packages/SystemUI/src/com/android/systemui/recents/tv/animations/ViewFocusAnimator.java

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.android.systemui.recents.tv.animations;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.ObjectAnimator;
import android.content.res.Resources;
import android.util.TypedValue;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.view.animation.Interpolator;
import com.android.systemui.R;

public class ViewFocusAnimator implements View.OnFocusChangeListener {
    private final float mUnselectedScale;
    private final float mSelectedScaleDelta;
    private final float mUnselectedZ;
    private final float mSelectedZDelta;
    private final int mAnimDuration;
    private final Interpolator mFocusInterpolator;

    protected View mTargetView;
    private float mFocusProgress;

    ObjectAnimator mFocusAnimation;

    public ViewFocusAnimator(View view) {
        mTargetView = view;
        final Resources res = view.getResources();

        mTargetView.setOnFocusChangeListener(this);

        TypedValue out = new TypedValue();
        res.getValue(R.raw.unselected_scale, out, true);
        mUnselectedScale = out.getFloat();
        mSelectedScaleDelta = res.getFraction(R.fraction.lb_focus_zoom_factor_medium, 1, 1) -
                mUnselectedScale;

        mUnselectedZ = res.getDimensionPixelOffset(R.dimen.recents_tv_unselected_item_z);
        mSelectedZDelta = res.getDimensionPixelOffset(R.dimen.recents_tv_selected_item_z_delta);

        mAnimDuration = res.getInteger(R.integer.item_scale_anim_duration);

        mFocusInterpolator = new AccelerateDecelerateInterpolator();

        mFocusAnimation = ObjectAnimator.ofFloat(this, "focusProgress", 0.0f);
        mFocusAnimation.setDuration(mAnimDuration);
        mFocusAnimation.setInterpolator(mFocusInterpolator);

        setFocusProgress(0.0f);

        mFocusAnimation.addListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationStart(Animator animation) {
                mTargetView.setHasTransientState(true);
            }

            @Override
            public void onAnimationEnd(Animator animation) {
                mTargetView.setHasTransientState(false);
            }
        });
    }

    public void setFocusProgress(float level) {
        mFocusProgress = level;

        float scale = mUnselectedScale + (level * mSelectedScaleDelta);
        float z = mUnselectedZ + (level * mSelectedZDelta);

        mTargetView.setScaleX(scale);
        mTargetView.setScaleY(scale);
        mTargetView.setZ(z);
    }

    public float getFocusProgress() {
        return mFocusProgress;
    }

    public void animateFocus(boolean focused) {
        if (mFocusAnimation.isStarted()) {
            mFocusAnimation.cancel();
        }

        float target = focused ? 1.0f : 0.0f;

        if (getFocusProgress() != target) {
            mFocusAnimation.setFloatValues(getFocusProgress(), target);
            mFocusAnimation.start();
        }
    }

    public void setFocusImmediate(boolean focused) {
        if (mFocusAnimation.isStarted()) {
            mFocusAnimation.cancel();
        }

        float target = focused ? 1.0f : 0.0f;

        setFocusProgress(target);
    }

    @Override
    public void onFocusChange(View v, boolean hasFocus) {
        if (v != mTargetView) {
            return;
        }
        changeSize(hasFocus);
    }

    protected void changeSize(boolean hasFocus) {
        ViewGroup.LayoutParams lp = mTargetView.getLayoutParams();
        int width = lp.width;
        int height = lp.height;

        if (width < 0 && height < 0) {
            mTargetView.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
            height = mTargetView.getMeasuredHeight();
        }

        if (mTargetView.isAttachedToWindow() && mTargetView.hasWindowFocus() &&
                mTargetView.getVisibility() == View.VISIBLE) {
            animateFocus(hasFocus);
        } else {
            setFocusImmediate(hasFocus);
        }
    }
}