问题
I want to implement collapsing toolbar with two EditText in it, for the purpose of user input. I'm following this answer. The answer gives perfect solution for adding two EditText into the collapsing toolbar. But the behavior is not as expected.
What I've achieved:
Expected Behavior:
My XML code
<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="wrap_content"
android:fitsSystemWindows="true">
<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:elevation="0dp"
app:expandedTitleTextAppearance="@style/Widget.AppCompat.ActionBar.TabText"
app:layout_scrollFlags="scroll|enterAlways"
app:statusBarScrim="?attr/colorAccent">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar_1"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="@color/primary"
android:minHeight="?attr/actionBarSize"
android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:layout_collapseMode="none"
app:layout_scrollFlags="scroll|exitUntilCollapsed"
app:popupTheme="@style/ThemeOverlay.AppCompat.Light">
</android.support.v7.widget.Toolbar>
</android.support.design.widget.CollapsingToolbarLayout>
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar_2"
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="none"
app:elevation="0dp"
app:layout_scrollFlags="scroll|exitUntilCollapsed"
app:popupTheme="@style/ThemeOverlay.AppCompat.Light">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:paddingLeft="32dp"
android:paddingTop="16dp"
android:paddingBottom="56dp"
android:paddingRight="16dp">
<android.support.design.widget.TextInputLayout
android:id="@+id/lNameLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/fNameLayout"
android:layout_marginTop="10dp">
<EditText
android:id="@+id/ltitle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Title"/>
</android.support.design.widget.TextInputLayout>
<android.support.design.widget.TextInputLayout
android:id="@+id/lNameLayout2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/fNameLayout"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp">
<EditText
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>
</LinearLayout>
</android.support.v7.widget.Toolbar>
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.NestedScrollView
android:layout_width="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingTop="10dp">
<!--my widgets here-->
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
I know I can do this type of styling using scrollFlag. I've read this post about scroll flags.But can't find exactly how to use it for this purpose.
I also want to change the font size of the EditText as shown in the above GIF.
But first question is how to fix one view in toolbar and hide another as user scrolls up. It would be nice if someone explain with suitable example.
回答1:
I'm sure Todoist is doing it another way, but still...
Here is the xml layout. The main idea is that the view, that supposed to be pinned, should be inside Toolbar, when another view, which you want to hide, should be inside CollapsingToolbarLayout with a decent top margin, to prevent overlapping:
<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>
Then, to achieve the same font size and top margin animation, we can implement AppBarLayout.OnOffsetChangedListener and animate our properties according to scrolling offset changes. Here is the activity class:
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);
}
}
So, here for expanded state I've used default values, that we applied in our xml. For collapsed state I've defined simple constants. Feel free to fit them for your needs.
Note, when you add a back button or menu items to the Toolbar, you should play around with left and right margins of the second view (the one you want to hide), because the first EditText is a part of Toolbar, therefore its margins will be changed according to what you did add.
Result:
Happy coding!
来源：https://stackoverflow.com/questions/44636574/how-to-fix-a-view-in-collapsing-toolbar-while-scrolling