超简单全屏或沉浸式状态栏下软键盘遮挡输入框解决方法

原文：android全屏或沉浸式状态栏下输入框被软键盘遮挡解决方法

使用方法：

activity 的onCreate() 中设置

SoftHideKeyBoardUtil.assistActivity(this);

工具类：

public class SoftHideKeyBoardUtil {

    public static void assistActivity(Activity activity) {
        new SoftHideKeyBoardUtil(activity);
    }

    private View mChildOfContent;

    private int usableHeightPrevious;

    private FrameLayout.LayoutParams frameLayoutParams;

    //为适应华为小米等手机键盘上方出现黑条或不适配
    private int contentHeight;//获取setContentView本来view的高度

    private boolean isfirst = true;//只用获取一次

    private int statusBarHeight;//状态栏高度

    private SoftHideKeyBoardUtil(Activity activity) {

        //1､找到Activity的最外层布局控件，它其实是一个DecorView,它所用的控件就是FrameLayout
        FrameLayout content = (FrameLayout) activity.findViewById(android.R.id.content);

        //2､获取到setContentView放进去的View
        mChildOfContent = content.getChildAt(0);

        //3､给Activity的xml布局设置View树监听，当布局有变化，如键盘弹出或收起时，都会回调此监听 
        mChildOfContent.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {

            //4､软键盘弹起会使GlobalLayout发生变化

            public void onGlobalLayout() {

                if (isfirst) {
                    contentHeight = mChildOfContent.getHeight();//兼容华为等机型
                    isfirst = false;
                }//5､当前布局发生变化时，对Activity的xml布局进行重绘

                possiblyResizeChildOfContent();

            }

        });

        //6､获取到Activity的xml布局的放置参数
        frameLayoutParams = (FrameLayout.LayoutParams) mChildOfContent.getLayoutParams();
    }

    // 获取界面可用高度，如果软键盘弹起后，Activity的xml布局可用高度需要减去键盘高度 
    private void possiblyResizeChildOfContent() {

        //1､获取当前界面可用高度，键盘弹起后，当前界面可用布局会减少键盘的高度

        int usableHeightNow = computeUsableHeight();

        //2､如果当前可用高度和原始值不一样

        if (usableHeightNow != usableHeightPrevious) {

            //3､获取Activity中xml中布局在当前界面显示的高度

            int usableHeightSansKeyboard = mChildOfContent.getRootView().getHeight();

            //4､Activity中xml布局的高度-当前可用高度

            int heightDifference = usableHeightSansKeyboard - usableHeightNow;

            //5､高度差大于屏幕1/4时，说明键盘弹出

            if (heightDifference > (usableHeightSansKeyboard / 4)) {

                // 6､键盘弹出了，Activity的xml布局高度应当减去键盘高度
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {

                    frameLayoutParams.height = usableHeightSansKeyboard - heightDifference + statusBarHeight;

                } else {

                    frameLayoutParams.height = usableHeightSansKeyboard - heightDifference;

                }

            } else {

                frameLayoutParams.height = contentHeight;

            }

            //7､ 重绘Activity的xml布局

            mChildOfContent.requestLayout();
            usableHeightPrevious = usableHeightNow;

        }

    }

    private int computeUsableHeight() {

        Rect r = new Rect();

        mChildOfContent.getWindowVisibleDisplayFrame(r);

        // 全屏模式下：直接返回r.bottom，r.top其实是状态栏的高度

        return (r.bottom - r.top);

    }

}