Question

这是我xml中最顶层的ll

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/rootLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/blue_bg"
    android:gravity="center_horizontal"
    android:orientation="vertical" >

然后我使用这段代码：

private void setKeyboardVisibilityListener()
{
    final View root = findViewById(R.id.rootLayout);

    root.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {

        @Override
        public void onGlobalLayout() {
            // TODO Auto-generated method stub
            View continueButton = findViewById(R.id.continueButton);
            int heightDiff = root.getRootView().getHeight() - root.getHeight();
                if (heightDiff > 100) { // more than 100 pixels is probably a keyboard
                    // keyboard is shown
                    mInputBox.setBackgroundResource(R.drawable.input_box_active);
                } else {
                    // keyboard is not shown
                    mInputBox.setBackgroundResource(R.drawable.input_box_idle);
                }
            }
        });
}

但是当软键盘进入和出现时，我总是得到heightDiff == 50

Answer 1

我为我的要求制作了这个Singleton帮助程序类，因此您可以根据需要轻松移植它：

public final class SoftInputUtils {

    private transient SoftReference<View> mView;
    private int mLastHeightDifference = 0;

    public void startDetectingSoftInput(final View view) {
        if (view.getViewTreeObserver().isAlive()) {
            mView = new SoftReference<View>(view);

            if (mView.get() != null) {
                View v = mView.get();
                v.getViewTreeObserver().addOnGlobalLayoutListener(
                        new OnGlobalLayoutListener() {

                            @Override
                            public void onGlobalLayout() {
                                checkPotentialSoftInputVisibility();
                            }
                        });
            }
        }
    }

    private void checkPotentialSoftInputVisibility() {
        if (mView != null && mView.get() != null) {
            View v = mView.get();

            Rect r = new Rect();
            v.getWindowVisibleDisplayFrame(r);

            int screenHeight = v.getRootView().getHeight();
            int heightDifference = screenHeight - (r.bottom - r.top);

            // Soft input potentially got visible, so we readjust view height
            if (heightDifference > screenHeight / 5
                    && heightDifference != mLastHeightDifference) {
                ViewGroup.LayoutParams lp = (ViewGroup.LayoutParams) v
                        .getLayoutParams();
                lp.height = screenHeight - heightDifference;
                v.requestLayout();

                mLastHeightDifference = heightDifference;
            } else if (heightDifference != mLastHeightDifference) {
                // And now most likely not visible so adjust height back
                ViewGroup.LayoutParams lp = (ViewGroup.LayoutParams) v
                        .getLayoutParams();
                lp.height = ViewGroup.LayoutParams.MATCH_PARENT;
                v.requestLayout();

                mLastHeightDifference = heightDifference;
            }
        }
    }
}

为什么在软键盘输入时以及何时输出时heightDiff == 50？

1 个答案: