我有一个正在运行的CollapsingToolbarLayout，我看到的唯一问题是当展开时显示的内容在向下滚动时快速消失，并且想知道是否有可能定义内容应该消失的道路的哪一点并且appbar出现。看起来好像在拼贴~25％之后它已经隐藏了内容并且只显示了appbar的颜色。在Google Play应用中，您可以看到，当几乎全部崩溃时，这种情况发生得非常晚。
答案 0 :(得分：0)
创建一个实现 AppBarLayout.OnOffsetChangedListener 的类并覆盖 onOffsetChanged 方法
<android.support.design.widget.CoordinatorLayout
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:layout_width="match_parent"
android:layout_height="match_parent"
tools:ignore="RtlHardcoded"
>
<android.support.design.widget.AppBarLayout
android:id="@+id/main.appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
>
<android.support.design.widget.CollapsingToolbarLayout
android:id="@+id/main.collapsing"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_scrollFlags="scroll|exitUntilCollapsed|snap"
>
<ImageView
android:id="@+id/main.imageview.placeholder"
android:layout_width="match_parent"
android:layout_height="300dp"
android:scaleType="centerCrop"
android:src="@drawable/quila2"
android:tint="#11000000"
app:layout_collapseMode="parallax"
app:layout_collapseParallaxMultiplier="0.9"
/>
<FrameLayout
android:id="@+id/main.framelayout.title"
android:layout_width="match_parent"
android:layout_height="100dp"
android:layout_gravity="bottom|center_horizontal"
android:background="@color/primary"
android:orientation="vertical"
app:layout_collapseMode="parallax"
app:layout_collapseParallaxMultiplier="0.3"
>
<LinearLayout
android:id="@+id/main.linearlayout.title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:orientation="vertical"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:gravity="bottom|center"
android:text="@string/quila_name"
android:textColor="@android:color/white"
android:textSize="30sp"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_marginTop="4dp"
android:text="@string/quila_tagline"
android:textColor="@android:color/white"
/>
</LinearLayout>
</FrameLayout>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v7.widget.Toolbar
android:id="@+id/main.toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="@color/primary"
app:layout_anchor="@id/main.framelayout.title"
app:theme="@style/ThemeOverlay.AppCompat.Dark"
app:title=""
>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:orientation="horizontal"
>
<Space
android:layout_width="@dimen/image_final_width"
android:layout_height="@dimen/image_final_width"
/>
<TextView
android:id="@+id/main.textview.title"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_marginLeft="8dp"
android:gravity="center_vertical"
android:text="@string/quila_name2"
android:textColor="@android:color/white"
android:textSize="20sp"
/>
</LinearLayout>
</android.support.v7.widget.Toolbar>
</android.support.design.widget.CoordinatorLayout>
更改 PERCENTAGE_TO_SHOW_TITLE_AT_TOOLBAR 和 PERCENTAGE_TO_HIDE_TITLE_DETAILS 以获得所需效果。
public class MainActivity extends AppCompatActivity implements AppBarLayout.OnOffsetChangedListener {
private static final float PERCENTAGE_TO_SHOW_TITLE_AT_TOOLBAR = 0.9f;
private static final float PERCENTAGE_TO_HIDE_TITLE_DETAILS = 0.3f;
private static final int ALPHA_ANIMATIONS_DURATION = 200;
private boolean mIsTheTitleVisible = false;
private boolean mIsTheTitleContainerVisible = true;
private LinearLayout mTitleContainer;
private TextView mTitle;
private AppBarLayout mAppBarLayout;
private Toolbar mToolbar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bindActivity();
mAppBarLayout.addOnOffsetChangedListener(this);
mToolbar.inflateMenu(R.menu.menu_main);
startAlphaAnimation(mTitle, 0, View.INVISIBLE);
}
private void bindActivity() {
mToolbar = (Toolbar) findViewById(R.id.main_toolbar);
mTitle = (TextView) findViewById(R.id.toolbar_title);
mTitleContainer = (LinearLayout) findViewById(R.id.linearlayout_title);
mAppBarLayout = (AppBarLayout) findViewById(R.id.appbar);
}
@Override
public void onOffsetChanged(AppBarLayout appBarLayout, int offset) {
int maxScroll = appBarLayout.getTotalScrollRange();
float percentage = (float) Math.abs(offset) / (float) maxScroll;
handleAlphaOnTitle(percentage);
handleToolbarTitleVisibility(percentage);
}
private void handleAlphaOnTitle(float percentage) {
if (percentage >= PERCENTAGE_TO_HIDE_TITLE_DETAILS) {
if(mIsTheTitleContainerVisible) {
startAlphaAnimation(mTitleContainer, ALPHA_ANIMATIONS_DURATION, View.INVISIBLE);
mIsTheTitleContainerVisible = false;
}
} else {
if (!mIsTheTitleContainerVisible) {
startAlphaAnimation(mTitleContainer, ALPHA_ANIMATIONS_DURATION, View.VISIBLE);
mIsTheTitleContainerVisible = true;
}
}
}
private void handleToolbarTitleVisibility(float percentage) {
if (percentage >= PERCENTAGE_TO_SHOW_TITLE_AT_TOOLBAR) {
if(!mIsTheTitleVisible) {
startAlphaAnimation(mTitle, ALPHA_ANIMATIONS_DURATION, View.VISIBLE);
mIsTheTitleVisible = true;
}
} else {
if (mIsTheTitleVisible) {
startAlphaAnimation(mTitle, ALPHA_ANIMATIONS_DURATION, View.INVISIBLE);
mIsTheTitleVisible = false;
}
}
}
public static void startAlphaAnimation (View v, long duration, int visibility) {
AlphaAnimation alphaAnimation = (visibility == View.VISIBLE) ? new AlphaAnimation(0f, 1f) : new AlphaAnimation(1f, 0f);
alphaAnimation.setDuration(duration);
alphaAnimation.setFillAfter(true);
v.startAnimation(alphaAnimation);
}
}
答案 1 :(得分：0)
我会举例说明我是如何实现你所需要的。
由于你希望内容在例如60％之后开始代替，首先，声明一个像这样的变量
private static final int PERCENTAGE_TO_SHOW_ELEMENT = 60;
然后你必须声明一个变量来知道你的元素是否已被隐藏，以及一个跟踪滚动百分比的变量
private int mMaxScrollSize;
private boolean mIsElementHidden;
之后，您必须向appBarLayout添加名为addOnOffsetChangedListener的侦听器，并覆盖方法onOffsetChanged：
yourAppBar.addOnOffsetChangedListener(this);
在方法onOffsetChanged中，使用以下代码：
@Override
public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {
if (mMaxScrollSize == 0)
mMaxScrollSize = appBarLayout.getTotalScrollRange();
int currentScrollPercentage = (Math.abs(verticalOffset)) * 100
/ mMaxScrollSize;
if (currentScrollPercentage >= PERCENTAGE_TO_SHOW_ELEMENT) {
if (!mIsElementHidden) {
mIsElementHidden= true;
ViewCompat.animate(yourView).scaleY(0).scaleX(0).start();
ViewCompat.animate(anotherView).scaleY(0).scaleX(0).start();
}
}
if (currentScrollPercentage < PERCENTAGE_TO_SHOW_ELEMENT) {
if (mIsElementHidden) {
mIsElementHidden= false;
ViewCompat.animate(yourView).scaleY(1).scaleX(1).start();
ViewCompat.animate(anotherView).scaleY(1).scaleX(1).start();
}
}
} else if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
//You can change something if your layout is different in LANDSCAPE
}
}
您可以使用变量PERCENTAGE_TO_SHOW_ELEMENT来决定何时使您的视图显示或消失。
答案 2 :(得分：0)
我找到了解决方案。你没有义务需要java代码，你可以使用样式属性 scrimVisibleHeightTrigger 来定义它，但请记住，使用的值应该大于动作栏的大小，遗憾的是使用？acionBarSize不起作用，所以你必须考虑appbar的高度并添加一些DP。
<android.support.design.widget.CollapsingToolbarLayout
android:id="@+id/collapsing_toolbar"
style="@style/Widget.MyCustomWidget.CollapsingHeader"
<style name="Widget.MyCustomWidget.CollapsingHeader" parent="@style/Widget.Design.CollapsingToolbar">
<item name="scrimAnimationDuration">200</item>
<item name="scrimVisibleHeightTrigger">1dp</item>
</style>