先看效果图：
public class FastScrollView extends ScrollView {
private Rect mBarRect = new Rect();
private int mScrollExWidth;
private int mScrollExHeight;
private boolean mScrollStart;
private int dx, dy;
private int mRightPadding;
public FastScrollView(Context context) {
super(context);
init();
}
public FastScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public FastScrollView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
mScrollExWidth = dip2px(16); //扩展拖动区域宽度，可自行修改
mScrollExHeight = dip2px(50); //扩展拖动区域高度，可自行修改
}
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
switch (ev.getAction() & ev.getActionMasked()) {
case MotionEvent.ACTION_DOWN:
//Log.e("fly", "down");
mScrollStart = false;
if (canScroll()) {
dx = (int) ev.getX();
dy = (int) ev.getY();
float scrollPos = (float) getHeight() / getChildView().getHeight();
int barHeight = (int) (scrollPos * getHeight());
//Log.e("fly", scrollPos+", "+ barHeight);
mBarRect.left = getWidth() - mRightPadding - getVerticalScrollbarWidth();
mBarRect.right = getWidth() - mRightPadding;
mBarRect.top = (int) (getScrollY() * scrollPos);
mBarRect.bottom = mBarRect.top + barHeight;
//Dbg.print(mBarRect.left, mBarRect.right, mBarRect.top, mBarRect.bottom, dx, dy);
if (dx >= mBarRect.left - mScrollExWidth
&& dx < mBarRect.right
&& dy >= mBarRect.top - mScrollExHeight
&& dy < mBarRect.bottom + mScrollExHeight) {
//Log.e("fly", "mScrollStart");
mScrollStart = true;
}
}
break;
case MotionEvent.ACTION_MOVE:
if (mScrollStart) {
int offsetY = (int) ev.getY() - dy;
//Log.e("fly", "move: " + ev.getY());
int top = mBarRect.top + offsetY;
float scrollPos = (float) top / getHeight();
int scrollY = (int) (scrollPos * getChildView().getHeight());
if (scrollY < 0) {
scrollY = 0;
}
if (scrollY > getChildView().getHeight() - getHeight()) {
scrollY = getChildView().getHeight() - getHeight();
}
setScrollY(scrollY);
return true;
}
break;
}
return super.dispatchTouchEvent(ev);
}
private boolean canScroll() {
View child = getChildView();
if (child != null && child.getHeight() > getHeight()) {
return true;
} else {
return false;
}
}
private View getChildView() {
if (getChildCount() > 0) {
return getChildAt(0);
} else {
return null;
}
}
private int dip2px(float dpValue) {
final float scale = getContext().getResources().getDisplayMetrics().density;
return (int) (dpValue * scale + 0.5f);
}
public void setRightPadding(int mRightPadding) {
this.mRightPadding = mRightPadding;
}
}布局中设置了大滚动条样式，滚动时更加明显：
<com.zwxuf.apkparserdemo.FastScrollView
android:id="@+id/mScrollView"
android:layout_width="0dp"
android:layout_weight="1"
android:scrollbarSize="10dp"
android:paddingRight="10dp"
android:scrollbarThumbVertical="@drawable/fast_scroll_thumb_drawable"
android:layout_height="match_parent">
<HorizontalScrollView
android:layout_width="match_parent"
android:layout_height="match_parent" >
<EditText
android:id="@+id/et_xml"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@null"
android:editable="false"
android:textColor="#000000"
android:textSize="10sp"
android:typeface="monospace"/>
</HorizontalScrollView>
</com.zwxuf.apkparserdemo.FastScrollView>同理，可以依此制作快速滚动的 HorizontalScrollView。
到此这篇关于Android实现快速滚动FastScrollView的文章就介绍到这了,更多相关android滚动FastScrollView内容请搜索编程网以前的文章或继续浏览下面的相关文章希望大家以后多多支持编程网！
