背景
最近在给项目添加沉浸式状态栏时遇到了一个很奇葩的问题，在Android4.4以上系统底部聊天及评论框不能被系统输入法顶上去。如下图1(图片引用自另外两种android沉浸式状态栏实现思路，更详细的问题描述也可进入这个链接查看)。
图1.png
原因是因为设置状态栏透明后没有设置android:fitsSystemWindows="true"这个属性。我的解决办法是使用AndroidBug5497Workaround 类动态计算布局的高度。这个方法原始代码在华为等手机上存在高度计算不准确的兼容性问题。我在源码的基础上做了一些修改，目前在华为，小米，三星等手机上测试均正常，修改后的代码如下。
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);
}
}
注意事项：
使用这个方法有个限制是布局内得包含有大小可调的布局如ListView,ScrollView等，并且最大高度(使用权重weight)至少得大于软键盘和输入框的高度之和。一般的聊天界面本身就是个ListView，所有不用担心这个问题。
使用方法
在你的Activity的oncreate()方法里调用AndroidBug5497Workaround.assistActivity(this);即可。注意：在setContentView(R.layout.xxx)之后调用。
关于AndroidBug5497Workaround更详细的介绍可以看这里android 软键盘在全屏下的布局计算问题
