思路

要求

ScrollView 嵌套 地址栏 和 WebView

手指滑屏向下滚动（网页向上），如果网页有滚动条，首先把 地址栏 滚动到消失，然后 WebView 才开始滚动；

手指滑屏向上滚动（网页向下），如果地址栏隐藏，那么 地址栏 首先慢慢显示，然后 WebView 才开始滚动。

实现方案

• 根据 View 的 onInterceptTouchEvent 和 onTouchEvent 原理。把 ScrollView 设置为 WebView 的一个变量，在 WebView的 onInterceptTouchEvent 方法里检测到 MotionEvent.ACTION_DOWN 事件后中断事件，在 WebView 的 onTouchEvent 事件中根据具体情况决定是把 MotionEvent.ACTION_MOVE 事件传送给 ScrollView 还是留给自己
• 由于MotionEvent.ACTION_MOVE 事件传送给 ScrollView 后无法在一次 Touch 事件中再接收，所以会导致如果有地址栏，向下滑动第一次只能滑动到 ScrollView 消失
  
• +
  
• Hack网页，加入JS脚本，前行让网页顶部空出来一段空白，空白处覆盖地址栏
• 优点是WebView大小不变化，容易控制
• 缺点是比较复杂要处理各种网页元素,各种 position 情况，实现复杂，效率低
• 由手势接管所有触发操作，再由它分发给需要滚动的控件

本文方法

资源

SrollView下面包含节点地址栏,WebView控件

<?xml version="1.0" encoding="utf-8"?><RelativeLayout android:id="@+id/root" xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity"> <samples.zjc.com.testbrowserfeature.MyScrollView android:id="@+id/scrollView" android:scrollbars="none" android:layout_width="match_parent" android:layout_height="match_parent"> <LinearLayout android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent"> <LinearLayout android:id="@+id/toolBar" android:background="#5ff0" android:orientation="horizontal" android:layout_width="match_parent" android:layout_height="wrap_content"> <EditText android:id="@+id/urlEdit" android:layout_weight="1" android:layout_width="0dp" android:layout_height="wrap_content"/> <Button android:id="@+id/goButton" android:text="Go" android:layout_width="wrap_content" android:layout_height="wrap_content"/> </LinearLayout> <samples.zjc.com.testbrowserfeature.MyWebView android:id="@+id/webView" android:layout_width="match_parent" android:layout_height="100dp" /> </LinearLayout> </samples.zjc.com.testbrowserfeature.MyScrollView></RelativeLayout>

ScrollView继承自 ScrollView

onTouchEvent 中阻止 MotionEvent.ACTION_MOVE 事件public class MyScrollView extends ScrollView { public MyScrollView(Context context) { super(context); } public MyScrollView(Context context, AttributeSet attrs) { super(context, attrs); } public MyScrollView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); } @TargetApi(Build.VERSION_CODES.LOLLIPOP) public MyScrollView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { super(context, attrs, defStyleAttr, defStyleRes); } @Override public boolean onTouchEvent(MotionEvent ev) { if(ev.getAction() == MotionEvent.ACTION_MOVE) { return true; } return super.onTouchEvent(ev); }}

MyWebView继承自 WebView

onTouchEvent 中阻止 MotionEvent.ACTION_MOVE 事件

onDrawListner

计算竖直滚动范围

public class MyWebView extends WebView { public interface MyWebViewListener { void afterDraw(WebView webView); } private MyWebViewListener mListener; private int mMoveCheckedCnt; public MyWebView(Context context) { super(context); } public MyWebView(Context context, AttributeSet attrs) { super(context, attrs); } public MyWebView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); } @TargetApi(Build.VERSION_CODES.LOLLIPOP) public MyWebView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { super(context, attrs, defStyleAttr, defStyleRes); } public MyWebView(Context context, AttributeSet attrs, int defStyleAttr, boolean privateBrowsing) { super(context, attrs, defStyleAttr, privateBrowsing); } public void setListener(MyWebViewListener listener) { mListener = listener; } @Override public boolean onTouchEvent(MotionEvent event) { switch (event.getAction()) { case MotionEvent.ACTION_DOWN: mMoveCheckedCnt = 0; flingScroll(0, 0); break; case MotionEvent.ACTION_MOVE: mMoveCheckedCnt++; return false; case MotionEvent.ACTION_UP: if(mMoveCheckedCnt >= 2) { event.setAction(MotionEvent.ACTION_CANCEL); mMoveCheckedCnt = 0; } break; } return super.onTouchEvent(event); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); MyWebViewListener listener = mListener; if(listener != null) { listener.afterDraw(this); } } public int getVScrollRange() { int v = computeVerticalScrollRange() - computeVerticalScrollExtent(); if(v < 0) { v = 0; } return v; }}

主窗口

GlobalLayoutListener 获取地址栏和滚动视图高度

GestureDetector 逻辑分发 - 决定是滑动webview还是改变webview高度从而改变ScrollView滚动范围（ScrollView总是滚动到最底）

WebView 重画之后检测当前地址栏偏移

public class MainActivity extends AppCompatActivity implements MyWebView.MyWebViewListener { MyWebView mWebView; GestureDetector mGesture = null; View mToolBar; int mToolBarHeight; MyScrollView mScrollView; int mScrollViewHeight; int mScrollOffset; EditText mUrlEdit; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mWebView = (MyWebView) findViewById(R.id.webView); mWebView.setWebViewClient(new WebViewClient() { @Override public boolean shouldOverrideUrlLoading(WebView view, String url) { return false; } }); mWebView.setListener(this); mWebView.loadUrl("http://"); mUrlEdit = (EditText) findViewById(R.id.urlEdit); findViewById(R.id.goButton).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { String url = mUrlEdit.getText().toString(); if (!url.startsWith("http://") && !url.startsWith("https://")) { url = "http://" + url; } mWebView.loadUrl(url); } }); mToolBar = findViewById(R.id.toolBar); mScrollView = (MyScrollView)findViewById(R.id.scrollView); ScrollView scrollView = (ScrollView) mScrollView; findViewById(R.id.root).getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() { @Override public void onGlobalLayout() { mToolBarHeight = mToolBar.getHeight(); mScrollViewHeight = mScrollView.getHeight(); adjustScrollView(); } }); mGesture = new GestureDetector(this, new GestureListener()); } @Override public boolean dispatchTouchEvent(MotionEvent ev) { mGesture.onTouchEvent(ev); return super.dispatchTouchEvent(ev); } @Override public void afterDraw(WebView webView) { if (mWebView.getVScrollRange() < mScrollOffset) { mScrollOffset = mWebView.getVScrollRange(); adjustScrollView(); } } class GestureListener extends GestureDetector.SimpleOnGestureListener { @Override public boolean onDoubleTap(MotionEvent e) { Log.e("Temp", "onDoubleTap"); return super.onDoubleTap(e); } @Override public boolean onDown(MotionEvent e) { Log.e("Temp", "onDown"); return super.onDown(e); } @Override public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) { Log.e("Temp", "onFling:velocityX = " + velocityX + " velocityY" + velocityY); int effectX = (int) velocityX; int effectY = (int) velocityY; if (effectOnScrollViewByScroll((velocityY < 0 ? 1 : -1) * 8000)) { effectY = 0; } mWebView.flingScroll(-effectX, -effectY); return super.onFling(e1, e2, velocityX, velocityY); } @Override public void onLongPress(MotionEvent e) { Log.e("Temp", "onLongPress"); super.onLongPress(e); } @Override public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) { Log.e("Temp", "onScroll:distanceX = " + distanceX + " distanceY = " + distanceY); int effectX = (int) distanceX; int effectY = (int) distanceY; if (effectOnScrollViewByScroll((int) distanceY)) { effectY = 0; } mWebView.scrollBy(effectX, effectY); return super.onScroll(e1, e2, distanceX, distanceY); } @Override public boolean onSingleTapUp(MotionEvent e) { Log.e("Temp", "onSingleTapUp"); return super.onSingleTapUp(e); } } private boolean effectOnScrollViewByScroll(int distanceY) { if (distanceY > 0) { // scroll up, the web will scroll down if (mScrollOffset >= mToolBarHeight || mScrollOffset >= mWebView.getVScrollRange()) { return false; } mScrollOffset += distanceY; if (mScrollOffset > mToolBarHeight) { mScrollOffset = mToolBarHeight; } if (mScrollOffset > mWebView.getVScrollRange()) { mScrollOffset = mWebView.getVScrollRange(); } } else { if (mScrollOffset <= 0) { return false; } mScrollOffset += distanceY; if (mScrollOffset <= 0) { mScrollOffset = 0; } } adjustScrollView(); return true; } private void adjustScrollView() { Log.e("Temp", "offset is " + mScrollOffset); ViewGroup.LayoutParams layoutParams = mWebView.getLayoutParams(); int newHeight = (mScrollViewHeight - mToolBarHeight) + mScrollOffset; Log.e("Temp", "newHeight is " + newHeight + ", layoutParams.height" + layoutParams.height); if (newHeight != layoutParams.height) { layoutParams.height = newHeight; mWebView.setLayoutParams(layoutParams); new Handler(Looper.getMainLooper()).post(new Runnable() { @Override public void run() { mScrollView.fullScroll(ScrollView.FOCUS_DOWN); } }); } }}

总结

以上所述是小编给大家介绍的Android 类似UC浏览器的效果：向上滑动地址栏隐藏功能，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对网站的支持！