检测用户何时关闭软键盘

我知道一种方法来做到这一点。子类化 EditText 并实现：

@Override
public boolean onKeyPreIme(int keyCode, KeyEvent event) {
  if (event.getKeyCode() == KeyEvent.KEYCODE_BACK) {
    // Do your thing.
    return true;  // So it is not propagated.
  }
  return super.dispatchKeyEvent(event);
}

以下是有关如何使用自定义视图的链接（用于子类化 EditText）：http://developer.android.com/guide/topics/ui/custom-components.html

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杰，你的解决方案很好！谢谢 ：）

public class EditTextBackEvent extends EditText {

    private EditTextImeBackListener mOnImeBack;

    public EditTextBackEvent(Context context) {
        super(context);
    }

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

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

    @Override
    public boolean onKeyPreIme(int keyCode, KeyEvent event) {
        if (event.getKeyCode() == KeyEvent.KEYCODE_BACK && 
            event.getAction() == KeyEvent.ACTION_UP) {
            if (mOnImeBack != null) 
                mOnImeBack.onImeBack(this, this.getText().toString());
        }
        return super.dispatchKeyEvent(event);
    }

    public void setOnEditTextImeBackListener(EditTextImeBackListener listener) {
        mOnImeBack = listener;
    }

}

public interface EditTextImeBackListener {
    public abstract void onImeBack(EditTextBackEvent ctrl, String text);
}

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我通过调用 super.onKeyPreIme() 对 Jay 的解决方案稍作改动：

_e = new EditText(inflater.getContext()) {
    @Override
    public boolean onKeyPreIme(int keyCode, KeyEvent event) {
        if (event.getKeyCode() == KeyEvent.KEYCODE_BACK){
            cancelTextInput();
        }
        return super.onKeyPreIme(keyCode, event);
    }
};

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这是我的自定义 EditText 来检测键盘是否显示

/**
 * Created by TheFinestArtist on 9/24/15.
 */
public class KeyboardEditText extends EditText {

    public KeyboardEditText(Context context) {
        super(context);
    }

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

    public KeyboardEditText(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onFocusChanged(boolean focused, int direction, Rect previouslyFocusedRect) {
        super.onFocusChanged(focused, direction, previouslyFocusedRect);
        if (listener != null)
            listener.onStateChanged(this, true);
    }

    @Override
    public boolean onKeyPreIme(int keyCode, @NonNull KeyEvent event) {
        if (event.getKeyCode() == KeyEvent.KEYCODE_BACK
                && event.getAction() == KeyEvent.ACTION_UP) {
            if (listener != null)
                listener.onStateChanged(this, false);
        }
        return super.onKeyPreIme(keyCode, event);
    }

    /**
     * Keyboard Listener
     */
    KeyboardListener listener;

    public void setOnKeyboardListener(KeyboardListener listener) {
        this.listener = listener;
    }

    public interface KeyboardListener {
        void onStateChanged(KeyboardEditText keyboardEditText, boolean showing);
    }
}

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现在是 2019 年......所以我用 Kotlin 创建了一个更简洁的解决方案

1.创建扩展函数：

fun Activity.addKeyboardToggleListener(onKeyboardToggleAction: (shown: Boolean) -> Unit): KeyboardToggleListener? {
    val root = findViewById<View>(android.R.id.content)
    val listener = KeyboardToggleListener(root, onKeyboardToggleAction)
    return root?.viewTreeObserver?.run {
        addOnGlobalLayoutListener(listener)
        listener
    }
}

2.切换监听器在哪里：

open class KeyboardToggleListener(
        private val root: View?,
        private val onKeyboardToggleAction: (shown: Boolean) -> Unit
) : ViewTreeObserver.OnGlobalLayoutListener {
    private var shown = false
    override fun onGlobalLayout() {
        root?.run {
            val heightDiff = rootView.height - height
            val keyboardShown = heightDiff > dpToPx(200f)
            if (shown != keyboardShown) {
                onKeyboardToggleAction.invoke(keyboardShown)
                shown = keyboardShown
            }
        }
    }
}

fun View.dpToPx(dp: Float) = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, resources.displayMetrics).roundToInt()

3.在任何活动中使用它，就像这样简单：

addKeyboardToggleListener {shown ->
          // hurray! Now you know when the keyboard is shown and hidden!!
      }

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使用@olivier_sdg 的答案，但转换为 Kotlin：

class KeyboardEditText : AppCompatEditText {

    var listener: Listener? = null
  
    constructor(context: Context) : super(context)
    constructor(context: Context, attrs: AttributeSet?) : super(context, attrs)
    constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int) : super(context, attrs, defStyleAttr)
  
    override fun onKeyPreIme(keyCode: Int, event: KeyEvent): Boolean {
        if (event.keyCode == KeyEvent.KEYCODE_BACK && event.action == KeyEvent.ACTION_UP) {
            listener?.onImeBack(this)
        }
        return super.dispatchKeyEvent(event)
    }
  
    interface Listener {
        fun onImeBack(editText: KeyboardEditText)
    }

}

用法：

keyboardEditText.listener = object : KeyboardEditText.Listener {
    override fun onImeBack(editText: KeyboardEditText) {
        //Back detected
    }
}

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只需创建一个扩展 Edittext 的类并在您的代码中使用该 edittext，您应该只覆盖自定义 edittext 中的以下方法：

@Override
 public boolean onKeyPreIme(int keyCode, KeyEvent event) {
 if (keyCode == KeyEvent.KEYCODE_BACK) {

    //Here it catch all back keys
    //Now you can do what you want.

} else if (keyCode == KeyEvent.KEYCODE_MENU) {
    // Eat the event
    return true;
}
return false;}

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这是关键侦听器的解决方案。我不知道为什么会这样，但是如果您只是在自定义 EditText 上完全覆盖 onKeyPreIme，则 OnKeyListener 会起作用。

SomeClass.java

customEditText.setOnKeyListener((v, keyCode, event) -> {
            if(event.getAction() == KeyEvent.ACTION_DOWN) {
                switch (keyCode) {
                    case KeyEvent.KEYCODE_BACK:
                        getPresenter().onBackPressed();
                        break;
                }
            }
            return false;
        }); 

CustomEditText.java

@Override
    public boolean onKeyPreIme(int keyCode, KeyEvent event) {
        return super.dispatchKeyEvent(event);
    }

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对于希望在 Xamarin 中做同样事情的任何人，我已经翻译了一些热门答案，因为它有点不同。我创建了一个要点 here，但总而言之，您创建了一个自定义 EditText 并覆盖 OnKeyPreIme，如下所示：

public class CustomEditText : EditText
{
    public event EventHandler BackPressed;

    // ...

    public override bool OnKeyPreIme([GeneratedEnum] Keycode keyCode, KeyEvent e)
    {
        if (e.KeyCode == Keycode.Back && e.Action == KeyEventActions.Up)
        {
            BackPressed?.Invoke(this, new EventArgs());
        }

        return base.OnKeyPreIme(keyCode, e);
    }
}

...然后在视图中...

editText = FindViewById<CustomEditText>(Resource.Id.MyEditText);
editText.BackPressed += (s, e) => 
{
    // <insert code here>
};

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hideSoftInputFromWindow 键盘关闭时返回 true 使用它的值来检测 android 中的键盘关闭

InputMethodManager imm = (InputMethodManager) getContext().getSystemService(Context.INPUT_METHOD_SERVICE);

        if (imm.hideSoftInputFromWindow(findFocus().getWindowToken(),
                InputMethodManager.HIDE_NOT_ALWAYS)) {
            //keyboard is closed now do what you need here
        }

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Koltin 也适用于横向模式的解决方案（如果用户在横向模式下按 Done 按钮，则不会调用 onKeyPreIme）：

class CustomEditText(context: Context, attrs: AttributeSet) : AppCompatEditText(context, attrs) {

    override fun onKeyUp(keyCode: Int, event: KeyEvent?): Boolean {
        if ((event?.keyCode == KeyEvent.KEYCODE_ENTER) && (event?.action == KeyEvent.ACTION_UP)) {
            if (hasFocus())
                clearFocus()
        }
        return super.onKeyUp(keyCode, event)
    }

    override fun onKeyPreIme(keyCode: Int, event: KeyEvent?): Boolean {
        if ((event?.keyCode == KeyEvent.KEYCODE_BACK) && (event?.action == KeyEvent.ACTION_UP)) {
            if (hasFocus())
                clearFocus()
        }
        return super.onKeyPreIme(keyCode, event)
    }
}

https://i.stack.imgur.com/IWN4J.png

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