android 仿微信点击图片放大效果实现
1、要实现点击图片放大不难，这里使用的图片显示是用fresco,用一般的ImageView不能显示网络获取的url图片。http://fresco-cn.org/docs/getting-started.html点击打开链接这个是fresco的详细使用介绍。下面介绍详细代码：
fresco库，在build.gradle中添加：
//网络图片
compile 'com.facebook.fresco:fresco:0.12.0'布局代码，主要是一个图片显示控件和一个textview控件用于显示具体到哪一张。也可改成ImageView用于显示本地图片
Intent intent = new Intent(getApplication(),PictureDisplayActivity.class);
intent.putExtra("position",position);
intent.putStringArrayListExtra("enlargeImage",imgUrl);
startActivity(intent);package com.coolgeer.aimeida.ui.circle;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.os.Bundle;
import android.util.LruCache;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.ViewGroup;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import com.coolgeer.aimeida.R;
import com.coolgeer.aimeida.utils.LogUtil;
import com.coolgeer.aimeida.view.circle.ImageService;
import com.facebook.drawee.view.SimpleDraweeView;
import java.io.IOException;
import java.util.List;
public class PictureDisplayActivity extends Activity {
private SimpleDraweeView imageView;
private TextView pictureDisplayText;
int downX = 0;
int moveX = 0;
int upX = 0;
int a = 1; //显示的图片位置
int imageKey = 1;
final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);
final int cacheSize = maxMemory / 9;//设置缓冲空间存储大小
private LruCache mMemoryCache = new LruCache<>(cacheSize);
Bitmap bitmap = null;
private final String TAG = "PictureDisplayActivity";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_picture_display);
initView();
}
private void initView() {
imageView = (SimpleDraweeView) findViewById(R.id.picture_display_image);
pictureDisplayText = (TextView) findViewById(R.id.picture_display_text);
new Thread(runa).start();
}
/**
* 显示下载图片
*/
private Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
if (msg.what == 0) {
updateImageView((Bitmap) msg.obj);
}
}
};
/**
* //将bitmap添加到缓存中
*
* @param bm
*/
private void updateImageView(Bitmap bm) {
//list.add(bm);
mMemoryCache.put("imageKey" + imageKey, bm);
imageView.setImageBitmap(mMemoryCache.get("imageKey" + a));
// LogUtil.e("NSC", "=====" + bm.toString());
imageKey++;
}
/**
*
*/
private Runnable runa = new Runnable() {
@Override
public void run() {
Intent intent = getIntent();
//int position = intent.getIntExtra("position");
int position = intent.getIntExtra("position", -1);
List url = intent.getStringArrayListExtra("enlargeImage");
LogUtil.e(TAG, "a==" + position);
a = position + 1;
pictureDisplayText.setText((Integer.valueOf(a)) + "/" + Integer.valueOf(url.size()));
// bit(urlPosition);//先显示传进来的第一张
for (int i = 0; i < url.size(); i++) {
bit(url.get(i).toString());
//LogUtil.e("NSC",url.get(i).toString()+"i = "+i);
// addView();
}
}
};
/**
* @param url
*/
private void bit(String url) {
byte[] data = new byte[0];
try {
data = ImageService.getImage(url);
bitmap = BitmapFactory.decodeByteArray(data, 0, data.length); //生成位图
// Looper.prepare();// 必须调用此方法，要不然会报错
Message msg = new Message();
msg.what = 0;
msg.obj = bitmap;
handler.sendMessage(msg);
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN://获取点击的时候屏幕位置
downX = (int) event.getRawX();
// LogUtil.e("NSC","x = "+x+" y="+y);
break;
case MotionEvent.ACTION_MOVE:
moveX = (int) event.getRawX();
//LogUtil.e("NSC","mx = "+mx+" my="+my);
break;
case MotionEvent.ACTION_UP://手离开的时候位置
upX = (int) event.getRawX();
int pValue = upX - downX;//滑动的距离差
LogUtil.e("NSC", "upX-downX = " + (upX - downX));
if (upX - downX > 120) {//右滑的时候
LogUtil.e("NSC", "a = " + a + ":" + mMemoryCache.size());
if (a <= mMemoryCache.size()) {
// LogUtil.e(TAG, mMemoryCache.get("imageKey"+a).getWidth()+":"+mMemoryCache.get("imageKey"+a).getHeight());
//mMemoryCache.get("imageKey"+a).getWidth();
Animation rInAnimIn = AnimationUtils.loadAnimation(this, R.anim.push_right_in);
imageView.setAnimation(rInAnimIn);
imageView.setImageBitmap(mMemoryCache.get("imageKey" + a));
pictureDisplayText.setText((Integer.valueOf(a)) + "/" + Integer.valueOf(mMemoryCache.size()));
a++;
if (a > mMemoryCache.size()) {
a = 1;
}
}
} else if (upX - downX < -120) {//左滑
LogUtil.e("NSC", "aaaa = " + a + ":" + mMemoryCache.size());
if (a > 0) {
Animation lInAnim = AnimationUtils.loadAnimation(this, R.anim.push_left_in); // 向左滑动左侧进入的渐变效果（alpha 0.1 -> 1.0）
imageView.setAnimation(lInAnim);
imageView.setImageBitmap(mMemoryCache.get("imageKey" + a));
pictureDisplayText.setText((Integer.valueOf(a)) + "/" + Integer.valueOf(mMemoryCache.size()));
a--;
if (a == 0) {
a = mMemoryCache.size();
}
}
}
if (pValue == 0) {//点击触摸就关闭窗口
finish();
}
break;
}
return super.onTouchEvent(event); // 注册手势事件
}
@Override
protected void onDestroy() {
super.onDestroy();
if (bitmap != null && !bitmap.isRecycled()) {
// 回收并且置为null
bitmap.recycle();
bitmap = null;
}
}
}
4、为了让效果更好需要将在权限文件将activity设置成窗口模式，因为使用的是网络图片记得加上网络权限。
实现效果：
