended doing this post anyways. tidbeck points out that he's unsure how it works with devices having keyboards. I can confirm that the behaviour seems to be exactly the same in either case. That being such that on portrait mode the software keyboard gets popped up and on landscape it doesn't. Having the physical keyboard slid out or not makes no difference on my phone.

因为，我个人觉得行为有点尴尬，我选择使用:InputMethodManager.SHOW_FORCED。这是我想要的效果。无论朝向如何，键盘都是可见的，然而，至少在我的设备上，如果硬件键盘已经滑出，它不会弹出。

import android.app.Service;
import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.EditText;

public class BringOutTheSoftInputOnFocusEditTextView extends EditText {

    protected InputMethodManager inputMethodManager;

    public BringOutTheSoftInputOnFocusEditTextView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init();
    }

    public BringOutTheSoftInputOnFocusEditTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public BringOutTheSoftInputOnFocusEditTextView(Context context) {
        super(context);
        init();
    }

    private void init() {
        this.inputMethodManager = (InputMethodManager)getContext().getSystemService(Service.INPUT_METHOD_SERVICE);
        this.setOnFocusChangeListener(new View.OnFocusChangeListener() {
            @Override
            public void onFocusChange(View v, boolean hasFocus) {
                if (hasFocus) {
                    BringOutTheSoftInputOnFocusEditTextView.this.inputMethodManager.showSoftInput(BringOutTheSoftInputOnFocusEditTextView.this, InputMethodManager.SHOW_FORCED);
                }
            }
        });
    }

    @Override
    protected void onVisibilityChanged(View changedView, int visibility) {
        super.onVisibilityChanged(changedView, visibility);
        if (visibility == View.VISIBLE) {
            BringOutTheSoftInputOnFocusEditTextView.this.requestFocus();
        }
    }

}

问题似乎是，因为你输入文本的地方最初是隐藏的(或嵌套或其他)，AlertDialog自动设置标志WindowManager.LayoutParams。FLAG_ALT_FOCUSABLE_IM或WindowManager.LayoutParams。FLAG_NOT_FOCUSABLE，这样就不会触发软输入来显示。

解决这个问题的方法是添加以下内容:

(...)
// Create the dialog and show it
Dialog dialog = builder.create()
dialog.show();

// After show (this is important specially if you have a list, a pager or other view that uses a adapter), clear the flags and set the soft input mode
dialog.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE|WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM);
dialog.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);