ActionbarActivity.java

package com.com.mr_wrong.Actionbar;

import android.app.ActionBar;
import android.app.Activity;
import android.graphics.RectF;
import android.os.Bundle;
import android.text.Spannable;
import android.text.SpannableString;
import android.util.Log;
import android.util.TypedValue;
import android.view.View;
import android.view.Window;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.widget.AbsListView;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.ListView;

import com.example.mr_wrong.androidstudioproject.R;

import java.util.ArrayList;

/**
 * Created by Mr_Wrong on 15/6/4.
 */
public class ActionbarActivity extends Activity {
    private static final String TAG = "NoBoringActionBarActivity";
    private int mActionBarTitleColor;
    private int mActionBarHeight;
    private int mHeaderHeight;
    private int mMinHeaderTranslation;
    private ListView mListView;
    private KenBurnsView mHeaderPicture;
    private ImageView mHeaderLogo;
    private View mHeader;
    private View mPlaceHolderView;
    private AccelerateDecelerateInterpolator mSmoothInterpolator;

    private RectF mRect1 = new RectF();
    private RectF mRect2 = new RectF();

    private AlphaForegroundColorSpan mAlphaForegroundColorSpan;
    private SpannableString mSpannableString;

    private TypedValue mTypedValue = new TypedValue();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getWindow().requestFeature(Window.FEATURE_ACTION_BAR_OVERLAY);
        mSmoothInterpolator = new AccelerateDecelerateInterpolator();
        mHeaderHeight = getResources().getDimensionPixelSize(R.dimen.header_height);
        mMinHeaderTranslation = -mHeaderHeight + getActionBarHeight();

        setContentView(R.layout.actionbar);

        mListView = (ListView) findViewById(R.id.lv_actionbar);
        mHeader = findViewById(R.id.head);
        mHeaderPicture = (KenBurnsView) findViewById(R.id.header_picture);
        mHeaderPicture.setResourceIds(R.drawable.picture0, R.drawable.picture1);
        mHeaderLogo = (ImageView) findViewById(R.id.header_logo);

        mActionBarTitleColor = getResources().getColor(R.color.actionbar_title_color);

        mSpannableString = new SpannableString(getString(R.string.noboringactionbar_title));
        mAlphaForegroundColorSpan = new AlphaForegroundColorSpan(mActionBarTitleColor);

        setupActionBar();
        setupListView();
    }

    private void setupListView() {
        ArrayList<String> FAKES = new ArrayList<String>();
        for (int i = 0; i < 1000; i++) {
            FAKES.add("entry " + i);
        }
        //占位head
        mPlaceHolderView = getLayoutInflater().inflate(R.layout.fake_header, mListView, false);
        mListView.addHeaderView(mPlaceHolderView);
        mListView.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, FAKES));
        mListView.setOnScrollListener(new AbsListView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {
            }

            @Override
            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
                int scrollY = getScrollY();
                //Log.e("----",scrollY+"");
                //Log.e("getTranslationY",mHeader.getTranslationY()+"");
                Log.e("max",Math.max(-scrollY, mMinHeaderTranslation)+"");
                //sticky actionbar
                mHeader.setTranslationY(Math.max(-scrollY, mMinHeaderTranslation));
                //header_logo --> actionbar icon
                float ratio = clamp(mHeader.getTranslationY() / mMinHeaderTranslation, 0.0f, 1.0f);
                interpolate(mHeaderLogo, getActionBarIconView(), mSmoothInterpolator.getInterpolation(ratio));

                setTitleAlpha(clamp(5.0F * ratio - 4.0F, 0.0F, 1.0F));
            }
        });
    }

    private void setTitleAlpha(float alpha) {
        mAlphaForegroundColorSpan.setAlpha(alpha);
        mSpannableString.setSpan(mAlphaForegroundColorSpan, 0, mSpannableString.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
        getActionBar().setTitle(mSpannableString);

    }

    public static float clamp(float value, float min, float max) {
        return Math.max(min, Math.min(value, max));//把valus控制在min和max之间
    }

    private void interpolate(View view1, View view2, float interpolation) {
        getOnScreenRect(mRect1, view1);
        getOnScreenRect(mRect2, view2);
        // Log.e("-----", interpolation + "");0-1
//        Log.e("-----",mRect2.width() / mRect1.width()+"");0.34
        // Log.e("-----1", mRect1.width() + "");94
        //Log.e("-----2", mRect2.width() + "");275

        float scaleX = 1.0F + interpolation * (mRect2.width() / mRect1.width() - 1.0F);
        float scaleY = 1.0F + interpolation * (mRect2.height() / mRect1.height() - 1.0F);
        float translationX = 0.5F * (interpolation * (mRect2.left + mRect2.right - mRect1.left - mRect1.right));
        float translationY = 0.5F * (interpolation * (mRect2.top + mRect2.bottom - mRect1.top - mRect1.bottom));

        view1.setTranslationX(translationX);
        view1.setTranslationY(translationY - mHeader.getTranslationY());
        view1.setScaleX(scaleX);
        view1.setScaleY(scaleY);
    }

    private RectF getOnScreenRect(RectF rect, View view) {
        rect.set(view.getLeft(), view.getTop(), view.getRight(), view.getBottom());
        return rect;
    }

    public int getScrollY() {
        //上 正 距离
        View c = mListView.getChildAt(0);
        if (c == null) {
            return 0;
        }

        int firstVisiblePosition = mListView.getFirstVisiblePosition();
        int top = c.getTop();

        int headerHeight = 0;
        if (firstVisiblePosition >= 1) {
            headerHeight = mPlaceHolderView.getHeight();
        }

        return -top + firstVisiblePosition * c.getHeight() + headerHeight;
    }

    private void setupActionBar() {
        ActionBar actionBar = getActionBar();
        actionBar.setIcon(R.drawable.ic_transparent);
        actionBar.setBackgroundDrawable(null);

        //getActionBarTitleView().setAlpha(0f);
    }

    private ImageView getActionBarIconView() {
        ImageView v = (ImageView) findViewById(android.R.id.home);

        return v;
    }

    /*private TextView getActionBarTitleView() {
        int id = Resources.getSystem().getIdentifier("action_bar_title", "id", "android");
        return (TextView) findViewById(id);
    }*/

    public int getActionBarHeight() {
        if (mActionBarHeight != 0) {
            return mActionBarHeight;
        }
        getTheme().resolveAttribute(android.R.attr.actionBarSize, mTypedValue, true);
        mActionBarHeight = TypedValue.complexToDimensionPixelSize(mTypedValue.data, getResources().getDisplayMetrics());
        return mActionBarHeight;
    }
}