在AlertDialog中从EditText显示软键盘的问题可能是在AlertDialog.show()中，因为在显示AlertDialog之后应用了EditText。我不确定所有版本的API都是这样，但我认为解决方案来自API级别21，因为它来自AlertDialog.create()，它应该在AlertDialog.show()之前调用。

这是我对这种情况的最佳解决方案。首先，在某个地方创建:

    private int showKeyboard(View view) {
        final InputMethodManager inputManager = (InputMethodManager) requireActivity().getSystemService(Context.INPUT_METHOD_SERVICE);
        if (inputManager != null) {
            boolean isShown = inputManager.showSoftInput(view, InputMethodManager.SHOW_IMPLICIT); // flag=InputMethodManager.SHOW_IMPLICIT ili =
            return (isShown) ? 1: -1;
        }
        return 0;
    }

然后，在AlertDialog之后。生成器生成器= new AlertDialog.Builder(requireContext());继续:

    EditText editText = new EditText(requireContext());
    builder.setView(editText);
    // ... put positive-negative buttons, and etc ...
    AlertDialog dialog = builder.create(); // Create dialog from builder
    dialog.setCancelable(false); // If you need
    Handler handler = new Handler();
    dialog.setOnShowListener(new DialogInterface.OnShowListener() {
        @Override
        public void onShow(DialogInterface dialog) { // 1. When a dialog is displayed
            editText.requestFocus();
            Runnable runnable = new Runnable() { // create one runnable
                int counter = 0;
                public void run() {
                    int status = showKeyboard(editText); // 2. Call func.above for keyboard, but...
                    if(status == -1 && counter < 10){ handler.postDelayed(this, 100); counter ++; } // ...if it inst shown call again after 100ms
                }
            };
            runnable.run(); // Execute runnable first time here
        }
    });
    dialog.show();

不要忘记导入android.os.Handler;等等;-)

感谢大家的投票。

让我指出一些额外的信息，解决yuku，因为我发现很难得到这个工作!我如何从我的AlertDialog. builder获得AlertDialog对象?嗯，这是alert.show()执行的结果:

final AlertDialog.Builder alert = new AlertDialog.Builder(getActivity());
final EditText input = new EditText(getActivity());
alert.setView(input);

// do what you need, like setting positive and negative buttons...

final AlertDialog dialog = alert.show();

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

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);
        }
    }
});

是的，你可以用setOnFocusChangeListener来做，它会帮助你。

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);
        }
    }
});

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);

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);