监听键盘弹起，防止底部布局上移

前言

最近做需求，遇到软键盘弹起底部布局按钮被顶起的情况，需求不一样，对应方法也会存在差异性，说说我遇到的问题及解决过程。

问题

登录页根布局是RelativeLayout，底部有一个登录按钮通过android:layout_alignParentBottom="true"放至最底部，软键盘弹起时按钮会被顶到键盘上，遮住输入框，体验巨差。

修改

1.在manifest里面加入键盘属性android:windowSoftInputMode="adjustPan”，关于它的参数
详情可以看看这篇文章https://www.jianshu.com/p/e59a0b49cdc1。虽然对我没什么用，不过还是记录下，万一对其他人有用呢。
2.布局里面加入Scrollerview，将要显示在软键盘之上的布局包裹起来，这样软键盘会一直在要显示的布局下方，但底部按钮不会跟着上移。亲测在部分机型上有用，但是有个华为手机任然无效。
3.无奈只能监听软键盘的弹起跟收入了，我是这么操作的，上代码

  /**
     * 监听键盘弹起，防止键盘顶起底部布局
     */
    private void setLayoutKayBoard() {
        //根布局
        RelativeLayout rootView = (RelativeLayout) findViewById(R.id.rl_rootview);
        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) {
             /*有的是根据if (bottom - oldBottom < -1) 跟（bottom - oldBottom > 1）来判断软键盘是否弹起的，
             但我实际打印出来两个值相等，所以并不能解决我的问题，于是我用了以下方式*/

 			   boolean softInputVisible = KeyboardUtils.isSoftInputVisible(LoginActivity.this);
              
                if (softInputVisible) {
                //Todo这个地方可以根据自己具体的业务需求进行相应的操作，我比较粗暴，直接隐藏了
                    mTvLogin.setVisibility(View.GONE);
                } else {
               //这里延时是为了交互效果，可以根据自己的情况自行修改
                    new Handler().postDelayed(new Runnable() {
                        @Override
                        public void run() {
                            mTvLogin.setVisibility(View.VISIBLE);
                        }
                    },10);

                }
            }
        });

    } 

我这里用到了一个软键盘工具类KeyboardUtils：

public final class KeyboardUtils {

    private static int sContentViewInvisibleHeightPre;
    private static OnGlobalLayoutListener  onGlobalLayoutListener;
    private static OnSoftInputChangedListener onSoftInputChangedListener;

    private KeyboardUtils() {
        throw new UnsupportedOperationException("u can't instantiate me...");
    }

    /**
     * Show the soft input.
     *
     * @param activity The activity.
     */
    public static void showSoftInput(final Activity activity) {
        InputMethodManager imm =
                (InputMethodManager) activity.getSystemService(Activity.INPUT_METHOD_SERVICE);
        if (imm == null) return;
        View view = activity.getCurrentFocus();
        if (view == null) {
            view = new View(activity);
            view.setFocusable(true);
            view.setFocusableInTouchMode(true);
            view.requestFocus();
        }
        imm.showSoftInput(view, InputMethodManager.SHOW_FORCED);
    }

    /**
     * Show the soft input.
     *
     * @param view The view.
     */
    public static void showSoftInput(final View view) {
        InputMethodManager imm =
                (InputMethodManager) Utils.getApp().getSystemService(Context.INPUT_METHOD_SERVICE);
        if (imm == null) return;
        view.setFocusable(true);
        view.setFocusableInTouchMode(true);
        view.requestFocus();
        imm.showSoftInput(view, InputMethodManager.SHOW_FORCED);
    }

    /**
     * Hide the soft input.
     *
     * @param activity The activity.
     */
    public static void hideSoftInput(final Activity activity) {
        InputMethodManager imm =
                (InputMethodManager) activity.getSystemService(Activity.INPUT_METHOD_SERVICE);
        if (imm == null) return;
        View view = activity.getCurrentFocus();
        if (view == null) view = new View(activity);
        imm.hideSoftInputFromWindow(view.getWindowToken(), 0);
    }

    /**
     * Hide the soft input.
     *
     * @param view The view.
     */
    public static void hideSoftInput(final View view) {
        InputMethodManager imm =
                (InputMethodManager) Utils.getApp().getSystemService(Context.INPUT_METHOD_SERVICE);
        if (imm == null) return;
        imm.hideSoftInputFromWindow(view.getWindowToken(), 0);
    }

    /**
     * Toggle the soft input display or not.
     */
    public static void toggleSoftInput() {
        InputMethodManager imm =
                (InputMethodManager) Utils.getApp().getSystemService(Context.INPUT_METHOD_SERVICE);
        if (imm == null) return;
        imm.toggleSoftInput(InputMethodManager.SHOW_FORCED, 0);
    }

    /**
     * Return whether soft input is visible.
     * <p>The minimum height is 200</p>
     *
     * @param activity The activity.
     * @return {@code true}: yes<br>{@code false}: no
     */
    public static boolean isSoftInputVisible(final Activity activity) {
        return isSoftInputVisible(activity, 200);
    }

    /**
     * Return whether soft input is visible.
     *
     * @param activity             The activity.
     * @param minHeightOfSoftInput The minimum height of soft input.
     * @return {@code true}: yes<br>{@code false}: no
     */
    public static boolean isSoftInputVisible(final Activity activity,
                                             final int minHeightOfSoftInput) {
        return getContentViewInvisibleHeight(activity) >= minHeightOfSoftInput;
    }

    private static int getContentViewInvisibleHeight(final Activity activity) {
        final View contentView = activity.findViewById(android.R.id.content);
        final Rect outRect = new Rect();
        contentView.getWindowVisibleDisplayFrame(outRect);
        LogUtils.d(contentView.getTop(), contentView.getBottom(), outRect.top, outRect.bottom);
        return contentView.getBottom() - outRect.bottom;
    }

    /**
     * Register soft input changed listener.
     *
     * @param activity The activity.
     * @param listener The soft input changed listener.
     */
    public static void registerSoftInputChangedListener(final Activity activity,
                                                        final OnSoftInputChangedListener listener) {
        final int flags = activity.getWindow().getAttributes().flags;
        if ((flags & WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS) != 0) {
            activity.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);
        }
        final View contentView = activity.findViewById(android.R.id.content);
        sContentViewInvisibleHeightPre = getContentViewInvisibleHeight(activity);
        onSoftInputChangedListener = listener;
        onGlobalLayoutListener = new OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                if (onSoftInputChangedListener != null) {
                    int height = getContentViewInvisibleHeight(activity);
                    if (sContentViewInvisibleHeightPre != height) {
                        onSoftInputChangedListener.onSoftInputChanged(height);
                        sContentViewInvisibleHeightPre = height;
                    }
                }
            }
        };
        contentView.getViewTreeObserver().addOnGlobalLayoutListener(onGlobalLayoutListener);
    }

    /**
     * Register soft input changed listener.
     *
     * @param activity The activity.
     */
    @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
    public static void unregisterSoftInputChangedListener(final Activity activity) {
        final View contentView = activity.findViewById(android.R.id.content);
        contentView.getViewTreeObserver().removeOnGlobalLayoutListener(onGlobalLayoutListener);
        onSoftInputChangedListener = null;
        onGlobalLayoutListener = null;
    }

    /**
     * Fix the leaks of soft input.
     * <p>Call the function in {@link Activity#onDestroy()}.</p>
     *
     * @param context The context.
     */
    public static void fixSoftInputLeaks(final Context context) {
        if (context == null) return;
        InputMethodManager imm =
                (InputMethodManager) Utils.getApp().getSystemService(Context.INPUT_METHOD_SERVICE);
        if (imm == null) return;
        String[] strArr = new String[]{"mCurRootView", "mServedView", "mNextServedView"};
        for (int i = 0; i < 3; i++) {
            try {
                Field declaredField = imm.getClass().getDeclaredField(strArr[i]);
                if (declaredField == null) continue;
                if (!declaredField.isAccessible()) {
                    declaredField.setAccessible(true);
                }
                Object obj = declaredField.get(imm);
                if (obj == null || !(obj instanceof View)) continue;
                View view = (View) obj;
                if (view.getContext() == context) {
                    declaredField.set(imm, null);
                } else {
                    return;
                }
            } catch (Throwable th) {
                th.printStackTrace();
            }
        }
    }

    /**
     * Click blankj area to hide soft input.
     * <p>Copy the following code in ur activity.</p>
     */
    public static void clickBlankArea2HideSoftInput() {
        Log.i("KeyboardUtils", "Please refer to the following code.");
        /*
        @Override
        public boolean dispatchTouchEvent(MotionEvent ev) {
            if (ev.getAction() == MotionEvent.ACTION_DOWN) {
                View v = getCurrentFocus();
                if (isShouldHideKeyboard(v, ev)) {
                    InputMethodManager imm =
                            (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
                    imm.hideSoftInputFromWindow(v.getWindowToken(),
                            InputMethodManager.HIDE_NOT_ALWAYS
                    );
                }
            }
            return super.dispatchTouchEvent(ev);
        }

        // Return whether touch the view.
        private boolean isShouldHideKeyboard(View v, MotionEvent event) {
            if (v != null && (v instanceof EditText)) {
                int[] l = {0, 0};
                v.getLocationInWindow(l);
                int left = l[0],
                        top = l[1],
                        bottom = top + v.getHeight(),
                        right = left + v.getWidth();
                return !(event.getX() > left && event.getX() < right
                        && event.getY() > top && event.getY() < bottom);
            }
            return false;
        }
        */
    }

    public interface OnSoftInputChangedListener {
        void onSoftInputChanged(int height);
    }
}

记录一下为了防止下次遇到又忘记或者查询半天无果浪费时间。