Android Moveview滑屏移動視圖類完整實例

本文示例所述程序為一個Android Moveview移動視圖類。其主要實現主屏左右滑屏拖動功能，並適時顯示拖動時候屏幕的顯示情況，該代碼中還包括完整的邏輯。其完整代碼如下：

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;//此處只是初始化為30 ，其實不起作用
 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) {//處理消息
  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);//參數為拖出來後主屏的坐標。
  }
  if (msg.what == 11) {
   isAimationMoving = false;
   moveToLeft(false); //滿足可以顯示的要求開始顯示，false只是一個判定條件，以區別按鈕起的效果
  }
  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) {//如果現在已經顯示左邊
   move(-1 * move_x_v);//那麼還原成主屏
   } 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) {//本函數顯示拖動的時候屏幕的顯示情況。
 int left = main_show_view.getView().getLeft();//left代表主屏左邊緣的位置坐標。
 if (now_state == MAIN) {
  if (left > 0) {//如果屏幕的左邊被移向右，則left變成正數
  if (move_state != MOVE_TO_LEFT) {
   move_state = MOVE_TO_LEFT;
  }
  left_show_view.getView().setVisibility(View.VISIBLE);//設置左邊可見
  //right_show_view.getView().setVisibility(View.GONE);
  } //else if (left < 0) {//如果屏幕的左邊被移向左，則left變成負數
  //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);//參數依次為左、上、右、下。
 } else {
  left = (int) (screen_w * WIDTH_RATE);//left為左邊應該留出的控件空間，或者主屏左邊應該在的位置
  if (now_state == RIGHT) {
  left = -1 * left;//若狀態是在右邊空出來，則主屏的左邊為負數
  }
  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);//留下預定的寬度，顯示各個view的參數設置。
  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為未指定的
  heightMeasureSpec);
 left_show_view.setWidth((int) (screen_w * WIDTH_RATE));//設置view寬度
 super.onMeasure(widthMeasureSpec, heightMeasureSpec);//調用父類的構造函數
 }
 private int start_x;
 private int start_y;
 private boolean isMoved;
 public boolean dispatchTouchEvent(MotionEvent ev) {//分發觸摸消息事件
 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上面移動的距離大於X上面移動的距離。
   super.onTouchEvent(ev);
   return true;
   } else {//X移動距離大於Y
   if (Math.abs(last_x - start_x) > 5) {//X移動距離大於5就被認為移動了
    isMoved = true;
   }
   }
  }
  if (isMoved) {
   if (this.touch_state == TOUCH_STATE_MOVING) {
   if (Math.abs(last_x - start_x) > 10) {//如果移動的X距離大於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) {//方向正確的移動才算是移動的狀態
    isMoved = false;
    break;
    }
    if (move_x < 0 && now_state == RIGHT) {//如果現在在顯示右邊，那麼再向右移就不反應。
    isMoved = false;
    break;
    }
    if (move_x < 0 && now_state ==MAIN){//如果現在在主屏，向右移動也是無效的
    isMoved = false;
    break;
    }
    if (move_x > 234 && now_state ==MAIN){
    isMoved = true;//設置為true那麼移動還是發生了，break之後還是會在ACTIONUP中起作用
    break;//break之後不會執行下面的move()語句,
    }
    if (move_x < -234 && now_state ==LEFT){
    isMoved = true;
    break;
    }
    move(move_x);//以移動的距離為參數調用move（）實現移動的動態顯示
   }
   }
   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;//為什麼現在又把now_state賦值為left？
 }
//  else {//else以及括號中的語句都是為原來的按鈕准備的。。。
//  mHandler.postDelayed(new Runnable() {//一個新的可運行的函數
//
//  @Override
//  public void run() {
//   int move_change = (int) (screen_w * WIDTH_RATE / 5);//五分之一要顯示的寬度
//   int left = (int) (screen_w * WIDTH_RATE - main_show_view
//    .getView().getLeft());//getleft()返回的是主屏左邊緣離左邊的距離
//   Message msg = new Message();
//   if (left > move_change) {//括號裡面不懂，起什麼作用？
//   msg.what = 1;
//   mHandler.sendMessage(msg);
//   mHandler.postDelayed(this, 10);//又調用自己，基本上非要是小於關系
//   } 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在這裡又被初始化為屏幕的一個比例大小
 initView();
 initContent();
 moveToMain(false);
 }
 public int getNowState() {
 return this.now_state;
 }
}