libgdx实现android ios监听键盘状态

由于项目中需要监听软键盘的弹出 消失，并且需要知道键盘弹出时的高度（为了将画布往上移动，不要挡住输入的UI）

1.我们先定义引擎(下面说的引擎，引擎端都是指core里面)统一接口：

public interface OnKeyboardChangeListener{
        public void onKeyboardChange(boolean visible,float keyboardHeight);
    }

2.android端实现：

private OnKeyboardChangeListener onKeyboardChangeListener;
private boolean isKeyboardShow;
private float gameKeyboardHeight,screenKeyboardHeight;
private int visibleWidth,visibleHeight;

//这里的context其实是activity
//在平台接口实现类的构造方法里面调用下面代码
final View rootView = this.context.getWindow().getDecorView().getRootView();
Rect rect = new Rect();
rootView.getWindowVisibleDisplayFrame(rect);
visibleWidth = rect.width();
visibleHeight = rect.height();

//this shifts min api to 11
rootView.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
    @Override
    public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
          Rect rect = new Rect();
          rootView.getWindowVisibleDisplayFrame(rect);

          if (!(visibleWidth == rect.width() && visibleHeight == rect.height())) {
             visibleWidth = rect.width();
             visibleHeight = rect.height();
            //这里将键盘高度由原生转换到引擎端与stage高度对应    
             float gameHeight = 1136;
             float hScale = Gdx.graphics.getHeight() / gameHeight;
                    
             screenKeyboardHeight = Gdx.graphics.getHeight() - visibleHeight;
             gameKeyboardHeight = (int) (screenKeyboardHeight / hScale);
             isKeyboardShow = gameKeyboardHeight > 2;

             if (onKeyboardChangeListener != null) {
                        onKeyboardChangeListener.onKeyboardChange(isKeyboardShow, gameKeyboardHeight);
            }
        }
    }
});

3.ios端实现：

private boolean keyBoardVisible;
private OnKeyboardChangeListener onKeyboardChangeListener;
private float keyboardHeight;
//在平台接口的初始化代码中调用下面代码
NSNotificationCenter center = NSNotificationCenter.getDefaultCenter();
center.addObserver(this, Selector.register("keyboardWillShow:"), UIWindow.KeyboardWillShowNotification(), null);
center.addObserver(this, Selector.register("keyboardWillHide:"), UIWindow.KeyboardWillHideNotification(), null);

//对应两个Selector方法实现
@SuppressWarnings("unchecked")
    @Method(selector="keyboardWillShow:")
    public void keyboardWillShow(NSNotification notification){
        keyBoardVisible = true;
        
        //获取键盘的高度
        NSDictionary userInfo = (NSDictionary) notification.getUserInfo();
        NSValue value = (NSValue) userInfo.get(UIKeyboardAnimation.Keys.FrameEnd());
        CGRect keyboardRect = NSValueExtensions.getRectValue(value);
        double height = keyboardRect.getSize().getHeight();
        //这里将键盘高度由原生转换到引擎端与stage高度对应
        float gameHeight = 1136;
        float hScale = (float) (UIScreen.getMainScreen().getBounds().getHeight() / gameHeight);  //1.69
        keyboardHeight = (int) (height / hScale);
        
        if (onKeyboardChangeListener != null) {
            onKeyboardChangeListener.onKeyboardChange(keyBoardVisible, keyboardHeight);
        }
    }
    
    @Method(selector="keyboardWillHide:")
    public void keyboardWillHide(NSNotification notification){
        keyBoardVisible = false;
        keyboardHeight = 0;
        if (onKeyboardChangeListener != null) {
            onKeyboardChangeListener.onKeyboardChange(keyBoardVisible, keyboardHeight);
        }
    }

//注意在不想监听的时候调用下面代码
NSNotificationCenter center = NSNotificationCenter.getDefaultCenter();
center.removeObserver(this);

//引擎端统一接口
public interface PlatformInterface{
        public void setOnKeyboardChangeListener(OnKeyboardChangeListener listener);
    public OnKeyboardChangeListener getOnKeyboardChangeListener();
        
        public interface OnKeyboardChangeListener{
        public void onKeyboardChange(boolean visible,float keyboardHeight);
    }
}

//接下来在引擎端调用
platformInterface.setOnKeyboardChangeListener(new OnKeyboardChangeListener() {
            public void onKeyboardChange(boolean visible, float keyboardHeight) {
                if (!visible) {
                    stage.setKeyboardFocus(null);
                    stage.getRoot().addAction(Actions.moveTo(0, 0, 0.2f));
                }else {
                    stage.getRoot().addAction(Actions.moveTo(0, keyboardHeight, 0.2f));
                }
            }
        });

然后在引擎端设置监听，然后就可以根据键盘高度移动画布。
至此，应该就可以实现键盘弹出时将画布向上推的效果，如果有什么不明白的，欢迎留言。