我需要在ImageView上實現動畫，類似於許多Android設備中存在的幻燈片來回答動畫。 的requiremnts：安卓幻燈片回答像ImageView動畫
我發現很多代碼樣本，並試圖實現它在我自己但所有這些要求的組合使得它變得非常困難，並且我無法得到一個體面的結果，所以請不要將鏈接指向谷歌搜索的第一頁的內容，因爲我花了很多時間來試圖實現這些示例，我將不勝感激一個工作代碼示例+ xml佈局（如果需要）
你可以做到這一點沒有太複雜的結合：
View.OnTouchListener（檢測拖動順序，基本上ACTION_DOWN，ACTION_MOVE，...，ACTION_UP）。首先，獲得ImageView對象並附上View.OnTouchListener它。
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
...
mImage = findViewById(...);
mImage.setOnTouchListener(mTouchListener);
}
其次，程序OnTouchListener捕獲ACTION_DOWN事件和存儲初始觸摸位置的X座標。然後爲每個ACTION_MOVE計算delta（用於平移和縮放），並且用於ACTION_UP將ImageView返回到其初始狀態。
private View.OnTouchListener mTouchListener = new View.OnTouchListener()
{
private float mStartX;
@Override
public boolean onTouch(View v, MotionEvent event)
{
switch (event.getActionMasked())
{
case MotionEvent.ACTION_DOWN :
mStartX = event.getRawX();
return true;
case MotionEvent.ACTION_MOVE :
float currentX = event.getRawX();
animateTo(currentX - mStartX, true); // Snap to drag
return true;
case MotionEvent.ACTION_UP :
case MotionEvent.ACTION_CANCEL :
animateTo(0, false); // Ease back
return true;
}
return false;
}
};
animateTo()將實現如下。 immediate標誌指示翻譯和縮放是否應該是即時的（對每個移動事件作出響應時爲真，在恢復初始位置和縮放時爲假）。
private void animateTo(float displacement, boolean immediate)
{
final int EASE_BACK_DURATION = 300; // ms
int duration = (immediate ? 0 : EASE_BACK_DURATION);
Display display = getWindowManager().getDefaultDisplay();
int totalWidth = display.getWidth();
float scale = 1.0f - Math.abs(displacement/totalWidth);
ViewPropertyAnimator.animate(mImage)
.translationX(displacement)
.scaleX(scale)
.scaleY(scale)
.setDuration(duration)
.start();
}
您可能想要調整縮放比例。正如所寫的，這意味着圖像將一直拖到屏幕邊界時將達到原始大小的50％。
該解決方案應該在API級別8沒有問題的情況下工作（儘管我沒有測試過它）。如果你想要的話，完整的要點是available here。
首先想到的是動畫LayoutParams，通過Handler。不知道它是否符合您的要求，這可能需要更多的測試。
在任何情況下，這是非常有趣的記憶數學^^因此，這裏是我的呢，只使用了原生的Android工具：
代碼：
package com.example.simon.draggableimageview;
import android.os.Handler;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
import android.widget.RelativeLayout;
/**
* Created by Simon on 2014 Nov 18.
*/
public class MainActivity extends ActionBarActivity {
private static final String TAG = "MainActivity";
// Avoid small values for the following two or setSize will start lagging behind
// The maximum time, animation (from smallest) to default size will take
private static final int MAX_DURATION = 500;
// Minimum delay (ms) for each loop
private static final int MIN_DELAY = 20;
// By how many px (at least) each (animation back to default state) loop will shift the image
private static final float MIN_X_SHIFT = 3;
private ImageView mImage;
private int mInitialW, mInitialH, mCenterX;
private int mMaxMargin;
private AnimateBack mAnimateBack;
private Handler mHandler;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mHandler = new Handler();
mImage = (ImageView) findViewById(R.id.imageView);
final RelativeLayout imageHolder = (RelativeLayout) findViewById(R.id.imageHolder);
mImage.post(new Runnable() {
@Override
public void run() {
// Image ready, measure it
mInitialH = mImage.getHeight();
mInitialW = mImage.getWidth();
imageHolder.post(new Runnable() {
@Override
public void run() {
// Calc other measurements
int containerWidth = imageHolder.getWidth();
mCenterX = containerWidth/2;
mMaxMargin = containerWidth - mInitialW;
}
});
}
});
imageHolder.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
switch (motionEvent.getAction()) {
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
mAnimateBack = new AnimateBack();
mAnimateBack.run();
break;
case MotionEvent.ACTION_MOVE:
mHandler.removeCallbacks(mAnimateBack);
if (motionEvent.getX() > mMaxMargin + mInitialW || motionEvent.getX() < 0) {
// Fake Action_Up if out of container bounds
motionEvent.setAction(MotionEvent.ACTION_UP);
onTouch(view, motionEvent);
return true;
}
setSize(motionEvent.getX() - mCenterX);
break;
}
return true;
}
});
}
private void setSize(float offsetFromCenter) {
// Calculate new left margin
RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) mImage.getLayoutParams();
params.leftMargin = (int) (mMaxMargin * offsetFromCenter/(mCenterX - mInitialW/2.0));
// Calculate dimensions
float ratio = 1 - (Math.abs(offsetFromCenter)/mCenterX);
params.width = (int) (mInitialW * ratio);
params.height = (int) (mInitialH * ratio);
mImage.setLayoutParams(params);
// Log.e(TAG, String.format("leftMargin: %d, W: %d, H: %d",
// params.leftMargin, params.width, params.height));
}
private class AnimateBack implements Runnable {
private int loopCount, loopDelay;
private float loopBy;
public AnimateBack() {
RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) mImage.getLayoutParams();
float offsetFromCenter = (float) params.leftMargin/mMaxMargin *
(mCenterX - mInitialW/2.0f);
float totalDuration = (Math.abs(offsetFromCenter) * MAX_DURATION/mCenterX);
loopBy = MIN_X_SHIFT;
loopCount = (int) Math.abs(offsetFromCenter/loopBy);
loopDelay = (int) (totalDuration/loopCount);
if (loopDelay < MIN_DELAY) {
// Use the minimum delay
loopDelay = MIN_DELAY;
// Minimum loop count is 1
loopCount = (int) Math.max(totalDuration/loopDelay, 1);
// Calculate by how much each loop will inc/dec the margin
loopBy = Math.round(Math.abs(offsetFromCenter/loopCount));
}
Log.d(TAG, String.format("Animate back will take: %fms. Will start from offset %d. " +
"It will advance by %dpx every %dms",
totalDuration, (int) offsetFromCenter, (int) loopBy, loopDelay));
}
@Override
public void run() {
--loopCount;
RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) mImage.getLayoutParams();
// Calculate offsetFromCenter
float offsetFromCenter = (float) ((float) params.leftMargin/mMaxMargin *
(mCenterX - mInitialW/2.0));
// Don't pass 0 when looping
if (params.leftMargin > 0) {
offsetFromCenter = Math.max(offsetFromCenter - loopBy, 0);
} else {
offsetFromCenter = Math.min(offsetFromCenter + loopBy, 0);
}
setSize(offsetFromCenter);
if (loopCount == 0) {
mHandler.removeCallbacks(this);
} else {
mHandler.postDelayed(this, loopDelay);
}
}
}
}
佈局：
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:id="@+id/imageHolder"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<ImageView
android:id="@+id/imageView"
android:layout_width="200dp"
android:layout_height="200dp"
android:src="@drawable/ic_launcher"/>
</RelativeLayout>
</RelativeLayout>
Preview：
作品像魅力:)謝謝 – Orr 2014-11-18 10:45:33