Android Moveview滑屏移动视图类完整实例

import android.study.shift.ItemView;
import android.study.shift.MainView;
import android.study.shift.Moveview;
import android.content.Context;
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.ViewGroup;
import android.view.View.MeasureSpec;
public class Moveview extends ViewGroup{
 private final static int TOUCH_STATE_REST = 0;
 private final static int TOUCH_STATE_MOVING = 1;
 private final static int MOVE_TO_LEFT = 1;
 //private final static int MOVE_TO_RIGHT = 2;
 private final static int MOVE_TO_REST = 0;
 public final static int MAIN = 0;
 public final static int LEFT = 1;
 public final static int RIGHT = 2;
 private int touch_state = TOUCH_STATE_REST;
 private int move_state = MOVE_TO_REST;
 private int now_state = MAIN;
 private final float WIDTH_RATE = 0.18f;
 private MainView main_show_view;
 private ItemView left_show_view;
 private int min_distance = 30;//此处只是初始化为30 ，其实不起作用
 private int screen_w;
 private int screen_h;
 private int move_x_v;
 private boolean isAimationMoving = false;
 private Handler mHandler = new Handler() {
 public void handleMessage(Message msg) {//处理消息
  synchronized (Moveview.this) {//同步
  isAimationMoving = true;
  int move_change = (int) (screen_w * WIDTH_RATE / 5);
  int left = main_show_view.getView().getLeft();
  if (msg.what == 1) {//主屏在向右拖曳。。。
   move(move_change + left);//参数为拖出来后主屏的坐标。
  }
  if (msg.what == 11) {
   isAimationMoving = false;
   moveToLeft(false); //满足可以显示的要求开始显示，false只是一个判定条件，以区别按钮起的效果
  }
  if (msg.what == 2) {//代表主屏向左在拖曳。。。
   move(-1 * move_change + left);
  }
  if (msg.what == 12) {
   isAimationMoving = false;
   //moveToRight(false);
  }
  if (msg.what == 0) {
   if (now_state == LEFT) {//如果现在已经显示左边
   move(-1 * move_x_v);//那么还原成主屏
   } else {
   move(move_x_v);
   }
  }
  if (msg.what == 10) {
   isAimationMoving = false;
   moveToMain(false);
  }
  }
 }
 };
 public Moveview(Context context) {
 super(context);
 }
 public Moveview(Context context, AttributeSet attrs) {
 super(context, attrs);
 }
 public Moveview(Context context, AttributeSet attrs, int defStyle) {
 super(context, attrs, defStyle);
 }
 public void initView() {
 if (main_show_view == null) {
  main_show_view = new MainView(this.getContext(), this);
  left_show_view = new ItemView(this.getContext());
  //right_show_view = new ItemView(this.getContext(), "aaa");
 }
 this.addView(left_show_view.getView());
 //this.addView(right_show_view.getView());
 this.addView(main_show_view.getView());
 }
 public void initContent() {
 }
 public void move(int start) {//本函数显示拖动的时候屏幕的显示情况。
 int left = main_show_view.getView().getLeft();//left代表主屏左边缘的位置坐标。
 if (now_state == MAIN) {
  if (left > 0) {//如果屏幕的左边被移向右，则left变成正数
  if (move_state != MOVE_TO_LEFT) {
   move_state = MOVE_TO_LEFT;
  }
  left_show_view.getView().setVisibility(View.VISIBLE);//设置左边可见
  //right_show_view.getView().setVisibility(View.GONE);
  } //else if (left < 0) {//如果屏幕的左边被移向左，则left变成负数
  //if (move_state != MOVE_TO_RIGHT) {
  // move_state = MOVE_TO_RIGHT;
  //}
  //right_show_view.getView().setVisibility(View.VISIBLE);
  //left_show_view.getView().setVisibility(View.GONE);
  //}
   else {
  move_state = MOVE_TO_REST;
  }
  main_show_view.getView().layout(start, 0, start + screen_w,
   screen_h);//参数依次为左、上、右、下。
 } else {
  left = (int) (screen_w * WIDTH_RATE);//left为左边应该留出的控件空间，或者主屏左边应该在的位置
  if (now_state == RIGHT) {
  left = -1 * left;//若状态是在右边空出来，则主屏的左边为负数
  }
  left = left + start;
  main_show_view.getView().layout(left, 0, left + screen_w, screen_h);
 }
 }
 @Override
 protected void onLayout(boolean arg0, int arg1, int arg2, int arg3, int arg4) {
 if (move_state == MOVE_TO_REST) {
  if (now_state == MAIN) {
  int w = (int) (screen_w * WIDTH_RATE);//留下预定的宽度，显示各个view的参数设置。
  main_show_view.getView().layout(0, 0, screen_w, screen_h);
  left_show_view.getView().layout(0, 0, w, screen_h);
  } else if (now_state == LEFT) {
  moveToLeft(false);
  } else {
  }
 }
 }
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 main_show_view.getView().measure(widthMeasureSpec, heightMeasureSpec);
 left_show_view.getView().measure(MeasureSpec.UNSPECIFIED,//unspecified为未指定的
  heightMeasureSpec);
 left_show_view.setWidth((int) (screen_w * WIDTH_RATE));//设置view宽度
 super.onMeasure(widthMeasureSpec, heightMeasureSpec);//调用父类的构造函数
 }
 private int start_x;
 private int start_y;
 private boolean isMoved;
 public boolean dispatchTouchEvent(MotionEvent ev) {//分发触摸消息事件
 if (isAimationMoving) {
  return super.dispatchTouchEvent(ev);
 } else {
  int action = ev.getAction();
  float x = ev.getX();
  float y = ev.getY();
  switch (action) {
  case MotionEvent.ACTION_DOWN:
  super.dispatchTouchEvent(ev);
  start_y = (int) y;
  move_x_v = 0;
  if (this.touch_state == TOUCH_STATE_REST) {
   this.touch_state = TOUCH_STATE_MOVING;
   start_x = (int) x;
   isMoved = false;
   move_state = MOVE_TO_REST;
  }
  break;
  case MotionEvent.ACTION_MOVE:
  int last_y = (int) y;
  int last_x = (int) x;
  super.dispatchTouchEvent(ev);
  if (!isMoved) {
   if (Math.abs(last_y - start_y) > Math.abs(last_x - start_x)) {//如果Y上面移动的距离大于X上面移动的距离。
   super.onTouchEvent(ev);
   return true;
   } else {//X移动距离大于Y
   if (Math.abs(last_x - start_x) > 5) {//X移动距离大于5就被认为移动了
    isMoved = true;
   }
   }
  }
  if (isMoved) {
   if (this.touch_state == TOUCH_STATE_MOVING) {
   if (Math.abs(last_x - start_x) > 10) {//如果移动的X距离大于10
    int left = main_show_view.getView().getLeft();
    Log.d("msg", "left:" + left);
    Log.d("msg", "x:" + last_x);
    isMoved = true;
    int move_x = last_x - start_x;
    if (move_x > 0 && now_state == LEFT) {//方向正确的移动才算是移动的状态
    isMoved = false;
    break;
    }
    if (move_x < 0 && now_state == RIGHT) {//如果现在在显示右边，那么再向右移就不反应。
    isMoved = false;
    break;
    }
    if (move_x < 0 && now_state ==MAIN){//如果现在在主屏，向右移动也是无效的
    isMoved = false;
    break;
    }
    if (move_x > 234 && now_state ==MAIN){
    isMoved = true;//设置为true那么移动还是发生了，break之后还是会在ACTIONUP中起作用
    break;//break之后不会执行下面的move()语句,
    }
    if (move_x < -234 && now_state ==LEFT){
    isMoved = true;
    break;
    }
    move(move_x);//以移动的距离为参数调用move（）实现移动的动态显示
   }
   }
   return false;
  }
  break;
  case MotionEvent.ACTION_UP://
  if (this.touch_state == TOUCH_STATE_MOVING) {
   if (isMoved) {
   last_x = (int) x;
   if (Math.abs(last_x - start_x) > min_distance) {//
    if (now_state == MAIN) {
    if (move_state == MOVE_TO_LEFT) {
     this.moveToLeft(false);
    }
    } else {
    this.moveToMain(false);
    }
   } else {  //
    if (now_state == MAIN) {
    this.moveToMain(false);
    }
    if (now_state == LEFT) {
    this.moveToLeft(false);
    }
    if (now_state == RIGHT) {
    //this.moveToRight(false);
    }
   }
   move_state = MOVE_TO_REST;
   }  else {
   super.dispatchTouchEvent(ev);
   this.touch_state = TOUCH_STATE_REST;
   return false;//
   }
  }
  super.onTouchEvent(ev);
  this.touch_state = TOUCH_STATE_REST;
  break;
  }
  return true;
 }
 }
 public boolean getIsMoved() {
 return isMoved;
 }
 public void moveToLeft(boolean b) {
 if (!b) {
  int move_x = (int) (screen_w * WIDTH_RATE);
  left_show_view.getView().layout(0, 0, screen_w, screen_h);
  //right_show_view.getView().layout(move_x, 0, move_x * 2, screen_h);
  main_show_view.getView().layout(move_x, 0, move_x + screen_w,
   screen_h);
  now_state = LEFT;//为什么现在又把now_state赋值为left？
 }
//  else {//else以及括号中的语句都是为原来的按钮准备的。。。
//  mHandler.postDelayed(new Runnable() {//一个新的可运行的函数
//
//  @Override
//  public void run() {
//   int move_change = (int) (screen_w * WIDTH_RATE / 5);//五分之一要显示的宽度
//   int left = (int) (screen_w * WIDTH_RATE - main_show_view
//    .getView().getLeft());//getleft()返回的是主屏左边缘离左边的距离
//   Message msg = new Message();
//   if (left > move_change) {//括号里面不懂，起什么作用？
//   msg.what = 1;
//   mHandler.sendMessage(msg);
//   mHandler.postDelayed(this, 10);//又调用自己，基本上非要是小于关系
//   } else {
//   msg.what = 11;
//   mHandler.sendMessage(msg);
//   mHandler.removeCallbacks(this);
//   }
//  }
//  }, 0);
// }
 }
 public void moveToMain(boolean b) {
 if (!b) {
  //right_show_view.getView().setVisibility(View.VISIBLE);
  left_show_view.getView().setVisibility(View.VISIBLE);
  int w = (int) (screen_w * WIDTH_RATE);
  main_show_view.getView().layout(0, 0, screen_w, screen_h);
  left_show_view.getView().layout(0, 0, w, screen_h);
  now_state = MAIN;
 }
 }
 public void initScreenSize(int w, int h) {
 this.screen_w = w;
 this.screen_h = h;
 Log.d("screen", "screen_w:" + w);
 this.setKeepScreenOn(true);
 min_distance = (int) (screen_w / 12.0);//min_distance在这里又被初始化为屏幕的一个比例大小
 initView();
 initContent();
 moveToMain(false);
 }
 public int getNowState() {
 return this.now_state;
 }
}