您还可以创建EditText的自定义扩展，该扩展在接收到焦点时知道打开软键盘。这就是我最后要做的。以下是对我有效的方法:

public class WellBehavedEditText extends EditText {
    private InputMethodManager inputMethodManager;
    private boolean showKeyboard = false;

    public WellBehavedEditText(Context context) {
        super(context);
        this.initializeWellBehavedEditText(context);
    }

    public WellBehavedEditText(Context context, AttributeSet attributes) {
        super(context, attributes);
        this.initializeWellBehavedEditText(context);
    }

    public WellBehavedEditText(Context context, AttributeSet attributes, int defStyleAttr) {
        super(context, attributes, defStyleAttr);
        this.initializeWellBehavedEditText(context);
    }

    public WellBehavedEditText(Context context, AttributeSet attributes, int defStyleAttr, int defStyleRes) {
        super(context, attributes, defStyleAttr, defStyleRes);
        this.initializeWellBehavedEditText(context);
    }

    private void initializeWellBehavedEditText(Context context) {
        this.inputMethodManager = (InputMethodManager)context.getSystemService(Context.INPUT_METHOD_SERVICE);

        final WellBehavedEditText editText = this;
        this.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                if(showKeyboard) {
                    showKeyboard = !(inputMethodManager.showSoftInput(editText, InputMethodManager.SHOW_FORCED));
                }
            }
        });
    }

    @Override
    protected void onFocusChanged(boolean focused, int direction, Rect previouslyFocusedRect) {
        if(!focused) this.showKeyboard = false;
        super.onFocusChanged(focused, direction, previouslyFocusedRect);
    }

    @Override
    public boolean requestFocus(int direction, Rect previouslyFocusedRect) {
        boolean result = super.requestFocus(direction, previouslyFocusedRect);
        this.showKeyboard = true;
        final WellBehavedEditText self = this;
        this.post(new Runnable() {
            @Override
            public void run() {
                showKeyboard = !(inputMethodManager.showSoftInput(self, InputMethodManager.SHOW_FORCED));
            }
        });
        return result;
    }
}

final InputMethodManager keyboard = (InputMethodManager) ctx.getSystemService(Context.INPUT_METHOD_SERVICE);
keyboard.toggleSoftInput(InputMethodManager.SHOW_FORCED,0);

我在各种不同的情况下都有同样的问题，我发现的解决方案在一些情况下工作，但在其他情况下不工作，所以这里是一个在我发现的大多数情况下工作的组合解决方案:

public static void showVirtualKeyboard(Context context, final View view) {
    if (context != null) {
        final InputMethodManager imm =  (InputMethodManager) context.getSystemService(Context.INPUT_METHOD_SERVICE);
        view.clearFocus();

        if(view.isShown()) {
            imm.showSoftInput(view, 0);
            view.requestFocus();
        } else {
            view.addOnAttachStateChangeListener(new View.OnAttachStateChangeListener() {
                @Override
                public void onViewAttachedToWindow(View v) {
                    view.post(new Runnable() {
                        @Override
                        public void run() {
                            view.requestFocus();
                            imm.showSoftInput(view, 0);
                        }
                    });

                    view.removeOnAttachStateChangeListener(this);
                }

                @Override
                public void onViewDetachedFromWindow(View v) {
                    view.removeOnAttachStateChangeListener(this);
                }
            });
        }
    }
}

以下代码摘自谷歌的4.1 SearchView源代码。这似乎也适用于较小版本的Android。

private Runnable mShowImeRunnable = new Runnable() {
    public void run() {
        InputMethodManager imm = (InputMethodManager) getContext()
                .getSystemService(Context.INPUT_METHOD_SERVICE);

        if (imm != null) {
            imm.showSoftInput(editText, 0);
        }
    }
};

private void setImeVisibility(final boolean visible) {
    if (visible) {
        post(mShowImeRunnable);
    } else {
        removeCallbacks(mShowImeRunnable);
        InputMethodManager imm = (InputMethodManager) getContext()
                .getSystemService(Context.INPUT_METHOD_SERVICE);

        if (imm != null) {
            imm.hideSoftInputFromWindow(getWindowToken(), 0);
        }
    }
}

此外，需要在创建控件/活动时添加以下代码。(在我的例子中，它是一个复合控件，而不是一个活动)。

this.editText.setOnFocusChangeListener(new View.OnFocusChangeListener() {
    public void onFocusChange(View v, boolean hasFocus) {
        setImeVisibility(hasFocus);
    }
});

有时劳科德鲁格的答案并不管用。我是这样做的，经过了一些尝试和错误:

public static void showKeyboard(Activity activity) {
    if (activity != null) {
        activity.getWindow()
                .setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);
    }
}

public static void hideKeyboard(Activity activity) {
    if (activity != null) {
        activity.getWindow()
                .setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);
    }
}

EditText部分:

    editText.setOnFocusChangeListener(new View.OnFocusChangeListener() {
        @Override
        public void onFocusChange(View v, boolean hasFocus) {
            if (!hasFocus) {
                hideKeyboard(getActivity());
            } else {
                showKeyboard(getActivity());
            }
        }
    });

使用Xamarin，这对我来说是一个片段:

using Android.Views.InputMethods;
using Android.Content;

...

if ( _txtSearch.RequestFocus() ) {
  var inputManager = (InputMethodManager) Activity.GetSystemService( Context.InputMethodService );
  inputManager.ShowSoftInput( _txtSearch, ShowFlags.Implicit );
}