Shulou(Shulou.com)06/02 Report--

This article is to share with you about how Android realizes the food turntable. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.

Effect video

Initialize SurfaceViewprivate void init () {mSurfaceHolder = this.getHolder (); / / manage the lifecycle of SurfaceView mSurfaceHolder.addCallback (this); this.setFocusable (true); this.setFocusableInTouchMode (true); this.setKeepScreenOn (true);} Measurement

Get the center point of the control by getting the height and width, and then subtracting the length of the mPadding, and then store the measured width and height

@ Override protected void onMeasure (int widthMeasureSpec, int heightMeasureSpec) {super.onMeasure (widthMeasureSpec, heightMeasureSpec); int width = Math.min (getMeasuredWidth (), getMeasuredHeight ()); mPadding = getPaddingLeft (); mRadius = width-mPadding * 2; / / Center point mCenter = width / 2; setMeasuredDimension (width, width);} draw

Draw the disc background

Set the background picture

Private Bitmap mBgBitmap = BitmapFactory.decodeResource (getResources (), R.drawable.turntable_bgcolor)

Draw the prominent part of the background

Private void drawBgColor () {mCanvas.drawColor (0xFFFFFFFF); mCanvas.drawBitmap (mBgBitmap, null, new Rect (mPadding / 2, mPadding / 2, getMeasuredWidth ()-mPadding / 2, getMeasuredWidth ()-mPadding / 2), null);} draw blocks private void drawArea () {/ / starting angle float tempAngle = mStartAngle; / / the angle of each block drawn float sweepAngele = 360 / mItemCount For (int I = 0; I < mItemCount; colors +) {mArcPaint.setColor (itemColors [I]); / draw mCanvas.drawArc (mRange, tempAngle, sweepAngele, true, mArcPaint); / / draw text drawText (tempAngle, sweepAngele, itemCharString [I]); / / draw icon drawIcon (tempAngle, mBitmaps [I]) TempAngle + = sweepAngele;} mStartAngle + = mSpeed; / / if you need to stop, let the speed gradually decrease until 0 if (isShouldEnd) {mSpeed-= mDifferSpeed;} if (create an oval.xml file under mSpeed drawable

The code is as follows:

Animation settin

Configure the circle style we established in the XML file

Android:background= "@ drawable/oval"

Then the animation is set in Activity, where the five parameters of the createCircularReveal () method are: control, X at the center where the animation begins, Y at the center at the beginning of the animation, radius at the beginning of the animation, and radius at the end of the animation

Private void RevealAnim (View view) {Animator animator = ViewAnimationUtils.createCircularReveal (view, view.getWidth () / 2, view.getHeight () / 2, view.getWidth (), 0); animator.setInterpolator (new AccelerateDecelerateInterpolator ()); animator.setDuration (2000); animator.start ();} Custom turntable Code public class Turntable extends SurfaceView implements SurfaceHolder.Callback, Runnable {private SurfaceHolder mSurfaceHolder; private Canvas mCanvas / * child thread for SurfaceView drawing * / private Thread mThread; / * controls the child thread switch * / private boolean isRunning; / * / private String [] itemCharString; / * picture * / private int [] itemImages; private Bitmap [] mBitmaps / * background * / private Bitmap mBgBitmap = BitmapFactory.decodeResource (getResources (), R.drawable.turntable_bgcolor); / * Color Block * / private int [] itemColors; / * * default equivalent * / private int mItemCount = 8; / * range of the entire disk * / private RectF mRange = new RectF () / * / private int mRadius; / * paint the brush of the block * / private Paint mArcPaint; / * the brush of the drawing text * / private Paint mTextPaint; / * font size * / private float mTextSize = TypedValue.applyDimension (TypedValue.COMPLEX_UNIT_SP, 20, getResources (). GetDisplayMetrics ()) / * the speed of the disk block scrolling * / private double mSpeed = 0; / * the center position of the turntable * / private int mCenter; / * where our padding directly takes paddingLeft * / private int mPadding; / * volatile to ensure the visibility between threads * / private volatile float mStartAngle = 0 / * determine whether the stop button is clicked * / private boolean isShouldEnd = false; / * set the minimum time for a single drawing. If the drawing is completed within this time, let the child threads sleep to the end of the change time * this prevents the thread from drawing frequently and consumes performance first * / private long mOneTimeMinMillionSeconds = 50; private int mDifferSpeed = 1 / / the decreasing speed difference after the call is stopped should be greater than 0 public Turntable (Context context) {super (context); init ();} public Turntable (Context context, AttributeSet attrs) {super (context, attrs); init ();} public Turntable (Context context, AttributeSet attrs, int defStyleAttr) {super (context, attrs, defStyleAttr); init () } public void InitNumber (int number) {if (number)

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