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解决Android中Webview软键盘与沉浸式的冲突的几种方式的分析

程序员文章站 2022-01-30 20:46:46
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问题

问题主要出现在使用Webview同时使用沉浸式的时候,软键盘会遮挡webview输入的显示,并且此时webview并不能滑动。这个问题的出自Android本身的一个bug,bug号5497,从编号就能看出这个bug已经很久远了,久远到官方都不出面解决,因为民间已经有了许多方法来绕过,或者部分情况下解决这个问题。

解决的方法有三种:

  • 不要使用沉浸式布局
  • AndroidBug5497Workaround
  • 自定义LinearLayout,relativityLayout

第一种(不要使用沉浸式布局)

故名思议,不要使用沉浸式布局,也就不会发生这个问题了。其实很多情况下,这个都是一条最好的解决方式。

第二种(AndroidBug5497Workaround)

Github上一位国外大神给出的解决方案,对于国产手机疯狂魔改的预计不足,效果能出来,但总是不尽如人意,下面是调整过适配了华为小米部分系统的代码(但其实显示上还是有些问题,比如华为的机型会底部上升一个statusbar的高度,等等),有兴趣并且有信心处理未来诸多机型系统的适配的话,可以一试。

public class AndroidBug5497Workaround {
    public static void assistActivity(Activity activity) {
        new AndroidBug5497Workaround(activity);
    }
    private View mChildOfContent;
    private int usableHeightPrevious;
    private FrameLayout.LayoutParams frameLayoutParams;
    private int contentHeight;
    private   boolean isfirst = true;
    private Activity activity;
    private  int statusBarHeight;

    private AndroidBug5497Workaround(Activity activity) {
        //获取状态栏的高度
        int resourceId = activity.getResources().getIdentifier("status_bar_height", "dimen", "android");
        statusBarHeight = activity.getResources().getDimensionPixelSize(resourceId);
        this.activity = activity;
        FrameLayout content = (FrameLayout)activity.findViewById(android.R.id.content);
        mChildOfContent = content.getChildAt(0);

        //界面出现变动都会调用这个监听事件
        mChildOfContent.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            public void onGlobalLayout() {
                if (isfirst) {
                    contentHeight = mChildOfContent.getHeight();//兼容华为等机型
                    isfirst = false;
                }
                possiblyResizeChildOfContent();
            }
        });

        frameLayoutParams = (FrameLayout.LayoutParams)
                mChildOfContent.getLayoutParams();
    }

    //重新调整跟布局的高度
    private void possiblyResizeChildOfContent() {

        int usableHeightNow = computeUsableHeight();

        //当前可见高度和上一次可见高度不一致 布局变动
        if (usableHeightNow != usableHeightPrevious) {
            //int usableHeightSansKeyboard2 = mChildOfContent.getHeight();//兼容华为等机型
            int usableHeightSansKeyboard = mChildOfContent.getRootView().getHeight();
            int heightDifference = usableHeightSansKeyboard - usableHeightNow;
            if (heightDifference > (usableHeightSansKeyboard / 4)) {
                // keyboard probably just became visible
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT){
                    //frameLayoutParams.height = usableHeightSansKeyboard - heightDifference;
                    frameLayoutParams.height = usableHeightSansKeyboard - heightDifference + statusBarHeight;
                } else {
                    frameLayoutParams.height = usableHeightSansKeyboard -heightDifference;
                }
            } else {
                frameLayoutParams.height = contentHeight;
            }

            mChildOfContent.requestLayout();
            usableHeightPrevious = usableHeightNow;
        }
    }
    /**     * 计算mChildOfContent可见高度     ** @return     */
    private int computeUsableHeight() {
        Rect r = new Rect();
        mChildOfContent.getWindowVisibleDisplayFrame(r);
        return (r.bottom - r.top);
    }
}

第三种(自定义LinearLayout,relativityLayout)

此方式适合内部布局比较简单的情况,自己就是用的这种方案,因为自己的布局就是两个Framelayout,一个装载webview,另一个装载遮挡布局。
记得在设置了布局根部使用此控件并且加上android:fitsSystemWindows="true"
代码如下:

  • ResizeRelativityLayout:
/**
 * ResizeRelativeLayout,配合fitsSystemWindows=true在根布局使用,解决软键盘布局调整的问题
 */
public class ResizeRelativeLayout extends RelativeLayout {

    private int[] mInsets = new int[4];

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

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

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

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public ResizeRelativeLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    protected final boolean fitSystemWindows(Rect insets) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            // Intentionally do not modify the bottom inset. For some reason,
            // if the bottom inset is modified, window resizing stops working.

            mInsets[0] = insets.left;
            mInsets[1] = insets.top;
            mInsets[2] = insets.right;

            insets.left = 0;
            insets.top = 0;
            insets.right = 0;
        }

        return super.fitSystemWindows(insets);
    }

    @Override
    public final WindowInsets onApplyWindowInsets(WindowInsets insets) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT_WATCH) {
            mInsets[0] = insets.getSystemWindowInsetLeft();
            mInsets[1] = insets.getSystemWindowInsetTop();
            mInsets[2] = insets.getSystemWindowInsetRight();
            return super.onApplyWindowInsets(insets.replaceSystemWindowInsets(0, 0, 0,
                    insets.getSystemWindowInsetBottom()));
        } else {
            return insets;
        }
    }

}
  • ResizeLinearLayout
/**
 * ResizeLinearLayout,配合fitsSystemWindows=true在根布局使用,解决软键盘布局调整的问题
 */
public class ResizeLinearLayout extends LinearLayout {

    private int[] mInsets = new int[4];

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

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

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

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public ResizeLinearLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    protected final boolean fitSystemWindows(Rect insets) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            // Intentionally do not modify the bottom inset. For some reason,
            // if the bottom inset is modified, window resizing stops working.

            mInsets[0] = insets.left;
            mInsets[1] = insets.top;
            mInsets[2] = insets.right;

            insets.left = 0;
            insets.top = 0;
            insets.right = 0;
        }

        return super.fitSystemWindows(insets);
    }

    @Override
    public final WindowInsets onApplyWindowInsets(WindowInsets insets) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT_WATCH) {
            mInsets[0] = insets.getSystemWindowInsetLeft();
            mInsets[1] = insets.getSystemWindowInsetTop();
            mInsets[2] = insets.getSystemWindowInsetRight();
            return super.onApplyWindowInsets(insets.replaceSystemWindowInsets(0, 0, 0,
                    insets.getSystemWindowInsetBottom()));
        } else {
            return insets;
        }
    }

}