[Refactor] Add annotations and final wherever possible.

Author: zhanghai

library/src/main/java/me/zhanghai/android/materialprogressbar/AnimationScaleIndeterminateCircularProgressDrawable.java

@@ -27,6 +27,7 @@ public void setUseIntrinsicPadding(boolean useIntrinsicPadding) {
         getIntrinsicPaddingDrawable().setUseIntrinsicPadding(useIntrinsicPadding);
     }
 
+    @NonNull
     private IntrinsicPaddingDrawable getIntrinsicPaddingDrawable() {
         return (IntrinsicPaddingDrawable) getCurrent();
     }

library/src/main/java/me/zhanghai/android/materialprogressbar/Animators.java

@@ -12,6 +12,7 @@
 import android.annotation.SuppressLint;
 import android.graphics.Path;
 
+import androidx.annotation.NonNull;
 import me.zhanghai.android.materialprogressbar.internal.ObjectAnimatorCompat;
 
 /**
@@ -81,7 +82,8 @@ private Animators() {}
      * @param target The object whose properties are to be animated.
      * @return An Animator object that is set up to behave the same as the its native counterpart.
      */
-    public static Animator createIndeterminateHorizontalRect1(Object target) {
+    @NonNull
+    public static Animator createIndeterminateHorizontalRect1(@NonNull Object target) {
 
         ObjectAnimator translateXAnimator = ObjectAnimatorCompat.ofFloat(target, "translateX", null,
                 PATH_INDETERMINATE_HORIZONTAL_RECT1_TRANSLATE_X);
@@ -109,7 +111,8 @@ public static Animator createIndeterminateHorizontalRect1(Object target) {
      * @param target The object whose properties are to be animated.
      * @return An Animator object that is set up to behave the same as the its native counterpart.
      */
-    public static Animator createIndeterminateHorizontalRect2(Object target) {
+    @NonNull
+    public static Animator createIndeterminateHorizontalRect2(@NonNull Object target) {
 
         ObjectAnimator translateXAnimator = ObjectAnimatorCompat.ofFloat(target, "translateX", null,
                 PATH_INDETERMINATE_HORIZONTAL_RECT2_TRANSLATE_X);
@@ -136,7 +139,8 @@ public static Animator createIndeterminateHorizontalRect2(Object target) {
      * @param target The object whose properties are to be animated.
      * @return An Animator object that is set up to behave the same as the its native counterpart.
      */
-    public static Animator createIndeterminate(Object target) {
+    @NonNull
+    public static Animator createIndeterminate(@NonNull Object target) {
 
         @SuppressLint("ObjectAnimatorBinding")
         ObjectAnimator trimPathStartAnimator = ObjectAnimator.ofFloat(target, "trimPathStart", 0,
@@ -172,7 +176,8 @@ public static Animator createIndeterminate(Object target) {
      * @param target The object whose properties are to be animated.
      * @return An Animator object that is set up to behave the same as the its native counterpart.
      */
-    public static Animator createIndeterminateRotation(Object target) {
+    @NonNull
+    public static Animator createIndeterminateRotation(@NonNull Object target) {
         @SuppressLint("ObjectAnimatorBinding")
         ObjectAnimator rotationAnimator = ObjectAnimator.ofFloat(target, "rotation", 0, 720);
         rotationAnimator.setDuration(6665);

library/src/main/java/me/zhanghai/android/materialprogressbar/BaseDrawable.java

@@ -16,19 +16,27 @@
 import android.graphics.drawable.Drawable;
 
 import androidx.annotation.ColorInt;
+import androidx.annotation.IntRange;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
 abstract class BaseDrawable extends Drawable implements TintableDrawable {
 
-    protected int mAlpha = 0xFF;
+    @IntRange(from = 0, to = 255)
+    protected int mAlpha = 255;
+    @Nullable
     protected ColorFilter mColorFilter;
+    @Nullable
     protected ColorStateList mTintList;
+    @NonNull
     protected PorterDuff.Mode mTintMode = PorterDuff.Mode.SRC_IN;
+    @Nullable
     protected PorterDuffColorFilter mTintFilter;
 
-    private DummyConstantState mConstantState = new DummyConstantState();
+    @NonNull
+    private final DummyConstantState mConstantState = new DummyConstantState();
 
+    @IntRange(from = 0, to = 255)
     @Override
     public int getAlpha() {
         return mAlpha;
@@ -38,7 +46,7 @@ public int getAlpha() {
      * {@inheritDoc}
      */
     @Override
-    public void setAlpha(int alpha) {
+    public void setAlpha(@IntRange(from = 0, to = 255) int alpha) {
         if (mAlpha != alpha) {
             mAlpha = alpha;
             invalidateSelf();
@@ -48,6 +56,7 @@ public void setAlpha(int alpha) {
     /**
      * {@inheritDoc}
      */
+    @Nullable
     @Override
     public ColorFilter getColorFilter() {
         return mColorFilter;
@@ -98,7 +107,7 @@ public boolean isStateful() {
     }
 
     @Override
-    protected boolean onStateChange(int[] state) {
+    protected boolean onStateChange(@NonNull int[] state) {
         return updateTintFilter();
     }
 
@@ -129,7 +138,7 @@ public int getOpacity() {
      * {@inheritDoc}
      */
     @Override
-    public void draw(Canvas canvas) {
+    public void draw(@NonNull Canvas canvas) {
 
         Rect bounds = getBounds();
         if (bounds.width() == 0 || bounds.height() == 0) {
@@ -142,17 +151,19 @@ public void draw(Canvas canvas) {
         canvas.restoreToCount(saveCount);
     }
 
+    @Nullable
     protected ColorFilter getColorFilterForDrawing() {
         return mColorFilter != null ? mColorFilter : mTintFilter;
     }
 
-    protected abstract void onDraw(Canvas canvas, int width, int height);
+    protected abstract void onDraw(@NonNull Canvas canvas, int width, int height);
 
     // Workaround LayerDrawable.ChildDrawable which calls getConstantState().newDrawable()
     // without checking for null.
     // We are never inflated from XML so the protocol of ConstantState does not apply to us. In
     // order to make LayerDrawable happy, we return ourselves from DummyConstantState.newDrawable().
 
+    @NonNull
     @Override
     public ConstantState getConstantState() {
         return mConstantState;

library/src/main/java/me/zhanghai/android/materialprogressbar/BaseIndeterminateProgressDrawable.java

@@ -12,15 +12,17 @@
 import android.graphics.Color;
 import android.graphics.drawable.Animatable;
 
+import androidx.annotation.NonNull;
 import me.zhanghai.android.materialprogressbar.internal.ThemeUtils;
 
 abstract class BaseIndeterminateProgressDrawable extends BaseProgressDrawable
         implements Animatable {
 
+    @NonNull
     protected Animator[] mAnimators;
 
     @SuppressLint("NewApi")
-    public BaseIndeterminateProgressDrawable(Context context) {
+    public BaseIndeterminateProgressDrawable(@NonNull Context context) {
         int controlActivatedColor = ThemeUtils.getColorFromAttrRes(R.attr.colorControlActivated,
                 Color.BLACK, context);
         // setTint() has been overridden for compatibility; DrawableCompat won't work because
@@ -32,7 +34,7 @@ public BaseIndeterminateProgressDrawable(Context context) {
      * {@inheritDoc}
      */
     @Override
-    public void draw(Canvas canvas) {
+    public void draw(@NonNull Canvas canvas) {
         super.draw(canvas);
 
         if (isStarted()) {

library/src/main/java/me/zhanghai/android/materialprogressbar/BasePaintDrawable.java

@@ -9,12 +9,16 @@
 import android.graphics.Color;
 import android.graphics.Paint;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
 abstract class BasePaintDrawable extends BaseDrawable {
 
+    @Nullable
     private Paint mPaint;
 
     @Override
-    protected final void onDraw(Canvas canvas, int width, int height) {
+    protected final void onDraw(@NonNull Canvas canvas, int width, int height) {
 
         if (mPaint == null) {
             mPaint = new Paint();
@@ -28,7 +32,8 @@ protected final void onDraw(Canvas canvas, int width, int height) {
         onDraw(canvas, width, height, mPaint);
     }
 
-    protected abstract void onPreparePaint(Paint paint);
+    protected abstract void onPreparePaint(@NonNull Paint paint);
 
-    protected abstract void onDraw(Canvas canvas, int width, int height, Paint paint);
+    protected abstract void onDraw(@NonNull Canvas canvas, int width, int height,
+                                   @NonNull Paint paint);
 }

library/src/main/java/me/zhanghai/android/materialprogressbar/BaseProgressLayerDrawable.java

@@ -15,6 +15,7 @@
 import android.util.Log;
 
 import androidx.annotation.ColorInt;
+import androidx.annotation.FloatRange;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.core.graphics.ColorUtils;
@@ -27,13 +28,17 @@ class BaseProgressLayerDrawable<
         extends LayerDrawable implements IntrinsicPaddingDrawable, MaterialProgressDrawable,
         ShowBackgroundDrawable, TintableDrawable {
 
+    @FloatRange(from = 0, to = 1)
     private float mBackgroundAlpha;
 
-    private BackgroundDrawableType mBackgroundDrawable;
-    private ProgressDrawableType mSecondaryProgressDrawable;
-    private ProgressDrawableType mProgressDrawable;
+    @NonNull
+    private final BackgroundDrawableType mBackgroundDrawable;
+    @NonNull
+    private final ProgressDrawableType mSecondaryProgressDrawable;
+    @NonNull
+    private final ProgressDrawableType mProgressDrawable;
 
-    public BaseProgressLayerDrawable(Drawable[] layers, Context context) {
+    public BaseProgressLayerDrawable(@NonNull Drawable[] layers, @NonNull Context context) {
         super(layers);
 
         mBackgroundAlpha = ThemeUtils.getFloatFromAttrRes(android.R.attr.disabledAlpha, 0, context);
@@ -116,7 +121,7 @@ public void setTintList(@Nullable ColorStateList tint) {
                 Log.w(getClass().getSimpleName(), "setTintList() called with a non-opaque" +
                         " ColorStateList, its original alpha will be discarded");
             }
-            backgroundTint = tint.withAlpha(Math.round(0xFF * mBackgroundAlpha));
+            backgroundTint = tint.withAlpha(Math.round(mBackgroundAlpha * 255));
         } else {
             backgroundTint = null;
         }

library/src/main/java/me/zhanghai/android/materialprogressbar/BaseSingleCircularProgressDrawable.java

@@ -9,20 +9,22 @@
 import android.graphics.Paint;
 import android.graphics.RectF;
 
+import androidx.annotation.NonNull;
+
 abstract class BaseSingleCircularProgressDrawable extends BaseProgressDrawable {
 
     private static final RectF RECT_BOUND = new RectF(-21, -21, 21, 21);
     private static final RectF RECT_PADDED_BOUND = new RectF(-24, -24, 24, 24);
     private static final RectF RECT_PROGRESS = new RectF(-19, -19, 19, 19);
 
     @Override
-    protected void onPreparePaint(Paint paint) {
+    protected void onPreparePaint(@NonNull Paint paint) {
         paint.setStyle(Paint.Style.STROKE);
         paint.setStrokeWidth(4);
     }
 
     @Override
-    protected void onDraw(Canvas canvas, int width, int height, Paint paint) {
+    protected void onDraw(@NonNull Canvas canvas, int width, int height, @NonNull Paint paint) {
 
         if (mUseIntrinsicPadding) {
             canvas.scale(width / RECT_PADDED_BOUND.width(), height / RECT_PADDED_BOUND.height());
@@ -35,9 +37,10 @@ protected void onDraw(Canvas canvas, int width, int height, Paint paint) {
         onDrawRing(canvas, paint);
     }
 
-    protected abstract void onDrawRing(Canvas canvas, Paint paint);
+    protected abstract void onDrawRing(@NonNull Canvas canvas, @NonNull Paint paint);
 
-    protected void drawRing(Canvas canvas, Paint paint, float startAngle, float sweepAngle) {
+    protected void drawRing(@NonNull Canvas canvas, @NonNull Paint paint, float startAngle,
+                            float sweepAngle) {
         // startAngle starts at 3 o'clock on a watch.
         canvas.drawArc(RECT_PROGRESS, -90 + startAngle, sweepAngle, false, paint);
     }

library/src/main/java/me/zhanghai/android/materialprogressbar/BaseSingleHorizontalProgressDrawable.java

@@ -10,23 +10,32 @@
 import android.graphics.Paint;
 import android.graphics.RectF;
 
+import androidx.annotation.Dimension;
+import androidx.annotation.NonNull;
+import androidx.annotation.Px;
+
 class BaseSingleHorizontalProgressDrawable extends BaseProgressDrawable {
 
+    @Dimension(unit = Dimension.DP)
     private static final int PROGRESS_INTRINSIC_HEIGHT_DP = 4;
+    @Dimension(unit = Dimension.DP)
     private static final int PADDED_INTRINSIC_HEIGHT_DP = 16;
     protected static final RectF RECT_BOUND = new RectF(-180, -1, 180, 1);
     private static final RectF RECT_PADDED_BOUND = new RectF(-180, -4, 180, 4);
 
-    private int mProgressIntrinsicHeight;
-    private int mPaddedIntrinsicHeight;
+    @Px
+    private final int mProgressIntrinsicHeight;
+    @Px
+    private final int mPaddedIntrinsicHeight;
 
-    public BaseSingleHorizontalProgressDrawable(Context context) {
+    public BaseSingleHorizontalProgressDrawable(@NonNull Context context) {
         float density = context.getResources().getDisplayMetrics().density;
         mProgressIntrinsicHeight = Math.round(PROGRESS_INTRINSIC_HEIGHT_DP * density);
         mPaddedIntrinsicHeight = Math.round(PADDED_INTRINSIC_HEIGHT_DP * density);
     }
 
     @Override
+    @Px
     public int getIntrinsicHeight() {
         return mUseIntrinsicPadding ? mPaddedIntrinsicHeight : mProgressIntrinsicHeight;
     }

library/src/main/java/me/zhanghai/android/materialprogressbar/CircularProgressBackgroundDrawable.java

@@ -8,6 +8,8 @@
 import android.graphics.Canvas;
 import android.graphics.Paint;
 
+import androidx.annotation.NonNull;
+
 class CircularProgressBackgroundDrawable extends BaseSingleCircularProgressDrawable
         implements ShowBackgroundDrawable {
 
@@ -27,14 +29,14 @@ public void setShowBackground(boolean show) {
     }
 
     @Override
-    public void draw(Canvas canvas) {
+    public void draw(@NonNull Canvas canvas) {
         if (mShow) {
             super.draw(canvas);
         }
     }
 
     @Override
-    protected void onDrawRing(Canvas canvas, Paint paint) {
+    protected void onDrawRing(@NonNull Canvas canvas, @NonNull Paint paint) {
         drawRing(canvas, paint, 0, 360);
     }
 }

library/src/main/java/me/zhanghai/android/materialprogressbar/CircularProgressDrawable.java

@@ -8,6 +8,8 @@
 import android.content.Context;
 import android.graphics.drawable.Drawable;
 
+import androidx.annotation.NonNull;
+
 /**
  * A new {@code Drawable} for determinate circular {@code ProgressBar}.
  */
@@ -19,7 +21,7 @@ public class CircularProgressDrawable extends BaseProgressLayerDrawable<
      *
      * @param context the {@code Context} for retrieving style information.
      */
-    public CircularProgressDrawable(int style, Context context) {
+    public CircularProgressDrawable(int style, @NonNull Context context) {
         super(new Drawable[] {
                 new CircularProgressBackgroundDrawable(),
                 new SingleCircularProgressDrawable(style),

library/src/main/java/me/zhanghai/android/materialprogressbar/HorizontalProgressBackgroundDrawable.java

@@ -8,12 +8,14 @@
 import android.content.Context;
 import android.graphics.Canvas;
 
+import androidx.annotation.NonNull;
+
 class HorizontalProgressBackgroundDrawable extends BaseSingleHorizontalProgressDrawable
         implements ShowBackgroundDrawable {
 
     private boolean mShow = true;
 
-    public HorizontalProgressBackgroundDrawable(Context context) {
+    public HorizontalProgressBackgroundDrawable(@NonNull Context context) {
         super(context);
     }
 
@@ -31,7 +33,7 @@ public void setShowBackground(boolean show) {
     }
 
     @Override
-    public void draw(Canvas canvas) {
+    public void draw(@NonNull Canvas canvas) {
         if (mShow) {
             super.draw(canvas);
         }

library/src/main/java/me/zhanghai/android/materialprogressbar/HorizontalProgressDrawable.java

@@ -8,6 +8,8 @@
 import android.content.Context;
 import android.graphics.drawable.Drawable;
 
+import androidx.annotation.NonNull;
+
 /**
  * A backported {@code Drawable} for determinate horizontal {@code ProgressBar}.
  */
@@ -19,7 +21,7 @@ public class HorizontalProgressDrawable extends BaseProgressLayerDrawable<
      *
      * @param context the {@code Context} for retrieving style information.
      */
-    public HorizontalProgressDrawable(Context context) {
+    public HorizontalProgressDrawable(@NonNull Context context) {
         super(new Drawable[] {
                 new HorizontalProgressBackgroundDrawable(context),
                 new SingleHorizontalProgressDrawable(context),