监听软键盘，在软键盘关闭时显示其他

参考：Android获取窗口可视区域大小: getWindowVisibleDisplayFrame()

布局：

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

    <TextView
        android:id="@+id/tv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="文本框输入字符后关闭软键盘才显示"
        android:textColor="@color/colorAccent"
        android:textSize="16sp"
        android:visibility="gone" />

    <EditText
        android:id="@+id/et1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:imeOptions="actionNext"
        android:inputType="number|numberDecimal"
        android:maxLength="4"
        android:selectAllOnFocus="true"
        android:textColor="#333333"
        android:textSize="15sp" />

    <EditText
        android:id="@+id/et2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:imeOptions="actionNext"
        android:inputType="number|numberDecimal"
        android:maxLength="4"
        android:selectAllOnFocus="true"
        android:textColor="#333333"
        android:textSize="15sp" />
</LinearLayout>

代码：

/**
 * 监听软键盘，在软键盘关闭时显示其他
 */
public class MainActivityI extends AppCompatActivity {

    private EditText mEt1;
    private boolean sLastVisiable;
    private TextView mTv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maini);

        mEt1 = (EditText) findViewById(R.id.et1);
        mTv = ((TextView) findViewById(R.id.tv));

        mEt1.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {

            }

            @Override
            public void afterTextChanged(Editable s) {
                String trim = mEt1.getText().toString().trim();
                if (TextUtils.isEmpty(trim)) {
                    mTv.setVisibility(View.GONE);
                }
            }
        });

        addOnSoftKeyBoardVisibleListener(this, new OnSoftKeyBoardVisibleListener() {
            @Override
            public void onSoftKeyBoardVisible(boolean visible) {
                String trim = mEt1.getText().toString().trim();
                if (!visible && !TextUtils.isEmpty(trim)) {
                    mTv.setVisibility(View.VISIBLE);
                }
            }
        });
    }

    interface OnSoftKeyBoardVisibleListener {
        void onSoftKeyBoardVisible(boolean visible);
    }

    /**
     * 监听软键盘状态
     */
    public void addOnSoftKeyBoardVisibleListener(Activity activity, final OnSoftKeyBoardVisibleListener listener) {
        final View decorView = activity.getWindow().getDecorView();
        decorView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                Rect rect = new Rect();
                //getWindowVisibleDisplayFrame()执行结果会受到系统状态栏，系统软键盘，系统虚拟按键的影响。
                decorView.getWindowVisibleDisplayFrame(rect);
                int displayHight = rect.bottom - rect.top;
                int hight = decorView.getHeight();
                Log.e("MainActivityI", "rect.bottom===" + rect.bottom);//1812,打开软键盘后会变
                Log.e("MainActivityI", "rect.top======" + rect.top);//72不会变
                Log.e("MainActivityI", "displayHight==" + displayHight);//1740，打开软键盘后会变
                Log.e("MainActivityI", "hight=========" + hight);//1920不会变

                //没打开软键盘时：0.90625，打开软键盘时：0.4119791666666667
                Log.e("MainActivityI", "(double) displayHight / hight=========" + ((double) displayHight / hight));
                boolean visible = (double) displayHight / hight < 0.8;

                if (visible != sLastVisiable) {
                    listener.onSoftKeyBoardVisible(visible);
                }
                sLastVisiable = visible;
            }
        });
    }
}