android自定义SeekBar，拖动时可弹出跟随窗口显示进度

package com.seekbar.demo; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Rect; import android.graphics.drawable.Drawable; import android.util.AttributeSet; import android.view.LayoutInflater; import android.view.MotionEvent; import android.view.View; import android.widget.AbsSeekBar; import android.widget.PopupWindow; import android.widget.SeekBar; import android.widget.TextView; public class ManaMySeekBar extends SeekBar { private PopupWindow mPopupWindow; private LayoutInflater mInflater; private View mView; private int[] mPosition; private final int mThumbWidth = 25; private TextView mTvProgress; public ManaMySeekBar(Context context, AttributeSet attrs) { super(context, attrs); // TODO Auto-generated constructor stub mInflater = LayoutInflater.from(context); mView = mInflater.inflate(R.layout.popwindow_layout, null); mTvProgress = (TextView)mView.findViewById(R.id.tvPop); mPopupWindow = new PopupWindow(mView, mView.getWidth(), mView.getHeight(), true); mPosition = new int[2]; } public void setSeekBarText(String str){ mTvProgress.setText(str); } @Override public boolean onTouchEvent(MotionEvent event) { // TODO Auto-generated method stub switch (event.getAction()) { case MotionEvent.ACTION_DOWN: this.getLocationOnScreen(mPosition); mPopupWindow.showAsDropDown(this, (int) event.getX(), mPosition[1] - 30); break; case MotionEvent.ACTION_UP: mPopupWindow.dismiss(); break; } return super.onTouchEvent(event); } private int getViewWidth(View v){ int w = View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED); int h = View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED); v.measure(w, h); return v.getMeasuredWidth(); } private int getViewHeight(View v){ int w = View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED); int h = View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED); v.measure(w, h); return v.getMeasuredHeight(); } @Override protected synchronized void onDraw(Canvas canvas) { // TODO Auto-generated method stub int thumb_x = this.getProgress() * (this.getWidth() - mThumbWidth) / this.getMax(); int middle = this.getHeight() / 2+40; super.onDraw(canvas); if (mPopupWindow != null) { try { this.getLocationOnScreen(mPosition); mPopupWindow.update(thumb_x+mPosition[0] - getViewWidth(mView) / 2+mThumbWidth/2, middle,getViewWidth(mView),getViewHeight(mView)); } catch (Exception e) { // TODO: handle exception } } } }