我确信Todoist正在以另一种方式做这件事,但仍然......
这里是XML布局。主要思想是,应该固定的视图应该位于内部Toolbar
,当您想要隐藏的另一个视图应该在里面时CollapsingToolbarLayout
具有适当的上边距,以防止重叠:
<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:id="@+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.design.widget.CollapsingToolbarLayout
android:id="@+id/collapsing_tool_bar_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_scrollFlags="scroll|exitUntilCollapsed"
app:statusBarScrim="?attr/colorAccent">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_collapseMode="parallax"
android:layout_marginLeft="72dp"
android:layout_marginRight="16dp"
android:layout_marginBottom="32dp"
android:layout_marginTop="136dp">
<android.support.design.widget.TextInputLayout
android:id="@+id/lNameLayout2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.design.widget.TextInputEditText
android:id="@+id/ldesc"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Description"/>
</android.support.design.widget.TextInputLayout>
</FrameLayout>
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@color/primary"
android:minHeight="?attr/actionBarSize"
android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:layout_collapseMode="pin"
app:popupTheme="@style/ThemeOverlay.AppCompat.Light">
<android.support.design.widget.TextInputLayout
android:id="@+id/lNameLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginRight="16dp"
android:layout_marginBottom="16dp"
android:layout_marginTop="48dp">
<android.support.design.widget.TextInputEditText
android:id="@+id/title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Title"
android:textSize="30sp"
android:textColor="@android:color/white"
android:ems="10"/>
</android.support.design.widget.TextInputLayout>
</android.support.v7.widget.Toolbar>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="none"
app:layout_behavior="@string/appbar_scrolling_view_behavior">
<!-- your content here -->
</android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>
然后,要实现相同的字体大小和上边距动画,我们可以实现AppBarLayout.OnOffsetChangedListener
并根据滚动偏移变化对我们的属性进行动画处理。这里是活动课:
public class MainActivity extends AppCompatActivity
implements AppBarLayout.OnOffsetChangedListener {
private static final float COLLAPSED_TEXT_SIZE_SP = 18f;
private static final float COLLAPSED_TOP_MARGIN_DP = 24f;
private static final float MARGIN_SCROLLER_MULTIPLIER = 4f;
private float expandedTextSize;
private float collapsedTextSize;
private int expandedTopMargin;
private int collapsedTopMargin;
private AppBarLayout mAppBarLayout;
private Toolbar mToolbar;
private TextInputEditText editText;
private TextInputLayout textInputLayout;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mToolbar = (Toolbar) findViewById(R.id.toolbar);
mAppBarLayout = (AppBarLayout) findViewById(R.id.appbar);
editText = (TextInputEditText) findViewById(R.id.title);
textInputLayout = (TextInputLayout) findViewById(R.id.lNameLayout);
setSupportActionBar(mToolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
mAppBarLayout.addOnOffsetChangedListener(this);
expandedTextSize = editText.getTextSize();
collapsedTextSize = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, COLLAPSED_TEXT_SIZE_SP, getResources().getDisplayMetrics());
expandedTopMargin = ((ViewGroup.MarginLayoutParams) textInputLayout.getLayoutParams()).topMargin;
collapsedTopMargin = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, COLLAPSED_TOP_MARGIN_DP, getResources().getDisplayMetrics());
}
@Override
public void onOffsetChanged(AppBarLayout appBarLayout, int offset) {
int maxScroll = appBarLayout.getTotalScrollRange();
float percentage = (float) Math.abs(offset) / maxScroll;
float textSizeDiff = Math.abs(expandedTextSize - collapsedTextSize);
int marginDiff = Math.abs(expandedTopMargin - collapsedTopMargin);
//change text size along with scrolling
editText.setTextSize(TypedValue.COMPLEX_UNIT_PX, expandedTextSize - textSizeDiff * percentage);
//change top view margin along with scrolling
((ViewGroup.MarginLayoutParams) textInputLayout.getLayoutParams()).topMargin = (int) (expandedTopMargin - marginDiff * Math.min(1, percentage * MARGIN_SCROLLER_MULTIPLIER));
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (item.getItemId() == android.R.id.home) {
finish();
return true;
}
return super.onOptionsItemSelected(item);
}
}
因此,对于扩展状态,我使用了我们在 xml 中应用的默认值。对于折叠状态,我定义了简单的常量。请随意满足您的需求。
Note,当您添加后退按钮或菜单项时Toolbar
,你应该玩弄left
and right
第二个视图(您要隐藏的视图)的边距,因为第一个EditText
是一部分Toolbar
,因此它的边距将根据您添加的内容而改变。
Result:
![](https://media.giphy.com/media/3og0ItU8kYa7ScyTXG/giphy.gif)
快乐编码!