Android自定义View实现拖动选择按钮

本文为大家分享了Android实现拖动选择按钮的具体代码，供大家参考，具体内容如下

效果图

View代码

第一步：自定义属性

 <declare-styleable name="DragView">
  <attr name="icon_drag" format="reference"/>
  <attr name="color_circle" format="color"/>
  <attr name="dot_num" format="integer"/>
 </declare-styleable>

第二步：自定义圆形

public class CircleView extends View {
 /**
  * 默认颜色
  */
 private final int DEFAULT_COLOR = Color.LTGRAY;
 /**
  * 默认半径dp
  */
 private final float DEFAULT_RADIUS = 32;
 private int mColor;
 private Paint mCirclePaint;
 private float mRadius;
 private float mCenterX;
 private float mCenterY;

 public CircleView(Context context)
 {
  this(context, null);
 }

 public CircleView(Context context, AttributeSet attrs)
 {
  this(context, attrs, 0);
 }

 public CircleView(Context context, AttributeSet attrs, int defStyleAttr)
 {
  super(context, attrs, defStyleAttr);
  TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.DragView);
  mColor = array.getColor(R.styleable.DragView_color_circle,DEFAULT_COLOR);
  mCirclePaint = new Paint();
  mCirclePaint.setColor(mColor);

  mCenterY = mCenterX = mRadius = getMeasuredWidth() == 0?DEFAULT_RADIUS:getMeasuredWidth()/2;
  array.recycle();
 }

 public float getRadius(){
  return mRadius;
 }

 public int getColor()
 {
  return mColor;
 }

 @Override
 protected void onDraw(Canvas canvas)
 {
  canvas.drawCircle(mCenterX,mCenterY,mRadius,mCirclePaint);
 }
}

第三步：自定义拖动按钮

public class DragView extends RelativeLayout implements View.OnTouchListener {

 private Drawable mDragIcon;//拖动图标
 private ImageView mDragView;//拖动图标ImageView
 private int mCircleColor;//圆的颜色
 private Context mContext;//上下文
 private int mDotNum;//节点数量

 private int mWidth;//组件的宽度
 private int mHight;//组件的高度
 private int mCircleRadius;//园的半径
 private int mDragWidth;//拖动图标的宽度
 private int mLineWidth,mLineHeight;//中间线的长宽

 private float mStartX;//开始拖动的屏幕坐标
 private float mCurX;//开始拖动的触点坐标
 private float mMinX;//拖动范围的最小值
 private float mMaxX;//拖动范围的最大值

 private OnNodeSelect mOnNodeSelect;//回调接口

 public DragView(Context context) {
  this(context,null);
 }

 public DragView(Context context, AttributeSet attrs) {
  this(context, attrs,0);
 }

 public DragView(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  TypedArray array=context.obtainStyledAttributes(attrs, R.styleable.DragView);
  mDragIcon=array.getDrawable(R.styleable.DragView_icon_drag);
  mCircleColor=array.getColor(R.styleable.DragView_color_circle,Color.WHITE);
  mDotNum=array.getInt(R.styleable.DragView_dot_num,2);
  array.recycle();
  mContext=context;
  initView();
 }

 /**
  *视图初始化，这个方法的作用是把所有的视图添加进来，并做一些初始化的配置
  * 其实可以用LayoutInflater把xml的布局文件加载进来，这样比较简便
  */
 public void initView(){
  for (int i=0;i<mDotNum;i++){
   CircleView circleView=new CircleView(mContext);
   circleView.setOnTouchListener(this);
   addView(circleView);
  }

  View view=new View(mContext);
  view.setBackgroundColor(mCircleColor);
  addView(view);

  // TODO: 2016/4/21 top not right
  mDragView=new ImageView(mContext);
  mDragView.setImageDrawable(mDragIcon);
  mDragView.setOnTouchListener(this);
  addView(mDragView);
 }

 /**
  *这一步主要是为了测量、配置每个view的大小，以便于后面触摸事件的处理
  */
 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  super.onMeasure(widthMeasureSpec, heightMeasureSpec);

  mWidth=getMeasuredWidth();
  mHight=getMeasuredHeight();

  mCircleRadius=dp2px(mContext,32);
  mDragWidth=dp2px(mContext,50);
  mLineWidth=mWidth-mDragWidth;
  mLineHeight=mCircleRadius/2;

  int count=getChildCount();
  for (int i=0;i<count;i++){
   View view=getChildAt(i);
   LinearLayout.LayoutParams params;
   if (view instanceof CircleView){
    params=new LinearLayout.LayoutParams(mCircleRadius,mCircleRadius);
    view.setLayoutParams(params);
   }else if (view instanceof ImageView){
    params=new LinearLayout.LayoutParams(mDragWidth,mDragWidth);
    view.setLayoutParams(params);
   }else {
    params=new LinearLayout.LayoutParams(mLineWidth,mLineHeight);
    view.setLayoutParams(params);
   }
  }

 }


 /**
  *这一步主要是为了放置每个view的位置，如果用LayoutInflater加载布局文件，那这一步就可以省略了
  */
 @Override
 protected void onLayout(boolean changed, int l, int t, int r, int b) {
//  super.onLayout(changed, l, t, r, b);
  if (changed){
   int count =getChildCount();

   int dLeft=0;
   int dTop=mHight/2-mDragWidth/2;

   int cLeft=mDragWidth/2-mCircleRadius/2;
   int cTop=dTop+mDragWidth/2-mCircleRadius/2;

   int lLeft=mDragWidth/2;
   int lTop=dTop+mDragWidth/2-mLineHeight/2;


   mMinX=dLeft;
   mMaxX=dLeft+mLineWidth;

   int cIndex=0;
   int cSpace=0;

   for (int i=0;i<count;i++){
    View view=getChildAt(i);
    if (view instanceof CircleView){
     cLeft=cLeft+cSpace;
     view.layout(cLeft,cTop,cLeft+mCircleRadius,cTop+mCircleRadius);
     cIndex++;
     cSpace=cIndex*mLineWidth;
    }else if (view instanceof ImageView){
     view.layout(dLeft,dTop,dLeft+mDragWidth,dTop+mDragWidth);
    }else {
     view.layout(lLeft,lTop,lLeft+mLineWidth,lTop+mLineHeight);
    }
   }
  }
 }


 /**
  *触碰事件的处理，这是自定义view比较重要的地方
  */
 @Override
 public boolean onTouch(View v, MotionEvent event) {
  if (v instanceof ImageView){
   switch (event.getAction()) {
    case MotionEvent.ACTION_DOWN:

     mStartX = (int) event.getRawX();
     mCurX = v.getTranslationX();//获取view的偏移量
     v.setPressed(true);
     break;

    case MotionEvent.ACTION_MOVE:
     float x = mCurX + event.getRawX() - mStartX;
     if (x >= 0 && x <= mMaxX - mMinX) {
      v.setTranslationX(mCurX + event.getRawX() - mStartX);
     }

     break;

    case MotionEvent.ACTION_UP:
    case MotionEvent.ACTION_CANCEL:

     int distance=(int) (event.getRawX()-mStartX);
     if (distance>0){
      if (Math.abs(distance)>mLineWidth/2){
       v.setTranslationX(mCurX + event.getRawX() - mStartX);
       setAnim(mLineWidth,1);
      }else {
       v.setTranslationX(mCurX + event.getRawX() - mStartX);
       setAnim(0,0);
      }
     }else if (distance<0){
      if (Math.abs(distance)>mLineWidth/2){
       v.setTranslationX(mCurX + event.getRawX() - mStartX);
       setAnim(0,0);
      }else {
       v.setTranslationX(mCurX + event.getRawX() - mStartX);
       setAnim(mLineWidth,1);
      }
     }

     break;
   }
  }else if (v instanceof CircleView){
   switch (event.getAction()) {
    case MotionEvent.ACTION_UP:
     if (event.getRawX()>getDisplayWidth()/2){
      setAnim(mLineWidth,1);
     }else {
      setAnim(0,0);
     }
     break;
   }
  }
  return true;
 }

 //设置平移动画
 private void setAnim(float moveX, final int scrollPosition) {
  ObjectAnimator animator = ObjectAnimator.ofFloat(mDragView, "translationX", mDragView.getTranslationX(), moveX);
  animator.setDuration(300);
  animator.start();
  if (mOnNodeSelect != null) {
   mOnNodeSelect.onNodeSelect(scrollPosition);
  }
 }

 public void setNodeSelectListener(OnNodeSelect onNodeSelect) {
  mOnNodeSelect = onNodeSelect;
 }

 //事件回调接口
 public interface OnNodeSelect {
  void onNodeSelect(int position);
 }

 //dp转px
 public int dp2px(Context context, float dpValue)
 {
  final float scale = context.getResources().getDisplayMetrics().density;
  return (int) (dpValue * scale + 0.5f);
 }

 //获取屏幕宽度
 public int getDisplayWidth(){
  DisplayMetrics metrics=new DisplayMetrics();
  ((Activity)mContext).getWindowManager().getDefaultDisplay().getMetrics(metrics);
  return metrics.widthPixels;
 }
}

使用方法

布局文件：

 <com.pengkv.apple.weight.DragView
  android:id="@+id/view_drag"
  android:layout_width="200dp"
  app:icon_drag="@drawable/ic_drag"
  app:color_circle="#CCCCCC"
  app:dot_num="2"
  android:layout_height="60dp"/>

页面代码：

 dragView=(DragView)view.findViewById(R.id.view_drag);
 dragView.setNodeSelectListener(new DragView.OnNodeSelect() {
  @Override
  public void onNodeSelect(int position) {
   Toast.makeText(getActivity(),"我选择了"+position,Toast.LENGTH_SHORT).show();
  }
 });

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持小牛知识库。