/**  * Author：Biligle.  * 自定義布局  */  public class MyViewGroup extends ViewGroup {   private MyViewGroupListener listener;//接口，監(jiān)聽滑動(dòng)事件  private int vertical = 0;//布局距離頂端距離（默認(rèn)0）   public MyViewGroup(Context context) {   super(context);  }   public MyViewGroup(Context context, AttributeSet attrs) {   super(context, attrs);  }   public MyViewGroup(Context context, AttributeSet attrs, int defStyleAttr) {   super(context, attrs, defStyleAttr);  }   @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)  public MyViewGroup(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {   super(context, attrs, defStyleAttr, defStyleRes);  }    private int downY = 0;//按下時(shí)的點(diǎn)  private int slide = 0;//最終移動(dòng)距離  @Override  public boolean onTouchEvent(MotionEvent event) {   switch (event.getAction()){    case MotionEvent.ACTION_DOWN:     downY = (int) event.getY();     break;    case MotionEvent.ACTION_MOVE:     slide = downY - (int)event.getY();     if(slide < 0){//下滑      vertical = listener.marginTop(Math.abs(slide));     }else if(slide > 0){//上滑      vertical = listener.marginTop(-slide);     }     break;    case MotionEvent.ACTION_UP:     if(vertical < 300){      //布局距離屏幕頂部小于300，就讓布局充滿整個(gè)屏幕      vertical = listener.marginTop(0);     }     break;   }   return true;  }   /**   * 測(cè)量子View   * @param widthMeasureSpec   * @param heightMeasureSpec   */  @Override  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {   super.onMeasure(widthMeasureSpec, heightMeasureSpec);   for (int i = 0; i < getChildCount(); i++) {    View child = getChildAt(i);    //系統(tǒng)測(cè)量    measureChild(child, widthMeasureSpec, heightMeasureSpec);   }  }   /**   * 安排子View的位置   * @param changed   * @param l 左邊距   * @param t 上邊距   * @param r 右邊距   * @param b 下邊距   */  @Override  protected void onLayout(boolean changed, int l, int t, int r, int b) {   int left = 0, top = 0, right = 0, bottom = 0;   for (int i = 0; i < getChildCount(); i++) {    View child = getChildAt(i);    right = left + child.getMeasuredWidth();    bottom = top + child.getMeasuredHeight();    child.layout(left, top, right, bottom);   }  }   public void setListener(MyViewGroupListener listener){   this.listener = listener;  }   interface MyViewGroupListener {   /**    * 設(shè)置topMargin，上下滑動(dòng)時(shí)觸發(fā)    * @param slide 滑動(dòng)距離    * @return 當(dāng)前上邊距    */   int marginTop(int slide);  } }

public class MainActivity extends AppCompatActivity implements MyViewGroup.MyViewGroupListener{   /** 自定義布局（外層布局）*/  private MyViewGroup myViewGroup;  /** 兩個(gè)圓形圖（在外層布局）*/  private ImageView iv1,iv2/*,cloud*/;  /** 包裹圓形圖的布局*/  private RelativeLayout relativeLayout;  /** 外層布局參數(shù)類（這里用到了params.topMargin：上邊距）*/  private ViewGroup.MarginLayoutParams params;  /** 透明值（改變兩個(gè)圓圖的透明值）*/  private float f;  /** 左右內(nèi)邊距（改變RelativeLayout內(nèi)邊距）*/  private int p;   @Override  protected void onCreate(Bundle savedInstanceState) {   super.onCreate(savedInstanceState);   setContentView(R.layout.activity_main);   myViewGroup = (MyViewGroup) findViewById(R.id.my);   myViewGroup.setListener(this);   iv1 = (ImageView) findViewById(R.id.iv1);   iv2 = (ImageView) findViewById(R.id.iv2);   relativeLayout = (RelativeLayout) findViewById(R.id.relative);   params = (ViewGroup.MarginLayoutParams) myViewGroup.getLayoutParams();   //初始化動(dòng)畫（自動(dòng)下滑一段兒距離），我這里寫死了900   ObjectAnimator animator = ObjectAnimator.ofFloat(myViewGroup,"translationY", 900);   animator.setDuration(2000);   animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {    @Override    public void onAnimationUpdate(ValueAnimator animation) {     float y = (float)animation.getAnimatedValue();     f = y/800;     p = (int) y/3;     alpha(f);     padding(p);    }   });   animator.start(); //  cloud = (ImageView) findViewById(R.id.cloud);  }    /**   * 設(shè)置上邊距   * @param slide 滑動(dòng)距離   * @return 返回下滑布局，距離屏幕左上角的垂直距離   */  @Override  public int marginTop(int slide) {   params.topMargin += slide;   myViewGroup.setLayoutParams(params);   int vertical = (900 + params.topMargin);   if(slide == 0){    //為了隱藏兩張圓圖，所以把Relativelayout的高度一并減除。    params.topMargin -= (vertical+relativeLayout.getHeight());    myViewGroup.setLayoutParams(params);   }   float alpha = f + (float) params.topMargin/800;//自定義一個(gè)算法   alpha(alpha);   int padding = p + params.topMargin/3;//自定義一個(gè)算法   padding(padding);   return vertical;  }   /**   * 設(shè)置透明度   * @param alpha 透明值   */  public void alpha(float alpha) {   iv1.setAlpha(alpha);   iv2.setAlpha(alpha);  }   /**   * 設(shè)置左右邊距   * @param padding 邊距值   */  public void padding(int padding) {   relativeLayout.setPadding(padding, 0, padding, 0);  } 

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout  xmlns:android="http://schemas.android.com/apk/res/android"  xmlns:app="http://schemas.android.com/apk/res-auto"  xmlns:tools="http://schemas.android.com/tools"  android:id="@+id/activity_main"  android:layout_width="match_parent"  android:layout_height="match_parent"  tools:context="com.wgl.viewgroup1.MainActivity">  <ImageView   android:id="@+id/iv"   android:layout_width="match_parent"   android:layout_height="match_parent"   android:src="@mipmap/pic"   android:scaleType="fitXY"/>   <!--<ImageView-->    <!--android:id="@+id/cloud"-->    <!--android:layout_width="wrap_content"-->    <!--android:layout_height="wrap_content"-->    <!--android:layout_centerHorizontal="true"-->    <!--android:alpha="0.8"-->    <!--android:src="@mipmap/cloud3"-->    <!--android:clickable="true"/>-->   <com.wgl.viewgroup1.MyViewGroup   android:id="@+id/my"   android:layout_width="match_parent"   android:layout_height="match_parent"   android:alpha="0.8"   android:layout_alignParentTop="true">   <LinearLayout    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical">    <RelativeLayout     android:id="@+id/relative"     android:layout_width="match_parent"     android:layout_height="wrap_content"     android:orientation="horizontal">     <com.wgl.viewgroup1.CircleImageView      android:id="@+id/iv1"      android:layout_width="wrap_content"      android:layout_height="wrap_content"      android:src="@mipmap/iv1"      app:civ_border_width="2dp"      app:civ_border_color="@color/colorAccent"      android:layout_alignParentLeft="true"/>      <com.wgl.viewgroup1.CircleImageView      android:id="@+id/iv2"      android:layout_width="wrap_content"      android:layout_height="wrap_content"      android:src="@mipmap/iv2"      app:civ_border_width="2dp"      app:civ_border_color="@color/colorAccent"      android:layout_alignParentRight="true"/>    </RelativeLayout>    <LinearLayout     android:layout_width="match_parent"     android:layout_height="match_parent"     android:alpha="0.8"     android:background="@color/colorPrimary">     </LinearLayout>   </LinearLayout>   </com.wgl.viewgroup1.MyViewGroup> </RelativeLayout>