垂直滾動的工具欄漸變顏色

Question

進入我的工具欄，以藍色開始......當我滾動我的colapsing工具欄的10％時，它會保持更黑，更多20％黑... 100％全回...

任何人都有任何想法我該怎麼做？

我使用此代碼，但只從藍到黑跳...

 appBar.addOnOffsetChangedListener(new AppBarStateChangeListener() { 
     @Override 
     public void onStateChanged(AppBarLayout appBarLayout, State state) { 
      if (state == State.COLLAPSED) { 
       btCollapseCards.setImageDrawable(ContextCompat.getDrawable(getContext(), R.drawable.ic_keyboard_arrow_down_white_24dp)); 
       if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) { 
        toolbarLayout.setBackgroundDrawable(ContextCompat.getDrawable(getActivity(), R.drawable.background_gradient_black)); 
        llCardTitle.setBackgroundDrawable(ContextCompat.getDrawable(getActivity(), R.drawable.background_gradient_black)); 
       } else { 
        toolbarLayout.setBackground(ContextCompat.getDrawable(getActivity(), R.drawable.background_gradient_black)); 
        llCardTitle.setBackground(ContextCompat.getDrawable(getActivity(), R.drawable.background_gradient_black)); 
       } 
      } else if (state == State.EXPANDED) { 
       btCollapseCards.setImageDrawable(ContextCompat.getDrawable(getContext(), R.drawable.ic_keyboard_arrow_up_white_24dp)); 
       if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) { 
        toolbarLayout.setBackgroundDrawable(ContextCompat.getDrawable(getActivity(), R.color.colorPrimary)); 
        llCardTitle.setBackgroundDrawable(ContextCompat.getDrawable(getActivity(), R.color.colorPrimary)); 
       } else { 
        toolbarLayout.setBackground(ContextCompat.getDrawable(getActivity(), R.color.colorPrimary)); 
        llCardTitle.setBackground(ContextCompat.getDrawable(getActivity(), R.color.colorPrimary)); 
       } 
      } 


       int toolBarHeight = toolbar.getMeasuredHeight(); 
      int appBarHeight = appBarLayout.getMeasuredHeight(); 
      Float f = ((((float) appBarHeight - toolBarHeight) + verticalOffset)/((float) appBarHeight - toolBarHeight)) * 255; 
      viewBackground.getBackground().setAlpha(255 - Math.round(f)); 
     } 
    }); 

請幫我...

編輯＃01

插入碼，當我向上滾動時發揮了我想要的效果......但是當我向下滾動時，不會得到相同的效果。

   int toolBarHeight = toolbar.getMeasuredHeight(); 
      int appBarHeight = appBarLayout.getMeasuredHeight(); 
      Float f = ((((float) appBarHeight - toolBarHeight) + verticalOffset)/((float) appBarHeight - toolBarHeight)) * 255; 
      viewBackground.getBackground().setAlpha(255 - Math.round(f)); 

Answer 1

嘗試這個實施例

activity_main.xml中

<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 

    <android.support.design.widget.AppBarLayout 
     android:layout_width="match_parent" 
     android:layout_height="250dp" 
     android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"> 

     <android.support.design.widget.CollapsingToolbarLayout 
      android:id="@+id/collapsing_toolbar" 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" 
      app:contentScrim="?attr/colorPrimary" 
      app:layout_scrollFlags="scroll|exitUntilCollapsed"> 


      <ImageView 
       android:layout_width="match_parent" 
       android:layout_height="match_parent" 
       android:scaleType="centerCrop" 
       android:fitsSystemWindows="true" 
       android:background="@drawable/profile_pic" 
       android:id="@+id/profile_id" 
       app:layout_collapseMode="parallax" /> 


      <android.support.v7.widget.Toolbar 
       android:id="@+id/toolbar" 
       android:layout_width="match_parent" 
       android:layout_height="?attr/actionBarSize" 
       app:layout_collapseMode="pin" /> 

     </android.support.design.widget.CollapsingToolbarLayout> 

    </android.support.design.widget.AppBarLayout> 

    <android.support.design.widget.TabLayout 
     android:id="@+id/tabs" 
     android:layout_width="match_parent" 
     android:layout_height="?attr/actionBarSize" 
     android:background="@color/abc_search_url_text_normal"/> 

    <android.support.v4.widget.NestedScrollView 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:background="#ffe5e5e5" 
     app:layout_behavior="@string/appbar_scrolling_view_behavior"> 

     <LinearLayout 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" 
      android:orientation="vertical" 
      android:layout_marginTop="10dp"> 

      <include layout="@layout/card_layout" /> 

      <include layout="@layout/card_layout" /> 

      <include layout="@layout/card_layout" /> 

     </LinearLayout> 


    </android.support.v4.widget.NestedScrollView> 

</android.support.design.widget.CoordinatorLayout> 

card_layout.xml

<?xml version="1.0" encoding="utf-8"?> 
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:layout_margin="10dp" 

    > 
    <LinearLayout 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:orientation="vertical" 
     android:padding="12dp"> 

     <TextView 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:text="Lorem ipsum" 
      android:textSize="20sp"/> 

     <TextView 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:text="@string/text_content" 
      android:textSize="18sp"/> 

    </LinearLayout> 

</android.support.v7.widget.CardView> 

MainActivity.java

public class MainActivity extends AppCompatActivity { 

    private CollapsingToolbarLayout collapsingToolbarLayout = null; 
    TabLayout tabs; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 


     Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
     setSupportActionBar(toolbar); 
     ActionBar actionBar = getSupportActionBar(); 
     actionBar.setDisplayHomeAsUpEnabled(true); 

     collapsingToolbarLayout = (CollapsingToolbarLayout) findViewById(R.id.collapsing_toolbar); 
     collapsingToolbarLayout.setTitle(getResources().getString(R.string.user_name)); 
     tabs = (TabLayout) findViewById(R.id.tabs); 

     dynamicToolbarColor(); 

     toolbarTextAppernce(); 
    } 


    private void dynamicToolbarColor() { 
     Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.profile_pic); 
     Palette.from(bitmap).generate(new Palette.PaletteAsyncListener() { 
      @Override 
      public void onGenerated(Palette palette) { 
       collapsingToolbarLayout.setContentScrimColor(palette.getMutedColor(R.attr.colorPrimary)); 
       collapsingToolbarLayout.setStatusBarScrimColor(palette.getMutedColor(R.attr.colorPrimaryDark)); 
//    tabs.setBackgroundColor(palette.getMutedColor(R.attr.colorPrimary)); 
      } 
     }); 
    } 


    private void toolbarTextAppernce() { 
     collapsingToolbarLayout.setCollapsedTitleTextAppearance(R.style.collapsedappbar); 
     collapsingToolbarLayout.setExpandedTitleTextAppearance(R.style.expandedappbar); 
    } 



    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.menu_main, menu); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     return super.onOptionsItemSelected(item); 
    } 


} 

的build.gradle

apply plugin: 'com.android.application' 

android { 
    compileSdkVersion 23 
    buildToolsVersion "23.0.1" 

    defaultConfig { 
     applicationId "com.tutorialsbuzz.collapsingtoolbardemo" 
     minSdkVersion 7 
     targetSdkVersion 22 
     versionCode 1 
     versionName "1.0" 
    } 
    buildTypes { 
     release { 
      minifyEnabled false 
      proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' 
     } 
    } 
} 

dependencies { 
    compile fileTree(dir: 'libs', include: ['*.jar']) 
    compile 'com.android.support:appcompat-v7:23.0.1' 
    compile 'com.android.support:design:23.0.1' 
    compile 'com.android.support:cardview-v7:23.0.1' 
    compile 'com.android.support:palette-v7:22.2.0' 
}