问题
In Chrome, the address bar will be hidden/shown when user swipes up/down the content.
Can I implement the similar logic to my app?
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity"
tools:ignore="MergeRootFrame">
<WebView
android:id="@+id/my_webview"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</FrameLayout>
I wonder if there is anything I can do by the following code, so that the ActionBar will be hidden/shown when user swipe up/down the webView.
WebView webView = (WebView) findViewById(R.id.my_webview);
webView.setOnTouchListener(new View.OnTouchListener() {
public boolean onTouch (View v, MotionEvent event) {
webView.onTouchEvent(event);
}
});
回答1:
First you need layout with alignParentBottom and match_parent WebView and some bar at top:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#ffff" >
<WebView
android:id="@+id/webView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentBottom="true" />
<RelativeLayout
android:id="@+id/actionBar"
android:layout_width="match_parent"
android:layout_height="50dp" >
<TextView
android:id="@+id/tvTitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:text="TextView" />
</RelativeLayout>
</RelativeLayout>
Then you need code:
1) Declare and set some internal values and resize WebView to make it below our bar:
private int baseHeight;
private int webViewOnTouchHeight;
private int barHeight;
private float heightChange;
private float startEventY;
barHeight = actionBar.getMeasuredHeight();
baseHeight = getView().getMeasuredHeight();
webView.getLayoutParams().height = webView.getMeasuredHeight() - barHeight;
webView.requestLayout();
webView.setOnTouchListener(listener);
2) Create resize method. Here we check new height with limits of screen top and bar height
private boolean resizeView(float delta) {
heightChange = delta;
int newHeight = (int)(webViewOnTouchHeight - delta);
if (newHeight > baseHeight){ // scroll over top
if (webView.getLayoutParams().height < baseHeight){
webView.getLayoutParams().height = baseHeight;
webView.requestLayout();
return true;
}
}else if (newHeight < baseHeight - barHeight){ // scroll below bar
if (webView.getLayoutParams().height > baseHeight - barHeight){
webView.getLayoutParams().height = baseHeight - barHeight;
webView.requestLayout();
return true;
}
} else { // scroll between top and bar
webView.getLayoutParams().height = (int)(webViewOnTouchHeight - delta);
webView.requestLayout();
return true;
}
return false;
}
3) Create custom onTouch listener where we will resize WebView and change Y-value of our bar
private OnTouchListener listener = new OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
startEventY = event.getY();
heightChange = 0;
webViewOnTouchHeight = webView.getLayoutParams().height;
break;
case MotionEvent.ACTION_MOVE:
float delta = (event.getY()+heightChange)-startEventY;
boolean heigthChanged = resizeView(delta);
if (heigthChanged){
actionBar.setTranslationY(baseHeight - webView.getLayoutParams().height - barHeight);
}
}
return false;
}
};
回答2:
This pattern is called Quick Return. Start with this blog post.
However, it is worthwhile reading this when considering its use.
回答3:
There is now a really clean way to accomplish this without writing any Java code using the Design Support Library. See Dhir Pratap's answer below:
(I would have placed this as a comment but I don't have enough rep.)
How to Hide ActionBar/Toolbar While Scrolling Down in Webview
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="@+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="fill_vertical"
app:layout_behavior="@string/appbar_scrolling_view_behavior">
<WebView
android:id="@+id/webview"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>
回答4:
try the following code, hope it works for you:
private void init(){
WebView web = new WebView(this);
final Context context = this;
web.setOnTouchListener(new OnTouchListener() {
public boolean onTouch(View arg0, MotionEvent event) {
// TODO Auto-generated method stub
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
// show action bar
((Activity) context).getActionBar().show();
break;
case MotionEvent.ACTION_UP:
// hide action bar
((Activity) context).getActionBar().hide();
break;
default:
break;
}
return false;
}
});
}
来源：https://stackoverflow.com/questions/20649079/how-can-i-implement-a-chrome-like-auto-hide-navigation-for-my-android-app