package com.lzy.ninegrid.preview;
import android.animation.Animator;
import android.animation.ValueAnimator;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Color;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.util.DisplayMetrics;
import android.view.View;
import android.view.ViewTreeObserver;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.TextView;
import com.lzy.ninegrid.ImageInfo;
import com.lzy.ninegrid.R;
import java.util.List;
public class ImagePreviewActivity extends Activity implements ViewTreeObserver.OnPreDrawListener {
public static final String IMAGE_INFO = "IMAGE_INFO";
public static final String CURRENT_ITEM = "CURRENT_ITEM";
public static final int ANIMATE_DURATION = 200;
private RelativeLayout rootView;
private ImagePreviewAdapter imagePreviewAdapter;
private List<ImageInfo> imageInfo;
private int currentItem;
private int imageHeight;
private int imageWidth;
private int screenWidth;
private int screenHeight;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_preview);
ViewPager viewPager = (ViewPager) findViewById(R.id.viewPager);
final TextView tv_pager = (TextView) findViewById(R.id.tv_pager);
rootView = (RelativeLayout) findViewById(R.id.rootView);
DisplayMetrics metric = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metric);
screenWidth = metric.widthPixels;
screenHeight = metric.heightPixels;
Intent intent = getIntent();
imageInfo = (List<ImageInfo>) intent.getSerializableExtra(IMAGE_INFO);
currentItem = intent.getIntExtra(CURRENT_ITEM, 0);
imagePreviewAdapter = new ImagePreviewAdapter(this, imageInfo);
viewPager.setAdapter(imagePreviewAdapter);
viewPager.setCurrentItem(currentItem);
viewPager.getViewTreeObserver().addOnPreDrawListener(this);
viewPager.addOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
currentItem = position;
tv_pager.setText(String.format(getString(R.string.select), currentItem + 1, imageInfo.size()));
}
});
tv_pager.setText(String.format(getString(R.string.select), currentItem + 1, imageInfo.size()));
}
@Override
public void onBackPressed() {
finishActivityAnim();
}
/** 绘制前开始动画 */
@Override
public boolean onPreDraw() {
rootView.getViewTreeObserver().removeOnPreDrawListener(this);
final View view = imagePreviewAdapter.getPrimaryItem();
final ImageView imageView = imagePreviewAdapter.getPrimaryImageView();
computeImageWidthAndHeight(imageView);
final ImageInfo imageData = imageInfo.get(currentItem);
final float vx = imageData.imageViewWidth * 1.0f / imageWidth;
final float vy = imageData.imageViewHeight * 1.0f / imageHeight;
ValueAnimator valueAnimator = ValueAnimator.ofFloat(0, 1.0f);
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
long duration = animation.getDuration();
long playTime = animation.getCurrentPlayTime();
float fraction = duration > 0 ? (float) playTime / duration : 1f;
if (fraction > 1) fraction = 1;
view.setTranslationX(evaluateInt(fraction, imageData.imageViewX + imageData.imageViewWidth / 2 - imageView.getWidth() / 2, 0));
view.setTranslationY(evaluateInt(fraction, imageData.imageViewY + imageData.imageViewHeight / 2 - imageView.getHeight() / 2, 0));
view.setScaleX(evaluateFloat(fraction, vx, 1));
view.setScaleY(evaluateFloat(fraction, vy, 1));
view.setAlpha(fraction);
rootView.setBackgroundColor(evaluateArgb(fraction, Color.TRANSPARENT, Color.BLACK));
}
});
addIntoListener(valueAnimator);
valueAnimator.setDuration(ANIMATE_DURATION);
valueAnimator.start();
return true;
}
/** activity的退场动画 */
public void finishActivityAnim() {
final View view = imagePreviewAdapter.getPrimaryItem();
final ImageView imageView = imagePreviewAdapter.getPrimaryImageView();
computeImageWidthAndHeight(imageView);
final ImageInfo imageData = imageInfo.get(currentItem);
final float vx = imageData.imageViewWidth * 1.0f / imageWidth;
final float vy = imageData.imageViewHeight * 1.0f / imageHeight;
final ValueAnimator valueAnimator = ValueAnimator.ofFloat(0, 1.0f);
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
long duration = animation.getDuration();
long playTime = animation.getCurrentPlayTime();
float fraction = duration > 0 ? (float) playTime / duration : 1f;
if (fraction > 1) fraction = 1;
view.setTranslationX(evaluateInt(fraction, 0, imageData.imageViewX + imageData.imageViewWidth / 2 - imageView.getWidth() / 2));
view.setTranslationY(evaluateInt(fraction, 0, imageData.imageViewY + imageData.imageViewHeight / 2 - imageView.getHeight() / 2));
view.setScaleX(evaluateFloat(fraction, 1, vx));
view.setScaleY(evaluateFloat(fraction, 1, vy));
view.setAlpha(1 - fraction);
rootView.setBackgroundColor(evaluateArgb(fraction, Color.BLACK, Color.TRANSPARENT));
}
});
addOutListener(valueAnimator);
valueAnimator.setDuration(ANIMATE_DURATION);
valueAnimator.start();
}
/** 计算图片的宽高 */
private void computeImageWidthAndHeight(ImageView imageView) {
// 获取真实大小
Drawable drawable = imageView.getDrawable();
int intrinsicHeight = drawable.getIntrinsicHeight();
int intrinsicWidth = drawable.getIntrinsicWidth();
// 计算出与屏幕的比例，用于比较以宽的比例为准还是高的比例为准，因为很多时候不是高度没充满，就是宽度没充满
float h = screenHeight * 1.0f / intrinsicHeight;
float w = screenWidth * 1.0f / intrinsicWidth;
if (h > w) h = w;
else w = h;
// 得出当宽高至少有一个充满的时候图片对应的宽高
imageHeight = (int) (intrinsicHeight * h);
imageWidth = (int) (intrinsicWidth * w);
}
/** 进场动画过程监听 */
private void addIntoListener(ValueAnimator valueAnimator) {
valueAnimator.addListener(new Animator.AnimatorListener() {
@Override
public void onAnimationStart(Animator animation) {
rootView.setBackgroundColor(0x0);
}
@Override
public void onAnimationEnd(Animator animation) {
}
@Override
public void onAnimationCancel(Animator animation) {
}
@Override
public void onAnimationRepeat(Animator animation) {
}
});
}
/** 退场动画过程监听 */
private void addOutListener(ValueAnimator valueAnimator) {
valueAnimator.addListener(new Animator.AnimatorListener() {
@Override
public void onAnimationStart(Animator animation) {
rootView.setBackgroundColor(0x0);
}
@Override
public void onAnimationEnd(Animator animation) {
finish();
overridePendingTransition(0, 0);
}
@Override
public void onAnimationCancel(Animator animation) {
}
@Override
public void onAnimationRepeat(Animator animation) {
}
});
}
/** Integer 估值器 */
public Integer evaluateInt(float fraction, Integer startValue, Integer endValue) {
int startInt = startValue;
return (int) (startInt + fraction * (endValue - startInt));
}
/** Float 估值器 */
public Float evaluateFloat(float fraction, Number startValue, Number endValue) {
float startFloat = startValue.floatValue();
return startFloat + fraction * (endValue.floatValue() - startFloat);
}
/** Argb 估值器 */
public int evaluateArgb(float fraction, int startValue, int endValue) {
int startA = (startValue >> 24) & 0xff;
int startR = (startValue >> 16) & 0xff;
int startG = (startValue >> 8) & 0xff;
int startB = startValue & 0xff;
int endA = (endValue >> 24) & 0xff;
int endR = (endValue >> 16) & 0xff;
int endG = (endValue >> 8) & 0xff;
int endB = endValue & 0xff;
return (startA + (int) (fraction * (endA - startA))) << 24//
| (startR + (int) (fraction * (endR - startR))) << 16//
| (startG + (int) (fraction * (endG - startG))) << 8//
| (startB + (int) (fraction * (endB - startB)));
}
}