软键盘挡住WebView中输入框解决方法

如果是EditText，弹出软键盘好处理，会自动把输入框顶上来。

但如果输入框实在WebView中，那就不好处理了。

什么设置android:windowSoftInputMode属性啊，什么套一层ScrollView布局之类的都无效，最后再这里找到了终极解决方法，测试过有效。

附上链接：https://www.jianshu.com/p/306482e17080，感谢博主分享。

里面已经描述听详细的了，这里我也把该方法记录下来。

其实这是Android本身的一个issue 5497的bug。

解决方法有两种：

一、不用全屏模式，包含WebView的Activity使用了全屏模式，比如说没有标题栏之类的，就会出现这种遮挡的问题，如果可以的话去掉全屏就没问题了。

二、一定要全屏的Activity，那么也很简单，借助一个填坑类就可以了：

1、填坑的类AndroidBug5497Workaround：

import android.app.Activity;
import android.graphics.Rect;
import android.view.View;
import android.view.ViewTreeObserver;
import android.widget.FrameLayout;

/**
 * 解决WebView中输入时弹出软键盘，挡住输入框的问题
 * copy from https://www.jianshu.com/p/306482e17080
 * Created by ldw on 2018/5/23.
 */

public class AndroidBug5497Workaround {

    // For more information, see https://code.google.com/p/android/issues/detail?id=5497
    // To use this class, simply invoke assistActivity() on an Activity that already has its content view set.

    public static void assistActivity (Activity activity) {
        new AndroidBug5497Workaround(activity);
    }

    private View mChildOfContent;
    private int usableHeightPrevious;
    private FrameLayout.LayoutParams frameLayoutParams;

    private AndroidBug5497Workaround(Activity activity) {
        FrameLayout content = (FrameLayout) activity.findViewById(android.R.id.content);
        mChildOfContent = content.getChildAt(0);
        mChildOfContent.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            public void onGlobalLayout() {
                possiblyResizeChildOfContent();
            }
        });
        frameLayoutParams = (FrameLayout.LayoutParams) mChildOfContent.getLayoutParams();
    }

    private void possiblyResizeChildOfContent() {
        int usableHeightNow = computeUsableHeight();
        if (usableHeightNow != usableHeightPrevious) {
            int usableHeightSansKeyboard = mChildOfContent.getRootView().getHeight();
            int heightDifference = usableHeightSansKeyboard - usableHeightNow;
            if (heightDifference > (usableHeightSansKeyboard/4)) {
                // keyboard probably just became visible
                frameLayoutParams.height = usableHeightSansKeyboard - heightDifference;
            } else {
                // keyboard probably just became hidden
                frameLayoutParams.height = usableHeightSansKeyboard;
            }
            mChildOfContent.requestLayout();
            usableHeightPrevious = usableHeightNow;
        }
    }

    private int computeUsableHeight() {
        Rect r = new Rect();
        mChildOfContent.getWindowVisibleDisplayFrame(r);
        return (r.bottom - r.top);// 全屏模式下： return r.bottom
    }

}

2、Activity中使用也很简单：

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_practise);
        AndroidBug5497Workaround.assistActivity(this);
    }

两种方法都很简单，结果也不再挡住输入框了。