如何为特定视图添加动画？求Activity 1转Activity 2时Bloc滑动动画方案

Hey there! Let me break down how to get that cool slide animation where Bloc A slides up from Activity 1 and Bloc B slides down into Activity 2 when you navigate between them. I’ve got two solid approaches for you—one quick and simple, and another more flexible for targeting specific UI blocks:

This method works well if you want the animation to apply to the entire Activity window (or if your Bloc A/B are the main content of each Activity).

Step 1: Create Animation XML Files #

First, define the slide animations in your res/anim folder:

1. Slide-up exit for Bloc A (Activity 1)
   res/anim/slide_up_exit.xml

   <?xml version="1.0" encoding="utf-8"?>
   <translate xmlns:android="http://schemas.android.com/apk/res/android"
       android:duration="500"
       android:fromYDelta="0%"
       android:toYDelta="-100%"
       android:interpolator="@android:anim/decelerate_interpolator"/>
   

2. Slide-down enter for Bloc B (Activity 2)
   res/anim/slide_down_enter.xml

   <?xml version="1.0" encoding="utf-8"?>
   <translate xmlns:android="http://schemas.android.com/apk/res/android"
       android:duration="500"
       android:fromYDelta="-100%"
       android:toYDelta="0%"
       android:interpolator="@android:anim/decelerate_interpolator"/>
   

Step 2: Trigger the Animation on Navigation #

In Activity 1, right after starting Activity 2, call overridePendingTransition:

Intent intent = new Intent(Activity1.this, Activity2.class);
startActivity(intent);
// First param: Activity 2's enter animation; Second param: Activity 1's exit animation
overridePendingTransition(R.anim.slide_down_enter, R.anim.slide_up_exit);

If you need to target only Bloc A/B (not the entire Activity), use the Activity Transition API (API 21+). This lets you animate specific views independently.

Step 1: Assign Transition Names to Blocs #

Add a unique transitionName to both Bloc A (Activity1) and Bloc B (Activity2) in their layouts:

Activity1's Bloc A:

<LinearLayout
    android:id="@+id/bloc_a"
    android:transitionName="bloc_slide_transition"
    <!-- Your layout attributes -->
    >
    <!-- Bloc A content -->
</LinearLayout>

Activity2's Bloc B:

<LinearLayout
    android:id="@+id/bloc_b"
    android:transitionName="bloc_slide_transition"
    <!-- Your layout attributes -->
    >
    <!-- Bloc B content -->
</LinearLayout>

Step 2: Create a Custom Transition Class #

This class defines the slide behavior for each bloc:

public class SlideUpDownTransition extends Transition {
    @Override
    public void captureStartValues(TransitionValues transitionValues) {
        // Capture the view's initial Y position
        transitionValues.values.put("initial_y", transitionValues.view.getY());
    }

    @Override
    public void captureEndValues(TransitionValues transitionValues) {
        View view = transitionValues.view;
        if (view.getId() == R.id.bloc_a) {
            // Bloc A slides up out of the screen
            transitionValues.values.put("target_y", -view.getHeight());
        } else if (view.getId() == R.id.bloc_b) {
            // Bloc B slides down into its final position
            transitionValues.values.put("target_y", 0f);
        }
    }

    @Override
    public Animator createAnimator(ViewGroup sceneRoot, TransitionValues startValues, TransitionValues endValues) {
        if (startValues == null || endValues == null) return null;

        Float startY = (Float) startValues.values.get("initial_y");
        Float endY = (Float) endValues.values.get("target_y");
        View targetView = endValues.view;

        ObjectAnimator slideAnimator = ObjectAnimator.ofFloat(targetView, "y", startY, endY);
        slideAnimator.setDuration(500);
        slideAnimator.setInterpolator(new DecelerateInterpolator());
        return slideAnimator;
    }
}

Step 3: Enable Transitions and Start Activity #

In Activity1, configure the transitions and launch Activity2 with scene animation:

// Enable content transitions for the window
getWindow().requestFeature(Window.FEATURE_CONTENT_TRANSITIONS);

// Set exit animation for Bloc A and enter animation for Bloc B
getWindow().setExitTransition(new SlideUpDownTransition());
getWindow().setEnterTransition(new SlideUpDownTransition());

// Launch Activity2 with shared element transition
Intent intent = new Intent(Activity1.this, Activity2.class);
View blocA = findViewById(R.id.bloc_a);
ActivityOptions options = ActivityOptions.makeSceneTransitionAnimation(this, blocA, "bloc_slide_transition");
startActivity(intent, options.toBundle());

Step 4: Enable Transitions in Your Theme #

Add this to your styles.xml to ensure transitions work:

<style name="AppTheme" parent="Theme.MaterialComponents.DayNight.NoActionBar">
    <!-- Other theme attributes -->
    <item name="android:windowContentTransitions">true</item>
</style>

• Compatibility: For API <21, combine overridePendingTransition with view animations triggered in onPause() (Activity1) and onCreate() (Activity2).
• Tweak the Animation: Adjust the duration or use interpolators like AccelerateDecelerateInterpolator for smoother motion.
• No Shared Element?: Skip the transitionName and shared element code—just set the enter/exit transitions on the window to animate the blocs independently.

内容的提问来源于stack exchange，提问作者Mxwan