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android自定义横竖双向滚动,Android自定义ViewGroup实现可滚动的横向布局(2)

这里直接代码:

package com.example.libingyuan.horizontallistview.ScrollViewGroup;

import android.content.Context;

import android.util.AttributeSet;

import android.view.MotionEvent;

import android.view.View;

import android.view.ViewGroup;

import android.widget.Scroller;

public class ScrollViewGroup extends ViewGroup {

private Scroller mScroller;

private float mLastMotionX = 0;

public ScrollViewGroup(Context context) {

this(context,null);

}

public ScrollViewGroup(Context context,AttributeSet attrs) {

this(context,attrs,0);

}

public ScrollViewGroup(Context context,AttributeSet attrs,int defStyleAttr) {

super(context,defStyleAttr);

init(context);

}

private void init(Context context) {

mScroller = new Scroller(context);

}

@Override

public void computeScroll() {

if (mScroller.computeScrollOffset()) {

scrollTo(mScroller.getCurrX(),mScroller.getCurrY());

postInvalidate();

}

}

@Override

public boolean onTouchEvent(MotionEvent event) {

// TODO Auto-generated method stub

int action = event.getAction();

float x = event.getX();

switch (action) {

case MotionEvent.ACTION_DOWN:

if (!mScroller.isFinished()) {

mScroller.abortAnimation();

}

mLastMotionX = event.getX();

break;

case MotionEvent.ACTION_MOVE:

float delt = mLastMotionX - x;

mLastMotionX = x;

scrollBy((int) delt,0);

break;

case MotionEvent.ACTION_UP:

invalidate();

break;

default:

break;

}

return true;

}

@Override

protected void onMeasure(int widthMeasureSpec,int heightMeasureSpec) {

//重新设置宽高

this.setMeasuredDimension(measureWidth(widthMeasureSpec,heightMeasureSpec),measureHeight(widthMeasureSpec,heightMeasureSpec));

}

private int measureWidth(int widthMeasureSpec,int heightMeasureSpec) {

// 宽度

int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);

int modeWidth = MeasureSpec.getMode(widthMeasureSpec);

//父控件的宽(wrap_content)

int width = 0;

int childCount = getChildCount();

//重新测量子view的宽度,以及最大高度

for (int i = 0; i < childCount; i++) {

View child = getChildAt(i);

measureChild(child,widthMeasureSpec,heightMeasureSpec);

MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();

int childWidth = child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;

width += childWidth;

}

return modeWidth == MeasureSpec.EXACTLY ? sizeWidth : width;

}

private int measureHeight(int widthMeasureSpec,int heightMeasureSpec) {

//高度

int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);

int modeHeight = MeasureSpec.getMode(heightMeasureSpec);

//父控件的高(wrap_content)

int height = 0;

int childCount = getChildCount();

//重新测量子view的宽度,以及最大高度

for (int i = 0; i < childCount; i++) {

View child = getChildAt(i);

measureChild(child,heightMeasureSpec);

MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();

int childHeight = child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin;

height += childHeight;

}

height = height / childCount;

return modeHeight == MeasureSpec.EXACTLY ? sizeHeight : height;

}

@Override

protected void onLayout(boolean changed,int l,int t,int r,int b) {

int childLeft = 0;

int childWidth;

int height = getHeight();

int childCount = getChildCount();

for (int i = 0; i < childCount; i++) {

View child = getChildAt(i);

MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();

childWidth = child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;

child.layout(childLeft,childLeft + childWidth,height);

childLeft += childWidth;

}

}

@Override

public LayoutParams generateLayoutParams(AttributeSet attrs) {

return new MarginLayoutParams(getContext(),attrs);

}

}

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