使用應用程式時,新資訊會一併顯示在畫面上,不會改變 系統就會移除相關資訊您可以直接變更螢幕上顯示的內容 讓使用者可能錯過突然出現的新內容。動畫速度緩慢 套用變更,並用動作來勾勒出使用者的視角 更加醒目
有三種常見的動畫可用來顯示或隱藏檢視畫面:顯示 動畫、交叉漸變動畫和 CardFlip 動畫。
建立交叉漸變動畫
交叉漸變動畫 (又稱為溶解液) 逐漸淡出
一張 View
或
同時ViewGroup
或淡出淡出的火花如果您要在部分情況下
在應用程式中切換內容或檢視模式這裡顯示的交叉漸變動畫會使用
ViewPropertyAnimator
、
適用於 Android 3.1 (API 級別 12) 以上版本。
以下是從進度指標到文字內容的交叉漸變範例:
建立檢視畫面
建立要交叉漸變的兩個檢視畫面。以下範例會建立 進度指標和可捲動的文字檢視區塊:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/content"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView style="?android:textAppearanceMedium"
android:lineSpacingMultiplier="1.2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/lorem_ipsum"
android:padding="16dp" />
</ScrollView>
<ProgressBar android:id="@+id/loading_spinner"
style="?android:progressBarStyleLarge"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center" />
</FrameLayout>
設定交叉漸變動畫
如要設定交叉漸變動畫,請按照下列步驟操作:
- 為要交叉淡出的檢視畫面建立成員變數。您需要具備 稍後在動畫期間修改檢視畫面時,這些參照會成為參考資源。
- 設定主題檢視畫面的顯示設定
GONE
。這可避免系統顯示 不會因為使用版面配置空間而省略了版面配置,所以在計算版面配置時 向上處理 - 快取
config_shortAnimTime
系統屬性。此屬性定義標準的「短」 時間長度。這個時間長度適用於細微的動畫或 出現經常發生的動畫config_longAnimTime
敬上 和config_mediumAnimTime
。 您也可以使用
以下範例使用先前程式碼片段的版面配置, 活動內容檢視畫面:
Kotlin
class CrossfadeActivity : Activity() { private lateinit var contentView: View private lateinit var loadingView: View private var shortAnimationDuration: Int = 0 ... override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_crossfade) contentView = findViewById(R.id.content) loadingView = findViewById(R.id.loading_spinner) // Initially hide the content view. contentView.visibility = View.GONE // Retrieve and cache the system's default "short" animation time. shortAnimationDuration = resources.getInteger(android.R.integer.config_shortAnimTime) } ... }
Java
public class CrossfadeActivity extends Activity { private View contentView; private View loadingView; private int shortAnimationDuration; ... @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_crossfade); contentView = findViewById(R.id.content); loadingView = findViewById(R.id.loading_spinner); // Initially hide the content view. contentView.setVisibility(View.GONE); // Retrieve and cache the system's default "short" animation time. shortAnimationDuration = getResources().getInteger( android.R.integer.config_shortAnimTime); } ... }
交叉淡出檢視畫面
正確設定檢視畫面後,如要交叉淡出,請按照下列步驟操作:
- 針對淡入效果的檢視畫面,將 Alpha 值設為 0,顯示設定
從初始的
VISIBLE
開始 設定GONE
。這樣一來,檢視區塊就會顯示,但會保持透明。 - 針對淡入效果的檢視區塊,為其 Alpha 值 0 到 1 加上動畫效果。對於 並以 1 到 0 的動畫方式設定 Alpha 值
- 使用
onAnimationEnd()
敬上 風格Animator.AnimatorListener
, 設定淡出至GONE
的檢視畫面的顯示設定。雖然 Alpha 值為 0,將檢視畫面的瀏覽權限設為GONE
會防止檢視畫面出現 不會因為使用版面配置空間而省略了版面配置,所以在計算版面配置時 後續處理作業
以下方法舉例說明相關做法:
Kotlin
class CrossfadeActivity : Activity() { private lateinit var contentView: View private lateinit var loadingView: View private var shortAnimationDuration: Int = 0 ... private fun crossfade() { contentView.apply { // Set the content view to 0% opacity but visible, so that it is // visible but fully transparent during the animation. alpha = 0f visibility = View.VISIBLE // Animate the content view to 100% opacity and clear any animation // listener set on the view. animate() .alpha(1f) .setDuration(shortAnimationDuration.toLong()) .setListener(null) } // Animate the loading view to 0% opacity. After the animation ends, // set its visibility to GONE as an optimization step so it doesn't // participate in layout passes. loadingView.animate() .alpha(0f) .setDuration(shortAnimationDuration.toLong()) .setListener(object : AnimatorListenerAdapter() { override fun onAnimationEnd(animation: Animator) { loadingView.visibility = View.GONE } }) } }
Java
public class CrossfadeActivity extends Activity { private View contentView; private View loadingView; private int shortAnimationDuration; ... private void crossfade() { // Set the content view to 0% opacity but visible, so that it is // visible but fully transparent during the animation. contentView.setAlpha(0f); contentView.setVisibility(View.VISIBLE); // Animate the content view to 100% opacity and clear any animation // listener set on the view. contentView.animate() .alpha(1f) .setDuration(shortAnimationDuration) .setListener(null); // Animate the loading view to 0% opacity. After the animation ends, // set its visibility to GONE as an optimization step so it doesn't // participate in layout passes. loadingView.animate() .alpha(0f) .setDuration(shortAnimationDuration) .setListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { loadingView.setVisibility(View.GONE); } }); } }
建立資訊卡翻轉動畫
資訊卡會顯示模擬內容的動畫,藉此切換內容檢視畫面
翻開卡片這裡顯示的資訊卡翻轉動畫會使用
FragmentTransaction
。
卡片外觀如下:
建立動畫物件
如要建立資訊卡翻轉動畫,請備妥 4 個動畫。兩個動畫師 查看資訊卡正面動畫效果和左邊動畫的時機 從左側開始其他兩張動畫師適用於卡片背面 在動畫播放前以及從右側進入動畫,而當動畫往右移動時。
<set xmlns:android="http://schemas.android.com/apk/res/android">
<!-- Before rotating, immediately set the alpha to 0. -->
<objectAnimator
android:valueFrom="1.0"
android:valueTo="0.0"
android:propertyName="alpha"
android:duration="0" />
<!-- Rotate. -->
<objectAnimator
android:valueFrom="-180"
android:valueTo="0"
android:propertyName="rotationY"
android:interpolator="@android:interpolator/accelerate_decelerate"
android:duration="@integer/card_flip_time_full" />
<!-- Halfway through the rotation, set the alpha to 1. See startOffset. -->
<objectAnimator
android:valueFrom="0.0"
android:valueTo="1.0"
android:propertyName="alpha"
android:startOffset="@integer/card_flip_time_half"
android:duration="1" />
</set>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<!-- Rotate. -->
<objectAnimator
android:valueFrom="0"
android:valueTo="180"
android:propertyName="rotationY"
android:interpolator="@android:interpolator/accelerate_decelerate"
android:duration="@integer/card_flip_time_full" />
<!-- Halfway through the rotation, set the alpha to 0. See startOffset. -->
<objectAnimator
android:valueFrom="1.0"
android:valueTo="0.0"
android:propertyName="alpha"
android:startOffset="@integer/card_flip_time_half"
android:duration="1" />
</set>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<!-- Before rotating, immediately set the alpha to 0. -->
<objectAnimator
android:valueFrom="1.0"
android:valueTo="0.0"
android:propertyName="alpha"
android:duration="0" />
<!-- Rotate. -->
<objectAnimator
android:valueFrom="180"
android:valueTo="0"
android:propertyName="rotationY"
android:interpolator="@android:interpolator/accelerate_decelerate"
android:duration="@integer/card_flip_time_full" />
<!-- Halfway through the rotation, set the alpha to 1. See startOffset. -->
<objectAnimator
android:valueFrom="0.0"
android:valueTo="1.0"
android:propertyName="alpha"
android:startOffset="@integer/card_flip_time_half"
android:duration="1" />
</set>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<!-- Rotate. -->
<objectAnimator
android:valueFrom="0"
android:valueTo="-180"
android:propertyName="rotationY"
android:interpolator="@android:interpolator/accelerate_decelerate"
android:duration="@integer/card_flip_time_full" />
<!-- Halfway through the rotation, set the alpha to 0. See startOffset. -->
<objectAnimator
android:valueFrom="1.0"
android:valueTo="0.0"
android:propertyName="alpha"
android:startOffset="@integer/card_flip_time_half"
android:duration="1" />
</set>
建立檢視畫面
資訊卡的每一面都是獨立的版面配置,可包含 例如兩個文字檢視區塊、兩張圖片,或是任意翻轉的組合 。稍後在製作動畫的片段中使用兩個版面配置。 下列版面配置會建立資訊卡的一側,顯示文字:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="#a6c"
android:padding="16dp"
android:gravity="bottom">
<TextView android:id="@android:id/text1"
style="?android:textAppearanceLarge"
android:textStyle="bold"
android:textColor="#fff"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/card_back_title" />
<TextView style="?android:textAppearanceSmall"
android:textAllCaps="true"
android:textColor="#80ffffff"
android:textStyle="bold"
android:lineSpacingMultiplier="1.2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/card_back_description" />
</LinearLayout>
下一個版面配置會建立資訊卡的另一面
ImageView
:
<ImageView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:src="@drawable/image1"
android:scaleType="centerCrop"
android:contentDescription="@string/description_image_1" />
建立片段
為資訊卡正面和背面建立片段類別。片段
類別,會傳回您從
onCreateView()
敬上
方法。接著,您就可以在父項活動中建立這個片段的例項
並在您要顯示資訊卡的時間點顯示資訊卡
以下範例顯示父項活動中的巢狀片段類別 使用 API
Kotlin
class CardFlipActivity : FragmentActivity() { ... /** * A fragment representing the front of the card. */ class CardFrontFragment : Fragment() { override fun onCreateView( inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle? ): View = inflater.inflate(R.layout.fragment_card_front, container, false) } /** * A fragment representing the back of the card. */ class CardBackFragment : Fragment() { override fun onCreateView( inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle? ): View = inflater.inflate(R.layout.fragment_card_back, container, false) } }
Java
public class CardFlipActivity extends FragmentActivity { ... /** * A fragment representing the front of the card. */ public class CardFrontFragment extends Fragment { @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { return inflater.inflate(R.layout.fragment_card_front, container, false); } } /** * A fragment representing the back of the card. */ public class CardBackFragment extends Fragment { @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { return inflater.inflate(R.layout.fragment_card_back, container, false); } } }
為卡片翻轉動畫
顯示父項活動中的片段。方法是建立版面配置
。以下範例會建立
FrameLayout
,你可以新增
執行階段的片段:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent" />
在活動程式碼中,將內容檢視畫面設為您建立的版面配置。 建議您在建立活動時顯示預設片段。 以下範例活動會說明如何按 預設:
Kotlin
class CardFlipActivity : FragmentActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_activity_card_flip) if (savedInstanceState == null) { supportFragmentManager.beginTransaction() .add(R.id.container, CardFrontFragment()) .commit() } } ... }
Java
public class CardFlipActivity extends FragmentActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_activity_card_flip); if (savedInstanceState == null) { getSupportFragmentManager() .beginTransaction() .add(R.id.container, new CardFrontFragment()) .commit(); } } ... }
卡片正面會顯示在卡片正面, 在適當時機翻轉動畫。建立顯示 執行以下作業的卡片:
- 設定您建立的自訂動畫,用於片段轉換功能。
- 將顯示的片段替換成新片段,並為此事件加上動畫效果 這部分就會顯示自訂動畫
- 將先前顯示的片段新增至片段返回堆疊, 使用者輕觸返回按鈕時,卡片就會翻回。
Kotlin
class CardFlipActivity : FragmentActivity() { ... private fun flipCard() { if (showingBack) { supportFragmentManager.popBackStack() return } // Flip to the back. showingBack = true // Create and commit a new fragment transaction that adds the fragment // for the back of the card, uses custom animations, and is part of the // fragment manager's back stack. supportFragmentManager.beginTransaction() // Replace the default fragment animations with animator // resources representing rotations when switching to the back // of the card, as well as animator resources representing // rotations when flipping back to the front, such as when the // system Back button is tapped. .setCustomAnimations( R.animator.card_flip_right_in, R.animator.card_flip_right_out, R.animator.card_flip_left_in, R.animator.card_flip_left_out ) // Replace any fragments in the container view with a fragment // representing the next page, indicated by the just-incremented // currentPage variable. .replace(R.id.container, CardBackFragment()) // Add this transaction to the back stack, letting users press // the Back button to get to the front of the card. .addToBackStack(null) // Commit the transaction. .commit() } }
Java
public class CardFlipActivity extends FragmentActivity { ... private void flipCard() { if (showingBack) { getSupportFragmentManager().popBackStack(); return; } // Flip to the back. showingBack = true; // Create and commit a new fragment transaction that adds the fragment // for the back of the card, uses custom animations, and is part of the // fragment manager's back stack. getSupportFragmentManager() .beginTransaction() // Replace the default fragment animations with animator // resources representing rotations when switching to the back // of the card, as well as animator resources representing // rotations when flipping back to the front, such as when the // system Back button is pressed. .setCustomAnimations( R.animator.card_flip_right_in, R.animator.card_flip_right_out, R.animator.card_flip_left_in, R.animator.card_flip_left_out) // Replace any fragments in the container view with a fragment // representing the next page, indicated by the just-incremented // currentPage variable. .replace(R.id.container, new CardBackFragment()) // Add this transaction to the back stack, letting users press // Back to get to the front of the card. .addToBackStack(null) // Commit the transaction. .commit(); } }
建立循環顯示動畫
顯示動畫可在您顯示或隱藏群組時,為使用者提供視覺上的連貫性
這三項重要工具
ViewAnimationUtils.createCircularReveal()
敬上
方法 可讓您建立裁剪圓形的動畫,藉此顯示或隱藏檢視畫面。這個
範本中
ViewAnimationUtils
類別,
適用於 Android 5.0 (API 級別 21) 以上版本。
以下範例說明如何顯示先前隱藏的檢視畫面:
Kotlin
// A previously invisible view. val myView: View = findViewById(R.id.my_view) // Check whether the runtime version is at least Android 5.0. if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) { // Get the center for the clipping circle. val cx = myView.width / 2 val cy = myView.height / 2 // Get the final radius for the clipping circle. val finalRadius = Math.hypot(cx.toDouble(), cy.toDouble()).toFloat() // Create the animator for this view. The start radius is 0. val anim = ViewAnimationUtils.createCircularReveal(myView, cx, cy, 0f, finalRadius) // Make the view visible and start the animation. myView.visibility = View.VISIBLE anim.start() } else { // Set the view to invisible without a circular reveal animation below // Android 5.0. myView.visibility = View.INVISIBLE }
Java
// A previously invisible view. View myView = findViewById(R.id.my_view); // Check whether the runtime version is at least Android 5.0. if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) { // Get the center for the clipping circle. int cx = myView.getWidth() / 2; int cy = myView.getHeight() / 2; // Get the final radius for the clipping circle. float finalRadius = (float) Math.hypot(cx, cy); // Create the animator for this view. The start radius is 0. Animator anim = ViewAnimationUtils.createCircularReveal(myView, cx, cy, 0f, finalRadius); // Make the view visible and start the animation. myView.setVisibility(View.VISIBLE); anim.start(); } else { // Set the view to invisible without a circular reveal animation below // Android 5.0. myView.setVisibility(View.INVISIBLE); }
ViewAnimationUtils.createCircularReveal()
動畫採用五個參數。
第一個參數是您想要在畫面中隱藏或顯示的檢視畫面。
接下來的兩個參數是剪裁中心的 X 和 Y 座標
社交圈。通常是檢視畫面的中心,但您也可以使用
在使用者輕觸之後,動畫就會從他們選取的位置開始播放。
第四個參數是剪裁圓的起始半徑。
在上一個範例中,初始半徑設為 0,因此檢視畫面會顯示 目前由社交圈隱藏。最後一個參數是最終的半徑 圓圈。顯示檢視畫面時,最終半徑應大於 ,這樣檢視畫面就能在動畫結束前完整顯示。
如要隱藏之前可見的檢視畫面,請執行下列步驟:
Kotlin
// A previously visible view. val myView: View = findViewById(R.id.my_view) // Check whether the runtime version is at least Android 5.0. if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) { // Get the center for the clipping circle. val cx = myView.width / 2 val cy = myView.height / 2 // Get the initial radius for the clipping circle. val initialRadius = Math.hypot(cx.toDouble(), cy.toDouble()).toFloat() // Create the animation. The final radius is 0. val anim = ViewAnimationUtils.createCircularReveal(myView, cx, cy, initialRadius, 0f) // Make the view invisible when the animation is done. anim.addListener(object : AnimatorListenerAdapter() { override fun onAnimationEnd(animation: Animator) { super.onAnimationEnd(animation) myView.visibility = View.INVISIBLE } }) // Start the animation. anim.start() } else { // Set the view to visible without a circular reveal animation below // Android 5.0. myView.visibility = View.VISIBLE }
Java
// A previously visible view. final View myView = findViewById(R.id.my_view); // Check whether the runtime version is at least Android 5.0. if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) { // Get the center for the clipping circle. int cx = myView.getWidth() / 2; int cy = myView.getHeight() / 2; // Get the initial radius for the clipping circle. float initialRadius = (float) Math.hypot(cx, cy); // Create the animation. The final radius is 0. Animator anim = ViewAnimationUtils.createCircularReveal(myView, cx, cy, initialRadius, 0f); // Make the view invisible when the animation is done. anim.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { super.onAnimationEnd(animation); myView.setVisibility(View.INVISIBLE); } }); // Start the animation. anim.start(); } else { // Set the view to visible without a circular reveal animation below Android // 5.0. myView.setVisibility(View.VISIBLE); }
在這種情況下,剪裁圓形的初始半徑會設為大
讓畫面在動畫開始播放前顯示。最後一個
dp 設為 0,以便在動畫結束後隱藏檢視畫面。
在動畫中新增事件監聽器,以便將檢視畫面的顯示設定設為
動畫播放時為 INVISIBLE
完成。