Android沉浸式状态栏 + actionBar渐变 + scrollView顶部伸缩效果

闲话不多说，直接上图。

给大家讲讲我的编程思想吧。

第一部分：沉浸式状态栏（API-Level 19, Android4.4 KitKat 之后加入的东西），而且在Api-Level 21版本中新增了一个属性（下面会说到）。所以，style文件应该声明三份。

values

<style name="TranslucentTheme" parent="@style/AppTheme">
</style>

values-19

<style name="TranslucentTheme" parent="@style/AppTheme">
<item name="android:windowTranslucentStatus">true</item>
<item name="android:windowTranslucentNavigation">false</item>
</style>

values-V21

<style name="TranslucentTheme" parent="@style/AppTheme">
<item name="android:windowTranslucentStatus">true</item>
<item name="android:windowTranslucentNavigation">false</item>
<!-- v-21 中新增的属性 -->
<item name="android:statusBarColor">@android:color/transparent</item>
</style>

至于以上属性的含义及使用方式，就不多做解释了。详细可参见 https://www.jb51.net/article/104485.htm

第二部分：actionBar渐变

因为要实现actionBar渐变，所以我没有使用系统的actionBar。而是自定义了一个继承自LinearLayout的ViewGroup。

直接给各位看代码

package test.com.widget;
import android.content.Context;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;
import test.com.R;
import test.com.impl.ActionBarClickListener;
/**
* 支持渐变的 actionBar
* Created by 晖仔(Milo) on 2016/12/28.
* email:303767416@qq.com
*/
public final class TranslucentActionBar extends LinearLayout {
private View layRoot;
private View vStatusBar;
private View layLeft;
private View layRight;
public TextView tvTitle;
private TextView tvLeft;
private TextView tvRight;
private View iconLeft;
private View iconRight;
public TranslucentActionBar(Context context) {
 this(context, null);
}
public TranslucentActionBar(Context context, AttributeSet attrs) {
 super(context, attrs);
 init();
}
public TranslucentActionBar(Context context, AttributeSet attrs, int defStyleAttr) {
 super(context, attrs, defStyleAttr);
}
private void init() {
 setOrientation(HORIZONTAL);
 View contentView = inflate(getContext(), R.layout.actionbar_trans, this);
 layRoot = contentView.findViewById(R.id.lay_transroot);
 vStatusBar = contentView.findViewById(R.id.v_statusbar);
 tvTitle = (TextView) contentView.findViewById(R.id.tv_actionbar_title);
 tvLeft = (TextView) contentView.findViewById(R.id.tv_actionbar_left);
 tvRight = (TextView) contentView.findViewById(R.id.tv_actionbar_right);
 iconLeft = contentView.findViewById(R.id.iv_actionbar_left);
 iconRight = contentView.findViewById(R.id.v_actionbar_right);
}
/**
 * 设置状态栏高度
 *
 * @param statusBarHeight
 */
public void setStatusBarHeight(int statusBarHeight) {
 ViewGroup.LayoutParams params = vStatusBar.getLayoutParams();
 params.height = statusBarHeight;
 vStatusBar.setLayoutParams(params);
}
/**
 * 设置是否需要渐变
 */
public void setNeedTranslucent() {
 setNeedTranslucent(true, false);
}
/**
 * 设置是否需要渐变,并且隐藏标题
 *
 * @param translucent
 */
public void setNeedTranslucent(boolean translucent, boolean titleInitVisibile) {
 if (translucent) {
  layRoot.setBackgroundDrawable(null);
 }
 if (!titleInitVisibile) {
  tvTitle.setVisibility(View.GONE);
 }
}
/**
 * 设置标题
 *
 * @param strTitle
 */
public void setTitle(String strTitle) {
 if (!TextUtils.isEmpty(strTitle)) {
  tvTitle.setText(strTitle);
 } else {
  tvTitle.setVisibility(View.GONE);
 }
}
/**
 * 设置数据
 *
 * @param strTitle
 * @param resIdLeft
 * @param strLeft
 * @param resIdRight
 * @param strRight
 * @param listener
 */
public void setData(String strTitle, int resIdLeft, String strLeft, int resIdRight, String strRight, final ActionBarClickListener listener) {
 if (!TextUtils.isEmpty(strTitle)) {
  tvTitle.setText(strTitle);
 } else {
  tvTitle.setVisibility(View.GONE);
 }
 if (!TextUtils.isEmpty(strLeft)) {
  tvLeft.setText(strLeft);
  tvLeft.setVisibility(View.VISIBLE);
 } else {
  tvLeft.setVisibility(View.GONE);
 }
 if (!TextUtils.isEmpty(strRight)) {
  tvRight.setText(strRight);
  tvRight.setVisibility(View.VISIBLE);
 } else {
  tvRight.setVisibility(View.GONE);
 }
 if (resIdLeft == 0) {
  iconLeft.setVisibility(View.GONE);
 } else {
  iconLeft.setBackgroundResource(resIdLeft);
  iconLeft.setVisibility(View.VISIBLE);
 }
 if (resIdRight == 0) {
  iconRight.setVisibility(View.GONE);
 } else {
  iconRight.setBackgroundResource(resIdRight);
  iconRight.setVisibility(View.VISIBLE);
 }
 if (listener != null) {
  layLeft = findViewById(R.id.lay_actionbar_left);
  layRight = findViewById(R.id.lay_actionbar_right);
  layLeft.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {
    listener.onLeftClick();
   }
  });
  layRight.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {
    listener.onRightClick();
   }
  });
 }
}
}

下面是actionbar_trans.xml的代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/lay_transroot"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@color/colorPrimary"
android:orientation="vertical">
<View
 android:id="@+id/v_statusbar"
 android:layout_width="match_parent"
 android:layout_height="1.0dp" />
<RelativeLayout
 android:layout_width="match_parent"
 android:layout_height="45dp"
 android:orientation="vertical">
 <RelativeLayout
  android:id="@+id/lay_actionbar_left"
  android:layout_width="100dp"
  android:layout_height="match_parent"
  android:orientation="horizontal">
  <ImageView
   android:id="@+id/iv_actionbar_left"
   android:layout_width="20dp"
   android:layout_height="20dp"
   android:layout_centerVertical="true"
   android:layout_marginLeft="10dp"
   android:background="@mipmap/ic_left_light"
   android:visibility="gone" />
  <TextView
   android:id="@+id/tv_actionbar_left"
   style="@style/text_white"
   android:layout_height="match_parent"
   android:layout_marginLeft="10dp"
   android:layout_toRightOf="@+id/iv_actionbar_left"
   android:gravity="center_vertical"
   android:maxLength="2"
   android:singleLine="true"
   android:text="返回"
   android:visibility="gone" />
 </RelativeLayout>
 <TextView
  android:id="@+id/tv_actionbar_title"
  style="@style/text_white"
  android:layout_centerInParent="true"
  android:text="标题"
  android:textSize="16sp" />
 <RelativeLayout
  android:id="@+id/lay_actionbar_right"
  android:layout_width="100dp"
  android:layout_height="match_parent"
  android:layout_alignParentRight="true"
  android:gravity="right"
  android:orientation="horizontal">
  <View
   android:id="@+id/v_actionbar_right"
   android:layout_width="20dp"
   android:layout_height="20dp"
   android:layout_alignParentRight="true"
   android:layout_centerVertical="true"
   android:layout_marginRight="10dp"
   android:visibility="gone" />
  <TextView
   android:id="@+id/tv_actionbar_right"
   style="@style/text_white"
   android:layout_height="match_parent"
   android:layout_marginRight="10dp"
   android:layout_toLeftOf="@+id/v_actionbar_right"
   android:gravity="center_vertical|right"
   android:singleLine="true"
   android:visibility="gone" />
 </RelativeLayout>
</RelativeLayout>
</LinearLayout>

这里我即没有用到 android:fitsSystemWindows="true" 属性，也没有用到 StatusBarUtils ，因为我发现使用的时候很容易造成兼容问题。

所以，我的做法是声明了一个高度为0.0dp的 statusbar，背景为透明，然后获取状态栏高度并赋值到它上，来实现兼容。事实证明，这样做的兼容效果最好。

获取状态栏高度代码：

/**
* 获取状态栏高度
*
* @return
*/
public int getStatusBarHeight() {
//获取status_bar_height资源的ID
int resourceId = getResources().getIdentifier("status_bar_height", "dimen", "android");
if (resourceId > 0) {
 //根据资源ID获取响应的尺寸值
 return getResources().getDimensionPixelSize(resourceId);
}
return 0;
}

设置 statusbar高度：

/**
* 设置状态栏高度
*
* @param statusBarHeight
*/
public void setStatusBarHeight(int statusBarHeight) {
ViewGroup.LayoutParams params = vStatusBar.getLayoutParams();
params.height = statusBarHeight;
vStatusBar.setLayoutParams(params);
}

开启渐变：

/**
* 设置是否需要渐变
*/
public void setNeedTranslucent() {
 setNeedTranslucent(true, false);
}
/**
* 设置是否需要渐变,并且隐藏标题
*
* @param translucent
*/
public void setNeedTranslucent(boolean translucent, boolean titleInitVisibile) {
 if (translucent) {
  layRoot.setBackgroundDrawable(null);
 }
 if (!titleInitVisibile) {
  tvTitle.setVisibility(View.GONE);
 }
}

第三步：实现ScrollView顶部伸缩

到了这里，必须得说一下，因为是个人项目中用到，所以并没有把功能做的很强大，本人都是以最简单、有效的方式实现的。所以，代码并不像gitHub上那些被下载很多次的开源项目一样，有很高的扩展性。
时间关系，我直接贴代码吧，代码里我都写了注释的。

package test.com.widget;
import android.animation.ObjectAnimator;
import android.animation.ValueAnimator;
import android.content.Context;
import android.graphics.Color;
import android.support.annotation.ColorInt;
import android.support.v4.graphics.ColorUtils;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.ScrollView;
import test.com.R;
import test.com.utils.SizeUtils;
/**
* Created by 晖仔(Milo) on 2017/2/13.
* email:303767416@qq.com
*/
public class TranslucentScrollView extends ScrollView {
static final String TAG = "TranslucentScrollView";
//伸缩视图
private View zoomView;
//伸缩视图初始高度
private int zoomViewInitHeight = 0;
// 记录首次按下位置
private float mFirstPosition = 0;
// 是否正在放大
private Boolean mScaling = false;
//渐变的视图
private View transView;
//渐变颜色
private int transColor = Color.WHITE;
//渐变开始位置
private int transStartY = 50;
//渐变结束位置
private int transEndY = 300;
//渐变开始默认位置，Y轴，50dp
private final int DFT_TRANSSTARTY = 50;
//渐变结束默认位置，Y轴，300dp
private final int DFT_TRANSENDY = 300;
private TranslucentScrollView.TranslucentChangedListener translucentChangedListener;
public interface TranslucentChangedListener {
 /**
  * 透明度变化，取值范围0-255
  *
  * @param transAlpha
  */
 void onTranslucentChanged(int transAlpha);
}
public TranslucentScrollView(Context context) {
 super(context);
}
public TranslucentScrollView(Context context, AttributeSet attrs) {
 super(context, attrs);
}
public TranslucentScrollView(Context context, AttributeSet attrs, int defStyleAttr) {
 super(context, attrs, defStyleAttr);
}
public void setTranslucentChangedListener(TranslucentScrollView.TranslucentChangedListener translucentChangedListener) {
 this.translucentChangedListener = translucentChangedListener;
}
/**
 * 设置伸缩视图
 *
 * @param zoomView
 */
public void setPullZoomView(View zoomView) {
 this.zoomView = zoomView;
 zoomViewInitHeight = zoomView.getLayoutParams().height;
 if (zoomViewInitHeight == LayoutParams.MATCH_PARENT || zoomViewInitHeight == WindowManager.LayoutParams.WRAP_CONTENT) {
  zoomView.post(new Runnable() {
   @Override
   public void run() {
    zoomViewInitHeight = TranslucentScrollView.this.zoomView.getHeight();
   }
  });
 }
}
/**
 * 设置渐变视图
 *
 * @param transView 渐变的视图
 */
public void setTransView(View transView) {
 setTransView(transView, getResources().getColor(R.color.colorPrimary), SizeUtils.dip2px(getContext(), DFT_TRANSSTARTY), SizeUtils.dip2px(getContext(), DFT_TRANSENDY));
}
/**
 * 设置渐变视图
 *
 * @param transView 渐变的视图
 * @param transColor 渐变颜色
 * @param transEndY 渐变结束位置
 */
public void setTransView(View transView, @ColorInt int transColor, int transStartY, int transEndY) {
 this.transView = transView;
 //初始视图-透明
 this.transView.setBackgroundColor(ColorUtils.setAlphaComponent(transColor, 0));
 this.transStartY = transStartY;
 this.transEndY = transEndY;
 this.transColor = transColor;
 if (transStartY > transEndY) {
  throw new IllegalArgumentException("transStartY 不得大于 transEndY .. ");
 }
}
/**
 * 获取透明度
 *
 * @return
 */
private int getTransAlpha() {
 float scrollY = getScrollY();
 if (transStartY != 0) {
  if (scrollY <= transStartY) {
   return 0;
  } else if (scrollY >= transEndY) {
   return 255;
  } else {
   return (int) ((scrollY - transStartY) / (transEndY - transStartY) * 255);
  }
 } else {
  if (scrollY >= transEndY) {
   return 255;
  }
  return (int) ((transEndY - scrollY) / transEndY * 255);
 }
}
/**
 * 重置ZoomView
 */
private void resetZoomView() {
 final ViewGroup.LayoutParams lp = zoomView.getLayoutParams();
 final float h = zoomView.getLayoutParams().height;// ZoomView当前高度
 // 设置动画
 ValueAnimator anim = ObjectAnimator.ofFloat(0.0F, 1.0F).setDuration(200);
 anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
  @Override
  public void onAnimationUpdate(ValueAnimator animation) {
   float cVal = (Float) animation.getAnimatedValue();
   lp.height = (int) (h - (h - zoomViewInitHeight) * cVal);
   zoomView.setLayoutParams(lp);
  }
 });
 anim.start();
}
@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
 super.onScrollChanged(l, t, oldl, oldt);
 int transAlpha = getTransAlpha();
 if (transView != null) {
  Log.d(TAG, "[onScrollChanged .. in ], 透明度 == " + transAlpha);
  transView.setBackgroundColor(ColorUtils.setAlphaComponent(transColor, transAlpha));
 }
 if (translucentChangedListener != null) {
  translucentChangedListener.onTranslucentChanged(transAlpha);
 }
}
@Override
public boolean onTouchEvent(MotionEvent event) {
 if (zoomView != null) {
  ViewGroup.LayoutParams params = zoomView.getLayoutParams();
  switch (event.getAction()) {
   case MotionEvent.ACTION_UP:
    //手指离开后恢复图片
    mScaling = false;
    resetZoomView();
    break;
   case MotionEvent.ACTION_MOVE:
    if (!mScaling) {
     if (getScrollY() == 0) {
      mFirstPosition = event.getY();
     } else {
      break;
     }
    }
    int distance = (int) ((event.getY() - mFirstPosition) * 0.6);
    if (distance < 0) {
     break;
    }
    mScaling = true;
    params.height = zoomViewInitHeight + distance;
    Log.d(TAG, "params.height == " + params.height + ", zoomViewInitHeight == " + zoomViewInitHeight + ", distance == " + distance);
    zoomView.setLayoutParams(params);
    return true;
  }
 }
 return super.onTouchEvent(event);
}
}

总结

以上所述是小编给大家介绍的Android沉浸式状态栏 + actionBar渐变 + scrollView顶部伸缩网站的支持！

来源：http://blog.csdn.net/yanjunhui2011/article/details/55190456