Android(安卓)标题栏和状态栏随ScrollView滑动颜色改变轻松实现

01、概述：

在开发过程中，这样的需求也是常见的，随着ScrollView 的滑动，标题栏和状态栏背景透明度发生变化。有多中实现方式，在这里记录一下自己用到的一种。

02、效果：

03、代码实现：

public class ZpScrollViewActivity extends Activity{    private View titleLine;    private View titleLine1;    private LinearLayout title;    private LinearLayout top;    private MyScrollView scrollView;    @Override    protected void onCreate(@Nullable Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_scrollview);        initView();    }    private void initView() {        setTranslucentStatus(this, true);        title = (LinearLayout) findViewById(R.id.ll_title);        title.getBackground().mutate().setAlpha(0);        top = (LinearLayout) findViewById(R.id.ll_title_top);        titleLine1 = findViewById(R.id.v_title_line_1);        titleLine = findViewById(R.id.v_title_line);        scrollView = (MyScrollView) findViewById(R.id.sv_content);        // 设置状态栏高度        int statusBarHeight = this.getResources().getDimensionPixelSize(this.getResources().getIdentifier("status_bar_height", "dimen", "android"));        LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, statusBarHeight);        titleLine.setLayoutParams(params);        titleLine1.setLayoutParams(params);        // 设置滑动        scrollView.setOnScrollistener(new MyScrollView.OnScrollistener() {            @Override            public void onScroll(int startY, int endY) {                //根据scrollview滑动更改标题栏透明度                changeAphla(startY, endY);            }        });    }    /**     * 根据内容窗体的移动改变标题栏背景透明度     *     * @param startY scrollview开始滑动的y坐标（相对值）     * @param endY   scrollview结束滑动的y坐标（相对值）     */    private void changeAphla(int startY, int endY) {        //获取标题高度        int titleHeight = title.getMeasuredHeight();        //获取背景高度        int backHeight = top.getMeasuredHeight();        //获取控件的绝对位置坐标        int[] location = new int[2];        top.getLocationInWindow(location);        //从屏幕顶部到控件顶部的坐标位置Y        int currentY = location[1];        //表示回到原位（滑动到顶部）        if (currentY >= 0) {            title.getBackground().mutate().setAlpha(0);        }        Log.e("zpan", "=titleHeight=" + titleHeight + "=backHeight=" + backHeight + "=currentY=" + currentY);        //颜色透明度改变        if (currentY < titleHeight && currentY >= -(backHeight - titleHeight)) {            //计算出滚动过程中改变的透明值            double y = Math.abs(currentY) * 1.0;            double height = (backHeight - titleHeight) * 1.0;            int changeValue = (int) (y / height * 255);            Log.e("zpan", "changeValue=" + changeValue);            //判断是向上还是向下            if (endY > startY) {    //向上;透明度值增加，实际透明度减小                title.getBackground().mutate().setAlpha(changeValue);            } else if (endY < startY) {     //向下；透明度值减小，实际透明度增加                title.getBackground().mutate().setAlpha(changeValue);            }        }        //红色背景移除屏幕        if (currentY < -(backHeight - titleHeight)) {            title.getBackground().mutate().setAlpha(255);        }    }    /**     * 设置状态栏透明     *     * @param activity     * @param on     */    public void setTranslucentStatus(Activity activity, boolean on) {        Window win = activity.getWindow();        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {            win.clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS                    | WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);            win.getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN//                    | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION //保证华为虚拟键盘能显示                    | View.SYSTEM_UI_FLAG_LAYOUT_STABLE);            win.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);            win.setStatusBarColor(Color.TRANSPARENT);//            win.setNavigationBarColor(Color.TRANSPARENT); //保证华为虚拟键盘是系统色        }        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT && Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {            WindowManager.LayoutParams winParams = win.getAttributes();            final int bits = WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS;            if (on) {                winParams.flags |= bits;            } else {                winParams.flags &= ~bits;            }            win.setAttributes(winParams);        }    }}

注：代码里面的关键位置，注释比较详细，在这里就不做过多的介绍，有兴趣可以实际的尝试一下。

04、布局：activity_scrollview

<?xml version="1.0" encoding="utf-8"?>

05、自定义ScrollView 滑动事件，是为了处理ScrollView 的向下兼容问题

public class MyScrollView extends ScrollView {    private OnScrollistener onScrollistener;    public OnScrollistener getOnScrollistener() {        return onScrollistener;    }    public void setOnScrollistener(OnScrollistener onScrollistener) {        this.onScrollistener = onScrollistener;    }    public MyScrollView(Context context, AttributeSet attrs, int defStyle) {        super(context, attrs, defStyle);    }    public MyScrollView(Context context, AttributeSet attrs) {        super(context, attrs);    }    public MyScrollView(Context context) {        super(context);    }    public interface OnScrollistener {        void onScroll(int startY, int endY);    }    @Override    protected void onScrollChanged(int l, int t, int oldl, int oldt) {        onScrollistener.onScroll(oldt, t);        super.onScrollChanged(l, t, oldl, oldt);    }}

注：代码意思比较简单，不做过多的解释

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