The role of ViewSwitcher is simply: show animation when transitioning between two views
Its two subclasses should be familiar, ImageSwitcher : add animation effects when converting pictures ; TextSwitcher : add animation effects when converting text ;
API translation
1. Structure
public class ViewSwitcher extends ViewAnimator
java.lang.Object
android.view.View
android.view.ViewGroup
android.widget.FrameLayout
android.widget.ViewAnimator
android.widget.ViewSwitcher
known direct subclasses
2. Overview
To display animations when transitioning between two views, there is a factory class that can create these views. You can use factories to create these views, or you can create them yourself. A ViewSwitcher is only allowed to contain two subviews , and only one can be displayed at a time.
(Translator's Note: Similar to the ViewFlipper class, but this class is not commonly used, and its two subclasses are commonly used : ImageSwitcher : add animation effects when converting pictures ; TextSwitcher : add animation effects when converting text )
Third, the inner class
interface ViewSwitcher.ViewFactory
Create Views in a ViewSwitcher
4. Constructor
public ViewSwitcher (Context context)
Constructs a new empty ViewSwitcher .
parameter context context
public ViewSwitcher (Context context, AttributeSet attrs)
Constructs an empty ViewSwitcher that specifies the context and property set .
parameter
context context
attrs attribute collection
5. Public methods
public void addView(View child, int index, ViewGroup.LayoutParams params)
Add a subview specifying layout parameters
parameter
child view added by child
index of the added subview
params layout parameters of the subview
abnormal
IllegalStateException if the switcher already contains two views.
public View getNextView ()
Return to the next view to be displayed
Return value - the next view to be displayed after the view switch
public void reset ()
Reset the ViewSwitcher to hide all existing views and bring the switcher to a state where one animation has not yet played.
public void setFactory (ViewSwitcher.ViewFactory factory)
Sets the factory used to generate the two views that will be switched in the view converter. You can also call addView(android.view.View, int, android.view.ViewGroup.LayoutParams) twice instead of using the factory method.
The parameter factory is used to generate the view factory of the converter content
The following uses a part of the OSChina open source code to demonstrate its specific use
"User login"
layout xml:
<ViewSwitcher
android:id="@+id/logindialog_view_switcher"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<RelativeLayout
layout. . . .
/>
<View
android:id="@+id/login_loading"
android:layout_width="135.0dip"
android:layout_height="135.0dip"
android:layout_gravity="center"
android:background="@anim/login_loading"/>
</ViewSwitcher>
动画类中：
01 Animation 1 11 Animation 2
Use layer overlay (because there are two animation effects )
<!-- Animation frame collection object -->
<?xml version="1.0" encoding="UTF-8"?>
<animation-list xmlns:android="http://schemas.android.com/apk/res/android"
android:oneshot="false">
<!--The animation frame object android:duration represents the time of each frame of animation display, and the animation picture placed under the drawable should not be too large, otherwise the memory will explode-->
<item android:duration="100">
<layer- list>
<item android:drawable="@drawable/login_loading_00" />
<item android:drawable="@drawable/login_loading_10" />
</layer-list>
</item>
<item android:duration="100">
<layer-list>
<item android:drawable="@drawable/login_loading_01" />
<item android:drawable="@drawable/login_loading_11" />
</layer-list>
</item>
<item android:duration="100">
<layer-list>
<item android:drawable="@drawable/login_loading_02" />
<item android:drawable="@drawable/login_loading_12" />
</layer-list>
</item>
</animation-list>
in entity class
initialization
private ViewSwitchermViewSwitcher;
private View loginLoading;
loginLoading = (View)findViewById(R.id.login_loading);
mViewSwitcher = (ViewSwitcher)findViewById(R.id.logindialog_view_switcher);
loadingAnimation = (AnimationDrawable)loginLoading.getBackground();
loadingAnimation.start();
mViewSwitcher .showNext();//When the login is successful
mViewSwitcher.showPrevious();//When login fails