<activity
    ...
    android:windowSoftInputMode="stateVisible" >
</activity>

or

getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_VISIBLE);

我有同样的问题，并解决了它与以下代码。我不确定它在有硬件键盘的手机上会有什么表现。

// TextEdit
final EditText textEdit = new EditText(this);

// Builder
AlertDialog.Builder alert = new AlertDialog.Builder(this);
alert.setTitle("Enter text");
alert.setView(textEdit);

alert.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
    @Override
    public void onClick(DialogInterface dialog, int which) {
        String text = textEdit.getText().toString();
        finish();
    }
});

alert.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
    @Override
    public void onClick(DialogInterface dialog, int which) {
        finish();
    }
});

// Dialog
AlertDialog dialog = alert.create();
dialog.setOnShowListener(new OnShowListener() {

    @Override
    public void onShow(DialogInterface dialog) {
        InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
        imm.showSoftInput(textEdit, InputMethodManager.SHOW_IMPLICIT);
    }
});

dialog.show();

只需将这一行添加到manifest文件必要的活动。

android：windowSoftInputMode=“stateVisible”

您可以在AlertDialog的EditText上创建一个焦点侦听器，然后获取AlertDialog的窗口。从那里你可以通过调用setSoftInputMode来显示软键盘。

final AlertDialog dialog = ...;

editText.setOnFocusChangeListener(new View.OnFocusChangeListener() {
    @Override
    public void onFocusChange(View v, boolean hasFocus) {
        if (hasFocus) {
            dialog.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);
        }
    }
});

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);

要显示键盘，对我来说，我必须执行以下操作

Android文本字段:设置焦点+软输入编程

基本上解决方案如下

@Override
public void onResume() {
    super.onResume();
    //passwordInput.requestFocus(); <-- that doesn't work
    passwordInput.postDelayed(new ShowKeyboard(), 325); //250 sometimes doesn't run if returning from LockScreen
}

ShowKeyboard在哪里

private class ShowKeyboard implements Runnable {
    @Override
    public void run() {
        passwordInput.setFocusableInTouchMode(true);
        //passwordInput.requestFocusFromTouch(); //this gives touch event to launcher in background -_-
        passwordInput.requestFocus();
        getActivity().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);
        ((InputMethodManager) getActivity().getSystemService(Context.INPUT_METHOD_SERVICE)).showSoftInput(passwordInput, 0);
    }
}

在成功输入之后，我还确保隐藏了键盘

getActivity().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_HIDDEN);
((InputMethodManager) getActivity().getSystemService(Context.INPUT_METHOD_SERVICE))
                    .hideSoftInputFromWindow(getView().getWindowToken(), 0);