android 页面滑动

android的页面滑动可以使用ViewPager实现，但是使用viewpage还是存在一些问题。

在网上找到了一个Demo，他是直接写一个布局来实现屏幕的滚动滑动，效果还不错。

分享一下。

源码如下，DEMO在附件中。

package com.work.demoa;

import android.content.Context;

import android.util.AttributeSet;

import android.util.Log;

import android.view.MotionEvent;

import android.view.VelocityTracker;

import android.view.View;

import android.view.ViewConfiguration;

import android.view.ViewGroup;

import android.widget.Scroller;

public class ScrollLayout extends ViewGroup {

private static final String TAG = "ScrollLayout";

private Scroller mScroller = null;

private VelocityTracker mVelocityTracker = null;

private int mCurScreen = 0;

private int mDefaultScreen = 1;

private static final int TOUCH_STATE_REST = 0;

private static final int TOUCH_STATE_SCROLLING = 1;

private static final int SNAP_VELOCITY = 600;

private int mTouchState = TOUCH_STATE_REST;

private int mTouchSlop = 0;

private float mLastMotionX = 0;

private float mLastMotionY = 0;

private OnScreenChangedListener mOnScreenChangedListener;

public void setOnScreenChangedListener(OnScreenChangedListener l) {

mOnScreenChangedListener = l;

}

public interface OnScreenChangedListener {

void onScreenChanged(ScrollLayout sc, int whichScreen);

}

public ScrollLayout(Context context, AttributeSet attrs) {

this(context, attrs, 0);

}

public ScrollLayout(Context context, AttributeSet attrs, int defStyle) {

super(context, attrs, defStyle);

mScroller = new Scroller(context);

mCurScreen = mDefaultScreen;

mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();

}

@Override

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

// TODO Auto-generated method stub

if (changed) {

int childLeft = 0;

final int childCount = getChildCount();

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

final View childView = getChildAt(i);

if (childView.getVisibility() != View.GONE) {

final int childWidth = childView.getMeasuredWidth();

childView.layout(childLeft, 0, childLeft + childWidth,

childView.getMeasuredHeight());

childLeft += childWidth;

}

@Override

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

Log.e(TAG, "onMeasure");

super.onMeasure(widthMeasureSpec, heightMeasureSpec);

final int width = MeasureSpec.getSize(widthMeasureSpec);

final int widthMode = MeasureSpec.getMode(widthMeasureSpec);

if (widthMode != MeasureSpec.EXACTLY) {

throw new IllegalStateException(

"ScrollLayout only can run at EXACTLY mode!");

}

final int heightMode = MeasureSpec.getMode(heightMeasureSpec);

if (heightMode != MeasureSpec.EXACTLY) {

throw new IllegalStateException(

"ScrollLayout only can run at EXACTLY mode!");

}

// The children are given the same width and height as the scrollLayout

final int count = getChildCount();

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

getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec);

}

// Log.e(TAG, "moving to screen "+mCurScreen);

scrollTo(mCurScreen * width, 0);

}

/**

* According to the position of current layout scroll to the destination

* page.

public void snapToDestination() {

final int screenWidth = getWidth();

final int destScreen = (getScrollX() + screenWidth / 2) / screenWidth;

snapToScreen(destScreen);

}

public void snapToScreen(int whichScreen) {

// get the valid layout page

whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() - 1));

if (getScrollX() != (whichScreen * getWidth())) {

final int delta = whichScreen * getWidth() - getScrollX();

mScroller.startScroll(getScrollX(), 0, delta, 0,

Math.abs(delta) * 2);

mCurScreen = whichScreen;

invalidate(); // Redraw the layout

mOnScreenChangedListener.onScreenChanged(this, mCurScreen);

}

public void setToScreen(int whichScreen) {

whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() - 1));

mCurScreen = whichScreen;

scrollTo(whichScreen * getWidth(), 0);

}

public int getCurScreen() {

return mCurScreen;

}

@Override

public void computeScroll() {

if (mScroller.computeScrollOffset()) {

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

postInvalidate();

}

@Override

public boolean onTouchEvent(MotionEvent event) {

if (mVelocityTracker == null) {

mVelocityTracker = VelocityTracker.obtain();

}

mVelocityTracker.addMovement(event);

final int action = event.getAction();

final float x = event.getX();

final float y = event.getY();

switch (action) {

case MotionEvent.ACTION_DOWN:

Log.e(TAG, "event down!");

if (!mScroller.isFinished()) {

mScroller.abortAnimation();

}

mLastMotionX = x;

break;

case MotionEvent.ACTION_MOVE:

// Log.e(TAG, "event down!");

//如果去掉if条件控制就会变成划到最后一个还会出现白色方框

if (mCurScreen != 0&&mCurScreen!=2) {

int deltaX = (int) (mLastMotionX - x);

mLastMotionX = x;

scrollBy(deltaX, 0);

}

break;

case MotionEvent.ACTION_UP:

Log.e(TAG, "event : up");

// if (mTouchState == TOUCH_STATE_SCROLLING) {

final VelocityTracker velocityTracker = mVelocityTracker;

velocityTracker.computeCurrentVelocity(1000);

int velocityX = (int) velocityTracker.getXVelocity();

Log.e(TAG, "velocityX:" + velocityX);

if (velocityX > SNAP_VELOCITY && mCurScreen > 0) {

// Fling enough to move left

Log.e(TAG, "snap left");

snapToScreen(mCurScreen - 1);

} else if (velocityX < -SNAP_VELOCITY

&& mCurScreen < getChildCount() - 1) {

// Fling enough to move right

Log.e(TAG, "snap right");

snapToScreen(mCurScreen + 1);

} else {

snapToDestination();

}

if (mVelocityTracker != null) {

mVelocityTracker.recycle();

mVelocityTracker = null;

}

// }

mTouchState = TOUCH_STATE_REST;

break;

case MotionEvent.ACTION_CANCEL:

mTouchState = TOUCH_STATE_REST;

break;

}

return true;

}

@Override

public boolean onInterceptTouchEvent(MotionEvent ev) {

Log.e(TAG, "onInterceptTouchEvent-slop:" + mTouchSlop);

final int action = ev.getAction();

if ((action == MotionEvent.ACTION_MOVE)

&& (mTouchState != TOUCH_STATE_REST)) {

return true;

}

final float x = ev.getX();

final float y = ev.getY();

switch (action) {

case MotionEvent.ACTION_MOVE:

final int xDiff = (int) Math.abs(mLastMotionX - x);

if (xDiff > mTouchSlop) {

mTouchState = TOUCH_STATE_SCROLLING;

}

break;

case MotionEvent.ACTION_DOWN:

mLastMotionX = x;

mLastMotionY = y;

mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST

: TOUCH_STATE_SCROLLING;

break;

case MotionEvent.ACTION_CANCEL:

case MotionEvent.ACTION_UP:

mTouchState = TOUCH_STATE_REST;

break;

}

return mTouchState != TOUCH_STATE_REST;

}

//----------------mainActiviyt-----------------

package com.work.demoa;

import com.work.demoa.ScrollLayout.OnScreenChangedListener;

import android.app.Activity;

import android.content.res.Resources;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnFocusChangeListener;

import android.widget.ImageView;

import android.widget.TextView;

public class MainActivity extends Activity implements OnScreenChangedListener {

private ImageView mImageView;

private TextView mTextView;

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

ScrollLayout scrollLayout = (ScrollLayout) findViewById(R.id.ScrollLayoutID);

int curScreen = scrollLayout.getCurScreen();

scrollLayout.setOnScreenChangedListener(this);

mImageView = (ImageView) findViewById(R.id.imageView1);

mTextView = (TextView) findViewById(R.id.textView_header);

}

@Override

public void onScreenChanged(ScrollLayout sc, int whichScreen) {

switch (whichScreen) {

case 0:

mImageView.setImageResource(R.color.blue);

mTextView.setText("left page");

break;

case 1:

mTextView.setText("center page");

mImageView.setImageResource(R.color.grayblack);

break;

case 2:

mTextView.setText("right page");

mImageView.setImageResource(R.color.green);

break;

}

//-------------------------布局文件----------------------

<?xml version="1.0" encoding="UTF-8"?>

<RelativeLayout

xmlns:Android="http://schemas.android.com/apk/res/android"

Android:layout_width="fill_parent"

Android:layout_height="fill_parent"

Android:orientation="vertical">

<RelativeLayout

Android:id="@+id/view_top"

Android:orientation="horizontal"

Android:layout_width="fill_parent"

Android:layout_height="wrap_content"

Android:layout_alignParentTop="true"

Android:gravity="center">

<TextView

Android:text="head"

Android:textSize="15pt"

Android:layout_width="fill_parent"

Android:layout_height="wrap_content" />

<ImageView

Android:layout_width="wrap_content"

Android:layout_height="wrap_content"

Android:src="@drawable/ic_launcher"

Android:id="@+id/imageView1"

Android:layout_alignParentTop="true"

Android:layout_alignParentRight="true"></ImageView>

<TextView

Android:layout_width="wrap_content"

Android:id="@+id/textView_header"

Android:text="center page"

Android:layout_height="wrap_content"

Android:textAppearance="?android:attr/textAppearanceMedium"

Android:layout_centerVertical="true"

Android:layout_alignParentLeft="true"

Android:layout_marginLeft="78dp"></TextView>

</RelativeLayout>

<RelativeLayout

Android:id="@+id/view_bottom"

Android:orientation="horizontal"

Android:layout_width="fill_parent"

Android:layout_height="wrap_content"

Android:layout_alignParentBottom="true"

Android:gravity="center">

<TextView

Android:text="footer"

Android:textSize="15pt"

Android:layout_width="fill_parent"

Android:layout_height="wrap_content" />

</RelativeLayout>

<com.work.demoa.ScrollLayout

xmlns:Android="http://schemas.android.com/apk/res/android"

Android:id="@+id/ScrollLayoutID"

Android:layout_width="fill_parent"

Android:layout_height="fill_parent"

Android:orientation="vertical"

Android:layout_above="@id/view_bottom"

Android:layout_below="@id/view_top">

<LinearLayout

Android:background="#0000ff"

Android:layout_width="fill_parent"

Android:layout_height="fill_parent">

<Button

Android:layout_width="wrap_content"

Android:layout_height="wrap_content"

Android:text="Left" />

</LinearLayout>

<LinearLayout

Android:background="#00ff00"

Android:layout_width="fill_parent"

Android:layout_height="fill_parent">

<Button

Android:layout_width="wrap_content"

Android:layout_height="wrap_content"

Android:text="Center" />

</LinearLayout>

<LinearLayout

Android:background="#ff0000"

Android:layout_width="wrap_content"

Android:layout_height="wrap_content">

<Button

Android:layout_width="wrap_content"

Android:layout_height="wrap_content"

Android:text="Right" />

</LinearLayout>

</com.work.demoa.ScrollLayout>

</RelativeLayout>

更多相关文章

随机推荐