Android实现IOS相机滑动控件

IOS相比于Android，动画效果是一方面优势，IOS相机切换时滑动的动画很不错，看着是有一个3D的效果，而且变化感觉很自然。Android也可以通过Graphics下面的Camera可以实现3D效果，开始尝试着用这个做了一下，效果不理想，滑动之后各组文字之间的距离就变了，从立体空间来说这是合逻辑的，但是看着很别捏。IOS相机的滑动效果文字之间的间隔在滑动的时候是不变的。

后面通过调整TextView X方向的scale使文字看着紧凑一点，然后通过计算的距离的方式，在滑动的时候保持各组文字之间的间隔一致，最后实现的效果还是和IOS的有一定的差距。先上个效果图的。

下面逐步来说下怎么实现：

MainaActivity.java: 

往自定义的控件加了6个TextView，对应各个模式。

这里面还实现了一个手势监听，来识别滑动事件。对动画做了一些限制，角度小于30度，滑动距离大于15才能生效。

package com.example.androidcustomnview;

import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.util.Log;
import android.view.GestureDetector;
import android.view.GestureDetector.OnGestureListener;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.MotionEvent;
import android.view.TextureView;
import android.view.ViewGroup;
import android.view.animation.Animation;
import android.view.animation.Animation.AnimationListener;
import android.view.animation.AnimationSet;
import android.view.animation.TranslateAnimation;
import android.widget.FrameLayout;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.TextView;

public class MainActivity extends Activity implements OnTouchListener{

 private static final String TAG = "MainActivity.TAG";
 CustomViewL mCustomViewL;
 String[] name = new String[] {"延时摄影","慢动作","视频","拍照","正方形","全景"};

 GestureDetector mGestureDetector;
 RelativeLayout rootView;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  mCustomViewL = (CustomViewL) findViewById(R.id.mCustomView);
  rootView = (RelativeLayout) findViewById(R.id.ViewRoot);
  rootView.setOnTouchListener(this);
  mCustomViewL.getParent();
  mCustomViewL.addIndicator(name);
  mGestureDetector = new GestureDetector(this, new myGestureDetectorLis()); 48  }

 class myGestureDetectorLis implements GestureDetector.OnGestureListener {

  private static final int degreeLimit = 30;
  private static final int distanceLimit = 15;

  private boolean isScroll = false;
  @Override
  public boolean onDown(MotionEvent e) {
   // TODO Auto-generated method stub
   Log.d(TAG, "myGestureDetectorLis onDown");
   isScroll = false;
   return true;
  }
  @Override
  public void onShowPress(MotionEvent e) {
   // TODO Auto-generated method stub

  }
  @Override
  public boolean onSingleTapUp(MotionEvent e) {
   // TODO Auto-generated method stub
   return false;
  }

  @Override
  public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
    float distanceY) {
   // TODO Auto-generated method stub
   if (isScroll) return false;
   double degree = Math.atan(Math.abs(e2.getY() - e1.getY()) / Math.abs(e2.getX() - e1.getX())) * 180 /Math.PI;
   float delta = e2.getX() - e1.getX();
   if (delta > distanceLimit && degree < degreeLimit) {
    Log.d(TAG, "向右滑");
    isScroll = true;
    mCustomViewL.scrollRight();
   } else if (delta < -distanceLimit && degree < degreeLimit) {
    Log.d(TAG, "向左滑");
    isScroll = true;
    mCustomViewL.scrollLeft();
   }
   return false;
  }

  @Override
  public void onLongPress(MotionEvent e) {
   // TODO Auto-generated method stub

  }
  @Override
  public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
    float velocityY) {
   // TODO Auto-generated method stub
   return false;
  }

 }

 @Override
 public boolean onTouch(View v, MotionEvent event) {
  // TODO Auto-generated method stub
  return mGestureDetector.onTouchEvent(event);
 }

}

CustomViewL.java:

自定义的控件，继承自LinearLayout。在onLayout里面，重新计算了下各个子控件的位置，因为各组文字的scale是不一样的，必须重新Layout一下各个子控件的位置，是文字的显示区域和点击区域是一样的，这样给各个子控件设置的onClick事件才有效。

dispatchDraw方法是重绘各个子控件，更具各个子控件到中心控件的位置的距离，设置了各个TextView X方向的scale,为了就是看着要有一个立体的效果。

滑动之后，开始一个动画，动画结束之后重新requestLayout一下，重新计算下各个控件的位置。这个可以连续滑动的，如果这次动画在执行，会保存一下，等动画完了之后会接着跑下一个动画。各个子控件滑动距离的计算有兴趣的可以自己研究下，这里就不赘述了，其实也是数学知识。

package com.example.androidcustomnview;

import android.content.Context;
import android.graphics.Camera;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Shader;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;
import android.view.animation.Animation;
import android.view.animation.Animation.AnimationListener;
import android.view.animation.TranslateAnimation;
import android.widget.LinearLayout;
import android.widget.TextView;

public class CustomViewL extends LinearLayout {

 private static final String TAG = "CustomViewL.TAG";
 private Matrix mMatrix;
 Camera mCamera;
 private int mCurrentItem = 2;
 private int screenWidth;
 private Paint mPaint;

 public static final float ItemScale = 0.1f;

 public CustomViewL(Context context) {
  super(context);
  // TODO Auto-generated constructor stub
  initView(context);
 }

 public CustomViewL(Context context, AttributeSet attrs, int defStyleAttr,
   int defStyleRes) {
  super(context, attrs, defStyleAttr, defStyleRes);
  initView(context);
 }

 public CustomViewL(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  initView(context);
 }

 public CustomViewL(Context context, AttributeSet attrs) {
  super(context, attrs);
  initView(context);
 }

 private void initView(Context context) {
  screenWidth = ((WindowManager)getContext().getSystemService(Context.WINDOW_SERVICE))
    .getDefaultDisplay().getWidth();
 }

 @Override
 protected void onLayout(boolean changed, int l, int t, int r, int b) {
  Log.d(TAG, "onLayout ");
  super.onLayout(changed, l , t, r, b);
  View v = getChildAt(mCurrentItem);
  int delta = getWidth() / 2 - v.getLeft() - v.getWidth()/2;

  for (int i = 0; i < getChildCount(); i++) {
   View v1 = getChildAt(i);
   if (i == mCurrentItem) {
    v1.layout(v1.getLeft() + delta, v1.getTop(),
     v1.getRight() + delta, v1.getBottom());
    continue;
   }
   float mScale = Math.abs(i - mCurrentItem) * ItemScale;
   int move = (int)(v1.getWidth() * mScale / 2);
   if (i < mCurrentItem) {
    for (int j = i + 1; j < mCurrentItem; j++) {
     View v2 = getChildAt(j);
     move += (int) (v2.getWidth() * Math.abs(j - mCurrentItem) * ItemScale);
    }
   } else {
    for (int j = i - 1; j > mCurrentItem; j--) {
     View v2 = getChildAt(j);
     move += (int)(v2.getWidth() * Math.abs(j - mCurrentItem) * ItemScale);
    }
    move = -move;
   }
   v1.layout(v1.getLeft() + delta + move, v1.getTop(),
     v1.getRight() + delta + move, v1.getBottom());
  }
  mRequstLayout = false;
 }

 @Override
 protected void dispatchDraw(Canvas canvas) {
  int count = getChildCount();
  for (int i = 0; i < count; i++) {
   updateChildItem(canvas,i);
  }
 }

 public void updateChildItem(Canvas canvas,int item) {
//  Log.d(TAG, "updateChildItem");
  View v = getChildAt(item);
  float desi = 1- Math.abs(item - mCurrentItem) * ItemScale;
  ((TextView)v).setScaleX(desi);
  drawChild(canvas, v, getDrawingTime());
  updateTextColor();
 }
 private void updateTextColor() {
  for (int i =0 ; i < getChildCount(); i++) {
   if (i == mCurrentItem) {
    ((TextView)getChildAt(i)).setTextColor(Color.YELLOW);
   } else {
    ((TextView)getChildAt(i)).setTextColor(Color.WHITE);
   }
  }
 }
 boolean scroolToRight = false;

 public void scrollRight() {
  if (mRequstLayout) return;
  if (mCurrentItem > 0) {
   if (mAnimationRunning) {
    if (AnimationRunningCount < 1) {
     currentItemCopy = mCurrentItem - 1;
     AnimationRunningCount++;
     scroolToRight = true;
    }
    return;
   }
   mCurrentItem--;
   startTraAnimation(mCurrentItem,mCurrentItem + 1);
   updateTextColor();
  }
 }

 private int currentItemCopy;
 public void scrollLeft() {
  if (mRequstLayout) return;
  if (mCurrentItem < getChildCount() - 1) {
   if (mAnimationRunning) {
    if (AnimationRunningCount < 1) {
     currentItemCopy = mCurrentItem + 1;
     AnimationRunningCount++;
     scroolToRight = false;
    }
    return;
   }
   mCurrentItem++;
   startTraAnimation(mCurrentItem,mCurrentItem-1);
   updateTextColor();
  }
 }

 public void addIndicator(String[] name) {
  for (int i=0; i< name.length; i++) {
   TextView mTextView = new TextView(getContext());
   mTextView.setText(name[i]);
   mTextView.setTextColor(Color.WHITE);
   mTextView.setLines(1);
   LinearLayout.LayoutParams ll = new LinearLayout.LayoutParams(
     LinearLayout.LayoutParams.WRAP_CONTENT,
     LinearLayout.LayoutParams.WRAP_CONTENT);
   ll.setMargins(20, 0, 20, 0);
   addView(mTextView,ll);
  }
 }

 class myAnimationListener implements android.view.animation.Animation.AnimationListener {

  @Override
  public void onAnimationStart(Animation animation) {
   Log.d(TAG, "onAnimationStart ");
   mAnimationRunning = true;
  }
  @Override
  public void onAnimationEnd(Animation animation) {
   // TODO Auto-generated method stub
   Log.d(TAG, "onAnimationEnd ");

   for (int i= 0; i < getChildCount(); i++) {
    getChildAt(i).clearAnimation();
   }
   mRequstLayout = true;
   requestLayout();
   mAnimationRunning = false;
   if (AnimationRunningCount > 0) {
    CustomViewL.this.post(new Runnable() {
     @Override
     public void run() {
      // TODO Auto-generated method stub
      AnimationRunningCount--;
      mCurrentItem = currentItemCopy;
      int lastItem = scroolToRight ? currentItemCopy + 1 : currentItemCopy - 1;
      startTraAnimation(currentItemCopy,lastItem);
      updateTextColor();
     }
    });
   }
  }
  @Override
  public void onAnimationRepeat(Animation animation) {
  }

 }

 private int AnimitionDurationTime = 300;
 private int AnimationRunningCount = 0;
 private boolean mAnimationRunning = false;
 private boolean mRequstLayout = false;
 public void startTraAnimation(int item,int last) {
  Log.d(TAG, "startTraAnimation item = " + item);
  View v = getChildAt(item);
  final int width = v.getWidth();
  final int childCount = getChildCount();
  int traslate = getWidth()/2 - v.getLeft() - width/2;

  int currentItemWidthScale = (int) (width * ItemScale);

  for (int i = 0; i < childCount; i++) {
   int delta = currentItemWidthScale / 2;
   Log.d(TAG, " i = " + i + " delta before = " + delta);
   if (i < item) {
    delta = -delta;
    for (int j = i; j < item; j++) {
     int a;
     if (i == j) {
      a = (int)(getChildAt(j).getWidth() * ItemScale / 2);
     } else {
      a = (int)(getChildAt(j).getWidth() * ItemScale);
     }
     delta = item < last ? delta - a : delta + a;
    }
   } else if (i > item){
    for (int j = item + 1; j <= i; j++) {
     int a;
     if (j == i) {
      a = (int)(getChildAt(j).getWidth() * ItemScale / 2);
     } else {
      a = (int)(getChildAt(j).getWidth() * ItemScale);
     }
     delta = item < last ? delta - a : delta + a;
    }
   } else {
    delta = 0;
   }
   Log.d(TAG, "delta = " + delta);
   delta += traslate;
   TranslateAnimation translateAni = new TranslateAnimation(0, delta, 0, 0);
   translateAni.setDuration(AnimitionDurationTime);
   translateAni.setFillAfter(true);
   if (i == item) translateAni.setAnimationListener(new myAnimationListener());
   mAnimationRunning = true;
   getChildAt(i).startAnimation(translateAni);
  }
 }
}

最后说一下布局文件，两边本来是要做一个阴影效果的，为了简便，复习了下PS,就在上面盖了张图片，显得两边有阴影。

<RelativeLayout 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"
 tools:context="com.example.androidcustomnview.MainActivity" >

 <RelativeLayout
  android:id="@+id/ViewRoot"
  android:gravity="center"
  android:layout_width="match_parent"
  android:layout_height="match_parent">
  <com.example.androidcustomnview.CustomViewL
   android:orientation="horizontal"
   android:background="@android:color/background_dark"
   android:id="@+id/mCustomView"
   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   >

  </com.example.androidcustomnview.CustomViewL>
  <ImageView
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:layout_alignLeft="@id/mCustomView"
   android:layout_alignTop="@id/mCustomView"
   android:layout_alignRight="@id/mCustomView"
   android:layout_alignBottom="@id/mCustomView"
   android:background="@drawable/test"/>

 </RelativeLayout>
</RelativeLayout>

整个来说其实也不复杂，有好些数学计算，几何问题，效果也没达到iphone的效果，如果有大神有想法，可以指导下。

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