Android实现图片点击放大

本文实例为大家分享了Android实现图片点击放大的具体代码,供大家参考,具体内容如下

在我的项目中,有点击图片banner后放大浏览的功能。我的做法就是创建一个专门的图片显示Activity,布局里面用ViewPage,这样就能控制图片的左右滑动,并且控制首先显示第几张图片。
功能是ok的,显示也是正常的。但我花费了好几天的时间来实现、完善这个功能。

ShowMoreImageActivity

/**
 * 图片放大
 */
public class ShowMoreImageActivity extends BaseActivity {

 @FindId(R.id.vp)
 private ViewPager vp;
 @FindId(R.id.ll_point)
 private LinearLayout ll_point;

 private List imgs;
 @FindId(R.id.btn_save)
 private ImageView btn_save;

 private int index;

 public static int type;
 private Activity activity;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_show_more_image);
  initViews();
 activity = this;
 }

 private void initViews() {
  AutoFindId.findId(context);

  imgs = (ArrayList) getIntent().getSerializableExtra("img");
  index = getIntent().getIntExtra("index", 0);

  type = getIntent().getIntExtra("type", 0);
  vp.setAdapter(new MoreImgPagerAdapter(context, imgs));


  vp.addOnPageChangeListener(new OnPageChangeListener() {
   @Override
   public void onPageSelected(int arg0) {
    index = arg0;
    setUpPoint(imgs.size(), arg0);
   }

   @Override
   public void onPageScrolled(int arg0, float arg1, int arg2) {
   }

   @Override
   public void onPageScrollStateChanged(int arg0) {
   }
  });
  setUpPoint(imgs.size(), 0);

  vp.setCurrentItem(index);
 }

 protected void downLoad(final String urls) {
  String[] split = urls.split("\\?");
  final String url = split[0];
  if (url.startsWith("file")) {
   G.toast(context, "此为本地图片,不用下载,路径为" + url.replace("file://", ""));
   return;
  }

  if (OKHttpUtils.isNetworkAvailable(context)) {
   G.showPd(context);
   TDUtils.execute(new Runnable() {
    @Override
    public void run() {
     try {
      File file = new File(C.getDownloadPath());
      if (!file.exists()) {
       file.mkdir();
      }
      File jpg = new File(C.getDownloadPath() + G.urlToFileName(url));
      // 如果已经存在则不需要下载
      if (jpg != null && jpg.exists()) {
       G.dismissProgressDialogInThread();

       G.toastInThread(context,
         "该文件已被下载到" + jpg.getParent() + context.getResources().getString(R.string.xia));
       return;
      }
      // 先从缓存中查找
      File tmpFile = NetAide.getBitmapUtils().getBitmapFileFromDiskCache(url);
      if (tmpFile != null && tmpFile.exists()) {
       G.look("---从缓存中查找到图片----");
       Bitmap bm = BitmapFactory.decodeFile(tmpFile.getAbsolutePath());

       FileOutputStream fos = new FileOutputStream(jpg);
       bm.compress(CompressFormat.JPEG, 100, fos);
       fos.close();
       G.dismissProgressDialogInThread();

       // 通知图库更新
       C.noticeImageRefresh(context, jpg);

       G.toastInThread(context, context.getResources().getString(R.string.downLoadUrl)
         + jpg.getParent() + context.getResources().getString(R.string.xia));
       return;
      }

      // 从网络上下载保存
      Bitmap bm = BitmapFactory.decodeStream(new URL(url).openStream());

      FileOutputStream fos = new FileOutputStream(jpg);
      bm.compress(CompressFormat.JPEG, 100, fos);
      fos.close();
      G.dismissProgressDialogInThread();

      // 通知图库更新
      C.noticeImageRefresh(context, jpg);
      G.toastInThread(context, "你现在可以在图库中查看该图片了");

     } catch (Exception e) {
      e.printStackTrace();
      G.dismissProgressDialogInThread();

      G.toastInThread(context, context.getResources().getString(R.string.downLoadFail));

      File jpg = new File(C.getDownloadPath() + G.urlToFileName(url));
      if (jpg != null && jpg.exists()) {
       jpg.delete();
      }
     }
    }
   });
  }

 }

 private void setUpPoint(int size, int choose) {
  ll_point.removeAllViews();
  if (size <= 1) {
   return;
  }

  for (int i = 0; i < size; i++) {
   ImageView point = new ImageView(context);
   point.setLayoutParams(new LinearLayout.LayoutParams(DensityUtil.dip2px(context, 15), -2));
   point.setScaleType(ScaleType.FIT_CENTER);
   if (i == choose) {
    point.setImageResource(R.drawable.white_choosed);
   } else {
    point.setImageResource(R.drawable.white_no_choosed);
   }
   ll_point.addView(point);
  }
 }

 public void doClcik(View view) {
  switch (view.getId()){
 case R.id.btn_save:
    PermissionUtils permissionUtils = new PermissionUtils();
    permissionUtils.setPermission(this, "存储", "保存图片", new PermissionUtils.AfterPermission() {
     @Override
     public void doNext() {
      downLoad(imgs.get(index));
     }
    },Manifest.permission.WRITE_EXTERNAL_STORAGE);
 break;
 }
 }
}

对应布局:




 

 

  

   

  

  

  
 

 

MoreImgPagerAdapter

public class MoreImgPagerAdapter extends PagerAdapter {

 private Context context;
 private List images;

 private SparseArray> ivs;

 public MoreImgPagerAdapter(Context context, List images) {
 this.context = context;
 this.images = images;
 ivs = new SparseArray>();
 }

 @Override
 public int getCount() {
 return images.size();
 }

 @Override
 public void destroyItem(ViewGroup arg0, int arg1, Object arg2) {
 SoftReference reference = ivs.get(arg1);
 if (reference != null && reference.get() != null) {
 arg0.removeView(reference.get());
 }
 }

 @Override
 public Object instantiateItem(ViewGroup arg0, final int arg1) {
 SoftReference reference = ivs.get(arg1);
 if (reference == null || reference.get() == null) {
 View v = LayoutInflater.from(context).inflate(R.layout.item_show_more_image, null);
 reference = new SoftReference(v);
 ivs.put(arg1, reference);
 }

 View v = reference.get();

 final ViewHolder holder = new ViewHolder(v);
 Glide.with(context).asBitmap().load(images.get(arg1)).into(holder.image);
 arg0.addView(v);

 return v;

 }



 @Override
 public boolean isViewFromObject(View arg0, Object arg1) {
 return arg0.equals(arg1);
 }

 class ViewHolder {
 @FindId(R.id.image)
 private ImageView image;

 @FindId(R.id.rl_percent)
 private RelativeLayout rl_percent;
 @FindId(R.id.tv_percent)
 private TextView tv_percent;
 @FindId(R.id.iv_top)
 private ImageView iv_top;
 
 public ViewHolder(View v) {
 AutoFindId.findIdByView(this, v);
 }
 }
}

对应布局:




 

  

  
 

 

  

  
 

上面都是次要的,因为我发现了一个更为简便的轮子。

github地址

在我的项目中,我只需要两步就完成了此功能。

第一步:

// 查看大图
implementation 'com.github.SherlockGougou:BigImageViewPager:v4_6.1.1'

第二步:

在点击图片事件那里调用:

ImagePreview
  .getInstance()
  // 上下文,必须是activity,不需要担心内存泄漏,本框架已经处理好;
  .setContext(context)
  // 设置从第几张开始看(索引从0开始)
  .setIndex(position)
  // 有三种设置数据集合的方式,根据自己的需求进行三选一:
  // 1:第一步生成的imageInfo List
  //.setImageInfoList(imageInfoList)
  // 2:直接传url List
  .setImageList(imageList)
  // 3:只有一张图片的情况,可以直接传入这张图片的url
  //.setImage(String image)
  // 开启预览
 .start();

就这样完成了图片放大浏览、下载的功能,在这里记录下。

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持脚本之家。

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