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自定義實(shí)現(xiàn)類似android主界面的滑屏換屏控件

實(shí)現(xiàn)思路，剛開始的時(shí)候我是用ViewFlipper控件來做非常的簡(jiǎn)單但是實(shí)現(xiàn)不了拖拽移動(dòng)屏幕的效果，最終放棄決定自定義一個(gè)控件實(shí)現(xiàn)這樣效果。

接下來我詳細(xì)的解說一下我開發(fā)時(shí)寫的這個(gè)實(shí)驗(yàn)demo，軟件中用的滑屏就是由這樣的代碼實(shí)現(xiàn)的。

首先新建一個(gè)控件類TouchPageView并且繼承自ViewGroup，左右滑動(dòng)換屏我的實(shí)現(xiàn)是在TouchPageView添加3個(gè)子view 分別代表看不到的左邊屏幕、可以看到的中間屏幕、看不到的右邊屏幕，這樣在滑屏?xí)r候就可以通過不斷調(diào)整這3個(gè)view的位置實(shí)現(xiàn)連續(xù)不間斷滑屏換屏，下面的實(shí)驗(yàn)中我分別把3個(gè)view設(shè)置成紅色、綠色、黃色這樣切換的時(shí)候可以看到明顯效果，這3個(gè)view在TouchPageView的構(gòu)造方法中調(diào)用 init方法進(jìn)行初始化：

private void init()
    {
        views= new ArrayList<LinearLayout>();
        view1=new LinearLayout(context);
        view1.setBackgroundColor(Color.YELLOW);
        this.addView(view1);
        TextView tv=new TextView(context);
        tv.setText("測(cè)試");
        view1.addView(tv);
        views.add(view1);
        
        
        view2=new LinearLayout(context);
        view2.setBackgroundColor(Color.RED);
        this.addView(view2);
        views.add(view2);
        
        view3=new LinearLayout(context);
        view3.setBackgroundColor(Color.GREEN);
        this.addView(view3);
        views.add(view3);
        
        final ViewConfiguration configuration = ViewConfiguration.get(getContext());
        mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
    }

復(fù)制代碼

接下來的實(shí)現(xiàn)是關(guān)鍵，重寫onLayout方法對(duì)3個(gè)view的顯示位置布局進(jìn)行控制，通過下面的這個(gè)方法，把3個(gè)view進(jìn)行水平一個(gè)跟著一個(gè)進(jìn)行布局顯示。

@Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        int childLeft = -1;
        final int count = views.size();
        //水平從左到右放置
        for (int i = 0; i < count; i++) {
            final View child =views.get(i);
            if (child.getVisibility() != View.GONE) {
                final int childWidth = child.getMeasuredWidth();
                if(childLeft==-1)
                {
                    childLeft=-childWidth;
                }
                child.layout(childLeft, 0, childLeft + childWidth, child.getMeasuredHeight());
                childLeft += childWidth;
            }
        }
        
    }

復(fù)制代碼

3個(gè)view位置放置好之后，接下來的實(shí)現(xiàn)實(shí)現(xiàn)手指在屏幕拖拽滑動(dòng)時(shí)讓3個(gè)view跟著手指的位置進(jìn)行變化顯示，這個(gè)肯定是在onTouchEvent 方法中實(shí)現(xiàn)了，分別在MotionEvent.ACTION_DOWN、MotionEvent.ACTION_MOVE、 MotionEvent.ACTION_UP三個(gè)手指狀態(tài)中進(jìn)行控制，在下面的實(shí)現(xiàn)中還采用了VelocityTracker的方法對(duì)手指的滑動(dòng)速度進(jìn)行跟蹤，這樣根據(jù)滑動(dòng)速度決定屏幕往哪個(gè)方向換屏，關(guān)鍵的代碼如下：

@Override
    public boolean onTouchEvent(MotionEvent ev){
        
        if(!lock)
        {
            if (mVelocityTracker == null) {
                mVelocityTracker = VelocityTracker.obtain();
            }
            mVelocityTracker.addMovement(ev);
            
            final int action = ev.getAction();
            final float x = ev.getX();
            final float y = ev.getY();
            
            switch (action) {
            case MotionEvent.ACTION_DOWN://按下去
                if(touchState==TOUCH_STATE_REST)
                {
                    //記錄按下去的的x坐標(biāo)
                    lastMotionX = x;
                    touchState=TOUCH_STATE_MOVING;
                    
                    isMoved=false;
                }
                
                break;
            case MotionEvent.ACTION_MOVE://拖動(dòng)時(shí)
                if(touchState==TOUCH_STATE_MOVING)
                {
                    float offsetX=x-lastMotionX;
                    float offsetY=y-lastMotionY;
                    
                    if(isMoved)
                    {
                        lastMotionX=x;
                        lastMotionY=y;

                        final int count = views.size();
                        //水平從左到右放置
                        for (int i = 0; i < count; i++) {
                            final View child =views.get(i);
                            if (child.getVisibility() != View.GONE) {
                                final int childWidth = child.getMeasuredWidth();
                                int childLeft = child.getLeft()+(int)offsetX;
                                child.layout(childLeft, 0, childLeft + childWidth, child.getMeasuredHeight());
                                childLeft += childWidth;
                            }
                        }
                    }
                    else if(Math.abs(offsetX)>TOUCH_SLOP||Math.abs(offsetY)>TOUCH_SLOP)
                    {
                        //移動(dòng)超過閾值，則表示移動(dòng)了
                        isMoved=true;
                        removeCallbacks(mLongPressRunnable);
                    }
                }
                
                break;
            case MotionEvent.ACTION_UP://放開時(shí)
                //釋放了
                removeCallbacks(mLongPressRunnable);
                
                if(isMoved)
                {
                    if(touchState==TOUCH_STATE_MOVING)
                    {
                        touchState=TOUCH_STATE_SLOWING;
                        int sign=0;
                        final VelocityTracker velocityTracker = mVelocityTracker;
                        //計(jì)算當(dāng)前速度
                        velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
                        //x方向的速度
                        int velocityX = (int) velocityTracker.getXVelocity();
                        if(velocityX > SNAP_VELOCITY)//足夠的能力向左
                        {
                            sign=1;
                            Log.e("enough to move left", "true");
                        }
                        else if (velocityX < -SNAP_VELOCITY)//足夠的能力向右
                        {
                            sign=-1;
                            Log.e("enough to move right", "right");
                        }
                        else
                        {
                            sign=0;
                        }
                        moveToFitView(sign);
                        if (mVelocityTracker != null) {
                            mVelocityTracker.recycle();
                            mVelocityTracker = null;
                        }
                        
                    }
                }
                
                
                break;
            }
        }
        return true;
    }

復(fù)制代碼

完成手指滑的功能后，最后在手指離開屏幕的時(shí)候，讓3個(gè)view滑動(dòng)到合適的位置，保證當(dāng)前屏幕只能看到一個(gè)完整的view另外2個(gè)view不可見，并且在滑動(dòng)的過程中為了達(dá)到比較自然的效果，采用減速滑動(dòng)的實(shí)現(xiàn)，這里是用了Handler進(jìn)行間隔的減速移動(dòng)效果，這樣滑動(dòng)起來比較舒服，其實(shí)最好的效果應(yīng)該加入阻尼效果，就是讓view一定程度的沖過屏幕邊界然后在回彈，經(jīng)過幾次這樣的緩減至速度為零然后最終停止，這個(gè)可以由各位自己去實(shí)現(xiàn)，并不難寫。

int offset=0;
    private void moveToFitView(int sign)
    {
        boolean b=swapView(sign);
        if(true)
        {
            View view1=views.get(1);
            int left=view1.getLeft();
            //int offset=0;
            if(left!=0)
            {
                offset=-1*left;
            }
            
            moveView();
        }
    }
    
    FlipAnimationHandler mAnimationHandler;
    int ovv=40;
    private void moveView()
    {
        final int count = views.size();
        
        if(offset!=0)
        {
            int ov=0;
            if(offset>0)
            {
                ov=ovv; 
            }
            else
            {
                ov=-1*ovv;
            }
            ovv=ovv-3;
            if(ovv<1)
            {
                ovv=3;
            }
            if(Math.abs(offset)<Math.abs(ov))
            {
                ov=offset;
                offset=0;
                
            }
            else
            {
                offset=offset-ov;
            }
            
            //水平從左到右放置
            for (int i = 0; i < count; i++) {
                final View child =views.get(i);
                final int childWidth = child.getMeasuredWidth();
                int childLeft = child.getLeft()+ov;
                child.layout(childLeft, 0, childLeft + childWidth, child.getMeasuredHeight());
                childLeft += childWidth;
            }
            
            if(mAnimationHandler==null)
            {
                mAnimationHandler = new FlipAnimationHandler();
            }
            mAnimationHandler.sleep(1);
        }
        else
        {
            ovv=40;
            touchState=TOUCH_STATE_REST;
        }
    }
    
    class FlipAnimationHandler extends Handler {
        @Override
        public void handleMessage(Message msg) {
            TouchPageView.this.moveView();
        }

        public void sleep(long millis) {
            this.removeMessages(0);
            sendMessageDelayed(obtainMessage(0), millis);
        }
    }

復(fù)制代碼

整個(gè)自定義控件核心的思路和代碼就上面這些了，實(shí)現(xiàn)效果請(qǐng)參看我的微讀效果。

完整的代碼：

package xx.weidu;

import java.util.ArrayList;

import java.util.List;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.os.Handler;

import android.os.Message;

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.LinearLayout;

import android.widget.TextView;

public class TouchPageView extends ViewGroup{

private LinearLayout view1;

private LinearLayout view2;

private LinearLayout view3;

//速度跟蹤

private VelocityTracker mVelocityTracker;

private int mMaximumVelocity;

//手勢(shì)臨界速度，當(dāng)速度超過這個(gè)時(shí)切換到下一屏

private static final int SNAP_VELOCITY = 100;

//停止?fàn)顟B(tài)

private final static int TOUCH_STATE_REST = 0;

//滾動(dòng)狀態(tài)

private final static int TOUCH_STATE_MOVING = 1;

//減速停止?fàn)顟B(tài)

private final static int TOUCH_STATE_SLOWING = 2;

//當(dāng)前觸摸狀態(tài)

private int touchState = TOUCH_STATE_REST;

private boolean lock=false;

private float lastMotionX;

private float lastMotionY;

private Context context;

private List<LinearLayout> views;

//是否移動(dòng)了

private boolean isMoved;

//長(zhǎng)按的runnable

private Runnable mLongPressRunnable;

//移動(dòng)的閾值

private static final int TOUCH_SLOP=10;

public int width;

public int height;

public TouchPageView(Context context) {

super(context);

this.context=context;

init();

}

private void init()

{

views= new ArrayList<LinearLayout>();

view1=new LinearLayout(context);

view1.setBackgroundColor(Color.YELLOW);

this.addView(view1);

TextView tv=new TextView(context);

tv.setText("測(cè)試");

view1.addView(tv);

views.add(view1);

view2=new LinearLayout(context);

view2.setBackgroundColor(Color.RED);

this.addView(view2);

views.add(view2);

view3=new LinearLayout(context);

view3.setBackgroundColor(Color.GREEN);

this.addView(view3);

views.add(view3);

final ViewConfiguration configuration = ViewConfiguration.get(getContext());

mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();

}

@Override

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec){

super.onMeasure(widthMeasureSpec, heightMeasureSpec);

final int count = views.size();

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

final View child =views.get(i);

child.measure(widthMeasureSpec,heightMeasureSpec);

}

int finalWidth, finalHeight;

finalWidth = measureWidth(widthMeasureSpec);

finalHeight = measureHeight(heightMeasureSpec);

this.width=finalWidth;

this.height=finalHeight;

}

private int measureWidth(int measureSpec) {

int result = 0;

int specMode = MeasureSpec.getMode(measureSpec);

int specSize = MeasureSpec.getSize(measureSpec);

if (specMode == MeasureSpec.EXACTLY) {

result = specSize;

} else {

result = specSize;

}

return result;

}

private int measureHeight(int measureSpec) {

int result = 0;

int specMode = MeasureSpec.getMode(measureSpec);

int specSize = MeasureSpec.getSize(measureSpec);

if (specMode == MeasureSpec.EXACTLY) {

result = specSize;

} else {

result = specSize;

}

return result;

}

@Override

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

int childLeft = -1;

final int count = views.size();

//水平從左到右放置

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

final View child =views.get(i);

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

final int childWidth = child.getMeasuredWidth();

if(childLeft==-1)

{

childLeft=-childWidth;

}

child.layout(childLeft, 0, childLeft + childWidth, child.getMeasuredHeight());

childLeft += childWidth;

}

//繪制子元素

@Override

protected void onDraw(Canvas canvas) {

//水平從左到右放置

int count = views.size();

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

View child =views.get(i);

drawChild(canvas, child, getDrawingTime());

}

@Override

public boolean onTouchEvent(MotionEvent ev){

if(!lock)

{

if (mVelocityTracker == null) {

mVelocityTracker = VelocityTracker.obtain();

}

mVelocityTracker.addMovement(ev);

final int action = ev.getAction();

final float x = ev.getX();

final float y = ev.getY();

switch (action) {

case MotionEvent.ACTION_DOWN://按下去

if(touchState==TOUCH_STATE_REST)

{

//記錄按下去的的x坐標(biāo)

lastMotionX = x;

touchState=TOUCH_STATE_MOVING;

isMoved=false;

}

break;

case MotionEvent.ACTION_MOVE://拖動(dòng)時(shí)

if(touchState==TOUCH_STATE_MOVING)

{

float offsetX=x-lastMotionX;

float offsetY=y-lastMotionY;

if(isMoved)

{

lastMotionX=x;

lastMotionY=y;

final int count = views.size();

//水平從左到右放置

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

final View child =views.get(i);

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

final int childWidth = child.getMeasuredWidth();

int childLeft = child.getLeft()+(int)offsetX;

child.layout(childLeft, 0, childLeft + childWidth, child.getMeasuredHeight());

childLeft += childWidth;

}

else if(Math.abs(offsetX)>TOUCH_SLOP||Math.abs(offsetY)>TOUCH_SLOP)

{

//移動(dòng)超過閾值，則表示移動(dòng)了

isMoved=true;

removeCallbacks(mLongPressRunnable);

}

break;

case MotionEvent.ACTION_UP://放開時(shí)

//釋放了

removeCallbacks(mLongPressRunnable);

if(isMoved)

{

if(touchState==TOUCH_STATE_MOVING)

{

touchState=TOUCH_STATE_SLOWING;

int sign=0;

final VelocityTracker velocityTracker = mVelocityTracker;

//計(jì)算當(dāng)前速度

velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);

//x方向的速度

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

if(velocityX > SNAP_VELOCITY)//足夠的能力向左

{

sign=1;

Log.e("enough to move left", "true");

}

else if (velocityX < -SNAP_VELOCITY)//足夠的能力向右

{

sign=-1;

Log.e("enough to move right", "right");

}

else

{

sign=0;

}

moveToFitView(sign);

if (mVelocityTracker != null) {

mVelocityTracker.recycle();

mVelocityTracker = null;

}

break;

}

return true;

}

int offset=0;

private void moveToFitView(int sign)

{

boolean b=swapView(sign);

if(true)

{

View view1=views.get(1);

int left=view1.getLeft();

//int offset=0;

if(left!=0)

{

offset=-1*left;

}

moveView();

}

FlipAnimationHandler mAnimationHandler;

int ovv=40;

private void moveView()

{

final int count = views.size();

if(offset!=0)

{

int ov=0;

if(offset>0)

{

ov=ovv;

}

else

{

ov=-1*ovv;

}

ovv=ovv-3;

if(ovv<1)

{

ovv=3;

}

if(Math.abs(offset)<Math.abs(ov))

{

ov=offset;

offset=0;

}

else

{

offset=offset-ov;

}

//水平從左到右放置

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

final View child =views.get(i);

final int childWidth = child.getMeasuredWidth();

int childLeft = child.getLeft()+ov;

child.layout(childLeft, 0, childLeft + childWidth, child.getMeasuredHeight());

childLeft += childWidth;

}

if(mAnimationHandler==null)

{

mAnimationHandler = new FlipAnimationHandler();

}

mAnimationHandler.sleep(1);

}

else

{

ovv=40;

touchState=TOUCH_STATE_REST;

}

class FlipAnimationHandler extends Handler {

@Override

public void handleMessage(Message msg) {

TouchPageView.this.moveView();

}

public void sleep(long millis) {

this.removeMessages(0);

sendMessageDelayed(obtainMessage(0), millis);

}

private boolean swapView(int sign)

{

boolean b=false;

if(sign==-1)//向左

{

View view0=views.get(0);

if(view0.getLeft()<=-1*view0.getMeasuredWidth())

{

swapViewIndex(sign);

View view2=views.get(1);

View view3=views.get(2);

int childWidth=view2.getMeasuredWidth();

int childLeft=view2.getLeft()+childWidth;

view3.layout(childLeft, 0, childLeft + view3.getMeasuredWidth(), view3.getMeasuredHeight());

b=true;

}

else if(sign==1)//向右

{

View view3=views.get(2);

if(view3.getLeft()>view3.getMeasuredWidth())

{

swapViewIndex(sign);

View view1=views.get(0);

View view2=views.get(1);

int childRight=view2.getLeft();

int childLeft=childRight-view1.getMeasuredWidth();

view1.layout(childLeft, 0, childRight, view1.getMeasuredHeight());

b=true;

}

return b;

}

private void swapViewIndex(int sign)

{

if(sign==-1)//向左

{

LinearLayout v=views.remove(0);

views.add(v);

}

else if(sign==1)//向右

{

LinearLayout v=views.remove(views.size()-1);

views.add(0, v);

}

posted on 2012-03-01 17:06 小果子閱讀(698) 評(píng)論(0) 編輯收藏引用所屬分類: Android & Ios

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